Land-use change and carbon sinks: Econometric estimation of the carbon sequestration supply function

Energy Technology Data Exchange (ETDEWEB)

Lubowski, Ruben N.; Plantinga, Andrew J.; Stavins, Robert N.

2001-01-01

Increased attention by policy makers to the threat of global climate change has brought with it considerable interest in the possibility of encouraging the expansion of forest area as a means of sequestering carbon dioxide. The marginal costs of carbon sequestration or, equivalently, the carbon sequestration supply function will determine the ultimate effects and desirability of policies aimed at enhancing carbon uptake. In particular, marginal sequestration costs are the critical statistic for identifying a cost-effective policy mix to mitigate net carbon dioxide emissions. We develop a framework for conducting an econometric analysis of land use for the forty-eight contiguous United States and employing it to estimate the carbon sequestration supply function. By estimating the opportunity costs of land on the basis of econometric evidence of landowners' actual behavior, we aim to circumvent many of the shortcomings of previous sequestration cost assessments. By conducting the first nationwide econometric estimation of sequestration costs, endogenizing prices for land-based commodities, and estimating land-use transition probabilities in a framework that explicitly considers the range of land-use alternatives, we hope to provide better estimates eventually of the true costs of large-scale carbon sequestration efforts. In this way, we seek to add to understanding of the costs and potential of this strategy for addressing the threat of global climate change.

The Net Carbon Flux due to Deforestation and Forest Re-Growth in the Brazilian Amazon: Analysis using a Process-Based Model

Science.gov (United States)

Hirsch, A. I.; Little, W. S.; Houghton, R. A.; Scott, N. A.; White, J. D.

2004-01-01

We developed a process-based model of forest growth, carbon cycling, and land cover dynamics named CARLUC (for CARbon and Land Use Change) to estimate the size of terrestrial carbon pools in terra firme (non-flooded) forests across the Brazilian Legal Amazon and the net flux of carbon resulting from forest disturbance and forest recovery from disturbance. Our goal in building the model was to construct a relatively simple ecosystem model that would respond to soil and climatic heterogeneity that allows us to study of the impact of Amazonian deforestation, selective logging, and accidental fire on the global carbon cycle. This paper focuses on the net flux caused by deforestation and forest re-growth over the period from 1970-1998. We calculate that the net flux to the atmosphere during this period reached a maximum of approx. 0.35 PgC/yr (1PgC = 1 x 10(exp I5) gC) in 1990, with a cumulative release of approx. 7 PgC from 1970- 1998. The net flux is higher than predicted by an earlier study by a total of 1 PgC over the period 1989-1 998 mainly because CARLUC predicts relatively high mature forest carbon storage compared to the datasets used in the earlier study. Incorporating the dynamics of litter and soil carbon pools into the model increases the cumulative net flux by approx. 1 PgC from 1970-1998, while different assumptions about land cover dynamics only caused small changes. The uncertainty of the net flux, calculated with a Monte-Carlo approach, is roughly 35% of the mean value (1 SD).

Effects of Land Use Change for Crops on Water and Carbon Budgets in the Midwest USA

Directory of Open Access Journals (Sweden)

Jian Sun

2017-02-01

Full Text Available Increasing demand for food and bioenergy has altered the global landscape dramatically in recent years. Land use and land cover change affects the environmental system in many ways through biophysical and biogeochemical mechanisms. In this study, we evaluate the impacts of land use and land cover change driven by recent crop expansion and conversion on the water budget, carbon exchange, and carbon storage in the Midwest USA. A dynamic global vegetation model was used to simulate and examine the impacts of landscape change in a historical case based on crop distribution data from the United States Department of Agriculture National Agricultural Statistics Services. The simulation results indicate that recent crop expansion not only decreased soil carbon sequestration (60 Tg less of soil organic carbon and net carbon flux into ecosystems (3.7 Tg·year−1 less of net biome productivity, but also lessened water consumption through evapotranspiration (1.04 × 1010 m3·year−1 less over 12 states in the Midwest. More water yield at the land surface does not necessarily make more water available for vegetation. Crop residue removal might also exacerbate the soil carbon loss.

Carbon Flux to the Atmosphere from Land-Use Changes: 1850 to 1990

Energy Technology Data Exchange (ETDEWEB)

Houghton, R.A.

2001-02-22

The database documented in this numeric data package, a revision to a database originally published by the Carbon Dioxide Information Analysis Center (CDIAC) in 1995, consists of annual estimates, from 1850 through 1990, of the net flux of carbon between terrestrial ecosystems and the atmosphere resulting from deliberate changes in land cover and land use, especially forest clearing for agriculture and the harvest of wood for wood products or energy. The data are provided on a year-by-year basis for nine regions (North America, South and Central America, Europe, North Africa and the Middle East, Tropical Africa, the Former Soviet Union, China, South and Southeast Asia, and the Pacific Developed Region) and the globe. Some data begin earlier than 1850 (e.g., for six regions, areas of different ecosystems are provided for the year 1700) or extend beyond 1990 (e.g., fuelwood harvest in South and Southeast Asia, by forest type, is provided through 1995). The global net flux during the period 1850 to 1990 was 124 Pg of carbon (1 petagram = 10{sup 15} grams). During this period, the greatest regional flux was from South and Southeast Asia (39 Pg of carbon), while the smallest regional flux was from North Africa and the Middle East (3 Pg of carbon). For the year 1990, the global total net flux was estimated to be 2.1 Pg of carbon.

Land-use change and carbon sinks: Econometric estimation of the carbon sequestration supply function; FINAL

International Nuclear Information System (INIS)

Lubowski, Ruben N.; Plantinga, Andrew J.; Stavins, Robert N.

2001-01-01

Increased attention by policy makers to the threat of global climate change has brought with it considerable interest in the possibility of encouraging the expansion of forest area as a means of sequestering carbon dioxide. The marginal costs of carbon sequestration or, equivalently, the carbon sequestration supply function will determine the ultimate effects and desirability of policies aimed at enhancing carbon uptake. In particular, marginal sequestration conts are the critical statistic for identifying a cost-effective policy mix to mitigate net carbon dioxide emissions. We develop a framework for conducting an econometric analysis of land use for the forty-eight contiguous United States and employing it to estimate the carbon sequestration supply function. By estimating the opportunity costs of land on the basis of econometric evidence of landowners' actual behavior, we aim to circumvent many of the shortcomings of previous sequestration cost assessments. By conducting the first nationwide econometric estimation of sequestration costs, endogenizing prices for land-based commodities, and estimating land-use transition probabilities in a framework that explicitly considers the range of land-use alternatives, we hope to provide better estimates eventually of the true costs of large-scale carbon sequestration efforts. In this way, we seek to add to understanding of the costs and potential of this strategy for addressing the threat of global climate change

Net change in carbon emissions with increased wood energy use in the United States

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Prakash Nepal; David N. Wear; Kenneth E. Skog

2014-01-01

Use of wood biomass for energy results in carbon (C) emissions at the time of burning and alters C stocks on the land because of harvest, regrowth, and changes in land use or management. This study evaluates the potential effects of expanded woody biomass energy use (for heat and power) on net C emissions over time. A scenario with increased wood energy use is compared...

Quantification of net carbon flux from plastic greenhouse vegetable cultivation: A full carbon cycle analysis

International Nuclear Information System (INIS)

Wang Yan; Xu Hao; Wu Xu; Zhu Yimei; Gu Baojing; Niu Xiaoyin; Liu Anqin; Peng Changhui; Ge Ying; Chang Jie

2011-01-01

Plastic greenhouse vegetable cultivation (PGVC) has played a vital role in increasing incomes of farmers and expanded dramatically in last several decades. However, carbon budget after conversion from conventional vegetable cultivation (CVC) to PGVC has been poorly quantified. A full carbon cycle analysis was used to estimate the net carbon flux from PGVC systems based on the combination of data from both field observations and literatures. Carbon fixation was evaluated at two pre-selected locations in China. Results suggest that: (1) the carbon sink of PGVC is 1.21 and 1.23 Mg C ha -1 yr -1 for temperate and subtropical area, respectively; (2) the conversion from CVC to PGVC could substantially enhance carbon sink potential by 8.6 times in the temperate area and by 1.3 times in the subtropical area; (3) the expansion of PGVC usage could enhance the potential carbon sink of arable land in China overall. - Highlights: → We used full carbon (C) cycle analysis to estimate the net C flux from cultivation. → The plastic greenhouse vegetable cultivation system in China can act as a C sink. → Intensified agricultural practices can generate C sinks. → Expansion of plastic greenhouse vegetable cultivation can enhance regional C sink. - The conversion from conventional vegetable cultivation to plastic greenhouse vegetable cultivation could substantially enhance carbon sink potential by 8.6 and 1.3 times for temperate and subtropical area, respectively.

Systematically variable planktonic carbon metabolism along a land-to-lake gradient in a Great Lakes coastal zone.

Science.gov (United States)

Weinke, Anthony D; Kendall, Scott T; Kroll, Daniel J; Strickler, Eric A; Weinert, Maggie E; Holcomb, Thomas M; Defore, Angela A; Dila, Deborah K; Snider, Michael J; Gereaux, Leon C; Biddanda, Bopaiah A

2014-11-01

During the summers of 2002-2013, we measured rates of carbon metabolism in surface waters of six sites across a land-to-lake gradient from the upstream end of drowned river-mouth Muskegon Lake (ML) (freshwater estuary) to 19 km offshore in Lake Michigan (LM) (a Great Lake). Despite considerable inter-year variability, the average rates of gross production (GP), respiration (R) and net production (NP) across ML (604 ± 58, 222 ± 22 and 381 ± 52 µg C L -1 day -1 , respectively) decreased steeply in the furthest offshore LM site (22 ± 3, 55 ± 17 and -33 ± 15 µg C L -1 day -1 , respectively). Along this land-to-lake gradient, GP decreased by 96 ± 1%, whereas R only decreased by 75 ± 9%, variably influencing the carbon balance along this coastal zone. All ML sites were consistently net autotrophic (mean GP:R = 2.7), while the furthest offshore LM site was net heterotrophic (mean GP:R = 0.4). Our study suggests that pelagic waters of this Great Lakes coastal estuary are net carbon sinks that transition into net carbon sources offshore. Reactive and dynamic estuarine coastal zones everywhere may contribute similarly to regional and global carbon cycles.

Quantifying the Effects of Historical Land Cover Conversion Uncertainty on Global Carbon and Climate Estimates

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Di Vittorio, A. V.; Mao, J.; Shi, X.; Chini, L.; Hurtt, G.; Collins, W. D.

2018-01-01

Previous studies have examined land use change as a driver of global change, but the translation of land use change into land cover conversion has been largely unconstrained. Here we quantify the effects of land cover conversion uncertainty on the global carbon and climate system using the integrated Earth System Model. Our experiments use identical land use change data and vary land cover conversions to quantify associated uncertainty in carbon and climate estimates. Land cover conversion uncertainty is large, constitutes a 5 ppmv range in estimated atmospheric CO2 in 2004, and generates carbon uncertainty that is equivalent to 80% of the net effects of CO2 and climate and 124% of the effects of nitrogen deposition during 1850-2004. Additionally, land cover uncertainty generates differences in local surface temperature of over 1°C. We conclude that future studies addressing land use, carbon, and climate need to constrain and reduce land cover conversion uncertainties.

Proposal methodology for Land Carbon Accounting across Europe

Science.gov (United States)

Simon, A.; Ivanov, E.; Anaya-Romero, M.; Weber, J.-L.

2012-04-01

The need to account natural resources as capital, in the same way as we account economic and financial resources, is getting an important awareness-raising channel for governments, producers, and consumers in order to manage the environment capital. Besides that, the forthcoming Part II of the revised System of Integrated Environmental and Economic Accounting will enclose a framework for experimental ecosystem accounts. This conceptual framework is an initiative led by the European Environment Agency and the World Bank WAVES global partnership for which robust data and indicators are needed. In this context, the aim of this work is to demonstrate a preliminary methodology for land carbon account across Europe. The study area covers EU+38. The territorial unit used was the Socio-Ecological Landscape Units based on the Land Cover Functional Units and other geographical dimensions such as relief, belonging to a river basin, or proximity to the sea. Finally, the grid size used for accounting was 1km x 1km. The characteristic indicator considered for ecosystem capital carbon accounts is the carbon content which is derived from the Net Primary Production (NPP) and its removal by agriculture, forestry. Accordingly, the output data obtained were the stocks of carbon recorded in tons of carbon. The current approach is based on the combination of CORINE Land cover, traditional remote sensing (RS) indicators like NDVI - Normalised Difference Vegetation Index and the modern advances on RS techniques where new indicators like GPP (Gross Primary Productivity) and NPP. Other additional attributes were temperature, precipitation and vegetation type or Land cover. Different national and European data sources were used for the analysis as well as downscales procedures. In the present work soil carbon content were assumed to be a fixed fraction. Nevertheless further research will also take into account soil carbon data considering scenarios of land use change.

Land use strategies to mitigate climate change in carbon dense temperate forests

Science.gov (United States)

Hudiburg, Tara W.; Berner, Logan T.; Kent, Jeffrey J.; Buotte, Polly C.; Harmon, Mark E.

2018-01-01

Strategies to mitigate carbon dioxide emissions through forestry activities have been proposed, but ecosystem process-based integration of climate change, enhanced CO2, disturbance from fire, and management actions at regional scales are extremely limited. Here, we examine the relative merits of afforestation, reforestation, management changes, and harvest residue bioenergy use in the Pacific Northwest. This region represents some of the highest carbon density forests in the world, which can store carbon in trees for 800 y or more. Oregon’s net ecosystem carbon balance (NECB) was equivalent to 72% of total emissions in 2011–2015. By 2100, simulations show increased net carbon uptake with little change in wildfires. Reforestation, afforestation, lengthened harvest cycles on private lands, and restricting harvest on public lands increase NECB 56% by 2100, with the latter two actions contributing the most. Resultant cobenefits included water availability and biodiversity, primarily from increased forest area, age, and species diversity. Converting 127,000 ha of irrigated grass crops to native forests could decrease irrigation demand by 233 billion m3⋅y−1. Utilizing harvest residues for bioenergy production instead of leaving them in forests to decompose increased emissions in the short-term (50 y), reducing mitigation effectiveness. Increasing forest carbon on public lands reduced emissions compared with storage in wood products because the residence time is more than twice that of wood products. Hence, temperate forests with high carbon densities and lower vulnerability to mortality have substantial potential for reducing forest sector emissions. Our analysis framework provides a template for assessments in other temperate regions. PMID:29555758

Net land-atmosphere flows of biogenic carbon related to bioenergy: towards an understanding of systemic feedbacks.

Science.gov (United States)

Haberl, Helmut

2013-07-01

The notion that biomass combustion is carbon neutral vis-a-vis the atmosphere because carbon released during biomass combustion is absorbed during plant regrowth is inherent in the greenhouse gas accounting rules in many regulations and conventions. But this 'carbon neutrality' assumption of bioenergy is an oversimplification that can result in major flaws in emission accounting; it may even result in policies that increase, instead of reduce, overall greenhouse gas emissions. This commentary discusses the systemic feedbacks and ecosystem succession/land-use history issues ignored by the carbon neutrality assumption. Based on recent literature, three cases are elaborated which show that the C balance of bioenergy may range from highly beneficial to strongly detrimental, depending on the plants grown, the land used (including its land-use history) as well as the fossil energy replaced. The article concludes by proposing the concept of GHG cost curves of bioenergy as a means for optimizing the climate benefits of bioenergy policies.

Impacts of land use changes on net ecosystem production in the Taihu Lake Basin of China from 1985 to 2010

Science.gov (United States)

Xu, Xibao; Yang, Guishan; Tan, Yan; Tang, Xuguang; Jiang, Hong; Sun, Xiaoxiang; Zhuang, Qianlai; Li, Hengpeng

2017-03-01

Land use changes play a major role in determining sources and sinks of carbon at regional and global scales. This study employs a modified Global biome model-biogeochemical cycle model to examine the changes in the spatiotemporal pattern of net ecosystem production (NEP) in the Taihu Lake Basin of China during 1985-2010 and the extent to which land use change impacted NEP. The model is calibrated with observed NEP at three flux sites for three dominant land use types in the basin including cropland, evergreen needleleaf forest, and mixed forest. Two simulations are conducted to distinguish the net effects of land use change and increasing atmospheric concentrations of CO2 and nitrogen deposition on NEP. The study estimates that NEP in the basin decreased by 9.8% (1.57 Tg C) from 1985 to 2010, showing an overall downward trend. The NEP distribution exhibits an apparent spatial heterogeneity at the municipal level. Land use changes during 1985-2010 reduced the regional NEP (3.21 Tg C in year 2010) by 19.9% compared to its 1985 level, while the increasing atmospheric CO2 concentrations and nitrogen deposition compensated for a half of the total carbon loss. Critical measures for regulating rapid urban expansion and population growth and reinforcing environment protection programs are recommended to increase the regional carbon sink.

Estimating Trends and Variation of Net Biome Productivity in India for 1980-2012 Using a Land Surface Model

Science.gov (United States)

Gahlot, Shilpa; Shu, Shijie; Jain, Atul K.; Baidya Roy, Somnath

2017-11-01

In this paper we explore the trend in net biome productivity (NBP) over India for the period 1980-2012 and quantify the impact of different environmental factors, including atmospheric CO2 concentrations ([CO2]), land use and land cover change, climate, and nitrogen deposition on carbon fluxes using a land surface model, Integrated Science Assessment Model. Results show that terrestrial ecosystems of India have been a carbon sink for this period. Driven by a strong CO2 fertilization effect, magnitude of NBP increased from 27.17 TgC/yr in the 1980s to 34.39 TgC/yr in the 1990s but decreased to 23.70 TgC/yr in the 2000s due to change in climate. Adoption of forest conservation, management, and reforestation policies in the past decade has promoted carbon sequestration in the ecosystems, but this effect has been offset by loss of carbon from ecosystems due to rising temperatures and decrease in precipitation.

An integrated approach to modeling changes in land use, land cover, and disturbance and their impact on ecosystem carbon dynamics: a case study in the Sierra Nevada Mountains of California

Directory of Open Access Journals (Sweden)

Benjamin M. Sleeter

2015-06-01

Full Text Available Increased land-use intensity (e.g. clearing of forests for cultivation, urbanization, often results in the loss of ecosystem carbon storage, while changes in productivity resulting from climate change may either help offset or exacerbate losses. However, there are large uncertainties in how land and climate systems will evolve and interact to shape future ecosystem carbon dynamics. To address this we developed the Land Use and Carbon Scenario Simulator (LUCAS to track changes in land use, land cover, land management, and disturbance, and their impact on ecosystem carbon storage and flux within a scenario-based framework. We have combined a state-and-transition simulation model (STSM of land change with a stock and flow model of carbon dynamics. Land-change projections downscaled from the Intergovernmental Panel on Climate Change’s (IPCC Special Report on Emission Scenarios (SRES were used to drive changes within the STSM, while the Integrated Biosphere Simulator (IBIS ecosystem model was used to derive input parameters for the carbon stock and flow model. The model was applied to the Sierra Nevada Mountains ecoregion in California, USA, a region prone to large wildfires and a forestry sector projected to intensify over the next century. Three scenario simulations were conducted, including a calibration scenario, a climate-change scenario, and an integrated climate- and land-change scenario. Based on results from the calibration scenario, the LUCAS age-structured carbon accounting model was able to accurately reproduce results obtained from the process-based biogeochemical model. Under the climate-only scenario, the ecoregion was projected to be a reliable net sink of carbon, however, when land use and disturbance were introduced, the ecoregion switched to become a net source. This research demonstrates how an integrated approach to carbon accounting can be used to evaluate various drivers of ecosystem carbon change in a robust, yet transparent

An integrated approach to modeling changes in land use, land cover, and disturbance and their impact on ecosystem carbon dynamics: a case study in the Sierra Nevada Mountains of California

Science.gov (United States)

Sleeter, Benjamin M.; Liu, Jinxun; Daniel, Colin; Frid, Leonardo; Zhu, Zhiliang

2015-01-01

Increased land-use intensity (e.g. clearing of forests for cultivation, urbanization), often results in the loss of ecosystem carbon storage, while changes in productivity resulting from climate change may either help offset or exacerbate losses. However, there are large uncertainties in how land and climate systems will evolve and interact to shape future ecosystem carbon dynamics. To address this we developed the Land Use and Carbon Scenario Simulator (LUCAS) to track changes in land use, land cover, land management, and disturbance, and their impact on ecosystem carbon storage and flux within a scenario-based framework. We have combined a state-and-transition simulation model (STSM) of land change with a stock and flow model of carbon dynamics. Land-change projections downscaled from the Intergovernmental Panel on Climate Change’s (IPCC) Special Report on Emission Scenarios (SRES) were used to drive changes within the STSM, while the Integrated Biosphere Simulator (IBIS) ecosystem model was used to derive input parameters for the carbon stock and flow model. The model was applied to the Sierra Nevada Mountains ecoregion in California, USA, a region prone to large wildfires and a forestry sector projected to intensify over the next century. Three scenario simulations were conducted, including a calibration scenario, a climate-change scenario, and an integrated climate- and land-change scenario. Based on results from the calibration scenario, the LUCAS age-structured carbon accounting model was able to accurately reproduce results obtained from the process-based biogeochemical model. Under the climate-only scenario, the ecoregion was projected to be a reliable net sink of carbon, however, when land use and disturbance were introduced, the ecoregion switched to become a net source. This research demonstrates how an integrated approach to carbon accounting can be used to evaluate various drivers of ecosystem carbon change in a robust, yet transparent modeling

Influence of ozone pollution and climate variability on net primary productivity and carbon storage in China's grassland ecosystems from 1961 to 2000

International Nuclear Information System (INIS)

Ren Wei; Tian Hanqin; Chen Guangsheng; Liu Mingliang; Zhang Chi; Chappelka, Arthur H.; Pan Shufen

2007-01-01

Our simulations with the Dynamic Land Ecosystem Model (DLEM) indicate that the combined effect of ozone, climate, carbon dioxide and land use have caused China's grasslands to act as a weak carbon sink during 1961-2000. This combined effect on national grassland net primary productivity (NPP) and carbon storage was small, but changes in annual NPP and total carbon storage across China's grasslands showed substantial spatial variation, with the maximum total carbon uptake reduction of more than 400 g m -2 in some places of northeastern China. The grasslands in the central northeastern China were more sensitive and vulnerable to elevated ozone pollution than other regions. The combined effect excluding ozone could potentially lead to an increase of 14 Tg C in annual NPP and 0.11 Pg C in total carbon storage for the same time period. This implies that improvement in air quality could significantly increase productivity and carbon storage in China's grassland ecosystems. - Net primary productivity and carbon storage across China's grassland in the late half of the 20th century have been assessed by using the Dynamic Land Ecosystem Model

Trading carbon for food: global comparison of carbon stocks vs. crop yields on agricultural land.

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West, Paul C; Gibbs, Holly K; Monfreda, Chad; Wagner, John; Barford, Carol C; Carpenter, Stephen R; Foley, Jonathan A

2010-11-16

Expanding croplands to meet the needs of a growing population, changing diets, and biofuel production comes at the cost of reduced carbon stocks in natural vegetation and soils. Here, we present a spatially explicit global analysis of tradeoffs between carbon stocks and current crop yields. The difference among regions is striking. For example, for each unit of land cleared, the tropics lose nearly two times as much carbon (∼120 tons·ha(-1) vs. ∼63 tons·ha(-1)) and produce less than one-half the annual crop yield compared with temperate regions (1.71 tons·ha(-1)·y(-1) vs. 3.84 tons·ha(-1)·y(-1)). Therefore, newly cleared land in the tropics releases nearly 3 tons of carbon for every 1 ton of annual crop yield compared with a similar area cleared in the temperate zone. By factoring crop yield into the analysis, we specify the tradeoff between carbon stocks and crops for all areas where crops are currently grown and thereby, substantially enhance the spatial resolution relative to previous regional estimates. Particularly in the tropics, emphasis should be placed on increasing yields on existing croplands rather than clearing new lands. Our high-resolution approach can be used to determine the net effect of local land use decisions.

Land use strategies to mitigate climate change in carbon dense temperate forests.

Science.gov (United States)

Law, Beverly E; Hudiburg, Tara W; Berner, Logan T; Kent, Jeffrey J; Buotte, Polly C; Harmon, Mark E

2018-04-03

Strategies to mitigate carbon dioxide emissions through forestry activities have been proposed, but ecosystem process-based integration of climate change, enhanced CO 2 , disturbance from fire, and management actions at regional scales are extremely limited. Here, we examine the relative merits of afforestation, reforestation, management changes, and harvest residue bioenergy use in the Pacific Northwest. This region represents some of the highest carbon density forests in the world, which can store carbon in trees for 800 y or more. Oregon's net ecosystem carbon balance (NECB) was equivalent to 72% of total emissions in 2011-2015. By 2100, simulations show increased net carbon uptake with little change in wildfires. Reforestation, afforestation, lengthened harvest cycles on private lands, and restricting harvest on public lands increase NECB 56% by 2100, with the latter two actions contributing the most. Resultant cobenefits included water availability and biodiversity, primarily from increased forest area, age, and species diversity. Converting 127,000 ha of irrigated grass crops to native forests could decrease irrigation demand by 233 billion m 3 ⋅y -1 Utilizing harvest residues for bioenergy production instead of leaving them in forests to decompose increased emissions in the short-term (50 y), reducing mitigation effectiveness. Increasing forest carbon on public lands reduced emissions compared with storage in wood products because the residence time is more than twice that of wood products. Hence, temperate forests with high carbon densities and lower vulnerability to mortality have substantial potential for reducing forest sector emissions. Our analysis framework provides a template for assessments in other temperate regions. Copyright © 2018 the Author(s). Published by PNAS.

Impacts of Land Use Change on Net Ecosystem Production in China's Taihu Lake Basin in 1985-2010

Science.gov (United States)

Xu, X.; Yang, G.

2017-12-01

Land use change play a major role in determining sources and sinks of carbon at regional and global scales. This study employs a modified BIOME-BGC model to examine the changes in the spatio-temporal pattern of net ecosystem production (NEP) in China's Taihu Lake Basin in 1985-2010 and the extent to which land use change impacted NEP. The BIOME-BGC model was calibrated with observed NEP at three open-path eddy covariance flux sites for three dominant land-use types in the Basin including cropland, evergreen needleleaf forest, and mixed forest. Land use data were interpreted from Landsat TM images in 1985, 2000, 2005 and 2010 at the scale of 1:100,000 based on a decision tree method. Two simulations are conducted to distinguish the net effects of land use change and increasing atmospheric concentrations of CO2 and nitrogen deposition on NEP. S1 deals with the actual outcomes of NEP under the interactions between land use change and increasing atmospheric concentration of CO2 and N deposition. S2 assumes that atmospheric CO2 concentration and N deposition remain unchanged at their 1985 levels: 338.32 ppm and 0.0005 kg m-2, respectively. The study estimates that NEP in the Basin showed an overall downward trend, decreasing by 9.8% (1.57 TgC) and 3.21 TgC (or 20.9%) from 1985 to 2010 under situation S1 and S2, respectively. The NEP distribution exhibits an apparent spatial heterogeneity at the municipal level. Land use changesin 1985-2010 reduced the regional NEP (3.21 Tg C in year 2010) by 19.9% compared to its 1985 level, while the increasing atmospheric CO2 concentrations and nitrogen deposition compensated for a half of the total carbon loss. Critical measures for regulating rapid urban expansion and population growth and reinforcing environment protection programs are recommended to increase the regional carbon sink.

Managing soil organic carbon in agriculture: the net effect on greenhouse gas emissions

International Nuclear Information System (INIS)

Marland, Gregg; West, Tristram O.; Schlamadinger, Bernhard; Canella, Lorenza

2003-01-01

A change in agricultural practice can increase carbon sequestration in agricultural soils. To know the net effect on greenhouse gas emissions to the atmosphere, however, we consider associated changes in CO 2 emissions resulting from the consumption of fossil fuels, emissions of other greenhouse gases and effects on land productivity and crop yield. We also consider how these factors will evolve over time. A change from conventional tillage to no-till agriculture, based on data for average practice in the U.S.; will result in net carbon sequestration in the soil that averages 337 kg C/ha/yr for the initial 20 yr with a decline to near zero in the following 20 yr, and continuing savings in CO 2 emissions because of reduced use of fossil fuels. The long-term results, considering all factors, can generally be expected to show decreased net greenhouse gas emissions. The quantitative details, however, depend on the site-specific impact of the conversion from conventional to no-till agriculture on agricultural yield and N 2 O emissions from nitrogen fertilizer

A Working Framework for Quantifying Carbon Sequestration in Disturbed Land Mosaics

Science.gov (United States)

Jiquan Chen; Kimberley Brosofske; Asko Noormets; Thomas R. Crow; Mary K. Bresee; James M. Le Moine; Eug& #233; nie Euskirchen; Steve V. Mather; Daolan Zheng; Daolan Zheng

2003-01-01

We propose a working framework for future studies of net carbon exchange (NCE) in disturbed landscapes at broad spatial scales based on the central idea that landscape-level NCE is determined by the land mosaic, including its age structure. Within this framework, we argue that the area-of-edge-influence (AEI), which is prevalent in many disturbed, fragmented landscapes...

Estimating California ecosystem carbon change using process model and land cover disturbance data: 1951-2000

Science.gov (United States)

Liu, Jinxun; Vogelmann, James E.; Zhu, Zhiliang; Key, Carl H.; Sleeter, Benjamin M.; Price, D.T.; Chen, Jing M.; Cochrane, Mark A.; Eidenshink, Jeffery C.; Howard, Stephen M.; Bliss, Norman B.; Jiang, Hong

2011-01-01

Land use change, natural disturbance, and climate change directly alter ecosystem productivity and carbon stock level. The estimation of ecosystem carbon dynamics depends on the quality of land cover change data and the effectiveness of the ecosystem models that represent the vegetation growth processes and disturbance effects. We used the Integrated Biosphere Simulator (IBIS) and a set of 30- to 60-m resolution fire and land cover change data to examine the carbon changes of California's forests, shrublands, and grasslands. Simulation results indicate that during 1951–2000, the net primary productivity (NPP) increased by 7%, from 72.2 to 77.1 Tg C yr−1 (1 teragram = 1012 g), mainly due to CO2 fertilization, since the climate hardly changed during this period. Similarly, heterotrophic respiration increased by 5%, from 69.4 to 73.1 Tg C yr−1, mainly due to increased forest soil carbon and temperature. Net ecosystem production (NEP) was highly variable in the 50-year period but on average equalled 3.0 Tg C yr−1 (total of 149 Tg C). As with NEP, the net biome production (NBP) was also highly variable but averaged −0.55 Tg C yr−1 (total of –27.3 Tg C) because NBP in the 1980s was very low (–5.34 Tg C yr−1). During the study period, a total of 126 Tg carbon were removed by logging and land use change, and 50 Tg carbon were directly removed by wildland fires. For carbon pools, the estimated total living upper canopy (tree) biomass decreased from 928 to 834 Tg C, and the understory (including shrub and grass) biomass increased from 59 to 63 Tg C. Soil carbon and dead biomass carbon increased from 1136 to 1197 Tg C.Our analyses suggest that both natural and human processes have significant influence on the carbon change in California. During 1951–2000, climate interannual variability was the key driving force for the large interannual changes of ecosystem carbon source and sink at the state level, while logging and fire

Relevance of methodological choices for accounting of land use change carbon fluxes

Science.gov (United States)

Pongratz, Julia; Hansis, Eberhard; Davis, Steven

2015-04-01

To understand and potentially steer how humans shape land-climate interactions it is important to accurately attribute greenhouse gas fluxes from land use and land cover change (LULCC) in space and time. However, such accounting of carbon fluxes from LULCC generally requires choosing from multiple options of how to attribute the fluxes to regions and to LULCC activities. Applying a newly-developed and spatially-explicit bookkeeping model, BLUE ("bookkeeping of land use emissions"), we quantify LULCC carbon fluxes and attribute them to land-use activities and countries by a range of different accounting methods. We present results with respect to a Kyoto Protocol-like ``commitment'' accounting period, using land use emissions of 2008-12 as example scenario. We assess the effect of accounting methods that vary (1) the temporal evolution of carbon stocks, (2) the state of the carbon stocks at the beginning of the period, (3) the temporal attribution of carbon fluxes during the period, and (4) treatment of LULCC fluxes that occurred prior to the beginning of the period. We show that the methodological choices result in grossly different estimates of carbon fluxes for the different attribution definitions. The global net flux in the accounting period varies between 4.3 Pg(C) uptake and 15.2 Pg(C) emissions, depending on the accounting method. Regional results show different modes of variation. This finding has implications for both political and scientific considerations: Not all methodological choices are currently specified under the UNFCCC treaties on land use, land-use change and forestry. Yet, a consistent accounting scheme is crucial to assure comparability of individual LULCC activities, quantify their relevance for the global annual carbon budget, and assess the effects of LULCC policies.

Potential strong contribution of future anthropogenic land-use and land-cover change to the terrestrial carbon cycle

Science.gov (United States)

Quesada, Benjamin; Arneth, Almut; Robertson, Eddy; de Noblet-Ducoudré, Nathalie

2018-06-01

Anthropogenic land-use and land cover changes (LULCC) affect global climate and global terrestrial carbon (C) cycle. However, relatively few studies have quantified the impacts of future LULCC on terrestrial carbon cycle. Here, using Earth system model simulations performed with and without future LULCC, under the RCP8.5 scenario, we find that in response to future LULCC, the carbon cycle is substantially weakened: browning, lower ecosystem C stocks, higher C loss by disturbances and higher C turnover rates are simulated. Projected global greening and land C storage are dampened, in all models, by 22% and 24% on average and projected C loss by disturbances enhanced by ~49% when LULCC are taken into account. By contrast, global net primary productivity is found to be only slightly affected by LULCC (robust +4% relative enhancement compared to all forcings, on average). LULCC is projected to be a predominant driver of future C changes in regions like South America and the southern part of Africa. LULCC even cause some regional reversals of projected increased C sinks and greening, particularly at the edges of the Amazon and African rainforests. Finally, in most carbon cycle responses, direct removal of C dominates over the indirect CO2 fertilization due to LULCC. In consequence, projections of land C sequestration potential and Earth’s greening could be substantially overestimated just because of not fully accounting for LULCC.

Climate-driven shifts in continental net primary production implicated as a driver of a recent abrupt increase in the land carbon sink

Science.gov (United States)

Buermann, Wolfgang; Beaulieu, Claudie; Parida, Bikash; Medvigy, David; Collatz, George J.; Sheffield, Justin; Sarmiento, Jorge L.

2016-03-01

The world's ocean and land ecosystems act as sinks for anthropogenic CO2, and over the last half century their combined sink strength grew steadily with increasing CO2 emissions. Recent analyses of the global carbon budget, however, have uncovered an abrupt, substantial ( ˜ 1 PgC yr-1) and sustained increase in the land sink in the late 1980s whose origin remains unclear. In the absence of this prominent shift in the land sink, increases in atmospheric CO2 concentrations since the late 1980s would have been ˜ 30 % larger than observed (or ˜ 12 ppm above current levels). Global data analyses are limited in regards to attributing causes to changes in the land sink because different regions are likely responding to different drivers. Here, we address this challenge by using terrestrial biosphere models constrained by observations to determine if there is independent evidence for the abrupt strengthening of the land sink. We find that net primary production significantly increased in the late 1980s (more so than heterotrophic respiration), consistent with the inferred increase in the global land sink, and that large-scale climate anomalies are responsible for this shift. We identify two key regions in which climatic constraints on plant growth have eased: northern Eurasia experienced warming, and northern Africa received increased precipitation. Whether these changes in continental climates are connected is uncertain, but North Atlantic climate variability is important. Our findings suggest that improved understanding of climate variability in the North Atlantic may be essential for more credible projections of the land sink under climate change.

Historical Carbon Dioxide Emissions Caused by Land-Use Changes are Possibly Larger than Assumed

Science.gov (United States)

Arneth, A.; Sitch, S.; Pongratz, J.; Stocker, B. D.; Ciais, P.; Poulter, B.; Bayer, A. D.; Bondeau, A.; Calle, L.; Chini, L. P.;

Net Biome Productivity of different land use at the sites of the Tharandt cluster

Science.gov (United States)

Grünwald, T.; Prescher, A.-K.; Bernhofer, Ch.

2009-04-01

Within the Tharandt cluster there are 5 flux monitoring sites including 3 CARBOEUROPE main sites. The CARBOEUROPE sites cover typical land use of the region (spruce [monitored since 1996], grassland [since 2003], cropland [since 2004]). For all sites estimates of the Net Biome Productivity (NBP) and its uncertainty have been derived using Net Ecosystem Productivity (NEP) based on the EC measurements and C exports and imports on an annual basis. The crop site is a small C sink (NEP of 30-110gCm-2a-1) only. The annual NEP values are dependent on the cultivated crop species (winter or summer crop). Including C export (harvest) and C import (manure spreading) lead to a considerable C source of 270-540gCm-2a-1. Organic fertilisation (C import) has a strong impact on NBP values expressed in a reduced annual net carbon source. Also, the largest interannual differences of NBP values are found at this site - mainly induced by the existence and the amount of a carbon import due to organic fertilisation. Management practices affect the NBP in a sensitive way at this crop site. Each crop shows a higher C export due to harvest than the annual NEP. To validate the calculated C equivalent using harvested grain biomass modelled NPP values are available. Uncertainty ranges of C export, C import and NBP as well as the grassland and spruce NBP (for comparison) are also stated. In general, land use and management strongly affect the annual NBP of non-forested ecosystems especially. So, this is the second main driver of the C budget besides the interannual variability in meteorological conditions and water availability with its influence on NEP, GPP and TER.

A global assessment of gross and net land change dynamics for current conditions and future scenarios

Science.gov (United States)

Fuchs, Richard; Prestele, Reinhard; Verburg, Peter H.

2018-05-01

The consideration of gross land changes, meaning all area gains and losses within a pixel or administrative unit (e.g. country), plays an essential role in the estimation of total land changes. Gross land changes affect the magnitude of total land changes, which feeds back to the attribution of biogeochemical and biophysical processes related to climate change in Earth system models. Global empirical studies on gross land changes are currently lacking. Whilst the relevance of gross changes for global change has been indicated in the literature, it is not accounted for in future land change scenarios. In this study, we extract gross and net land change dynamics from large-scale and high-resolution (30-100 m) remote sensing products to create a new global gross and net change dataset. Subsequently, we developed an approach to integrate our empirically derived gross and net changes with the results of future simulation models by accounting for the gross and net change addressed by the land use model and the gross and net change that is below the resolution of modelling. Based on our empirical data, we found that gross land change within 0.5° grid cells was substantially larger than net changes in all parts of the world. As 0.5° grid cells are a standard resolution of Earth system models, this leads to an underestimation of the amount of change. This finding contradicts earlier studies, which assumed gross land changes to appear in shifting cultivation areas only. Applied in a future scenario, the consideration of gross land changes led to approximately 50 % more land changes globally compared to a net land change representation. Gross land changes were most important in heterogeneous land systems with multiple land uses (e.g. shifting cultivation, smallholder farming, and agro-forestry systems). Moreover, the importance of gross changes decreased over time due to further polarization and intensification of land use. Our results serve as an empirical database for

Comparing the effects of different land management strategies across several land types on California's landscape carbon and associated greenhouse gas budgets

Science.gov (United States)

Di Vittorio, A. V.; Simmonds, M.; Nico, P. S.

2017-12-01

Land-based carbon sequestration and GreenHouse Gas (GHG) reduction strategies are often implemented in small patches and evaluated independently from each other, which poses several challenges to determining their potential benefits at the regional scales at which carbon/GHG targets are defined. These challenges include inconsistent methods, uncertain scalability to larger areas, and lack of constraints such as land ownership and competition among multiple strategies. To address such challenges we have developed an integrated carbon and GHG budget model of California's entire landscape, delineated by geographic region, land type, and ownership. This empirical model has annual time steps and includes net ecosystem carbon exchange, wildfire, multiple forest management practices including wood and bioenergy production, cropland and rangeland soil management, various land type restoration activities, and land cover change. While the absolute estimates vary considerably due to uncertainties in initial carbon densities and ecosystem carbon exchange rates, the estimated effects of particular management activities with respect to baseline are robust across these uncertainties. Uncertainty in land use/cover change data is also critical, as different rates of shrubland to grassland conversion can switch the system from a carbon source to a sink. The results indicate that reducing urban area expansion has substantial and consistent benefits, while the effects of direct land management practices vary and depend largely on the available management area. Increasing forest fuel reduction extent over the baseline contributes to annual GHG costs during increased management, and annual benefits after increased management ceases. Cumulatively, it could take decades to recover the cost of 14 years of increased fuel reduction. However, forest carbon losses can be completely offset within 20 years through increases in urban forest fraction and marsh restoration. Additionally, highly

Interactions between nitrogen deposition, land cover conversion, and climate change determine the contemporary carbon balance of Europe

Science.gov (United States)

Churkina, G.; Zaehle, S.; Hughes, J.; Viovy, N.; Chen, Y.; Jung, M.; Heumann, B. W.; Ramankutty, N.; Heimann, M.; Jones, C.

2010-09-01

European ecosystems are thought to take up large amounts of carbon, but neither the rate nor the contributions of the underlying processes are well known. In the second half of the 20th century, carbon dioxide concentrations have risen by more that 100 ppm, atmospheric nitrogen deposition has more than doubled, and European mean temperatures were increasing by 0.02 °C yr-1. The extents of forest and grasslands have increased with the respective rates of 5800 km2 yr-1 and 1100 km2 yr-1 as agricultural land has been abandoned at a rate of 7000 km2 yr-1. In this study, we analyze the responses of European land ecosystems to the aforementioned environmental changes using results from four process-based ecosystem models: BIOME-BGC, JULES, ORCHIDEE, and O-CN. The models suggest that European ecosystems sequester carbon at a rate of 56 TgC yr-1 (mean of four models for 1951-2000) with strong interannual variability (±88 TgC yr-1, average across models) and substantial inter-model uncertainty (±39 TgC yr-1). Decadal budgets suggest that there has been a continuous increase in the mean net carbon storage of ecosystems from 85 TgC yr-1 in 1980s to 108 TgC yr-1 in 1990s, and to 114 TgC yr-1 in 2000-2007. The physiological effect of rising CO2 in combination with nitrogen deposition and forest re-growth have been identified as the important explanatory factors for this net carbon storage. Changes in the growth of woody vegetation are suggested as an important contributor to the European carbon sink. Simulated ecosystem responses were more consistent for the two models accounting for terrestrial carbon-nitrogen dynamics than for the two models which only accounted for carbon cycling and the effects of land cover change. Studies of the interactions of carbon-nitrogen dynamics with land use changes are needed to further improve the quantitative understanding of the driving forces of the European land carbon balance.

A global assessment of gross and net land change dynamics for current conditions and future scenarios

Directory of Open Access Journals (Sweden)

R. Fuchs

2018-05-01

Full Text Available The consideration of gross land changes, meaning all area gains and losses within a pixel or administrative unit (e.g. country, plays an essential role in the estimation of total land changes. Gross land changes affect the magnitude of total land changes, which feeds back to the attribution of biogeochemical and biophysical processes related to climate change in Earth system models. Global empirical studies on gross land changes are currently lacking. Whilst the relevance of gross changes for global change has been indicated in the literature, it is not accounted for in future land change scenarios. In this study, we extract gross and net land change dynamics from large-scale and high-resolution (30–100 m remote sensing products to create a new global gross and net change dataset. Subsequently, we developed an approach to integrate our empirically derived gross and net changes with the results of future simulation models by accounting for the gross and net change addressed by the land use model and the gross and net change that is below the resolution of modelling. Based on our empirical data, we found that gross land change within 0.5° grid cells was substantially larger than net changes in all parts of the world. As 0.5° grid cells are a standard resolution of Earth system models, this leads to an underestimation of the amount of change. This finding contradicts earlier studies, which assumed gross land changes to appear in shifting cultivation areas only. Applied in a future scenario, the consideration of gross land changes led to approximately 50 % more land changes globally compared to a net land change representation. Gross land changes were most important in heterogeneous land systems with multiple land uses (e.g. shifting cultivation, smallholder farming, and agro-forestry systems. Moreover, the importance of gross changes decreased over time due to further polarization and intensification of land use. Our results serve as

Net energy benefits of carbon nanotube applications

International Nuclear Information System (INIS)

Zhai, Pei; Isaacs, Jacqueline A.; Eckelman, Matthew J.

2016-01-01

Highlights: • Life cycle net energy benefits are examined. • CNT-enabled and the conventional technologies are compared. • Flash memory with CNT switches show significant positive net energy benefit. • Lithium-ion batteries with MWCNT cathodes show positive net energy benefit. • Lithium-ion batteries with SWCNT anodes tend to exhibit negative net energy benefit. - Abstract: Implementation of carbon nanotubes (CNTs) in various applications can reduce material and energy requirements of products, resulting in energy savings. However, processes for the production of carbon nanotubes (CNTs) are energy-intensive and can require extensive purification. In this study, we investigate the net energy benefits of three CNT-enabled technologies: multi-walled CNT (MWCNT) reinforced cement used as highway construction material, single-walled CNT (SWCNT) flash memory switches used in cell phones and CNT anodes and cathodes used in lithium-ion batteries used in electric vehicles. We explore the avoided or additional energy requirement in the manufacturing and use phases and estimate the life cycle net energy benefits for each application. Additional scenario analysis and Monte Carlo simulation of parameter uncertainties resulted in probability distributions of net energy benefits, indicating that net energy benefits are dependent on the application with confidence intervals straddling the breakeven line in some cases. Analysis of simulation results reveals that SWCNT switch flash memory and MWCNT Li-ion battery cathodes have statistically significant positive net energy benefits (α = 0.05) and SWCNT Li-ion battery anodes tend to have negative net energy benefits, while positive results for MWCNT-reinforced cement were significant only under an efficient CNT production scenario and a lower confidence level (α = 0.1).

A Restricted Boltzman Neural Net to Infer Carbon Uptake from OCO-2 Satellite Data

Science.gov (United States)

Halem, M.; Dorband, J. E.; Radov, A.; Barr-Dallas, M.; Gentine, P.

2015-12-01

For several decades, scientists have been using satellite observations to infer climate budgets of terrestrial carbon uptake employing inverse methods in conjunction with ecosystem models and coupled global climate models. This is an extremely important Big Data calculation today since the net annual photosynthetic carbon uptake changes annually over land and removes on average ~20% of the emissions from human contributions to atmospheric loading of CO2 from fossil fuels. Unfortunately, such calculations have large uncertainties validated with in-situ networks of measuring stations across the globe. One difficulty in using satellite data for these budget calculations is that the models need to assimilate surface fluxes of CO2 as well as soil moisture, vegatation cover and the eddy covariance of latent and sensible heat to calculate the carbon fixed in the soil while satellite spectral observations only provide near surface concentrations of CO2. In July 2014, NASA successfully launched OCO-2 which provides 3km surface measurements of CO2 over land and oceans. We have collected nearly one year of Level 2 XCO2 data from the OCO-2 satellite for 3 sites of ~200 km2 at equatorial, temperate and high latitudes. Each selected site was part of the Fluxnet or ARM system with tower stations for measuring and collecting CO2 fluxes on an hourly basis, in addition to eddy transports of the other parameters. We are also planning to acquire the 4km NDVI products from MODIS and registering the data to the 3km XCO2 footprints for the three sites. We have implemented a restricted Boltzman machine on the quantum annealing D-Wave computer, a novel deep learning neural net, to be used for training with station data to infer CO2 fluxes from collocated XCO2, MODIS vegetative land cover and MERRA reanalysis surface exchange products. We will present performance assessments of the D-Wave Boltzman machine for generating XCO2 fluxes from the OCO-2 satellite observations for the 3 sites by

Effects of land use change on soil carbon cycling in the conterminous United States from 1900 to 2050

Science.gov (United States)

Peter B. Woodbury; Linda S. Heath; James E. Smith

2007-01-01

We developed matrices representing historical area transitions between forest and other land uses. We projected future transitions on the basis of historical transitions and econometric model results. These matrices were used to drive a model of changes in soil and forest floor carbon stocks. Our model predicted net carbon emission from 1900 until 1982, then...

Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance

DEFF Research Database (Denmark)

Kindler, Reimo; Siemens, Jan; Kaiser, Klaus

2011-01-01

ecosystem exchange (NEE) plus carbon inputs with fertilization minus carbon removal with harvest. Carbon leaching increased the net losses from cropland soils by 24–105% (median: 25%). For the majority of forest sites, leaching hardly affected actual net ecosystem carbon balances because of the small...... solubility of CO2 in acidic forest soil solutions and large NEE. Leaching of CH4 proved to be insignificant compared with other fluxes of carbon. Overall, our results show that leaching losses are particularly important for the carbon balance of agricultural systems....

Committed carbon emissions, deforestation, and community land conversion from oil palm plantation expansion in West Kalimantan, Indonesia.

Science.gov (United States)

Carlson, Kimberly M; Curran, Lisa M; Ratnasari, Dessy; Pittman, Alice M; Soares-Filho, Britaldo S; Asner, Gregory P; Trigg, Simon N; Gaveau, David A; Lawrence, Deborah; Rodrigues, Hermann O

2012-05-08

Industrial agricultural plantations are a rapidly increasing yet largely unmeasured source of tropical land cover change. Here, we evaluate impacts of oil palm plantation development on land cover, carbon flux, and agrarian community lands in West Kalimantan, Indonesian Borneo. With a spatially explicit land change/carbon bookkeeping model, parameterized using high-resolution satellite time series and informed by socioeconomic surveys, we assess previous and project future plantation expansion under five scenarios. Although fire was the primary proximate cause of 1989-2008 deforestation (93%) and net carbon emissions (69%), by 2007-2008, oil palm directly caused 27% of total and 40% of peatland deforestation. Plantation land sources exhibited distinctive temporal dynamics, comprising 81% forests on mineral soils (1994-2001), shifting to 69% peatlands (2008-2011). Plantation leases reveal vast development potential. In 2008, leases spanned ∼65% of the region, including 62% on peatlands and 59% of community-managed lands, yet carbon emissions. Intact forest cover declines to 4%, and the proportion of emissions sourced from peatlands increases 38%. Prohibiting intact and logged forest and peatland conversion to oil palm reduces emissions only 4% below BAU, because of continued uncontrolled fire. Protecting logged forests achieves greater carbon emissions reductions (21%) than protecting intact forests alone (9%) and is critical for mitigating carbon emissions. Extensive allocated leases constrain land management options, requiring trade-offs among oil palm production, carbon emissions mitigation, and maintaining community landholdings.

Scaling net ecosystem production and net biome production over a heterogeneous region in the Western United States

Science.gov (United States)

D.P. Turner; W.D. Ritts; B.E. Law; W.B. Cohen; Z. Yan; T. Hudiburg; J.L. Campbell; M. Duane

2007-01-01

Bottom-up scaling of net ecosystem production (NEP) and net biome production (NBP) was used to generate a carbon budget for a large heterogeneous region (the state of Oregon, 2.5x105 km2 ) in the Western United States. Landsat resolution (30 m) remote sensing provided the basis for mapping land cover and disturbance history...

Assessment on the rates and potentials of soil organic carbon sequestration in agricultural lands in Japan using a process-based model and spatially explicit land-use change inventories - Part 2: Future potentials

Science.gov (United States)

Yagasaki, Y.; Shirato, Y.

2014-08-01

Future potentials of the sequestration of soil organic carbon (SOC) in agricultural lands in Japan were estimated using a simulation system we recently developed to simulate SOC stock change at country-scale under varying land-use change, climate, soil, and agricultural practices, in a spatially explicit manner. Simulation was run from 1970 to 2006 with historical inventories, and subsequently to 2020 with future scenarios of agricultural activity comprised of various agricultural policy targets advocated by the Japanese government. Furthermore, the simulation was run subsequently until 2100 while forcing no temporal changes in land-use and agricultural activity to investigate duration and course of SOC stock change at country scale. A scenario with an increased rate of organic carbon input to agricultural fields by intensified crop rotation in combination with the suppression of conversion of agricultural lands to other land-use types was found to have a greater reduction of CO2 emission by enhanced soil carbon sequestration, but only under a circumstance in which the converted agricultural lands will become settlements that were considered to have a relatively lower rate of organic carbon input. The size of relative reduction of CO2 emission in this scenario was comparable to that in another contrasting scenario (business-as-usual scenario of agricultural activity) in which a relatively lower rate of organic matter input to agricultural fields was assumed in combination with an increased rate of conversion of the agricultural fields to unmanaged grasslands through abandonment. Our simulation experiment clearly demonstrated that net-net-based accounting on SOC stock change, defined as the differences between the emissions and removals during the commitment period and the emissions and removals during a previous period (base year or base period of Kyoto Protocol), can be largely influenced by variations in future climate. Whereas baseline-based accounting, defined

Squaroglitter: A 3,4-Connected Carbon Net

KAUST Repository

Prasad, Dasari L. V. K.

2013-08-13

Theoretical calculations are presented on a new hypothetical 3,4-connected carbon net (called squaroglitter) incorporating 1,4 cyclohexadiene units. The structure has tetragonal space group P4/mmm (No. 123) symmetry. The optimized geometry shows normal distances, except for some elongated bonds in the cyclobutane ring substructures in the network. Squaroglitter has an indirect bandgap of about 1.0 eV. The hypothetical lattice, whose density is close to graphite, is more stable than other 3,4-connected carbon nets. A relationship to a (4,4)nanotube is explored, as is a potential threading of the lattice with metal needles. © 2013 American Chemical Society.

Managing forest and marginal agricultural land for multiple tradeoffs : compromising on economic, carbon and structural biodiversity objectives

NARCIS (Netherlands)

Krcmar, E.; Kooten, van G.C.; Vertinsky, I.

2005-01-01

In this paper, we use compromise programming to solve a multiple-objective land use and forest management planning model. Long- and short- (`fast¿) term carbon uptake, maintenance of structural diversity, and economic (net returns to forestry and agriculture) objectives are simultaneously achieved

Changes in Carbon Emissions in Colombian Savannas Derived From Recent Land use and Land Cover Change

Science.gov (United States)

Etter, A.; Sarmiento, A.

2007-12-01

The global contribution of carbon emissions from land use dynamics and change to the global carbon (C) cycle is still uncertain, a major concern in global change modeling. Carbon emission from fires in the tropics is significant and represents 9% of the net primary production, and 50% of worldwide C emissions from fires are attributable to savanna fires. Such emissions may vary significantly due to differences in ecosystem types. Most savanna areas are devoted to grazing land uses making methane emissions also important in savanna ecosystems. Land use change driven by intensification of grazing and cropping has become a major factor affecting C emission dynamics from savanna regions. Colombia has some 17 MHa of mesic savannas which have been historically burned. Due to changes in market demands and improved accessibility during the last 20 years, important areas of savannas changed land use from predominantly extensive grazing to crops and intensive grazing systems. This research models and evaluates the impacts of such land use changes on the spatial and temporal burning patterns and C emissions in the Orinoco savannas of Colombia. We address the effects of land use change patterns using remote sensing data from MODIS and Landsat, ecosystem mapping products, and spatial GIS analysis. First we map the expansion of the agricultural frontier from the 1980s-2000s. We then model the changes in land use from the 1980s using a statistical modeling approach to analyze and quantify the impact of accessibility, ecosystem type and land tenure. We calculate the effects on C emissions from fire regimes and other sources of C based on patterns and extent of burned areas in the 2000s for different savanna ecosystem types and land uses. In the Llanos the fire regime exhibits a marked seasonal variability with most fire events occurring during the dry season between December-March. Our analysis shows that fire frequencies vary consistently between 0.6 and 2.8 fires.yr-1 per 2

Carbon balances during land conversion in early bioenergy systems

Science.gov (United States)

Zenone, T.; Chen, J.; Gelfand, I.; Robertson, G. P.; Hamilton, S. K.

2012-12-01

In this study, we established a field experiment and deployed seven eddy-covariance towers to quantify the roles of land use change and the subsequent carbon (C) balances of three different bioenergy systems (corn, switchgrass, and mixed prairie species) that were developed from two historical land use types: monocultural grasslands dominated by smooth brome (Bromus inermis Leyss) and lands in the Conservation Reserve Program (CRP). Three CRP fields and three cropland fields were converted to soybean in 2009 (conversion year) before establishing the cellulosic biofuel cropping systems in 2010 (establishment year). A CRP perennial grassland site was kept undisturbed as a reference. Conversion of CRP to soybean induced net C emissions during the conversion year (134 -262 g C m-2 yr-1), while in the same year the net C balance at the CRP grassland reference was -35 g C m-2 yr-1 (i.e., net C sequestration). The establishment of switchgrass and mixed prairie induced a cumulative C balance of -113 g C m-2 (switchgrass from CRP), 250 g C m-2 (switchgrass from cropland), 706 g C m-2 (mixed prairie from CRP), and 59 g C m-2 (mixed prairie from cropland) over the three-year study period. The cumulative three-year C balance of corn converted from CRP and from cropland was -151 g C m-2 and -183 g C m-2, respectively. Eddy flux measurements during cellulosic biofuel crop establishment reveal annual changes in C balance that cannot be detected using conventional mass balance approaches. When end-use of harvested biomass was considered, the C balances for all studied systems, except the reference site, exhibited large C emissions ranging from 150 to 990 g C m-2 over the three-year conversion phase.

Evaluating land cover influences on model uncertainties—A case study of cropland carbon dynamics in the Mid-Continent Intensive Campaign region

Science.gov (United States)

Li, Zhengpeng; Liu, Shuguang; Zhang, Xuesong; West, Tristram O.; Ogle, Stephen M.; Zhou, Naijun

2016-01-01

Quantifying spatial and temporal patterns of carbon sources and sinks and their uncertainties across agriculture-dominated areas remains challenging for understanding regional carbon cycles. Characteristics of local land cover inputs could impact the regional carbon estimates but the effect has not been fully evaluated in the past. Within the North American Carbon Program Mid-Continent Intensive (MCI) Campaign, three models were developed to estimate carbon fluxes on croplands: an inventory-based model, the Environmental Policy Integrated Climate (EPIC) model, and the General Ensemble biogeochemical Modeling System (GEMS) model. They all provided estimates of three major carbon fluxes on cropland: net primary production (NPP), net ecosystem production (NEP), and soil organic carbon (SOC) change. Using data mining and spatial statistics, we studied the spatial distribution of the carbon fluxes uncertainties and the relationships between the uncertainties and the land cover characteristics. Results indicated that uncertainties for all three carbon fluxes were not randomly distributed, but instead formed multiple clusters within the MCI region. We investigated the impacts of three land cover characteristics on the fluxes uncertainties: cropland percentage, cropland richness and cropland diversity. The results indicated that cropland percentage significantly influenced the uncertainties of NPP and NEP, but not on the uncertainties of SOC change. Greater uncertainties of NPP and NEP were found in counties with small cropland percentage than the counties with large cropland percentage. Cropland species richness and diversity also showed negative correlations with the model uncertainties. Our study demonstrated that the land cover characteristics contributed to the uncertainties of regional carbon fluxes estimates. The approaches we used in this study can be applied to other ecosystem models to identify the areas with high uncertainties and where models can be improved to

Organic carbon balance and net ecosystem metabolism in Chesapeake Bay

Science.gov (United States)

Kemp, W.M.; Smith, E.M.; Marvin-DiPasquale, M.; Boynton, W.R.

1997-01-01

The major fluxes of organic carbon associated with physical transport and biological metabolism were compiled, analyzed and compared for the mainstem portion of Chesapeake Bay (USA). In addition, 5 independent methods were used to calculate the annual mean net ecosystem metabolism (NEM = production - respiration) for the integrated Bay. These methods, which employed biogeochemical models, nutrient mass-balances anti summation of individual organic carbon fluxes, yielded remarkably similar estimates, with a mean NEM of +50 g C m-2 yr-1 (?? SE = 751, which is approximately 8% of the estimated annual average gross primary production. These calculations suggest a strong cross-sectional pattern in NEM throughout the Bay, wherein net heterotrophic metabolism prevails in the pelagic zones of the main channel, while net autotrophy occurs in the littoral zones which flank the deeper central area. For computational purposes, the estuary was separated into 3 regions along the land-sea gradient: (1) the oligohaline Upper Bay (11% of total area); (2) the mesohaline Mid Bay (36% of area); and (3) the polyhaline Lower Bay (53% of area). A distinct regional trend in NEM was observed along this salinity gradient, with net here(atrophy (NEM = 87 g C m-2 yr-1) in the Upper Bay, balanced metabolism in the Mid Bay and net autotrophy (NEM = +92 g C m-2 yr-1) in the Lower Bay. As a consequence of overall net autotrophy, the ratio of dissolved inorganic nitrogen (DIN) to total organic nitrogen (TON) changed from DIN:TON = 5.1 for riverine inputs to DIN:TON = 0.04 for water exported to the ocean. A striking feature of this organic C mass-balance was the relative dominance of biologically mediated metabolic fluxes compared to physical transport fluxes. The overall ratio of physical TOC inputs (1) to biotic primary production (P) was 0.08 for the whole estuary, but varied dramatically from 2.3 in the Upper Bay to 0.03 in the Mid and Lower Bay regions. Similarly, ecosystem respiration was

Implications of net energy-return-on-investment for a low-carbon energy transition

Science.gov (United States)

King, Lewis C.; van den Bergh, Jeroen C. J. M.

2018-04-01

Low-carbon energy transitions aim to stay within a carbon budget that limits potential climate change to 2 °C—or well below—through a substantial growth in renewable energy sources alongside improved energy efficiency and carbon capture and storage. Current scenarios tend to overlook their low net energy returns compared to the existing fossil fuel infrastructure. Correcting from gross to net energy, we show that a low-carbon transition would probably lead to a 24-31% decline in net energy per capita by 2050, which implies a strong reversal of the recent rising trends of 0.5% per annum. Unless vast end-use efficiency savings can be achieved in the coming decades, current lifestyles might be impaired. To maintain the present net energy returns, solar and wind renewable power sources should grow two to three times faster than in other proposals. We suggest a new indicator, `energy return on carbon', to assist in maximizing the net energy from the remaining carbon budget.

Spring hydrology determines summer net carbon uptake in northern ecosystems

International Nuclear Information System (INIS)

Yi, Yonghong; Kimball, John S; Reichle, Rolf H

2014-01-01

Increased photosynthetic activity and enhanced seasonal CO 2 exchange of northern ecosystems have been observed from a variety of sources including satellite vegetation indices (such as the normalized difference vegetation index; NDVI) and atmospheric CO 2 measurements. Most of these changes have been attributed to strong warming trends in the northern high latitudes (⩾50° N). Here we analyze the interannual variation of summer net carbon uptake derived from atmospheric CO 2 measurements and satellite NDVI in relation to surface meteorology from regional observational records. We find that increases in spring precipitation and snow pack promote summer net carbon uptake of northern ecosystems independent of air temperature effects. However, satellite NDVI measurements still show an overall benefit of summer photosynthetic activity from regional warming and limited impact of spring precipitation. This discrepancy is attributed to a similar response of photosynthesis and respiration to warming and thus reduced sensitivity of net ecosystem carbon uptake to temperature. Further analysis of boreal tower eddy covariance CO 2 flux measurements indicates that summer net carbon uptake is positively correlated with early growing-season surface soil moisture, which is also strongly affected by spring precipitation and snow pack based on analysis of satellite soil moisture retrievals. This is attributed to strong regulation of spring hydrology on soil respiration in relatively wet boreal and arctic ecosystems. These results document the important role of spring hydrology in determining summer net carbon uptake and contrast with prevailing assumptions of dominant cold temperature limitations to high-latitude ecosystems. Our results indicate potentially stronger coupling of boreal/arctic water and carbon cycles with continued regional warming trends. (letters)

Spring Hydrology Determines Summer Net Carbon Uptake in Northern Ecosystems

Science.gov (United States)

Yi, Yonghong; Kimball, John; Reichle, Rolf H.

2014-01-01

Increased photosynthetic activity and enhanced seasonal CO2 exchange of northern ecosystems have been observed from a variety of sources including satellite vegetation indices (such as the Normalized Difference Vegetation Index; NDVI) and atmospheric CO2 measurements. Most of these changes have been attributed to strong warming trends in the northern high latitudes (greater than or equal to 50N). Here we analyze the interannual variation of summer net carbon uptake derived from atmospheric CO2 measurements and satellite NDVI in relation to surface meteorology from regional observational records. We find that increases in spring precipitation and snow pack promote summer net carbon uptake of northern ecosystems independent of air temperature effects. However, satellite NDVI measurements still show an overall benefit of summer photosynthetic activity from regional warming and limited impact of spring precipitation. This discrepancy is attributed to a similar response of photosynthesis and respiration to warming and thus reduced sensitivity of net ecosystem carbon uptake to temperature. Further analysis of boreal tower eddy covariance CO2 flux measurements indicates that summer net carbon uptake is positively correlated with early growing-season surface soil moisture, which is also strongly affected by spring precipitation and snow pack based on analysis of satellite soil moisture retrievals. This is attributed to strong regulation of spring hydrology on soil respiration in relatively wet boreal and arctic ecosystems. These results document the important role of spring hydrology in determining summer net carbon uptake and contrast with prevailing assumptions of dominant cold temperature limitations to high-latitude ecosystems. Our results indicate potentially stronger coupling of boreal/arctic water and carbon cycles with continued regional warming trends.

Interactions between nitrogen deposition, land cover conversion, and climate change determine the contemporary carbon balance of Europe

Directory of Open Access Journals (Sweden)

G. Churkina

2010-09-01

Full Text Available European ecosystems are thought to take up large amounts of carbon, but neither the rate nor the contributions of the underlying processes are well known. In the second half of the 20th century, carbon dioxide concentrations have risen by more that 100 ppm, atmospheric nitrogen deposition has more than doubled, and European mean temperatures were increasing by 0.02 °C yr⁻¹. The extents of forest and grasslands have increased with the respective rates of 5800 km² yr⁻¹ and 1100 km² yr⁻¹ as agricultural land has been abandoned at a rate of 7000 km² yr⁻¹. In this study, we analyze the responses of European land ecosystems to the aforementioned environmental changes using results from four process-based ecosystem models: BIOME-BGC, JULES, ORCHIDEE, and O-CN. The models suggest that European ecosystems sequester carbon at a rate of 56 TgC yr⁻¹ (mean of four models for 1951–2000 with strong interannual variability (±88 TgC yr⁻¹, average across models and substantial inter-model uncertainty (±39 TgC yr⁻¹. Decadal budgets suggest that there has been a continuous increase in the mean net carbon storage of ecosystems from 85 TgC yr⁻¹ in 1980s to 108 TgC yr⁻¹ in 1990s, and to 114 TgC yr⁻¹ in 2000–2007. The physiological effect of rising CO₂ in combination with nitrogen deposition and forest re-growth have been identified as the important explanatory factors for this net carbon storage. Changes in the growth of woody vegetation are suggested as an important contributor to the European carbon sink. Simulated ecosystem responses were more consistent for the two models accounting for terrestrial carbon-nitrogen dynamics than for the two models which only accounted for carbon cycling and the effects of land cover change. Studies of the interactions of carbon-nitrogen dynamics with

Assessing the implications of human land-use change for the transient climate response to cumulative carbon emissions

International Nuclear Information System (INIS)

Simmons, C T; Matthews, H D

2016-01-01

Recent research has shown evidence of a linear climate response to cumulative CO 2 emissions, which implies that the source, timing, and amount of emissions does not significantly influence the climate response per unit emission. Furthermore, these analyses have generally assumed that the climate response to land-use CO 2 emissions is equivalent to that of fossil fuels under the assumption that, once in the atmosphere, the radiative forcing induced by CO 2 is not sensitive to the emissions source. However, land-cover change also affects surface albedo and the strength of terrestrial carbon sinks, both of which have an additional climate effect. In this study, we use a coupled climate-carbon cycle model to assess the climate response to historical and future cumulative land-use CO 2 emissions, in order to compare it to the response to fossil fuel CO 2 . We find that when we isolate the CO 2 -induced (biogeochemical) temperature changes associated with land-use change, then the climate response to cumulative land-use emissions is equivalent to that of fossil fuel CO 2 . We show further that the globally-averaged albedo-induced biophysical cooling from land-use change is non-negligible and may be of comparable magnitude to the biogeochemical warming, with the result that the net climate response to land-use change is substantially different from a linear response to cumulative emissions. However, our new simulations suggest that the biophysical cooling from land-use change follows its own independent (negative) linear response to cumulative net land-use CO 2 emissions, which may provide a useful scaling factor for certain applications when evaluating the full transient climate response to emissions. (letter)

Nitrogen and phosphorous limitation reduces the effects of land use change on land carbon uptake or emission

International Nuclear Information System (INIS)

Wang, Ying-Ping; Zhang, Qian; Dai, Yongjiu; Pitman, Andrew J

2015-01-01

We used an Earth System Model that includes both nitrogen (N) and phosphorus (P) cycling to simulate the impacts of land-use and land-cover change (LULCC) for two representative concentration pathways (RCPs): a reforestation scenario (RCP4.5) and a deforestation scenario (RCP8.5). For each RCP, we performed simulations with and without LULCC using the carbon (C only) mode or including the full C, N and P cycles (CNP). We show, for the first time, that inclusion of N and P cycling reduces both the carbon uptake from reforestation in RCP4.5 and the carbon emission from deforestation in RCP8.5. Specifically, carbon-nutrient interaction reduces carbon uptake in RCP4.5 from 55 Pg C (C only) to 21 Pg C (CNP), or the emissions in RCP8.5 from 72 Pg C (C only) to 56 Pg C (CNP). Most of those reductions result from much weaker responses of net primary production to CO 2 fertilization and climate change when carbon-nutrient interaction is taken into account, as compared to C only simulations. Our results highlight the importance of including nutrient-carbon interaction in estimating the carbon benefit from reforestation and carbon loss from deforestation in a future world with higher CO 2 and a warmer climate. Because of the stronger nutrient limitation, carbon gain from reforestation in the temperate and boreal regions is much less than the carbon loss from deforestation in the subtropical and tropical regions from 2006 to 2100 for the two RCPs. Therefore protecting the existing subtropical and tropical forests is about twice as effective as planting new forests in the temperate and boreal regions for climate mitigation. (letter)

Accelerating Net Terrestrial Carbon Uptake During the Warming Hiatus Due to Reduced Respiration

Science.gov (United States)

Ballantyne, Ashley; Smith, William; Anderegg, William; Kauppi, Pekka; Sarmiento, Jorge; Tans, Pieter; Shevliakova, Elena; Pan, Yude; Poulter, Benjamin; Anav, Alessandro;

Historical and future perspectives of global soil carbon response to climate and land-use changes

Science.gov (United States)

Eglin, T.; Ciais, P.; Piao, S. L.; Barre, P.; Bellassen, V.; Cadule, P.; Chenu, C.; Gasser, T.; Koven, C.; Reichstein, M.; Smith, P.

2010-11-01

ABSTRACT In this paper, we attempt to analyse the respective influences of land-use and climate changes on the global and regional balances of soil organic carbon (SOC) stocks. Two time periods are analysed: the historical period 1901-2000 and the period 2000-2100. The historical period is analysed using a synthesis of published data as well as new global and regional model simulations, and the future is analysed using models only. Historical land cover changes have resulted globally in SOC release into the atmosphere. This human induced SOC decrease was nearly balanced by the net SOC increase due to higher CO2 and rainfall. Mechanization of agriculture after the 1950s has accelerated SOC losses in croplands, whereas development of carbon-sequestering practices over the past decades may have limited SOC loss from arable soils. In some regions (Europe, China and USA), croplands are currently estimated to be either a small C sink or a small source, but not a large source of CO2 to the atmosphere. In the future, according to terrestrial biosphere and climate models projections, both climate and land cover changes might cause a net SOC loss, particularly in tropical regions. The timing, magnitude, and regional distribution of future SOC changes are all highly uncertain. Reducing this uncertainty requires improving future anthropogenic CO2 emissions and land-use scenarios and better understanding of biogeochemical processes that control SOC turnover, for both managed and un-managed ecosystems.

[Greenhouse gas emissions, carbon leakage and net carbon sequestration from afforestation and forest management: A review.

Science.gov (United States)

Liu, Bo Jie; Lu, Fei; Wang, Xiao Ke; Liu, Wei Wei

2017-02-01

Forests play an important role in climate change mitigation and concentration of CO 2 reduction in the atmosphere. Forest management, especially afforestation and forest protection, could increase carbon stock of forests significantly. Carbon sequestration rate of afforestation ranges from 0.04 to 7.52 t C·hm -2 ·a -1 , while that of forest protection is 0.33-5.20 t C·hm -2 ·a -1 . At the same time, greenhouse gas (GHG) is generated within management boundary due to the production and transportation of the materials consumed in relevant activities of afforestation and forest management. In addition, carbon leakage is also generated outside boundary from activity shifting, market effects and change of environments induced by forest management. In this review, we summarized the definition of emission sources of GHG, monitoring methods, quantity and rate of greenhouse gas emissions within boundary of afforestation and forest management. In addition, types, monitoring methods and quantity of carbon leakage outside boundary of forest management were also analyzed. Based on the reviewed results of carbon sequestration, we introduced greenhouse gas emissions within boundary and carbon leakage, net carbon sequestration as well as the countervailing effects of greenhouse gas emissions and carbon leakage to carbon sequestration. Greenhouse gas emissions within management boundary counteract 0.01%-19.3% of carbon sequestration, and such counteraction could increase to as high as 95% considering carbon leakage. Afforestation and forest management have substantial net carbon sequestration benefits, when only taking direct greenhouse gas emissions within boundary and measurable carbon leakage from activity shifting into consideration. Compared with soil carbon sequestration measures in croplands, afforestation and forest management is more advantageous in net carbon sequestration and has better prospects for application in terms of net mitigation potential. Along with the

The effects of land cover and land use change on the contemporary carbon balance of the arctic and boreal terrestrial ecosystems of northern Eurasia

Science.gov (United States)

Hayes, Daniel J.; McGuire, A. David; Kicklighter, David W.; Burnside , Todd J.; Melillo, Jerry M.

2010-01-01

Recent changes in climate, disturbance regimes and land use and management systems in Northern Eurasia have the potential to disrupt the terrestrial sink of atmospheric CO2 in a way that accelerates global climate change. To determine the recent trends in the carbon balance of the arctic and boreal ecosystems of this region, we performed a retrospective analysis of terrestrial carbon dynamics across northern Eurasia over a recent 10-year period using a terrestrial biogeochemical process model. The results of the simulations suggest a shift in direction of the net flux from the terrestrial sink of earlier decades to a net source on the order of 45 Tg C year−1between 1997 and 2006. The simulation framework and subsequent analyses presented in this study attribute this shift to a large loss of carbon from boreal forest ecosystems, which experienced a trend of decreasing precipitation and a large area burned during this time period.

Partitioning of net carbon dioxide flux measured by automatic transparent chamber

Science.gov (United States)

Dyukarev, EA

2018-03-01

Mathematical model was developed for describing carbon dioxide fluxes at open sedge-sphagnum fen during growing season. The model was calibrated using the results of observations from automatic transparent chamber and it allows us to estimate autotrophic, heterotrophic and ecosystem respiration fluxes, gross and net primary vegetation production, and the net carbon balance.

Options for including all lands in a future greenhouse gas accounting framework

International Nuclear Information System (INIS)

Cowie, Annette L.; Kirschbaum, Miko U.F.; Ward, Murray

2007-01-01

The current framework through which greenhouse gas emissions and removals in the land use sector are accounted under the Kyoto Protocol has several problems. They include a complex structure, onerous monitoring and reporting requirements, and potential for omission of some important fluxes. One solution that may overcome some of these problems is to include all lands and associated processes within a country's jurisdiction, rather than restrict accounting to specific nominated land categories or activities. Ideally, the accounting approach should cover all significant biospheric sources and sinks, avoid biased or unbalanced accounting, avoid leakage and require no arbitrary adjustments to remedy unintended consequences. Furthermore, accounting should focus on the direct human-induced component of biospheric emissions/removals so that debits/credits can be allocated equitably and provide appropriate incentives to adopt land-use management options with beneficial outcomes for the atmosphere. This paper focuses on biospheric emissions and removals resulting from carbon stock changes. It considers four alternative accounting options that include all land areas: Gross-Net Accounting, Net-Net Accounting, Net Accounting with Negotiated Baselines and the Average Carbon Stocks approach. Each option is described, and assessed with respect to defined criteria for effectiveness. Gross-Net Accounting and Net-Net Accounting do not adequately distinguish the anthropogenic component of carbon-stock changes from indirect and natural effects, so large undeserved credits or debits could be created. Under Net Accounting with Negotiated Baselines, countries' projected emissions and removals during the commitment period would be taken into account in the negotiation of emissions targets. In the commitment period, countries would then gain credits/debits for biospheric removals/emissions. Difficulties with this approach would lie in reaching agreed baselines for emissions and removals

Value of Soil Organic Carbon in Agricultural Lands

Energy Technology Data Exchange (ETDEWEB)

Wander, M.; Nissen, T. [Department of Natural Resources and Environmental Sciences, University of Illinois, 1102 S. Goodwin Ave. Urbana IL 61801 (United States)

2004-10-01

Immediate efforts to increase soil carbon sequestration and minimize terrestrial greenhouse gas emissions are needed to mitigate global warming. Whether or not terrestrial stocks become sinks or net sources of C over the next century will depend upon how fast and at what level we are able to stabilize carbon dioxide levels. The cost of soil C sequestration is at present relatively low compared to other C emission reduction technologies making soil C sinks an important short-term solution to be used while competing technologies are developed. However, efforts to use C sequestration in soils as CO2 emissions offsets have faced numerous challenges. Difficulties associated with C stock validation (direct measurement) and the impermanence and saturability of soil C reservoirs raise concerns over whether soil C reservoirs are good long-term investments. Pragmatism has led to the development of indirect inventorying of the C reserves held at national and regional scales. Such indirect accounting systems will advance as validation methods are refined and as process models improve their ability to accurately predict how existing soil condition and specific land management practices will influence soil C storage and NO2 and CH4 emissions. Improved documentation of the value of environmental services and sustained productive potential derived from optimized land use and associated increases in soil quality will also add to the estimated value of soil C sinks. Policies must evolve simultaneously with the theoretical and technical tools needed to promote optimization of land use practices to mitigate climate change now and to minimize future contributions of soil C to atmospheric CO2.

Terrestrial Carbon Sequestration in National Parks: Values for the Conterminous United States

Science.gov (United States)

Richardson, Leslie A.; Huber, Christopher; Zhu, Zhi-Liang; Koontz, Lynne

2015-01-01

Lands managed by the National Park Service (NPS) provide a wide range of beneficial services to the American public. This study quantifies the ecosystem service value of carbon sequestration in terrestrial ecosystems within NPS units in the conterminous United States for which data were available. Combining annual net carbon balance data with spatially explicit NPS land unit boundaries and social cost of carbon estimates, this study calculates the net metric tons of carbon dioxide sequestered annually by park unit under baseline conditions, as well as the associated economic value to society. Results show that, in aggregate, NPS lands in the conterminous United States are a net carbon sink, sequestering more than 14.8 million metric tons of carbon dioxide annually. The associated societal value of this service is estimated at approximately $582.5 million per year. While this analysis provides a broad overview of the annual value of carbon sequestration on NPS lands averaged over a five year baseline period, it should be noted that carbon fluxes fluctuate from year to year, and there can be considerable variation in net carbon balance and its associated value within a given park unit. Future research could look in-depth at the spatial heterogeneity of carbon flux within specific NPS land units.

Estimating ecosystem carbon change in the Conterminous United States based on 40 years of land-use change and disturbance

Science.gov (United States)

Sleeter, B. M.; Rayfield, B.; Liu, J.; Sherba, J.; Daniel, C.; Frid, L.; Wilson, T. S.; Zhu, Z.

2016-12-01

Since 1970, the combined changes in land use, land management, climate, and natural disturbances have dramatically altered land cover in the United States, resulting in the potential for significant changes in terrestrial carbon storage and flux between ecosystems and the atmosphere. Processes including urbanization, agricultural expansion and contraction, and forest management have had impacts - both positive and negative - on the amount of natural vegetation, the age structure of forests, and the amount of impervious cover. Anthropogenic change coupled with climate-driven changes in natural disturbance regimes, particularly the frequency and severity of wildfire, together determine the spatio-temporal patterns of land change and contribute to changing ecosystem carbon dynamics. Quantifying this effect and its associated uncertainties is fundamental to developing a rigorous and transparent carbon monitoring and assessment programs. However, large-scale systematic inventories of historical land change and their associated uncertainties are sparse. To address this need, we present a newly developed modeling framework, the Land Use and Carbon Scenario Simulator (LUCAS). The LUCAS model integrates readily available high quality, empirical land-change data into a stochastic space-time simulation model representing land change feedbacks on carbon cycling in terrestrial ecosystems. We applied the LUCAS model to estimate regional scale changes in carbon storage, atmospheric flux, and net biome production in 84 ecological regions of the conterminous United States for the period 1970-2015. The model was parameterized using a newly available set of high resolution (30 m) land-change data, compiled from Landsat remote sensing imagery, including estimates of uncertainty. Carbon flux parameters for each ecological region were derived from the IBIS dynamic global vegetation model with full carbon cycle accounting. This paper presents our initial findings describing regional and

Implication of Land-Use and Land-Cover Change into Carbon Dioxide Emissions in Karang Gading and Langkat Timur Wildlife Reserve, North Sumatra, Indonesia

Directory of Open Access Journals (Sweden)

Mohammad Basyuni

2015-06-01

Full Text Available Mangrove forest in the context of climate change is important sector to be included in the inventory of greenhouse gas (GHG emissions. The present study describes land-use and land-cover change during 2006–2012 of a mangrove forest conservation area, Karang Gading and Langkat Timur Laut Wildlife Reserve (KGLTLWR in North Sumatra, Indonesia and their implications to carbon dioxide emissions. A land-use change matrix showed that the decrease of mangrove forest due to increases of other land-use such as aquaculture (50.00% and oil palm plantation (28.83%. Furthermore, the net cumulative of carbon emissions in KGLTLWR for 2006 was 3804.70 t CO2-eq year-1, whereas predicting future emissions in 2030 was 11,318.74 t CO2-eq year-1 or an increase of 33.61% for 12 years. Source of historical emissions mainly from changes of secondary mangrove forests into aquaculture and oil palm plantation were 3223.9 t CO2-eq year-1 (84.73% and 959.00 t CO2-eq year-1 (25.21%, respectively, indicating that the KGLTLWR is still a GHG emitter. Mitigation scenario with no conversion in secondary mangrove forest reduced 16.21% and 25.8% carbon emissions in 2024 and 2030, respectively. This study suggested that aquaculture and oil palm plantation are drivers of deforestation as well as the largest of GHG emission source in this area. Keywords: carbon emission, climate change, deforestation, forest degradation, mangrove conservation

Projected changes in terrestrial carbon storage in Europe under climate and land-use change, 1990-2100

International Nuclear Information System (INIS)

Zaehle, S.; Bondeau, A.; Cramer, W.; Erhard, M.; Sitch, S.; Smith, P.C.; Zaehle, S.; Smith, P.C.; Carter, T.R.; Erhard, M.; Prentice, C.; Prentice, C.; Reginster, I.; Rounsevell, M.D.A.; Sitch, S.; Smith, B.; Sykes, M

2007-01-01

Changes in climate and land use, caused by socio-economic changes, greenhouse gas emissions, agricultural policies and other factors, are known to affect both natural and managed ecosystems, and will likely impact on the European terrestrial carbon balance during the coming decades. This study presents a comprehensive European Union wide (EU15 plus Norway and Switzerland, EU*) assessment of potential future changes in terrestrial carbon storage considering these effects based on four illustrative IPCC-SRES story-lines (A1FI, A2, B1, B2). A process-based land vegetation model (LPJ-DGVM), adapted to include a generic representation of managed ecosystems, is forced with changing fields of land-use patterns from 1901 to 2100 to assess the effect of land-use and cover changes on the terrestrial carbon balance of Europe. The uncertainty in the future carbon balance associated with the choice of a climate change scenario is assessed by forcing LPJ-DGVM with output from four different climate models (GCMs: CGCM2, CSIRO2, HadCM3, PCM2) for the same SRES story-line. Decrease in agricultural areas and afforestation leads to simulated carbon sequestration for all land-use change scenarios with an average net uptake of 17-38 Tg C/year between 1990 and 2100, corresponding to 1.9-2.9% of the EU*s CO 2 emissions over the same period. Soil carbon losses resulting from climate warming reduce or even offset carbon sequestration resulting from growth enhancement induced by climate change and increasing atmospheric CO 2 concentrations in the second half of the twenty-first century. Differences in future climate change projections among GCMs are the main cause for uncertainty in the cumulative European terrestrial carbon uptake of 4.4-10.1 Pg C between 1990 and 2100. (authors)

Accountable Accounting: Carbon-Based Management on Marginal Lands

Directory of Open Access Journals (Sweden)

Tara L. DiRocco

2014-04-01

Full Text Available Substantial discussion exists concerning the best land use options for mitigating greenhouse gas (GHG emissions on marginal land. Emissions-mitigating land use options include displacement of fossil fuels via biofuel production and afforestation. Comparing C recovery dynamics under these different options is crucial to assessing the efficacy of offset programs. In this paper, we focus on forest recovery on marginal land, and show that there is substantial inaccuracy and discrepancy in the literature concerning carbon accumulation. We find that uncertainty in carbon accumulation occurs in estimations of carbon stocks and models of carbon dynamics over time. We suggest that analyses to date have been largely unsuccessful at determining reliable trends in site recovery due to broad land use categories, a failure to consider the effect of current and post-restoration management, and problems with meta-analysis. Understanding of C recovery could be greatly improved with increased data collection on pre-restoration site quality, prior land use history, and management practices as well as increased methodological standardization. Finally, given the current and likely future uncertainty in C dynamics, we recommend carbon mitigation potential should not be the only environmental service driving land use decisions on marginal lands.

Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity

Energy Technology Data Exchange (ETDEWEB)

Li, Xi, E-mail: icy124@hotmail.com [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Toma, Yo [Faculty of Agriculture, Ehime University, 3-5-7, Tarumi, Matsuyama 790-8566, Ehime (Japan); Yeluripati, Jagadeesh [The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland (United Kingdom); Iwasaki, Shinya [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Bellingrath-Kimura, Sonoko D. [Leibniz Centre for Agricultural Landscape Research, Institute of Land Use Systems (Germany); Jones, Edward O. [Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London (United Kingdom); Hatano, Ryusuke [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan)

2016-06-01

Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959–2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from − 1.26 Mg C ha{sup −1} yr{sup −1} in 1959–0.26 Mg C ha{sup −1} yr{sup −1} in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959–2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. - Highlights: • We compared C stocks change by two methods: (i) net biome productivity (NBP) and (ii) soil inventory. • Variation in net primary productivity (NPP), plant C input, NBP can be predicted by climate

Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity

International Nuclear Information System (INIS)

Li, Xi; Toma, Yo; Yeluripati, Jagadeesh; Iwasaki, Shinya; Bellingrath-Kimura, Sonoko D.; Jones, Edward O.; Hatano, Ryusuke

2016-01-01

Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959–2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from − 1.26 Mg C ha"−"1 yr"−"1 in 1959–0.26 Mg C ha"−"1 yr"−"1 in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959–2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. - Highlights: • We compared C stocks change by two methods: (i) net biome productivity (NBP) and (ii) soil inventory. • Variation in net primary productivity (NPP), plant C input, NBP can be predicted by climate conditions. • NBP

Assessing double counting of carbon emissions between forest land cover change and forest wildfires: a case study in the United States, 1992-2006

Science.gov (United States)

Daolan Zheng; Linda S. Heath; Mark J. Ducey; Brad. Quayle

2013-01-01

The relative contributions of double counting of carbon emissions between forest-to-nonforest cover change (FNCC) and forest wildfires are an unknown in estimating net forest carbon exchanges at large scales. This study employed land-cover change maps and forest fire data in the four representative states (Arkansas, California, Minnesota, and Washington) of the US for...

Lateral transport of soil carbon and land-atmosphere CO2 flux induced by water erosion in China.

Science.gov (United States)

Yue, Yao; Ni, Jinren; Ciais, Philippe; Piao, Shilong; Wang, Tao; Huang, Mengtian; Borthwick, Alistair G L; Li, Tianhong; Wang, Yichu; Chappell, Adrian; Van Oost, Kristof

2016-06-14

Soil erosion by water impacts soil organic carbon stocks and alters CO2 fluxes exchanged with the atmosphere. The role of erosion as a net sink or source of atmospheric CO2 remains highly debated, and little information is available at scales larger than small catchments or regions. This study attempts to quantify the lateral transport of soil carbon and consequent land-atmosphere CO2 fluxes at the scale of China, where severe erosion has occurred for several decades. Based on the distribution of soil erosion rates derived from detailed national surveys and soil carbon inventories, here we show that water erosion in China displaced 180 ± 80 Mt C⋅y(-1) of soil organic carbon during the last two decades, and this resulted a net land sink for atmospheric CO2 of 45 ± 25 Mt C⋅y(-1), equivalent to 8-37% of the terrestrial carbon sink previously assessed in China. Interestingly, the "hotspots," largely distributed in mountainous regions in the most intensive sink areas (>40 g C⋅m(-2)⋅y(-1)), occupy only 1.5% of the total area suffering water erosion, but contribute 19.3% to the national erosion-induced CO2 sink. The erosion-induced CO2 sink underwent a remarkable reduction of about 16% from the middle 1990s to the early 2010s, due to diminishing erosion after the implementation of large-scale soil conservation programs. These findings demonstrate the necessity of including erosion-induced CO2 in the terrestrial budget, hence reducing the level of uncertainty.

Soil carbon sequestration and biochar as negative emission technologies.

Science.gov (United States)

Smith, Pete

2016-03-01

Despite 20 years of effort to curb emissions, greenhouse gas (GHG) emissions grew faster during the 2000s than in the 1990s, which presents a major challenge for meeting the international goal of limiting warming to deforestation, showed that all NETs have significant limits to implementation, including economic cost, energy requirements, land use, and water use. In this paper, I assess the potential for negative emissions from soil carbon sequestration and biochar addition to land, and also the potential global impacts on land use, water, nutrients, albedo, energy and cost. Results indicate that soil carbon sequestration and biochar have useful negative emission potential (each 0.7 GtCeq. yr(-1) ) and that they potentially have lower impact on land, water use, nutrients, albedo, energy requirement and cost, so have fewer disadvantages than many NETs. Limitations of soil carbon sequestration as a NET centre around issues of sink saturation and reversibility. Biochar could be implemented in combination with bioenergy with carbon capture and storage. Current integrated assessment models do not represent soil carbon sequestration or biochar. Given the negative emission potential of SCS and biochar and their potential advantages compared to other NETs, efforts should be made to include these options within IAMs, so that their potential can be explored further in comparison with other NETs for climate stabilization. © 2016 John Wiley & Sons Ltd.

Reforestation Effects on Carbon Stocks in the Northeast USA: Interactions among Earthworms, Land-Use History and Soil Properties

Science.gov (United States)

Ross, D. S.; Görres, J. H.; Knowles, M.; Cogbill, C. V.

2017-12-01

Reforestation has occurred in many areas of the northeastern USA that were cleared for agriculture in the 1700s and 1800s. Net gains in carbon have occurred but these gains may be affected by earthworm invasions. All earthworm species common to New England were introduced from either Europe or, more recently, Asia. We have been monitoring 18 managed forest stands in Vermont to be able to determine long-term changes in carbon stores. In addition to measuring carbon with depth into the C horizon, we have documented land use history dating back to colonial times, determined earthworm species and density, measured tree species and site metrics, and measured a suite of soil chemical parameters. We also determined carbon distribution in soil microaggregates in a subset of sites. Prior land use in the 18 monitored plots included cultivation, pasture, farm woodlot and possibly iron mining. Higher earthworm species diversity correlated with reduced forest floor depth, higher mineral soil carbon, and greater stability (microaggregate-protected) of that carbon. Sites with the highest worm density and species richness had a history of more intense agricultural land use (although not all former agricultural sites had earthworms). There were also positive interactions between exchangeable calcium pools and earthworm density, and between elevation and carbon in the forest floor. With only 18 sites, it is difficult to establish statistically robust relationships. The effect of reforestation on present-day carbon stores appears to be a complex interaction of land-use history, site location, earthworm history and soil chemistry.

Relationship between Organic Carbon Runoff to River and Land Cover

Science.gov (United States)

Kim, G. S.; Lee, S. G.; Lim, C. H.; Lee, W.; Yoo, S.; Kim, S. J.; Heo, S.; Lee, W. K.

2017-12-01

Carbon is an important unit in understanding the ecosystem and energy circulation. Each ecosystem, land, water, and atmosphere, is interconnected through the exchange of energy and organic carbon. In the rivers, primary producers utilize the organic carbon from the land. Understanding the organic carbon uptake into the river is important for understanding the mechanism of river ecosystems. The main organic carbon source of the river is land. However, it is difficult to observe the amount of organic carbon runoff to the river. Therefore, an indirect method should be used to estimate the amount of organic carbon runoff to the river. The organic carbon inflow is caused by the runoff of organic carbon dissolved in water or the inflow of organic carbon particles by soil loss. Therefore, the hydrological model was used to estimate organic carbon runoff through the flow of water. The land cover correlates with soil respiration, soil loss, and so on, and the organic carbon runoff coefficient will be estimated to the river by land cover. Using the organic carbon concentration from water quality data observed at each point in the river, we estimate the amount of organic carbon released from the land. The reason is that the runoff from the watershed converges into the rivers in the watershed, the watershed simulation is conducted based on the water quality data observation point. This defines a watershed that affects organic carbon observation sites. The flow rate of each watershed is calculated by the SWAT (Soil and Water Assessment Tool), and the total organic carbon runoff is calculated by using flow rate and organic carbon concentration. This is compared with the factors related to the amount of organic carbon such as land cover, soil loss, and soil organic carbon, and spatial analysis is carried out to estimate the organic carbon runoff coefficient per land cover.

Distinguishing the drivers of trends in land carbon fluxes and plant volatile emissions over the past 3 decades

Science.gov (United States)

Yue, X.; Unger, N.; Zheng, Y.

2015-10-01

The terrestrial biosphere has experienced dramatic changes in recent decades. Estimates of historical trends in land carbon fluxes remain uncertain because long-term observations are limited on the global scale. Here, we use the Yale Interactive terrestrial Biosphere (YIBs) model to estimate decadal trends in land carbon fluxes and emissions of biogenic volatile organic compounds (BVOCs) and to identify the key drivers for these changes during 1982-2011. Driven by hourly meteorology from WFDEI (WATCH forcing data methodology applied to ERA-Interim data), the model simulates an increasing trend of 297 Tg C a-2 in gross primary productivity (GPP) and 185 Tg C a-2 in the net primary productivity (NPP). CO2 fertilization is the main driver for the flux changes in forest ecosystems, while meteorology dominates the changes in grasslands and shrublands. Warming boosts summer GPP and NPP at high latitudes, while drought dampens carbon uptake in tropical regions. North of 30° N, increasing temperatures induce a substantial extension of 0.22 day a-1 for the growing season; however, this phenological change alone does not promote regional carbon uptake and BVOC emissions. Nevertheless, increases of leaf area index at peak season accounts for ~ 25 % of the trends in GPP and isoprene emissions at the northern lands. The net land sink shows statistically insignificant increases of only 3 Tg C a-2 globally because of simultaneous increases in soil respiration. Global BVOC emissions are calculated using two schemes. With the photosynthesis-dependent scheme, the model predicts increases of 0.4 Tg C a-2 in isoprene emissions, which are mainly attributed to warming trends because CO2 fertilization and inhibition effects offset each other. Using the MEGAN (Model of Emissions of Gases and Aerosols from Nature) scheme, the YIBs model simulates global reductions of 1.1 Tg C a-2 in isoprene and 0.04 Tg C a-2 in monoterpene emissions in response to the CO2 inhibition effects. Land use

Using land to mitigate climate change: hitting the target, recognizing the trade-offs.

Science.gov (United States)

Reilly, John; Melillo, Jerry; Cai, Yongxia; Kicklighter, David; Gurgel, Angelo; Paltsev, Sergey; Cronin, Timothy; Sokolov, Andrei; Schlosser, Adam

2012-06-05

Land can be used in several ways to mitigate climate change, but especially under changing environmental conditions there may be implications for food prices. Using an integrated global system model, we explore the roles that these land-use options can play in a global mitigation strategy to stabilize Earth's average temperature within 2 °C of the preindustrial level and their impacts on agriculture. We show that an ambitious global Energy-Only climate policy that includes biofuels would likely not achieve the 2 °C target. A thought-experiment where the world ideally prices land carbon fluxes combined with biofuels (Energy+Land policy) gets the world much closer. Land could become a large net carbon sink of about 178 Pg C over the 21st century with price incentives in the Energy+Land scenario. With land carbon pricing but without biofuels (a No-Biofuel scenario) the carbon sink is nearly identical to the case with biofuels, but emissions from energy are somewhat higher, thereby results in more warming. Absent such incentives, land is either a much smaller net carbon sink (+37 Pg C - Energy-Only policy) or a net source (-21 Pg C - No-Policy). The significant trade-off with this integrated land-use approach is that prices for agricultural products rise substantially because of mitigation costs borne by the sector and higher land prices. Share of income spent on food for wealthier regions continues to fall, but for the poorest regions, higher food prices lead to a rising share of income spent on food.

Carbon dioxide emissions from forestry and peat land using land-use/land-cover changes in North Sumatra, Indonesia

Science.gov (United States)

Basyuni, M.; Sulistyono, N.; Slamet, B.; Wati, R.

2018-03-01

Forestry and peat land including land-based is one of the critical sectors in the inventory of CO2 emissions and mitigation efforts of climate change. The present study analyzed the land-use and land-cover changes between 2006 and 2012 in North Sumatra, Indonesia with emphasis to CO2 emissions. The land-use/land-cover consists of twenty-one classes. Redd Abacus software version 1.1.7 was used to measure carbon emission source as well as the predicted 2carbon dioxide emissions from 2006-2024. Results showed that historical emission (2006-2012) in this province, significant increases in the intensive land use namely dry land agriculture (109.65%), paddy field (16.23%) and estate plantation (15.11%). On the other hand, land-cover for forest decreased significantly: secondary dry land forest (7.60%), secondary mangrove forest (9.03%), secondary swamp forest (33.98%), and the largest one in the mixed dry land agriculture (79.96%). The results indicated that North Sumatra province is still a CO2 emitter, and the most important driver of emissions mostly derived from agricultural lands that contributed 2carbon dioxide emissions by 48.8%, changing from forest areas into degraded lands (classified as barren land and shrub) shared 30.6% and estate plantation of 22.4%. Mitigation actions to reduce carbon emissions was proposed such as strengthening the forest land, rehabilitation of degraded area, development and plantation forest, forest protection and forest fire control, and reforestation and conservation activity. These mitigation actions have been simulated to reduce 15% for forestry and 18% for peat land, respectively. This data is likely to contribute to the low emission development in North Sumatra.

Tropical forests are a net carbon source based on aboveground measurements of gain and loss

Science.gov (United States)

Baccini, A.; Walker, W.; Carvalho, L.; Farina, M.; Sulla-Menashe, D.; Houghton, R. A.

2017-10-01

The carbon balance of tropical ecosystems remains uncertain, with top-down atmospheric studies suggesting an overall sink and bottom-up ecological approaches indicating a modest net source. Here we use 12 years (2003 to 2014) of MODIS pantropical satellite data to quantify net annual changes in the aboveground carbon density of tropical woody live vegetation, providing direct, measurement-based evidence that the world’s tropical forests are a net carbon source of 425.2 ± 92.0 teragrams of carbon per year (Tg C year-1). This net release of carbon consists of losses of 861.7 ± 80.2 Tg C year-1 and gains of 436.5 ± 31.0 Tg C year-1. Gains result from forest growth; losses result from deforestation and from reductions in carbon density within standing forests (degradation or disturbance), with the latter accounting for 68.9% of overall losses.

Unraveling net carbon exchange into its component processes of photosynthesis and respiration

Science.gov (United States)

Ballantyne, A.

2017-12-01

The recent `warming hiatus' presents an excellent opportunity to investigate climate sensitivity of carbon cycle processes. Herewe combine satellite and atmospheric observations to show that the rate of net biome productivity (NBP) has significantlyaccelerated from 0.007+/-0.065 PgC yr-2 over the warming period (1982 to 1998) to 0.119+/-0.071 PgC yr-2 over thewarminghiatus (1998-2012). This acceleration in NBP is not due to increased primary productivity, but rather reduced respiration thatis correlated (r2 0.58; P = 0.0007) and sensitive ( gamma= 4.05 to 9.40 PgC yr-1 per deg C) to land temperatures. Global landmodels do not fully capture this apparent reduced respiration over the warming hiatus; however, an empirical model includingsoil temperature and moisture observations seems to better captures the reduced respiration.

Carbon stewardship: land management decisions and the potential for carbon sequestration in Colorado, USA

International Nuclear Information System (INIS)

Failey, Elisabeth L; Dilling, Lisa

2010-01-01

Land use and its role in reducing greenhouse gases is a key element of policy negotiations to address climate change. Calculations of the potential for enhanced terrestrial sequestration have largely focused on the technical characteristics of carbon stocks, such as vegetation type and management regime, and to some degree, on economic incentives. However, the actual potential for carbon sequestration critically depends on who owns the land and additional land management decision drivers. US land ownership patterns are complex, and consequently land use decision making is driven by a variety of economic, social and policy incentives. These patterns and incentives make up the 'carbon stewardship landscape'-that is, the decision making context for carbon sequestration. We examine the carbon stewardship landscape in the US state of Colorado across several public and private ownership categories. Achieving the full potential for land use management to help mitigate carbon emissions requires not only technical feasibility and financial incentives, but also effective implementing mechanisms within a suite of often conflicting and hard to quantify factors such as multiple-use mandates, historical precedents, and non-monetary decision drivers.

Distinguishing the drivers of trends in land carbon fluxes and plant volatile emissions over the past three decades

Science.gov (United States)

Yue, X.; Unger, N.; Zheng, Y.

2015-08-01

The terrestrial biosphere has experienced dramatic changes in recent decades. Estimates of historical trends in land carbon fluxes remain uncertain because long-term observations are limited on the global scale. Here, we use the Yale Interactive terrestrial Biosphere (YIBs) model to estimate decadal trends in land carbon fluxes and emissions of biogenic volatile organic compounds (BVOCs) and to identify the key drivers for these changes during 1982-2011. Driven with hourly meteorology from WFDEI (WATCH Forcing Data methodology applied to ERA-Interim data), the model simulates an increasing trend of 297 Tg C a-2 in gross primary productivity (GPP) and 185 Tg C a-2 in the net primary productivity (NPP). CO2 fertilization is the main driver for the flux changes in forest ecosystems, while meteorology dominates the changes in grasslands and shrublands. Warming boosts summer GPP and NPP at high latitudes, while drought dampens carbon uptake in tropical regions. North of 30° N, increasing temperatures induce a substantial extension of 0.22 day a-1 for the growing season; however, this phenological change alone does not promote regional carbon uptake and BVOC emissions. Nevertheless, increases of LAI at peak season accounts for ~ 25 % of the trends in GPP and isoprene emissions at the northern lands. The net land sink shows statistically insignificant increases of only 3 Tg C a-2 globally because of simultaneous increases in soil respiration. In contrast, driven with alternative meteorology from MERRA (Modern Era-Retrospective Analysis), the model predicts significant increases of 59 Tg C a-2 in the land sink due to strengthened uptake in the Amazon. Global BVOC emissions are calculated using two schemes. With the photosynthesis-dependent scheme, the model predicts increases of 0.4 Tg C a-2 in isoprene emissions, which are mainly attributed to warming trends because CO2 fertilization and inhibition effects offset each other. Using the MEGAN (Model of Emissions of Gases

Land Use Effects on Net Greenhouse Gas Fluxes in the US Great Plains: Historical Trends and Model Projections

Science.gov (United States)

Del Grosso, S. J.; Parton, W. J.; Ojima, D. S.; Mosier, A. R.; Mosier, A. R.; Paustian, K.; Peterson, G. A.

2001-12-01

We present maps showing regional patterns of land use change and soil C levels in the US Great Plains during the 20th century and time series of net greenhouse gas fluxes associated with different land uses. Net greenhouse gas fluxes were calculated by accounting for soil CO2 fluxes, the CO2 equivalents of N2O emissions and CH4 uptake, and the CO2 costs of N fertilizer production. Both historical and modern agriculture in this region have been net sources of greenhouse gases. The primary reason for this, prior to 1950, is that agriculture mined soil C and resulted in net CO2 emissions. When chemical N fertilizer became widely used in the 1950's agricultural soils began to sequester CO2-C but these soils were still net greenhouse gas sources if the effects of increased N2O emissions and decreased CH4 uptake are included. The sensitivity of net greenhouse gas fluxes to conventional and alternative land uses was explored using the DAYCENT ecosystem model. Model projections suggest that conversion to no-till, reduction of the fallow period, and use of nitrification inhibitors can significantly decrease net greenhouse gas emissions in dryland and irrigated systems, while maintaining or increasing crop yields.

International trade causes large net economic losses in tropical countries via the destruction of ecosystem services.

Science.gov (United States)

Chang, Junning; Symes, William S; Lim, Felix; Carrasco, L Roman

2016-05-01

Despite the large implications of the use of tropical land for exports ("land absorption") on ecosystem services (ES) and global biodiversity conservation, the magnitude of these externalities is not known. We quantify the net value of ES lost in tropical countries as a result of cropland, forestland and pastureland absorption for exports after deducting ES gains through imports ("land displacement"). We find that net ES gains occur only in 7 out of the 41 countries and regions considered. We estimate global annual net losses of over 1.7 x 10(12) international dollars (I$) (I$1.1 x 10(12) if carbon-related services are not considered). After deducting the benefits from agricultural, forest and livestock rents in land replacing tropical forests, the net annual losses are I$1.3 and I$0.7 x 10(12), respectively. The results highlight the large magnitude of tropical ES losses through international trade that are not compensated by the rents of land uses in absorbed land.

Net carbon exchange across the Arctic tundra-boreal forest transition in Alaska 1981-2000

Science.gov (United States)

Thompson, Catharine Copass; McGuire, A.D.; Clein, Joy S.; Chapin, F. S.; Beringer, J.

2006-01-01

Shifts in the carbon balance of high-latitude ecosystems could result from differential responses of vegetation and soil processes to changing moisture and temperature regimes and to a lengthening of the growing season. Although shrub expansion and northward movement of treeline should increase carbon inputs, the effects of these vegetation changes on net carbon exchange have not been evaluated. We selected low shrub, tall shrub, and forest tundra sites near treeline in northwestern Alaska, representing the major structural transitions expected in response to warming. In these sites, we measured aboveground net primary production (ANPP) and vegetation and soil carbon and nitrogen pools, and used these data to parameterize the Terrestrial Ecosystem Model. We simulated the response of carbon balance components to air temperature and precipitation trends during 1981-2000. In areas experiencing warmer and dryer conditions, Net Primary Production (NPP) decreased and heterotrophic respiration (R H ) increased, leading to a decrease in Net Ecosystem Production (NEP). In warmer and wetter conditions NPP increased, but the response was exceeded by an increase in R H ; therefore, NEP also decreased. Lastly, in colder and wetter regions, the increase in NPP exceeded a small decline in R H , leading to an increase in NEP. The net effect for the region was a slight gain in ecosystem carbon storage over the 20 year period. This research highlights the potential importance of spatial variability in ecosystem responses to climate change in assessing the response of carbon storage in northern Alaska over the last two decades. ?? Springer 2005.

Emissions from land use change and forestry

International Nuclear Information System (INIS)

Ochanda, N.

1998-01-01

This inventory focuses on net input of carbon dioxide into the atmosphere as a result of land use change and forestry. The report shows the importance of dynamics of the afforestation and defforestation processes in determining the presence of carbon dioxide in the air

Tropical forests are a net carbon source based on aboveground measurements of gain and loss.

Science.gov (United States)

Baccini, A; Walker, W; Carvalho, L; Farina, M; Sulla-Menashe, D; Houghton, R A

2017-10-13

The carbon balance of tropical ecosystems remains uncertain, with top-down atmospheric studies suggesting an overall sink and bottom-up ecological approaches indicating a modest net source. Here we use 12 years (2003 to 2014) of MODIS pantropical satellite data to quantify net annual changes in the aboveground carbon density of tropical woody live vegetation, providing direct, measurement-based evidence that the world's tropical forests are a net carbon source of 425.2 ± 92.0 teragrams of carbon per year (Tg C year -1 ). This net release of carbon consists of losses of 861.7 ± 80.2 Tg C year -1 and gains of 436.5 ± 31.0 Tg C year -1 Gains result from forest growth; losses result from deforestation and from reductions in carbon density within standing forests (degradation or disturbance), with the latter accounting for 68.9% of overall losses. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Land, carbon and water footprints in Taiwan

International Nuclear Information System (INIS)

Lee, Yung-Jaan

2015-01-01

The consumer responsibility approach uses footprints as indicators of the total direct and indirect effects of a product or consumption activity. This study used a time-series analysis of three environmental pressures to quantify the total environmental pressures caused by consumption in Taiwan: land footprint, carbon footprint, and water footprint. Land footprint is the pressure from appropriation of biologically productive land and water area. Carbon footprint is the pressure from greenhouse gas emissions. Water footprint is the pressure from freshwater consumption. Conventional carbon footprint is the total CO 2 emitted by a certain activity or the CO 2 accumulation during a product life cycle. This definition cannot be used to convert CO 2 emissions into land units. This study responds to the needs of “CO 2 land” in the footprint family by applying the carbon footprint concept used by GFN. The analytical results showed that consumption by the average Taiwan citizen in 2000 required appropriation of 5.39 gha (hectares of land with global-average biological productivity) and 3.63 gha in 2011 in terms of land footprint. The average Taiwan citizen had a carbon footprint of 3.95 gha in 2000 and 5.94 gha in 2011. These results indicate that separately analyzing the land and carbon footprints enables their trends to be compared and appropriate policies and strategies for different sectors to be proposed accordingly. The average Taiwan citizen had a blue water footprint of 801 m 3 in 2000 and 784 m 3 in 2011. By comparison, their respective global averages were 1.23 gha, 2.36 gha and 163 m 3 blue water in 2011, respectively. Overall, Taiwan revealed higher environmental pressures compared to the rest of the world, demonstrating that Taiwan has become a high footprint state and has appropriated environmental resources from other countries. That is, through its imports of products with embodied pressures and its exports, Taiwan has transferred the environmental

Land, carbon and water footprints in Taiwan

Energy Technology Data Exchange (ETDEWEB)

Lee, Yung-Jaan, E-mail: yungjaanlee@gmail.com

2015-09-15

The consumer responsibility approach uses footprints as indicators of the total direct and indirect effects of a product or consumption activity. This study used a time-series analysis of three environmental pressures to quantify the total environmental pressures caused by consumption in Taiwan: land footprint, carbon footprint, and water footprint. Land footprint is the pressure from appropriation of biologically productive land and water area. Carbon footprint is the pressure from greenhouse gas emissions. Water footprint is the pressure from freshwater consumption. Conventional carbon footprint is the total CO{sub 2} emitted by a certain activity or the CO{sub 2} accumulation during a product life cycle. This definition cannot be used to convert CO{sub 2} emissions into land units. This study responds to the needs of “CO{sub 2} land” in the footprint family by applying the carbon footprint concept used by GFN. The analytical results showed that consumption by the average Taiwan citizen in 2000 required appropriation of 5.39 gha (hectares of land with global-average biological productivity) and 3.63 gha in 2011 in terms of land footprint. The average Taiwan citizen had a carbon footprint of 3.95 gha in 2000 and 5.94 gha in 2011. These results indicate that separately analyzing the land and carbon footprints enables their trends to be compared and appropriate policies and strategies for different sectors to be proposed accordingly. The average Taiwan citizen had a blue water footprint of 801 m{sup 3} in 2000 and 784 m{sup 3} in 2011. By comparison, their respective global averages were 1.23 gha, 2.36 gha and 163 m{sup 3} blue water in 2011, respectively. Overall, Taiwan revealed higher environmental pressures compared to the rest of the world, demonstrating that Taiwan has become a high footprint state and has appropriated environmental resources from other countries. That is, through its imports of products with embodied pressures and its exports, Taiwan has

Ten years of multiple data stream assimilation with the ORCHIDEE land surface model to improve regional to global simulated carbon budgets: synthesis and perspectives on directions for the future

Science.gov (United States)

Peylin, P. P.; Bacour, C.; MacBean, N.; Maignan, F.; Bastrikov, V.; Chevallier, F.

2017-12-01

Predicting the fate of carbon stocks and their sensitivity to climate change and land use/management strongly relies on our ability to accurately model net and gross carbon fluxes. However, simulated carbon and water fluxes remain subject to large uncertainties, partly because of unknown or poorly calibrated parameters. Over the past ten years, the carbon cycle data assimilation system at the Laboratoire des Sciences du Climat et de l'Environnement has investigated the benefit of assimilating multiple carbon cycle data streams into the ORCHIDEE LSM, the land surface component of the Institut Pierre Simon Laplace Earth System Model. These datasets have included FLUXNET eddy covariance data (net CO2 flux and latent heat flux) to constrain hourly to seasonal time-scale carbon cycle processes, remote sensing of the vegetation activity (MODIS NDVI) to constrain the leaf phenology, biomass data to constrain "slow" (yearly to decadal) processes of carbon allocation, and atmospheric CO2 concentrations to provide overall large scale constraints on the land carbon sink. Furthermore, we have investigated technical issues related to multiple data stream assimilation and choice of optimization algorithm. This has provided a wide-ranging perspective on the challenges we face in constraining model parameters and thus better quantifying, and reducing, model uncertainty in projections of the future global carbon sink. We review our past studies in terms of the impact of the optimization on key characteristics of the carbon cycle, e.g. the partition of the northern latitudes vs tropical land carbon sink, and compare to the classic atmospheric flux inversion approach. Throughout, we discuss our work in context of the abovementioned challenges, and propose solutions for the community going forward, including the potential of new observations such as atmospheric COS concentrations and satellite-derived Solar Induced Fluorescence to constrain the gross carbon fluxes of the ORCHIDEE

ENHANCEMENT OF TERRESTRIAL CARBON SINKS THROUGH RECLAMATION OF ABANDONED MINE LANDS IN THE APPALACHIAN REGION

Energy Technology Data Exchange (ETDEWEB)

Gary D. Kronrad

2002-12-01

The U.S.D.I. Office of Surface Mining (OSM) estimates that there are approximately 1 million acres of abandoned mine land (AML) in the Appalachian region. AML lands are classified as areas that were inadequately reclaimed or were left unreclaimed prior to the passage of the 1977 Surface Mining Control and Reclamation Act, and where no federal or state laws require any further reclamation responsibility to any company or individual. Reclamation and afforestation of these sites have the potential to provide landowners with cyclical timber revenues, generate environmental benefits to surrounding communities, and sequester carbon in the terrestrial ecosystem. Through a memorandum of understanding, the OSM and the U.S. Department of Energy (DOE) have decided to investigate reclaiming and afforesting these lands for the purpose of mitigating the negative effects of anthropogenic carbon dioxide in the atmosphere. This study determined the carbon sequestration potential of northern red oak (Quercus rubra L.), one of the major reclamation as well as commercial species, planted on West Virginia AML sites. Analyses were conducted to (1) calculate the total number of tons that can be stored, (2) determine the cost per ton to store carbon, and (3) calculate the profitability of managing these forests for timber production alone and for timber production and carbon storage together. The Forest Management Optimizer (FORMOP) was used to simulate growth data on diameter, height, and volume for northern red oak. Variables used in this study included site indices ranging from 40 to 80 (base age 50), thinning frequencies of 0, 1, and 2, thinning percentages of 20, 25, 30, 35, and 40, and a maximum rotation length of 100 years. Real alternative rates of return (ARR) ranging from 0.5% to 12.5% were chosen for the economic analyses. A total of 769,248 thinning and harvesting combinations, net present worths, and soil expectation values were calculated in this study. Results indicate that

Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity.

Science.gov (United States)

Li, Xi; Toma, Yo; Yeluripati, Jagadeesh; Iwasaki, Shinya; Bellingrath-Kimura, Sonoko D; Jones, Edward O; Hatano, Ryusuke

2016-06-01

Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959-2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from -1.26MgCha(-1)yr(-1) in 1959-0.26 Mg Cha(-1)yr(-1) in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959-2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. Copyright © 2016 Elsevier B.V. All rights reserved.

Integrating livestock manure with a corn-soybean bioenergy cropping system improves short-term carbon sequestration rates and net global warming potential

International Nuclear Information System (INIS)

Thelen, K.D.; Fronning, B.E.; Kravchenko, A.; Min, D.H.; Robertson, G.P.

2010-01-01

Carbon cycling and the global warming potential (GWP) of bioenergy cropping systems with complete biomass removal are of agronomic and environmental concern. Corn growers who plan to remove corn stover as a feedstock for the emerging cellulosic ethanol industry will benefit from carbon amendments such as manure and compost, to replace carbon removed with the corn stover. The objective of this research was to determine the effect of beef cattle feedlot manure and composted dairy manure on short-term carbon sequestration rates and net global warming potential (GWP) in a corn-soybean rotation with complete corn-stover removal. Field experiments consisting of a corn-soybean rotation with whole-plant corn harvest, were conducted near East Lansing, MI over a three-year period beginning in 2002. Compost and manure amendments raised soil carbon (C) at a level sufficient to overcome the C debt associated with manure production, manure collection and storage, land application, and post-application field emissions. The net GWP in carbon dioxide equivalents for the manure and compost amended cropping systems was -934 and -784 g m -2 y -1 , respectively, compared to 52 g m -2 y -1 for the non-manure amended synthetic fertilizer check. This work further substantiates the environmental benefits associated with renewable fuels and demonstrates that with proper management, the integration of livestock manures in biofuel cropping systems can enhance greenhouse gas (GHG) remediation.

A Preliminary Study of the Carbon Emissions Reduction Effects of Land Use Control.

Science.gov (United States)

Chuai, Xiaowei; Huang, Xianjin; Qi, Xinxian; Li, Jiasheng; Zuo, Tianhui; Lu, Qinli; Li, Jianbao; Wu, Changyan; Zhao, Rongqin

2016-11-15

Land use change not only directly influences carbon storage in terrestrial ecosystems but can also cause energy-related carbon emissions. This study examined spatiotemporal land use change across Jiangsu Province, China; calculated vegetation carbon storage loss caused by land use change and energy-related carbon emissions; analysed the relationship among land use change, carbon emissions and social-economic development; and optimized land use structure to maximize carbon storage. Our study found that 13.61% of the province's land area underwent a change in type of land use between 1995 and 2010, mainly presented as built-up land expansion and cropland shrinkage, especially in southern Jiangsu. Land use change caused a 353.99 × 10 4 t loss of vegetation carbon storage loss. Energy-related carbon emissions increased 2.5 times from 1995 to 2013; the energy consumption structure has been improved to some extent while still relying on coal. The selected social-economic driving forces have strong relationships with carbon emissions and land use changes, while there are also other determinants driving land use change, such as land use policy. The optimized land use structure will slow the rate of decline in vegetation carbon storage compared with the period between 1995 and 2010 and will also reduce energy-related carbon emissions by 12%.

Simulating the effect of land use and climate change on upland soil carbon stock of Wales using ECOSSE

Science.gov (United States)

Rani Nayak, Dali; Gottschalk, Pia; Evans, Chris; Smith, Pete; Smith, Jo

2010-05-01

Within Wales soils hold between 400-500 MtC, over half of this carbon is stored in organic and organo-mineral soil which cover less than 20% of the land area of Wales. It has been predicted that climate change will increasingly have an impact on the C stock of soils in Wales. Higher temperatures will increase the rate of decomposition of organic matter, leading to increased C losses. However increased net primary production (NPP), leading to increased inputs of organic matter, may offset this. Land use plays a major role in determining the level of soil C and the direction of change in status (soil as a source or sink). We present here an assessment of the effect of land use change and climate change on the upland soil carbon stock of Wales in 3 different catchments i.e. Migneint, Plynlimon and Pontbren using a process-based model of soil carbon and nitrogen dynamics, ECOSSE. The uncertainties introduced in the simulations by using only the data available at national scale are determined. The ECOSSE model (1,2) has been developed to simulate greenhouse gas emissions from both organic and mineral soils. ECOSSE was derived from RothC (3) and SUNDIAL (4,5) and predicts the impacts of changes in land use and climate on emissions and soil carbon stock. Simulated changes in soil C are dependent on the type of land use change, the soil type where the land use change is occurring, and the C content of soil under the initial and final land uses. At Migneint and Plynlimon, the major part of the losses occurs due to the conversion of semi-natural land to grassland. Reducing the land use change from semi-natural to grassland is the main measure needed to mitigate losses of soil C. At Pontbren, the model predicts a net gain in soil C with the predicted land use change, so there is no need to mitigate. Simulations of future changes in soil C to 2050 showed very small changes in soil C due to climate compared to changes due to land use change. At the selected catchments, changes

Spatiotemporal Variability of Carbon Flux from Different Land Use and Land Cover Changes: A Case Study in Hubei Province, China

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Li Gao

2014-04-01

Full Text Available Carbon sources and sinks as a result of land use and land cover changes (LUCC are significant for global climate change. This paper aims to identify and analyze the temporal and spatial changes of land use-based carbon emission in the Hubei Province in China. We use a carbon emission coefficient to calculate carbon emissions in different land use patterns in Hubei Province from 1998 to 2009. The results indicate that regional land use is facing tremendous pressure from rapid carbon emission growth. Source:sink ratios and average carbon emission intensity values of urban land are increasing, while slow-growing carbon sinks fail to offset the rapidly expanding carbon sources. Overall, urban land carbon emissions have a strong correlation with the total carbon emissions, and will continue to increase in the future mainly due to the surge of industrialization and urbanization. Furthermore, carbon emission in regions with more developed industrial structures is much higher than in regions with less advanced industrial structures. Lastly, carbon emission per unit of GDP has declined since 2004, indicating that a series of reform measures i.e., economic growth mode transformation and land-use structure optimization, has initiated the process of carbon emission reduction.

The impacts of tropical cyclones on the net carbon balance of eastern US forests (1851-2000)

Science.gov (United States)

Fisk, J. P.; Hurtt, G. C.; Chambers, J. Q.; Zeng, H.; Dolan, K. A.; Negrón-Juárez, R. I.

2013-12-01

In temperate forests of the eastern US, tropical cyclones are a principal agent of catastrophic wind damage, with dramatic impacts on the structure and functioning of forests. Substantial progress has been made to quantify forest damage and resulting gross carbon emissions from tropical cyclones. However, the net effect of storms on the carbon balance of forests depends not only on the biomass lost in single events, but also on the uptake during recovery from a mosaic of past events. This study estimates the net impacts of tropical cyclones on the carbon balance of US forests over the period 1851-2000. To track both disturbance and recovery and to isolate the effects of storms, a modeling framework is used combining gridded historical estimates of mortality and damage with a mechanistic model using an ensemble approach. The net effect of tropical cyclones on the carbon balance is shown to depend strongly on the spatial and temporal scales of analysis. On average, tropical cyclones contribute a net carbon source over latter half of the 19th century. However, throughout much of the 20th century a regional carbon sink is estimated resulting from periods of forest recovery exceeding damage. The large-scale net annual flux resulting from tropical cyclones varies by up to 50 Tg C yr-1, an amount equivalent to 17%-36% of the US forest carbon sink.

A semi-analytical solution to accelerate spin-up of a coupled carbon and nitrogen land model to steady state

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J. Y. Xia

2012-10-01

Full Text Available The spin-up of land models to steady state of coupled carbon–nitrogen processes is computationally so costly that it becomes a bottleneck issue for global analysis. In this study, we introduced a semi-analytical solution (SAS for the spin-up issue. SAS is fundamentally based on the analytic solution to a set of equations that describe carbon transfers within ecosystems over time. SAS is implemented by three steps: (1 having an initial spin-up with prior pool-size values until net primary productivity (NPP reaches stabilization, (2 calculating quasi-steady-state pool sizes by letting fluxes of the equations equal zero, and (3 having a final spin-up to meet the criterion of steady state. Step 2 is enabled by averaged time-varying variables over one period of repeated driving forcings. SAS was applied to both site-level and global scale spin-up of the Australian Community Atmosphere Biosphere Land Exchange (CABLE model. For the carbon-cycle-only simulations, SAS saved 95.7% and 92.4% of computational time for site-level and global spin-up, respectively, in comparison with the traditional method (a long-term iterative simulation to achieve the steady states of variables. For the carbon–nitrogen coupled simulations, SAS reduced computational cost by 84.5% and 86.6% for site-level and global spin-up, respectively. The estimated steady-state pool sizes represent the ecosystem carbon storage capacity, which was 12.1 kg C m⁻² with the coupled carbon–nitrogen global model, 14.6% lower than that with the carbon-only model. The nitrogen down-regulation in modeled carbon storage is partly due to the 4.6% decrease in carbon influx (i.e., net primary productivity and partly due to the 10.5% reduction in residence times. This steady-state analysis accelerated by the SAS method can facilitate comparative studies of structural differences in determining the ecosystem carbon storage capacity among biogeochemical models. Overall, the

Integrating livestock manure with a corn-soybean bioenergy cropping system improves short-term carbon sequestration rates and net global warming potential

Energy Technology Data Exchange (ETDEWEB)

Thelen, K.D.; Fronning, B.E.; Kravchenko, A.; Min, D.H.; Robertson, G.P. [Michigan State University, East Lansing, MI 48824 (United States)

2010-07-15

Carbon cycling and the global warming potential (GWP) of bioenergy cropping systems with complete biomass removal are of agronomic and environmental concern. Corn growers who plan to remove corn stover as a feedstock for the emerging cellulosic ethanol industry will benefit from carbon amendments such as manure and compost, to replace carbon removed with the corn stover. The objective of this research was to determine the effect of beef cattle feedlot manure and composted dairy manure on short-term carbon sequestration rates and net global warming potential (GWP) in a corn-soybean rotation with complete corn-stover removal. Field experiments consisting of a corn-soybean rotation with whole-plant corn harvest, were conducted near East Lansing, MI over a three-year period beginning in 2002. Compost and manure amendments raised soil carbon (C) at a level sufficient to overcome the C debt associated with manure production, manure collection and storage, land application, and post-application field emissions. The net GWP in carbon dioxide equivalents for the manure and compost amended cropping systems was -934 and -784 g m{sup -2} y{sup -1}, respectively, compared to 52 g m{sup -2} y{sup -1} for the non-manure amended synthetic fertilizer check. This work further substantiates the environmental benefits associated with renewable fuels and demonstrates that with proper management, the integration of livestock manures in biofuel cropping systems can enhance greenhouse gas (GHG) remediation. (author)

Simulated carbon emissions from land-use change are substantially enhanced by accounting for agricultural management

International Nuclear Information System (INIS)

Pugh, T A M; Arneth, A; Bayer, A D; Olin, S; Lindeskog, M; Schurgers, G; Ahlström, A; Klein Goldewijk, K

2015-01-01

It is over three decades since a large terrestrial carbon sink (S T ) was first reported. The magnitude of the net sink is now relatively well known, and its importance for dampening atmospheric CO 2 accumulation, and hence climate change, widely recognised. But the contributions of underlying processes are not well defined, particularly the role of emissions from land-use change (E LUC ) versus the biospheric carbon uptake (S L ; S T  = S L  − E LUC ). One key aspect of the interplay of E LUC and S L is the role of agricultural processes in land-use change emissions, which has not yet been clearly quantified at the global scale. Here we assess the effect of representing agricultural land management in a dynamic global vegetation model. Accounting for harvest, grazing and tillage resulted in cumulative E LUC since 1850 ca. 70% larger than in simulations ignoring these processes, but also changed the timescale over which these emissions occurred and led to underestimations of the carbon sequestered by possible future reforestation actions. The vast majority of Earth system models in the recent IPCC Fifth Assessment Report omit these processes, suggesting either an overestimation in their present-day S T , or an underestimation of S L , of up to 1.0 Pg C a −1 . Management processes influencing crop productivity per se are important for food supply, but were found to have little influence on E LUC . (letter)

Importance of soil thermal dynamics on land carbon sequestration in Northern Eurasia during the 21st century

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Kicklighter, David; Monier, Erwan; Sokolov, Andrei; Zhuang, Qianlai; Melillo, Jerry

2015-04-01

Recent modeling studies have suggested that carbon sinks in pan-arctic ecosystems may be weakening partially as a result of warming-induced increases in soil organic matter (SOM) decomposition and the exposure of previously frozen SOM to decomposition. This weakening of carbon sinks is likely to continue in the future as vast amount of carbon in permafrost soils is vulnerable to thaw. Here, we examine the importance of considering soil thermal dynamics when determining the effects of climate change and land-use change on carbon dynamics in Northern Eurasia during the 21st century. This importance is assessed by comparing results for a "business as usual" scenario between a version of the Terrestrial Ecosystem Model that does not consider soil thermal dynamics (TEM 4.4) and a version that does consider these dynamics (TEM 6.0). In this scenario, which is similar to the IPCC Representative Concentration Pathways (RCP) 8.5 scenario, the net area covered by food crops and pastures in Northern Eurasia is assumed to remain relatively constant over the 21st century, but the area covered by secondary forests is projected to double as a result of timber harvest and the abandonment of land associated with displacement of agricultural land. Enhanced decomposition from the newly exposed SOM from permafrost thaw also increases nitrogen availability for plant production so that the loss of carbon from the enhanced decomposition is partially compensated by enhanced uptake and storage of atmospheric carbon dioxide in vegetation. Our results indicate that consideration of soil thermal dynamics have a large influence on how simulated terrestrial carbon dynamics in Northern Eurasia respond to changes in climate, atmospheric chemistry (e.g., carbon dioxide fertilization, ozone pollution, nitrogen deposition) and disturbances.

Pathways to Carbon-Negative Liquid Biofuels

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Woolf, D.; Lehmann, J.

2017-12-01

Many climate change mitigation scenarios assume that atmospheric carbon dioxide removal will be delivered at scale using bioenergy power generation with carbon capture and storage (BECCS). However, other pathways to negative emission technologies (NETs) in the energy sector are possible, but have received relatively little attention. Given that the costs, benefits and life-cycle emissions of technologies vary widely, more comprehensive analyses of the policy options for NETs are critical. This study provides a comparative assessment of the potential pathways to carbon-negative liquid biofuels. It is often assumed that that decarbonisation of the transport sector will include use of liquid biofuels, particularly for applications that are difficult to electrify such as aviation and maritime transport. However, given that biomass and land on which to grow it sustainably are limiting factors in the scaling up of both biofuels and NETs, these two strategies compete for shared factors of production. One way to circumvent this competition is carbon-negative biofuels. Because capture of exhaust CO2 in the transport sector is impractical, this will likely require carbon capture during biofuel production. Potential pathways include, for example, capture of CO2 from fermentation, or sequestration of biochar from biomass pyrolysis in soils, in combination with thermochemical or bio-catalytic conversion of syngas to alcohols or alkanes. Here we show that optimal pathway selection depends on specific resource constraints. As land availability becomes increasingly limiting if bioenergy is scaled up—particularly in consideration that abandoned degraded land is widely considered to be an important resource that does not compete with food fiber or habitat—then systems which enhance land productivity by increasing soil fertility using soil carbon sequestration become increasingly preferable compared to bioenergy systems that deplete or degrade the land resource on which they

Comparisons of a Quantum Annealing and Classical Computer Neural Net Approach for Inferring Global Annual CO2 Fluxes over Land

Science.gov (United States)

Halem, M.; Radov, A.; Singh, D.

2017-12-01

Investigations of mid to high latitude atmospheric CO2 show growing amplitudes in seasonal variations over the past several decades. Recent high-resolution satellite measurements of CO2 concentration are now available for three years from the Orbiting Carbon Observatory-2. The Atmospheric Radiation Measurement (ARM) program of DOE has been making long-term CO2-flux measurements (in addition to CO2 concentration and an array of other meteorological quantities) at several towers and mobile sites located around the globe at half-hour frequencies. Recent papers have shown CO2 fluxes inferred by assimilating CO2 observations into ecosystem models are largely inconsistent with station observations. An investigation of how the biosphere has reacted to changes in atmospheric CO2 is essential to our understanding of potential climate-vegetation feedbacks. Thus, new approaches for calculating CO2-flux for assimilation into land surface models are necessary for improving the prediction of annual carbon uptake. In this study, we calculate and compare the predicted CO2 fluxes results employing a Feed Forward Backward Propagation Neural Network model on two architectures, (i) an IBM Minsky Computer node and (ii) a hybrid version of the ARC D-Wave quantum annealing computer. We compare the neural net results of predictions of CO2 flux from ARM station data for three different DOE ecosystem sites; an arid plains near Oklahoma City, a northern arctic site at Barrows AL, and a tropical rainforest site in the Amazon. Training times and predictive results for the calculating annual CO2 flux for the two architectures for each of the three sites are presented. Comparative results of predictions as measured by RMSE and MAE are discussed. Plots and correlations of observed vs predicted CO2 flux are also presented for all three sites. We show the estimated training times for quantum and classical calculations when extended to calculating global annual Carbon Uptake over land. We also

Spatial Patterns of Soil Organic Carbon in the United States

Science.gov (United States)

Bliss, N. B.

2005-12-01

The Department of the Interior (DOI) has jurisdiction influencing approximately 22 percent of the land area of the United States. The poster presents estimates of the current stocks of soil organic carbon (SOC) on all lands and Federal lands. The DOI lands have about 22 percent of the nation's SOC, so the average carbon intensity (8.66 kg C m-2) about matches the average for all lands (8.81 kg C m-2). However the carbon on DOI lands is not evenly distributed. Of the 17.76 Petagrams (1 Pg = 1015 grams) of SOC on DOI lands, 13.07 Pg (74 percent) are in Alaska, and 4.69 Pg (26 percent) are in the Conterminous U.S. The Alaska soils are wetter and colder than the national average, and the DOI lands in the conterminous U.S. are warmer and drier than the average. A set of SOC maps is shown, developed by intersecting the State Soil Geographic (STATSGO) database with data on federal lands from the National Atlas. With 22 percent of the nation's soil carbon, the DOI lands are important in a national accounting of greenhouse gas emission and sequestration. Future behavior of these lands is uncertain, but in scenarios of warming or drying, carbon released by respiration may exceed carbon captured by photosynthesis, resulting in a net release of carbon to the atmosphere. If warming stimulates a net release of greenhouse gases, this represents a positive feedback contributing to future global warming, a very unstable condition for the global climate system.

CMIP5 land surface models systematically underestimate inter-annual variability of net ecosystem exchange in semi-arid southwestern North America.

Science.gov (United States)

MacBean, N.; Scott, R. L.; Biederman, J. A.; Vuichard, N.; Hudson, A.; Barnes, M.; Fox, A. M.; Smith, W. K.; Peylin, P. P.; Maignan, F.; Moore, D. J.

2017-12-01

Recent studies based on analysis of atmospheric CO2 inversions, satellite data and terrestrial biosphere model simulations have suggested that semi-arid ecosystems play a dominant role in the interannual variability and long-term trend in the global carbon sink. These studies have largely cited the response of vegetation activity to changing moisture availability as the primary mechanism of variability. However, some land surface models (LSMs) used in these studies have performed poorly in comparison to satellite-based observations of vegetation dynamics in semi-arid regions. Further analysis is therefore needed to ensure semi-arid carbon cycle processes are well represented in global scale LSMs before we can fully establish their contribution to the global carbon cycle. In this study, we evaluated annual net ecosystem exchange (NEE) simulated by CMIP5 land surface models using observations from 20 Ameriflux sites across semi-arid southwestern North America. We found that CMIP5 models systematically underestimate the magnitude and sign of NEE inter-annual variability; therefore, the true role of semi-arid regions in the global carbon cycle may be even more important than previously thought. To diagnose the factors responsible for this bias, we used the ORCHIDEE LSM to test different climate forcing data, prescribed vegetation fractions and model structures. Climate and prescribed vegetation do contribute to uncertainty in annual NEE simulations, but the bias is primarily caused by incorrect timing and magnitude of peak gross carbon fluxes. Modifications to the hydrology scheme improved simulations of soil moisture in comparison to data. This in turn improved the seasonal cycle of carbon uptake due to a more realistic limitation on photosynthesis during water stress. However, the peak fluxes are still too low, and phenology is poorly represented for desert shrubs and grasses. We provide suggestions on model developments needed to tackle these issues in the future.

Divertor plate concept with carbon based armour for NET

International Nuclear Information System (INIS)

Moons, F.; Howard, R.; Kneringer, G.; Stickler, R.

1989-01-01

A series of tests has been performed on simulated divertor elements for NET at the JET neutral beam injector test bed. The test section consisted of a water cooled main structure, the surface of which was protected with a carbon based armour in the form of tiles. The scope of these was to study the thermal behaviour of mechanically attached tiles with the use of an intermediate soft carbon layer to improve the thermal contact under divertor relevant conditions. (author). 4 refs.; 4 figs.; 1 tab

Land use and land management effects on soil organic carbon stock in Mediterranean agricultural areas (Southern Spain)

Science.gov (United States)

Parras-Alcántara, Luis; Lozano-García, Beatriz

2014-05-01

INTRODUCTION Soils play a key role in the carbon geochemical cycle. Agriculture contributes to carbon sequestration through photosynthesis and the incorporation of carbon into carbohydrates. Soil management is one of the best tools for climate change mitigation. Small increases or decreases in soil carbon content due to changes in land use or management practices, may result in a significant net exchange of carbon between the soil carbon pool and the atmosphere. In the last decades arable crops (AC) have been transformed into olive grove cultivations (OG) or vineyards (V) in Mediterranean areas. A field study was conducted to determine long-term effects of land use change (LUC) (AC by OG and V) on soil organic carbon (SOC), total nitrogen (TN), C:N ratio and their stratification in Calcic-Chromic Luvisols (LVcc/cr) in Mediterranean conditions. MATERIAL AND METHODS An unirrigated farm in Montilla-Moriles (Córdoba, Spain) cultivated under conventional tillage (animal power with lightweight reversible plows and non-mineral fertilization or pesticides) was selected for study in 1965. In 1966, the farm was divided into three plots with three different uses (AC, OG and V). The preliminary analyses were realized in 1965 for AC (AC1), and the second analyses were realized in 2011 for AC (AC2 - winter crop rotation with annual wheat and barley, receiving mineral fertilization or pesticides), OG (annual passes with disk harrow and cultivator in the spring, followed by a tine harrow in the summer receiving mineral fertilization and weed control with residual herbicides), and V (with three or five chisel passes a year from early spring to early autumn with mineral fertilization or pesticides.). In all cases (AC1, AC2, OG and V) were collected soil entire profiles. Soil properties determined were: soil particle size, bulk density, SOC, TN, C:N ratio, stocks and SRs. The statistical significance of the differences in the variables between land use practices was tested using the

Ignoring detailed fast-changing dynamics of land use overestimates regional terrestrial carbon sequestration

Directory of Open Access Journals (Sweden)

S. Q. Zhao

2009-08-01

Full Text Available Land use change is critical in determining the distribution, magnitude and mechanisms of terrestrial carbon budgets at the local to global scales. To date, almost all regional to global carbon cycle studies are driven by a static land use map or land use change statistics with decadal time intervals. The biases in quantifying carbon exchange between the terrestrial ecosystems and the atmosphere caused by using such land use change information have not been investigated. Here, we used the General Ensemble biogeochemical Modeling System (GEMS, along with consistent and spatially explicit land use change scenarios with different intervals (1 yr, 5 yrs, 10 yrs and static, respectively, to evaluate the impacts of land use change data frequency on estimating regional carbon sequestration in the southeastern United States. Our results indicate that ignoring the detailed fast-changing dynamics of land use can lead to a significant overestimation of carbon uptake by the terrestrial ecosystem. Regional carbon sequestration increased from 0.27 to 0.69, 0.80 and 0.97 Mg C ha⁻¹ yr⁻¹ when land use change data frequency shifting from 1 year to 5 years, 10 years interval and static land use information, respectively. Carbon removal by forest harvesting and prolonged cumulative impacts of historical land use change on carbon cycle accounted for the differences in carbon sequestration between static and dynamic land use change scenarios. The results suggest that it is critical to incorporate the detailed dynamics of land use change into local to global carbon cycle studies. Otherwise, it is impossible to accurately quantify the geographic distributions, magnitudes, and mechanisms of terrestrial carbon sequestration at the local to global scales.

Full effects of land use change in the representative concentration pathways

International Nuclear Information System (INIS)

Davies-Barnard, T; Valdes, P J; Singarayer, J S; Pacifico, F M; Jones, C D

2014-01-01

Future land use change (LUC) is an important component of the IPCC representative concentration pathways (RCPs), but in these scenarios’ radiative forcing targets the climate impact of LUC only includes greenhouse gases. However, climate effects due to physical changes of the land surface can be as large. Here we show the critical importance of including non-carbon impacts of LUC when considering the RCPs. Using an ensemble of climate model simulations with and without LUC, we show that the net climate effect is very different from the carbon-only effect. Despite opposite signs of LUC, all the RCPs assessed here have a small net warming from LUC because of varying biogeophysical effects, and in RCP4.5 the warming is outside of the expected variability. The afforestation in RCP4.5 decreases surface albedo, making the net global temperature anomaly over land around five times larger than RCPs 2.6 and 8.5, for around twice the amount of LUC. Consequent changes to circulation in RCP4.5 in turn reduce Arctic sea ice cover. The small net positive temperature effect from LUC could make RCP4.5’s universal carbon tax, which incentivizes retaining and growing forest, counter productive with respect to climate. However, there are spatial differences in the balance of impacts, and potential climate gains would need to be assessed against other environmental aims. (letter)

Not carbon neutral: Assessing the net emissions impact of residues burned for bioenergy

Science.gov (United States)

Booth, Mary S.

2018-03-01

Climate mitigation requires emissions to peak then decline within two decades, but many mitigation models include 100 EJ or more of bioenergy, ignoring emissions from biomass oxidation. Treatment of bioenergy as ‘low carbon’ or carbon neutral often assumes fuels are agricultural or forestry residues that will decompose and emit CO2 if not burned for energy. However, for ‘low carbon’ assumptions about residues to be reasonable, two conditions must be met: biomass must genuinely be material left over from some other process; and cumulative net emissions, the additional CO2 emitted by burning biomass compared to its alternative fate, must be low or negligible in a timeframe meaningful for climate mitigation. This study assesses biomass use and net emissions from the US bioenergy and wood pellet manufacturing sectors. It defines the ratio of cumulative net emissions to combustion, manufacturing and transport emissions as the net emissions impact (NEI), and evaluates the NEI at year 10 and beyond for a variety of scenarios. The analysis indicates the US industrial bioenergy sector mostly burns black liquor and has an NEI of 20% at year 10, while the NEI for plants burning forest residues ranges from 41%-95%. Wood pellets have a NEI of 55%-79% at year 10, with net CO2 emissions of 14-20 tonnes for every tonne of pellets; by year 40, the NEI is 26%-54%. Net emissions may be ten times higher at year 40 if whole trees are harvested for feedstock. Projected global pellet use would generate around 1% of world bioenergy with cumulative net emissions of 2 Gt of CO2 by 2050. Using the NEI to weight biogenic CO2 for inclusion in carbon trading programs and to qualify bioenergy for renewable energy subsidies would reduce emissions more effectively than the current assumption of carbon neutrality.

North America's net terrestrial CO2 exchange with the atmosphere 1990-2009

Science.gov (United States)

King, A. W.; Andres, R. J.; Davis, K. J.; Hafer, M.; Hayes, D. J.; Huntzinger, D. N.; de Jong, B.; Kurz, W. A.; McGuire, A. D.; Vargas, R.; Wei, Y.; West, T. O.; Woodall, C. W.

2015-01-01

Scientific understanding of the global carbon cycle is required for developing national and international policy to mitigate fossil fuel CO2 emissions by managing terrestrial carbon uptake. Toward that understanding and as a contribution to the REgional Carbon Cycle Assessment and Processes (RECCAP) project, this paper provides a synthesis of net land-atmosphere CO2 exchange for North America (Canada, United States, and Mexico) over the period 1990-2009. Only CO2 is considered, not methane or other greenhouse gases. This synthesis is based on results from three different methods: atmospheric inversion, inventory-based methods and terrestrial biosphere modeling. All methods indicate that the North American land surface was a sink for atmospheric CO2, with a net transfer from atmosphere to land. Estimates ranged from -890 to -280 Tg C yr-1, where the mean of atmospheric inversion estimates forms the lower bound of that range (a larger land sink) and the inventory-based estimate using the production approach the upper (a smaller land sink). This relatively large range is due in part to differences in how the approaches represent trade, fire and other disturbances and which ecosystems they include. Integrating across estimates, "best" estimates (i.e., measures of central tendency) are -472 ± 281 Tg C yr-1 based on the mean and standard deviation of the distribution and -360 Tg C yr-1 (with an interquartile range of -496 to -337) based on the median. Considering both the fossil fuel emissions source and the land sink, our analysis shows that North America was, however, a net contributor to the growth of CO2 in the atmosphere in the late 20th and early 21st century. With North America's mean annual fossil fuel CO2 emissions for the period 1990-2009 equal to 1720 Tg C yr-1 and assuming the estimate of -472 Tg C yr-1 as an approximation of the true terrestrial CO2 sink, the continent's source : sink ratio for this time period was 1720:472, or nearly 4:1.

Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions, and a new approach for estimating net ecosystem exchange from inventory-based data

Science.gov (United States)

Hayes, Daniel J.; Turner, David P.; Stinson, Graham; McGuire, A. David; Wei, Yaxing; West, Tristram O.; Heath, Linda S.; de Jong, Bernardus; McConkey, Brian G.; Birdsey, Richard A.; Kurz, Werner A.; Jacobson, Andrew R.; Huntzinger, Deborah N.; Pan, Yude; Post, W. Mac; Cook, Robert B.

2012-01-01

We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000–2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2, while accounting for lateral transfers of forest and crop products as well as their eventual emissions. The total NEE estimate of a -327 ± 252 TgC yr-1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (-248 TgC yr-1), largely in the Northwest and Southeast regions of the US, and in the Crop Lands sector (-297 TgC yr-1), predominantly in the Midwest US states. These sinks are counteracted by the carbon source estimated for the Other Lands sector (+218 TgC yr-1), where much of the forest and crop products are assumed to be returned to the atmosphere (through livestock and human consumption). The ecosystems of Mexico are estimated to be a small net source (+18 TgC yr-1) due to land use change between 1993 and 2002. We compare these inventory-based estimates with results from a suite of terrestrial biosphere and atmospheric inversion models, where the mean continental-scale NEE estimate for each ensemble is -511 TgC yr-1 and -931 TgC yr-1, respectively. In the modeling approaches, all sectors, including Other Lands, were generally estimated to be a carbon sink, driven in part by assumed CO2 fertilization and/or lack of consideration of carbon sources from disturbances and product emissions. Additional fluxes not measured by the inventories, although highly uncertain, could add an additional -239 TgC yr-1 to the inventory-based NA sink estimate, thus suggesting some convergence with the modeling approaches.

Wind Erosion Caused by Land Use Changes Significantly Reduces Ecosystem Carbon Storage and Carbon Sequestration Potentials in Grassland

Science.gov (United States)

Li, P.; Chi, Y. G.; Wang, J.; Liu, L.

2017-12-01

Wind erosion exerts a fundamental influence on the biotic and abiotic processes associated with ecosystem carbon (C) cycle. However, how wind erosion under different land use scenarios will affect ecosystem C balance and its capacity for future C sequestration are poorly quantified. Here, we established an experiment in a temperate steppe in Inner Mongolia, and simulated different intensity of land uses: control, 50% of aboveground vegetation removal (50R), 100% vegetation removal (100R) and tillage (TI). We monitored lateral and vertical carbon flux components and soil characteristics from 2013 to 2016. Our study reveals three key findings relating to the driving factors, the magnitude and consequence of wind erosion on ecosystem C balance: (1) Frequency of heavy wind exerts a fundamental control over the severity of soil erosion, and its interaction with precipitation and vegetation characteristics explained 69% variation in erosion intensity. (2) With increases in land use intensity, the lateral C flux induced by wind erosion increased rapidly, equivalent to 33%, 86%, 111% and 183% of the net ecosystem exchange of the control site under control, 50R, 100R and TI sites, respectively. (3) After three years' treatment, erosion induced decrease in fine fractions led to 31%, 43%, 85% of permanent loss of C sequestration potential in the surface 5cm soil for 50R, 100R and TI sites. Overall, our study demonstrates that lateral C flux associated with wind erosion is too large to be ignored. The loss of C-enriched fine particles not only reduces current ecosystem C content, but also results in irreversible loss of future soil C sequestration potential. The dynamic soil characteristics need be considered when projecting future ecosystem C balance in aeolian landscape. We also propose that to maintain the sustainability of grassland ecosystems, land managers should focus on implementing appropriate land use rather than rely on subsequent managements on degraded soils.

The impacts of tropical cyclones on the net carbon balance of eastern US forests (1851–2000)

International Nuclear Information System (INIS)

Fisk, J P; Hurtt, G C; Dolan, K A; Chambers, J Q; Zeng, H; Negrón-Juárez, R I

2013-01-01

In temperate forests of the eastern US, tropical cyclones are a principal agent of catastrophic wind damage, with dramatic impacts on the structure and functioning of forests. Substantial progress has been made to quantify forest damage and resulting gross carbon emissions from tropical cyclones. However, the net effect of storms on the carbon balance of forests depends not only on the biomass lost in single events, but also on the uptake during recovery from a mosaic of past events. This study estimates the net impacts of tropical cyclones on the carbon balance of US forests over the period 1851–2000. To track both disturbance and recovery and to isolate the effects of storms, a modeling framework is used combining gridded historical estimates of mortality and damage with a mechanistic model using an ensemble approach. The net effect of tropical cyclones on the carbon balance is shown to depend strongly on the spatial and temporal scales of analysis. On average, tropical cyclones contribute a net carbon source over latter half of the 19th century. However, throughout much of the 20th century a regional carbon sink is estimated resulting from periods of forest recovery exceeding damage. The large-scale net annual flux resulting from tropical cyclones varies by up to 50 Tg C yr −1 , an amount equivalent to 17%–36% of the US forest carbon sink. (letter)

Carbon, Nitrogen, and Water Response to Land Use and Management Decisions under a Changing Climate in Pennsylvania during the 21st Century

Science.gov (United States)

Felzer, B. S.; Kicklighter, D. W.

2011-12-01

The effects of future climate change and increases in atmospheric CO2 levels in Pennsylvania must be considered in the context of land use and management decisions. While Pennsylvania was originally completely forested at the outset of the colonial period, 19th century land clearing and subsequent regrowth has changed the forest cover of Pennsylvania from 32% to 64% of the land area. Recent trends from 1992-2005 show that developed land has increased by 131% at the expense of agricultural land and forests. Future climate projections indicate that Pennsylvania will get significantly warmer and wetter due to continued increases in greenhouse gases. Using the Terrestrial Ecosystem Model version Hydro (TEM-Hydro), this study explores the role of land use and management in carbon and water dynamics during the 20th century and for four land use scenarios in the 21st century including: 1) a potential vegetation land cover of 100% forest; 2) a current land cover comprising mature forests, crops, pasture, and developed area; 3) a current land cover with younger forests; and 4) a future land cover scenario based on expanding development at the rate of 639,284 acres per decade adjacent to existing developed lands. Common assumptions are made about land use management, but we also explore the effect of crop tilling. TEM-Hydro runs are forced by 20th century climate from the PRISM model and 21st century climate from the NCAR CCSM3.0 IPCC A2 and B1 scenarios downscaled and bias corrected to 1/8o resolution. Regrowing forests are the only ecosystem with positive Net Carbon Exchange (NCE, Net Ecosystem Productivity minus carbon losses from the conversion of natural vegetation to cultivation and decomposition of agricultural and wood products, where positive indicates ecosystem sink), and sequester about 11,000 g C m-2 over the 20th century. The highest rates of leaching of dissolved inorganic nitrogen (DIN) occur in those areas that are fertilized, which include urban turf lawns

Relationships between net photosynthesis and foliar nitrogen concentrations in a loblobby pine forest ecosystem grown in elevated atmospheric carbon dioxide

International Nuclear Information System (INIS)

Springer, C. J.; Thomas, R. B.; Delucia, E. H.

2005-01-01

The effects of elevated carbon dioxide concentration on the relationship between light-saturated net photosynthesis and area-based foliar nitrogen concentration in the canopy of a loblobby pine forest at the Duke Forest FACE experiment was examined. Two overstory and four understory tree species were examined at their growth carbon dioxide concentrations during the early summer and late summer of 1999, 2001 and 2002. Light-saturated net photosynthesis and foliar nitrogen relationship were compared to determine if the stimulatory effects of elevated carbon dioxide on net photosynthesis had declined. Results at all three sample times showed no difference in either the slopes, or in the y-intercepts of the net photosynthesis-foliar nitrogen relationship when measured at common carbon dioxide concentrations. Net photosynthesis was also unaffected by growth in elevated carbon dioxide, indicating that these overstory and understory trees continued to show strong stimulation of photosynthesis by elevated carbon dioxide. 46 refs., 6 tabs., 3 figs

Multi-year net ecosystem carbon balance at a horticulture-extracted restored peatland

Science.gov (United States)

Nugent, Kelly; Strachan, Ian; Strack, Maria

2017-04-01

Restoration of previously extracted peatlands is essential to minimize the impact of drainage and peat removal. Best practices restoration methods have been developed that include ditch blocking, site leveling and reintroducing bog vegetation using the moss layer transfer technique. A long term goal of restoration is the return to a peat accumulating ecosystem. Bois-des-Bel is a cool-temperate bog, located in eastern Quebec, Canada, that was vacuum harvested until 1980 and restored in 1999. While several studies have used discrete (chamber) methods to determine the net carbon exchange from rewetted or restored peatlands, ours appears to be the first to have multiple complete years of net ecosystem carbon exchange from a restored northern peatland. An eddy covariance flux tower instrumented with a sonic anemometer and open-path CO2/H2O and CH4 analyzers was operated continuously over three years to produce a robust estimate of net carbon sequestration. Our initial results indicate that this restored peatland was a consistent moderate annual net sink for CO2, a moderate source of CH4 and had low losses of dissolved organic carbon compared to undisturbed northern latitude peatlands. Closed chambers combined with a fast response CO2/H2O/CH4 analyzer were used to investigate ecohydrological controls on net ecosystem exchange of CO2 (NEE) and CH4 flux from the restored fields and remnant ditches at the site. CH4 release was found to be an order of magnitude higher in the ditches compared to the fields, with non-vegetated ditch showing a greater range in flux compared to areas invaded by Typha latifolia. Bubble magnitude and count were highest in the non-vegetated ditch, followed by Typha plots and were undetectable in the restored fields. The latter may be partially attributed to the high cover of Eriophorum vaginatum in the restored fields, plants that have aerenchymous tissue, as well as a much deeper water table level. While the non-vegetated ditch areas were a steady

Annual measurements of gain and loss in aboveground carbon density

Science.gov (United States)

Baccini, A.; Walker, W. S.; Carvalho, L.; Farina, M.; Sulla-menashe, D. J.; Houghton, R. A.

2017-12-01

Tropical forests hold large stores of carbon, but their net carbon balance is uncertain. Land use and land-cover change (LULCC) are believed to release between 0.81 and 1.14 PgC yr-1, while intact native forests are thought to be a net carbon sink of approximately the same magnitude. Reducing the uncertainty of these estimates is not only fundamental to the advancement of carbon cycle science but is also of increasing relevance to national and international policies designed to reduce emissions from deforestation and forest degradation (e.g., REDD+). Contemporary approaches to estimating the net carbon balance of tropical forests rely on changes in forest area between two periods, typically derived from satellite data, together with information on average biomass density. These approaches tend to capture losses in biomass due to deforestation (i.e., wholesale stand removals) but are limited in their sensitivity to forest degradation (e.g., selective logging or single-tree removals), which can account for additional biomass losses on the order of 47-75% of deforestation. Furthermore, while satellite-based estimates of forest area loss have been used successfully to estimate associated carbon losses, few such analyses have endeavored to determine the rate of carbon sequestration in growing forests. Here we use 12 years (2003-2014) of pantropical satellite data to quantify net annual changes in the aboveground carbon density of woody vegetation (MgC ha-1yr-1), providing direct, measurement-based evidence that the world's tropical forests are a net carbon source of 425.2 ± 92.0 Tg C yr-1. This net release of carbon consists of losses of 861.7 ± 80.2 Tg C yr-1 and gains of -436.5 ± 31.0 Tg C yr-1 . Gains result from forest growth; losses result from reductions in forest area due to deforestation and from reductions in biomass density within standing forests (degradation), with the latter accounting for 68.9% of overall losses. Our findings advance previous research

Tropical Africa: Land use, biomass, and carbon estimates for 1980

Energy Technology Data Exchange (ETDEWEB)

Brown, S. [Environmental Protection Agency, Corvallis, OR (United States). Western Ecology Division; Gaston, G. [Environmental Protection Agency, Corvallis, OR (United States). National Research Council; Daniels, R.C. [ed.] [Oak Ridge National Lab., TN (United States)

1996-06-01

This document describes the contents of a digital database containing maximum potential aboveground biomass, land use, and estimated biomass and carbon data for 1980 and describes a methodology that may be used to extend this data set to 1990 and beyond based on population and land cover data. The biomass data and carbon estimates are for woody vegetation in Tropical Africa. These data were collected to reduce the uncertainty associated with the possible magnitude of historical releases of carbon from land use change. Tropical Africa is defined here as encompassing 22.7 x 10{sup 6} km{sup 2} of the earth`s land surface and includes those countries that for the most part are located in Tropical Africa. Countries bordering the Mediterranean Sea and in southern Africa (i.e., Egypt, Libya, Tunisia, Algeria, Morocco, South Africa, Lesotho, Swaziland, and Western Sahara) have maximum potential biomass and land cover information but do not have biomass or carbon estimate. The database was developed using the GRID module in the ARC/INFO{sup TM} geographic information system. Source data were obtained from the Food and Agriculture Organization (FAO), the U.S. National Geophysical Data Center, and a limited number of biomass-carbon density case studies. These data were used to derive the maximum potential and actual (ca. 1980) aboveground biomass-carbon values at regional and country levels. The land-use data provided were derived from a vegetation map originally produced for the FAO by the International Institute of Vegetation Mapping, Toulouse, France.

Predicted net efflux of radiocarbon from the ocean and increase in atmospheric radiocarbon content

Science.gov (United States)

Caldeira, Ken; Rau, Greg H.; Duffy, Philip B.

Prior to changes introduced by man, production of radiocarbon (14C) in the stratosphere nearly balanced the flux of 14C from the atmosphere to the ocean and land biosphere, which in turn nearly balanced radioactive decay in these 14C reservoirs. This balance has been altered by land-use changes, fossil-fuel burning, and atmospheric nuclear detonations. Here, we use a model of the global carbon cycle to quantify these radiocarbon fluxes and make predictions about their magnitude in the future. Atmospheric nuclear detonations increased atmospheric 14C content by about 80% by the mid-1960's. Since that time, the 14C content of the atmosphere has been diminishing as this bomb radiocarbon has been entering the oceans and terrestrial biosphere. However, we predict that atmospheric 14C content will reach a minimum and start to increase within the next few years if fossil-fuel burning continues according to a “business-as-usual” scenario, even though fossil fuels are devoid of 14C. This will happen because fossil-fuel carbon diminishes the net flux of 14C from the atmosphere to the oceans and land biosphere, forcing 14C to accumulate in the atmosphere. Furthermore, the net flux of both bomb and natural 14C into the ocean are predicted to continue to slow and then, in the middle of the next century, to reverse, so that there will be a net flux of 14C from the ocean to the atmosphere. The predicted reversal of net 14C fluxes into the ocean is a further example of human impacts on the global carbon cycle.

Estimation of net ecosystem carbon exchange for the conterminous United States by combining MODIS and AmeriFlux data

Science.gov (United States)

Jingfeng Xiao; Qianlai Zhuang; Dennis D. Baldocchi; Beverly E. Law; Andrew D. Richardson; Jiquan Chen; Ram Oren; Gegory Starr; Asko Noormets; Siyan Ma; Sashi B. Verma; Sonia Wharton; Steven C. Wofsy; Paul V. Bolstad; Sean P. Burns; David R. Cook; Peter S. Curtis; Bert G. Drake; Matthias Falk; MArc L. Fischer; David R. Foster; Lianhong Gu; Julian L. Hadley; David Y. Hollinger; Gabriel G. Katul; Marcy Litvak; Timothy Martin; Roser Matamala; Steve McNulty; Tilden P. Meyers; Russell K. Monson; J. William Munger; Walter C. Oechel; Kyaw Tha Paw U; Hans Peter Schmid; Russell L. Scott; Ge Sun; Andrew E. Suyker; Margaret S. Torn

2008-01-01

Eddy covariance flux towers provide continuous measurements of net ecosystem carbon exchange (NEE) for a wide range of climate and biome types. However, these measurements only represent the carbon fluxes at the scale of the tower footprint. To quantify the net exchange of carbon dioxide between the terrestrial biosphere and the atmosphere for regions or continents,...

Environmental change and the carbon balance of Amazonian forests

International Nuclear Information System (INIS)

Aragao, Luiz E.O.C.; Poulter, Benjamin

2014-01-01

Extreme climatic events and land-use change are known to influence strongly the current carbon cycle of Amazonia, and have the potential to cause significant global climate impacts. This review intends to evaluate the effects of both climate and anthropogenic perturbations on the carbon balance of the Brazilian Amazon and to understand how they interact with each other. By analysing the outputs of the Intergovernmental Panel for Climate Change (IPCC) Assessment Report 4 (AR4) model ensemble, we demonstrate that Amazonian temperatures and water stress are both likely to increase over the 21. Century. Curbing deforestation in the Brazilian Amazon by 62% in 2010 relative to the 1990's mean decreased the Brazilian Amazon's deforestation contribution to global land use carbon emissions from 17% in the 1990's and early 2000's to 9% by 2010. Carbon sources in Amazonia are likely to be dominated by climatic impacts allied with forest fires (48.3% relative contribution) during extreme droughts. The current net carbon sink (net biome productivity, NBP) of +0.16 (ranging from +0.11 to +0.21) PgCyear-1 in the Brazilian Amazon, equivalent to 13.3% of global carbon emissions from land-use change for 2008, can be negated or reversed during drought years [NBP=-0.06 (-0.31 to +0.01) PgCyear -1 ]. Therefore, reducing forest fires, in addition to reducing deforestation, would be an important measure for minimizing future emissions. Conversely, doubling the current area of secondary forests and avoiding additional removal of primary forests would help the Amazonian gross forest sink to offset approximately 42% of global land-use change emissions. We conclude that a few strategic environmental policy measures are likely to strengthen the Amazonian net carbon sink with global implications. Moreover, these actions could increase the resilience of the net carbon sink to future increases in drought frequency. (authors)

Environmental change and the carbon balance of Amazonian forests.

Science.gov (United States)

Aragão, Luiz E O C; Poulter, Benjamin; Barlow, Jos B; Anderson, Liana O; Malhi, Yadvinder; Saatchi, Sassan; Phillips, Oliver L; Gloor, Emanuel

2014-11-01

Extreme climatic events and land-use change are known to influence strongly the current carbon cycle of Amazonia, and have the potential to cause significant global climate impacts. This review intends to evaluate the effects of both climate and anthropogenic perturbations on the carbon balance of the Brazilian Amazon and to understand how they interact with each other. By analysing the outputs of the Intergovernmental Panel for Climate Change (IPCC) Assessment Report 4 (AR4) model ensemble, we demonstrate that Amazonian temperatures and water stress are both likely to increase over the 21st Century. Curbing deforestation in the Brazilian Amazon by 62% in 2010 relative to the 1990s mean decreased the Brazilian Amazon's deforestation contribution to global land use carbon emissions from 17% in the 1990s and early 2000s to 9% by 2010. Carbon sources in Amazonia are likely to be dominated by climatic impacts allied with forest fires (48.3% relative contribution) during extreme droughts. The current net carbon sink (net biome productivity, NBP) of +0.16 (ranging from +0.11 to +0.21) Pg C year(-1) in the Brazilian Amazon, equivalent to 13.3% of global carbon emissions from land-use change for 2008, can be negated or reversed during drought years [NBP = -0.06 (-0.31 to +0.01) Pg C year(-1) ]. Therefore, reducing forest fires, in addition to reducing deforestation, would be an important measure for minimizing future emissions. Conversely, doubling the current area of secondary forests and avoiding additional removal of primary forests would help the Amazonian gross forest sink to offset approximately 42% of global land-use change emissions. We conclude that a few strategic environmental policy measures are likely to strengthen the Amazonian net carbon sink with global implications. Moreover, these actions could increase the resilience of the net carbon sink to future increases in drought frequency. © 2014 The Authors. Biological Reviews © 2014 Cambridge Philosophical

Sub-grid scale representation of vegetation in global land surface schemes: implications for estimation of the terrestrial carbon sink

Directory of Open Access Journals (Sweden)

J. R. Melton

2014-02-01

Full Text Available Terrestrial ecosystem models commonly represent vegetation in terms of plant functional types (PFTs and use their vegetation attributes in calculations of the energy and water balance as well as to investigate the terrestrial carbon cycle. Sub-grid scale variability of PFTs in these models is represented using different approaches with the "composite" and "mosaic" approaches being the two end-members. The impact of these two approaches on the global carbon balance has been investigated with the Canadian Terrestrial Ecosystem Model (CTEM v 1.2 coupled to the Canadian Land Surface Scheme (CLASS v 3.6. In the composite (single-tile approach, the vegetation attributes of different PFTs present in a grid cell are aggregated and used in calculations to determine the resulting physical environmental conditions (soil moisture, soil temperature, etc. that are common to all PFTs. In the mosaic (multi-tile approach, energy and water balance calculations are performed separately for each PFT tile and each tile's physical land surface environmental conditions evolve independently. Pre-industrial equilibrium CLASS-CTEM simulations yield global totals of vegetation biomass, net primary productivity, and soil carbon that compare reasonably well with observation-based estimates and differ by less than 5% between the mosaic and composite configurations. However, on a regional scale the two approaches can differ by > 30%, especially in areas with high heterogeneity in land cover. Simulations over the historical period (1959–2005 show different responses to evolving climate and carbon dioxide concentrations from the two approaches. The cumulative global terrestrial carbon sink estimated over the 1959–2005 period (excluding land use change (LUC effects differs by around 5% between the two approaches (96.3 and 101.3 Pg, for the mosaic and composite approaches, respectively and compares well with the observation-based estimate of 82.2 ± 35 Pg C over the same

Benefits of collaborative and comparative research on land use change and climate mitigation

Science.gov (United States)

Zhu, Zhiliang; Gong, Peng

2016-04-01

The world's two largest economies are also the latest greenhouse gas emitters. The United States is committed to reduce the net greenhouse gas emission by 28% below the 2005 level by 2025. Similarly China also announced significant climate mitigation steps at the Paris climate convention. These policy plans will require actions including reduction of GHG emissions as well as protection of carbon stored in biologic pools and increase of carbon sequestration by the natural ecosystems. Major drivers of ecosystem carbon sequestration and protection of existing carbon resources include land use, disturbances, and climate change. Recent studies indicate that vegetated ecosystems in the United States remain as a carbon sink but the sink is weakening due to increased disturbances (such as wildfire and harvesting) and aging of forests. Unique land use policies in China such as large-scale afforestation in the recent decades have reportedly led to significant increase in total forest area and aboveground biomass, although it is not clear to what degree the increase has translated to strengthened net uptake of atmospheric CO2 and the rate of sequestration by vegetated ecosystems. What lessons can we draw from different land management and land use practices in the U.S. and China that can benefit scientific advances and climate mitigation goals? Research conducted collaboratively by the U.S. Geological Survey and China Ministry of Science and Technology has led to improved techniques for tracking and modeling land use change and ecosystem disturbances and improved understanding of consequences of different land use change and management practices on ecosystem carbon sequestration capacities.

Large uncertainty in carbon uptake potential of land-based climate-change mitigation efforts.

Science.gov (United States)

Krause, Andreas; Pugh, Thomas A M; Bayer, Anita D; Li, Wei; Leung, Felix; Bondeau, Alberte; Doelman, Jonathan C; Humpenöder, Florian; Anthoni, Peter; Bodirsky, Benjamin L; Ciais, Philippe; Müller, Christoph; Murray-Tortarolo, Guillermo; Olin, Stefan; Popp, Alexander; Sitch, Stephen; Stehfest, Elke; Arneth, Almut

2018-07-01

Most climate mitigation scenarios involve negative emissions, especially those that aim to limit global temperature increase to 2°C or less. However, the carbon uptake potential in land-based climate change mitigation efforts is highly uncertain. Here, we address this uncertainty by using two land-based mitigation scenarios from two land-use models (IMAGE and MAgPIE) as input to four dynamic global vegetation models (DGVMs; LPJ-GUESS, ORCHIDEE, JULES, LPJmL). Each of the four combinations of land-use models and mitigation scenarios aimed for a cumulative carbon uptake of ~130 GtC by the end of the century, achieved either via the cultivation of bioenergy crops combined with carbon capture and storage (BECCS) or avoided deforestation and afforestation (ADAFF). Results suggest large uncertainty in simulated future land demand and carbon uptake rates, depending on the assumptions related to land use and land management in the models. Total cumulative carbon uptake in the DGVMs is highly variable across mitigation scenarios, ranging between 19 and 130 GtC by year 2099. Only one out of the 16 combinations of mitigation scenarios and DGVMs achieves an equivalent or higher carbon uptake than achieved in the land-use models. The large differences in carbon uptake between the DGVMs and their discrepancy against the carbon uptake in IMAGE and MAgPIE are mainly due to different model assumptions regarding bioenergy crop yields and due to the simulation of soil carbon response to land-use change. Differences between land-use models and DGVMs regarding forest biomass and the rate of forest regrowth also have an impact, albeit smaller, on the results. Given the low confidence in simulated carbon uptake for a given land-based mitigation scenario, and that negative emissions simulated by the DGVMs are typically lower than assumed in scenarios consistent with the 2°C target, relying on negative emissions to mitigate climate change is a highly uncertain strategy. © 2018 John

Derived crop management data for the LandCarbon Project

Science.gov (United States)

Schmidt, Gail; Liu, Shu-Guang; Oeding, Jennifer

2011-01-01

The LandCarbon project is assessing potential carbon pools and greenhouse gas fluxes under various scenarios and land management regimes to provide information to support the formulation of policies governing climate change mitigation, adaptation and land management strategies. The project is unique in that spatially explicit maps of annual land cover and land-use change are created at the 250-meter pixel resolution. The project uses vast amounts of data as input to the models, including satellite, climate, land cover, soil, and land management data. Management data have been obtained from the U.S. Department of Agriculture (USDA) National Agricultural Statistics Service (NASS) and USDA Economic Research Service (ERS) that provides information regarding crop type, crop harvesting, manure, fertilizer, tillage, and cover crop (U.S. Department of Agriculture, 2011a, b, c). The LandCarbon team queried the USDA databases to pull historic crop-related management data relative to the needs of the project. The data obtained was in table form with the County or State Federal Information Processing Standard (FIPS) and the year as the primary and secondary keys. Future projections were generated for the A1B, A2, B1, and B2 Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) scenarios using the historic data values along with coefficients generated by the project. The PBL Netherlands Environmental Assessment Agency (PBL) Integrated Model to Assess the Global Environment (IMAGE) modeling framework (Integrated Model to Assess the Global Environment, 2006) was used to develop coefficients for each IPCC SRES scenario, which were applied to the historic management data to produce future land management practice projections. The LandCarbon project developed algorithms for deriving gridded data, using these tabular management data products as input. The derived gridded crop type, crop harvesting, manure, fertilizer, tillage, and cover crop

Contributions of fallow lands in the Brazilian Amazon to CO2 balance, deforestation and the agrarian economy: Inequalities among competing land use trajectories

Directory of Open Access Journals (Sweden)

Francisco de Assis Costa

2016-10-01

Full Text Available Abstract Development of regulations limiting greenhouse gas emissions is creating demands and new markets for land-based carbon sinks. Expectations of development of clean technologies and new sources of clean energy are affecting the supply side, creating opportunities for remuneration for sustainable development of natural resources. This paper[1] presents a model developed to gain a realistic understanding of the heterogeneous roles of capoeira (fallow agricultural land in land use dynamics and CO2 balance in the Brazilian Amazon. The model estimates the areas and CO2 balance of different types of capoeira in association with different farming activities and also monitors carbon intensity over time in the context of technological trajectories (distinct farming systems. Modeling with agricultural census data compared six different, competing technological trajectories of capoeira for changes in major land use variables and impacts on CO2 balance from 1990 to 2011. Results revealed that: a technological trajectories contribute differently to net emissions of CO2, with livestock for meat enterprises being the highest net emitters and peasant agroforestry and plantation enterprises the lower emitters; b carbon intensity tends to diminish over time because of increased weight of trajectories with lower carbon intensity, in combination with reduced carbon intensity of trajectories with higher carbon intensity; and c for most trajectories, reuse of “old land” becomes increasingly more important for explaining the essence of agricultural dynamics, including CO2 balance, than is deforestation for opening up new agricultural land. These results draw attention to the role of capoeiras in modernization and intensification of the agricultural sector through renovation of deforested land. The model allows evaluation of deforestation and CO2 emissions as functions of the evolution of markets for agricultural products and of deforestation dynamics

Relationship Study on Land Use Spatial Distribution Structure and Energy-Related Carbon Emission Intensity in Different Land Use Types of Guangdong, China, 1996–2008

Directory of Open Access Journals (Sweden)

Yi Huang

2013-01-01

Full Text Available This study attempts to discuss the relationship between land use spatial distribution structure and energy-related carbon emission intensity in Guangdong during 1996–2008. We quantized the spatial distribution structure of five land use types including agricultural land, industrial land, residential and commercial land, traffic land, and other land through applying spatial Lorenz curve and Gini coefficient. Then the corresponding energy-related carbon emissions in each type of land were calculated in the study period. Through building the reasonable regression models, we found that the concentration degree of industrial land is negatively correlated with carbon emission intensity in the long term, whereas the concentration degree is positively correlated with carbon emission intensity in agricultural land, residential and commercial land, traffic land, and other land. The results also indicate that land use spatial distribution structure affects carbon emission intensity more intensively than energy efficiency and production efficiency do. These conclusions provide valuable reference to develop comprehensive policies for energy conservation and carbon emission reduction in a new perspective.

Net ecosystem productivity and carbon dynamics of the traditionally managed Imperata grasslands of North East India.

Science.gov (United States)

Pathak, Karabi; Malhi, Yadvinder; Sileshi, G W; Das, Ashesh Kumar; Nath, Arun Jyoti

2018-09-01

There have been few comprehensive descriptions of how fire management and harvesting affect the carbon dynamics of grasslands. Grasslands dominated by the invasive weed Imperata cylindrica are considered as environmental threats causing low land productivity throughout the moist tropical regions in Asia. Imperata grasslands in North East India are unique in that they are traditionally managed and culturally important in the rural landscapes. Given the importance of fire in the management of Imperata grassland, we aimed to assess (i) the seasonal pattern of biomass production, (ii) the eventual pathways for the produced biomass, partitioned between in situ decomposition, harvesting and combustion, and (iii) the effect of customary fire management on the ecosystem carbon cycle. Comparatively high biomass production was recorded during pre-monsoon (154 g m -2  month -1 ) and monsoon (214 g m -2  month -1 ) compared to the post-monsoon (91 g m -2  month -1 ) season, and this is attributed to nutrient return into the soil immediately after fire in February. Post fire effects might have killed roots and rhizomes leading to high belowground litter production 30-35 g m -2 during March to August. High autotrophic respiration was recorded during March-July, which was related to high belowground biomass production (35-70 g m -2 ) during that time. Burning removed all the surface litter in March and this appeared to hinder surface decomposition and result in low heterotrophic respiration. Annual total biomass carbon production was estimated at 886 g C m -2 . Annual harvest of biomass (estimated at 577 g C m -2 ) was the major pathway for carbon fluxes from the system. Net ecosystem production (NEP) of Imperata grassland was estimated at 91 g C m -2  yr -1 indicating that these grasslands are a net sink of CO 2 , although this is greatly influenced by weather and fire management. Crown Copyright © 2018. Published by Elsevier B

Carbon dioxide addition to coral reef waters suppresses net community calcification

Science.gov (United States)

Albright, Rebecca; Takeshita, Yuichiro; Koweek, David A.; Ninokawa, Aaron; Wolfe, Kennedy; Rivlin, Tanya; Nebuchina, Yana; Young, Jordan; Caldeira, Ken

2018-03-01

Coral reefs feed millions of people worldwide, provide coastal protection and generate billions of dollars annually in tourism revenue. The underlying architecture of a reef is a biogenic carbonate structure that accretes over many years of active biomineralization by calcifying organisms, including corals and algae. Ocean acidification poses a chronic threat to coral reefs by reducing the saturation state of the aragonite mineral of which coral skeletons are primarily composed, and lowering the concentration of carbonate ions required to maintain the carbonate reef. Reduced calcification, coupled with increased bioerosion and dissolution, may drive reefs into a state of net loss this century. Our ability to predict changes in ecosystem function and associated services ultimately hinges on our understanding of community- and ecosystem-scale responses. Past research has primarily focused on the responses of individual species rather than evaluating more complex, community-level responses. Here we use an in situ carbon dioxide enrichment experiment to quantify the net calcification response of a coral reef flat to acidification. We present an estimate of community-scale calcification sensitivity to ocean acidification that is, to our knowledge, the first to be based on a controlled experiment in the natural environment. This estimate provides evidence that near-future reductions in the aragonite saturation state will compromise the ecosystem function of coral reefs.

Past and present of sediment and carbon biogeochemical cycling models

Directory of Open Access Journals (Sweden)

F. T. Mackenzie

2004-01-01

Full Text Available The global carbon cycle is part of the much more extensive sedimentary cycle that involves large masses of carbon in the Earth's inner and outer spheres. Studies of the carbon cycle generally followed a progression in knowledge of the natural biological, then chemical, and finally geological processes involved, culminating in a more or less integrated picture of the biogeochemical carbon cycle by the 1920s. However, knowledge of the ocean's carbon cycle behavior has only within the last few decades progressed to a stage where meaningful discussion of carbon processes on an annual to millennial time scale can take place. In geologically older and pre-industrial time, the ocean was generally a net source of CO2 emissions to the atmosphere owing to the mineralization of land-derived organic matter in addition to that produced in situ and to the process of CaCO3 precipitation. Due to rising atmospheric CO2 concentrations because of fossil fuel combustion and land use changes, the direction of the air-sea CO2 flux has reversed, leading to the ocean as a whole being a net sink of anthropogenic CO2. The present thickness of the surface ocean layer, where part of the anthropogenic CO2 emissions are stored, is estimated as of the order of a few hundred meters. The oceanic coastal zone net air-sea CO2 exchange flux has also probably changed during industrial time. Model projections indicate that in pre-industrial times, the coastal zone may have been net heterotrophic, releasing CO2 to the atmosphere from the imbalance between gross photosynthesis and total respiration. This, coupled with extensive CaCO3 precipitation in coastal zone environments, led to a net flux of CO2 out of the system. During industrial time the coastal zone ocean has tended to reverse its trophic status toward a non-steady state situation of net autotrophy, resulting in net uptake of anthropogenic CO2 and storage of carbon in the coastal ocean, despite the significant calcification

Global net primary production and heterotrophic respiration for 1987

Energy Technology Data Exchange (ETDEWEB)

Hunt, R.E. Jr.; Piper, S.C.; Nemani, R. [Univ. of Montana, Missoula, MT (United States)]|[Scripps Institute of Oceanography, La Jolla, CA (United States)] [and others

1995-06-01

An ecosystem process model, BIOME-BGC, was parameterized and used to simulate the actual net primary production and heterotrophic respiration using daily climatic data, land cover type, leaf area index gridded to 1{degree} latitude by 1{degree} longitude grid cells for the year 1987. Global net primary production was 52 Pg C. These estimates were validated directly by two different methods. First, the grid cells were aggregated and used as inputs to a 3D atmospheric transport model, to compare CO{sub 2} station data with predictions. We simulated the intra-annual variation of atmospheric CO{sub 2} well for the northern hemisphere, but not for the southern hemisphere. Second, we calculated the net {sup 13}C uptake of vegetation, which is a function of water use efficiency. The {sup 13}C/{sup 12}C ratios agreed with measured data, indicating a strong limitation of global primary processes by the hydrologic cycle, especially precipitation. These are different from other global carbon models as we can simulate the year-to-year variation of climate, including El Nino, on the global carbon cycle.

Research Needs for Carbon Management in Agriculture, Forestry and Other Land Uses

Science.gov (United States)

Negra, C.; Lovejoy, T.; Ojima, D. S.; Ashton, R.; Havemann, T.; Eaton, J.

2009-12-01

Improved management of terrestrial carbon in agriculture, forestry, and other land use sectors is a necessary part of climate change mitigation. It is likely that governments will agree in Copenhagen in December 2009 to incentives for improved management of some forms of terrestrial carbon, including maintaining existing terrestrial carbon (e.g., avoiding deforestation) and creating new terrestrial carbon (e.g., afforestation, soil management). To translate incentives into changes in land management and terrestrial carbon stocks, a robust technical and scientific information base is required. All terrestrial carbon pools (and other greenhouse gases from the terrestrial system) that interact with the atmosphere at timescales less than centuries, and all land uses, have documented mitigation potential, however, most activity has focused on above-ground forest biomass. Despite research advances in understanding emissions reduction and sequestration associated with different land management techniques, there has not yet been broad-scale implementation of land-based mitigation activity in croplands, peatlands, grasslands and other land uses. To maximize long-term global terrestrial carbon volumes, further development of relevant data, methodologies and technologies are needed to complement policy and financial incentives. The Terrestrial Carbon Group, in partnership with UN-REDD agencies, the World Bank and CGIAR institutions, is reviewing literature, convening leading experts and surveying key research institutions to develop a Roadmap for Terrestrial Carbon: Research Needs for Implementation of Carbon Management in Agriculture, Forestry and Other Land Uses. This work will summarize the existing knowledge base for emissions reductions and sequestration through land management as well as the current availability of tools and methods for measurement and monitoring of terrestrial carbon. Preliminary findings indicate a number of areas for future work. Enhanced information

The role of protected areas in land use/land cover change and the carbon cycle in the conterminous United States

Energy Technology Data Exchange (ETDEWEB)

Lu, Xiaoliang [The Ecosystems Center, Marine Biological Laboratory, Woods Hole MA USA; Zhou, Yuyu [Departments of Geological and Atmospheric Sciences, Iowa State University, Ames IA USA; Liu, Yaling [Pacific Northwest National Laboratory, Joint Global Change Research Institute, College Park MD USA; Le Page, Yannick [Department Tapada da Ajuda, Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, Lisbon Portugal

2017-08-08

Protected areas (PAs) cover about 22% of the conterminous United States. Understanding their role on historical land use and land cover change (LULCC) and on the carbon cycle is essential to provide guidance for environmental policies. In this study, we compiled historical LULCC and PAs data to explore these interactions within the terrestrial ecosystem model (TEM). We found that intensive LULCC occurred in the conterminous United States from 1700 to 2005. More than 3 million km2 of forest, grassland and shrublands were converted into agricultural lands, which caused 10,607 Tg C release from land ecosystems to atmosphere. PAs had experienced little LULCC as they were generally established in the 20th century after most of the agricultural expansion had occurred. PAs initially acted as a carbon source due to land use legacies, but their accumulated carbon budget switched to a carbon sink in the 1960s, sequestering an estimated 1,642 Tg C over 1700–2005, or 13.4% of carbon losses in non-PAs. We also find that PAs maintain larger carbon stocks and continue sequestering carbon in recent years (2001–2005), but at a lower rate due to increased heterotrophic respiration as well as lower productivity associated to aging ecosystems. It is essential to continue efforts to maintain resilient, biodiverse ecosystems and avoid large-scale disturbances that would release large amounts of carbon in PAs.

Multi-Model Assessment of Trends and Variability in Terrestrial Carbon Uptake in India

Science.gov (United States)

Rao, A. S.; Bala, G.; Ravindranath, N. H.

2015-12-01

Indian terrestrial ecosystem exhibits large temporal and spatial variability in carbon sources and sinks due to its monsoon based climate system, diverse land use and land cover distribution and cultural practices. In this study, a multi-model based assessment is made to study the trends and variability in the land carbon uptake for India over the 20th century. Data from nine models which are a part of a recent land surface model intercomparison project called TRENDY is used for the study. These models are driven with common forcing data over the period of 1901-2010. Model output variables assessed include: gross primary production (GPP), heterotrophic respiration (Rh), autotrophic respiration (Ra) and net primary production (NPP). The net ecosystem productivity (NEP) for the Indian region was calculated as a difference of NPP and Rh and it was found that NEP for the region indicates an estimated increase in uptake over the century by -0.6 TgC/year per year. NPP for India also shows an increasing trend of 2.03% per decade from 1901-2010. Seasonal variation in the multimodel mean NPP is maximum during the southwest monsoon period (JJA) followed by the post monsoon period (SON) and is attributed to the maximum in rainfall for the region during the months of JJA. To attribute the changes seen in the land carbon variables, influence of climatic drivers such as precipitation, temperature and remote influences of large scale phenomenon such as ENSO on the land carbon of the region are also estimated in the study. It is found that although changes in precipitation shows a good correlation to the changes seen in NEP, remote drivers like ENSO do not have much effect on them. The Net Ecosystem Exchange is calculated with the inclusion of the land use change flux and fire flux from the models. NEE suggests that the region behaves as a small sink for carbon with an net uptake of 5 GtC over the past hundred years.

A case study of carbon fluxes from land change in the southwest Brazilian Amazon

Science.gov (United States)

Barrett, K.; Rogan, J.; Eastman, J.R.

2009-01-01

Worldwide, land change is responsible for one-fifth of anthropogenic carbon emissions. In Brazil, three-quarters of carbon emissions originate from land change. This study represents a municipal-scale study of carbon fluxes from vegetation in Rio Branco, Brazil. Land-cover maps of pasture, forest, and secondary growth from 1993, 1996, 1999, and 2003 were produced using an unsupervised classification method (overall accuracy = 89%). Carbon fluxes from land change over the decade of imagery were estimated from transitions between land-cover categories for each time interval. This article presents new methods for estimating emissions reductions from carbon stored in the vegetation that replaces forests (e.g., pasture) and sequestration by new (>10-15 years) forests, which reduced gross emissions by 16, 15, and 22% for the period of 1993-1996, 1996-1999, and 1999-2003, respectively. The methods used in the analysis are broadly applicable and provide a comprehensive characterization of regional-scale carbon fluxes from land change.

Modeling Net Land Occupation of Hydropower Reservoirs in Norway for Use in Life Cycle Assessment.

Science.gov (United States)

Dorber, Martin; May, Roel; Verones, Francesca

2018-02-20

Increasing hydropower electricity production constitutes a unique opportunity to mitigate climate change impacts. However, hydropower electricity production also impacts aquatic and terrestrial biodiversity through freshwater habitat alteration, water quality degradation, and land use and land use change (LULUC). Today, no operational model exists that covers any of these cause-effect pathways within life cycle assessment (LCA). This paper contributes to the assessment of LULUC impacts of hydropower electricity production in Norway in LCA. We quantified the inundated land area associated with 107 hydropower reservoirs with remote sensing data and related it to yearly electricity production. Therewith, we calculated an average net land occupation of 0.027 m 2 ·yr/kWh of Norwegian storage hydropower plants for the life cycle inventory. Further, we calculated an adjusted average land occupation of 0.007 m 2 ·yr/kWh, accounting for an underestimation of water area in the performed maximum likelihood classification. The calculated land occupation values are the basis to support the development of methods for assessing the land occupation impacts of hydropower on biodiversity in LCA at a damage level.

Anthropogenic perturbation of the carbon fluxes from land to ocean

KAUST Repository

Regnier, Pierre

2013-06-09

A substantial amount of the atmospheric carbon taken up on land through photosynthesis and chemical weathering is transported laterally along the aquatic continuum from upland terrestrial ecosystems to the ocean. So far, global carbon budget estimates have implicitly assumed that the transformation and lateral transport of carbon along this aquatic continuum has remained unchanged since pre-industrial times. A synthesis of published work reveals the magnitude of present-day lateral carbon fluxes from land to ocean, and the extent to which human activities have altered these fluxes. We show that anthropogenic perturbation may have increased the flux of carbon to inland waters by as much as 1.0 Pg C yr -1 since pre-industrial times, mainly owing to enhanced carbon export from soils. Most of this additional carbon input to upstream rivers is either emitted back to the atmosphere as carbon dioxide (∼0.4 Pg C yr -1) or sequestered in sediments (∼0.5 Pg C yr -1) along the continuum of freshwater bodies, estuaries and coastal waters, leaving only a perturbation carbon input of ∼0.1 Pg C yr -1 to the open ocean. According to our analysis, terrestrial ecosystems store ∼0.9 Pg C yr -1 at present, which is in agreement with results from forest inventories but significantly differs from the figure of 1.5 Pg C yr -1 previously estimated when ignoring changes in lateral carbon fluxes. We suggest that carbon fluxes along the land-ocean aquatic continuum need to be included in global carbon dioxide budgets.

Biodiverse planting for carbon and biodiversity on indigenous land.

Science.gov (United States)

Renwick, Anna R; Robinson, Catherine J; Martin, Tara G; May, Tracey; Polglase, Phil; Possingham, Hugh P; Carwardine, Josie

2014-01-01

Carbon offset mechanisms have been established to mitigate climate change through changes in land management. Regulatory frameworks enable landowners and managers to generate saleable carbon credits on domestic and international markets. Identifying and managing the associated co-benefits and dis-benefits involved in the adoption of carbon offset projects is important for the projects to contribute to the broader goal of sustainable development and the provision of benefits to the local communities. So far it has been unclear how Indigenous communities can benefit from such initiatives. We provide a spatial analysis of the carbon and biodiversity potential of one offset method, planting biodiverse native vegetation, on Indigenous land across Australia. We discover significant potential for opportunities for Indigenous communities to achieve carbon sequestration and biodiversity goals through biodiverse plantings, largely in southern and eastern Australia, but the economic feasibility of these projects depend on carbon market assumptions. Our national scale cost-effectiveness analysis is critical to enable Indigenous communities to maximise the benefits available to them through participation in carbon offset schemes.

Distributions of carbon in calcareous soils under different land uses in western Iran

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H. Sepahvand

2016-10-01

Full Text Available Concentrations of Natural stable and unstable carbon in ecosystems have been used extensively to help to understand a wide range of soil processes and functions. This study was conducted to explore the effects of land use changes on different carbon fractions (F1, F2, F3 and F4, permanganate oxidizable carbon (POXC, soil organic carbon (SOC and total organic carbon (TOC associated with soils in calcareous soils of western Iran. Four popular land uses in the selected site including natural forest, range land, dryland farming and irrigated farming systems were employed as the basis of soil sampling. The results showed a strong relationship between land use conversion and SOC stocks changes. The greatest mean values for carbon content and the least mean values of CaCO3 in bulk topsoil (0–15 cm in the forest land were observed. Dryland farming had the least both active and passive pools of C in comparison with the other land uses. The positive and significant correlations was observed between SOC, Total C and POXC contents and different C fractions. Taking C and POXC pools into account, a more definitive picture of the soil C is obtained than when only total C is measured. The influence of land use changes on overall soil carbon stocks could be helpful for making management decision for farmers and policy makers in the future, for enhancing the potential of C sequestration in western Iran.

Livestock and human use of land: Productivity trends and dietary choices as drivers of future land and carbon dynamics

Science.gov (United States)

Weindl, Isabelle; Popp, Alexander; Bodirsky, Benjamin Leon; Rolinski, Susanne; Lotze-Campen, Hermann; Biewald, Anne; Humpenöder, Florian; Dietrich, Jan Philipp; Stevanović, Miodrag

2017-12-01

Land use change has been the primary driving force of human alteration of terrestrial ecosystems. With 80% of agricultural land dedicated to livestock production, the sector is an important lever to attenuate land requirements for food production and carbon emissions from land use change. In this study, we quantify impacts of changing human diets and livestock productivity on land dynamics and depletion of carbon stored in vegetation, litter and soils. Across all investigated productivity pathways, lower consumption of livestock products can substantially reduce deforestation (47-55%) and cumulative carbon losses (34-57%). On the supply side, already minor productivity growth in extensive livestock production systems leads to substantial CO2 emission abatement, but the emission saving potential of productivity gains in intensive systems is limited, also involving trade-offs with soil carbon stocks. If accounting for uncertainties related to future trade restrictions, crop yields and pasture productivity, the range of projected carbon savings from changing diets increases to 23-78%. Highest abatement of carbon emissions (63-78%) can be achieved if reduced consumption of animal-based products is combined with sustained investments into productivity increases in plant production. Our analysis emphasizes the importance to integrate demand- and supply-side oriented mitigation strategies and to combine efforts in the crop and livestock sector to enable synergies for climate protection.

Global Tree Cover and Biomass Carbon on Agricultural Land: The contribution of agroforestry to global and national carbon budgets.

Science.gov (United States)

Zomer, Robert J; Neufeldt, Henry; Xu, Jianchu; Ahrends, Antje; Bossio, Deborah; Trabucco, Antonio; van Noordwijk, Meine; Wang, Mingcheng

2016-07-20

Agroforestry systems and tree cover on agricultural land make an important contribution to climate change mitigation, but are not systematically accounted for in either global carbon budgets or national carbon accounting. This paper assesses the role of trees on agricultural land and their significance for carbon sequestration at a global level, along with recent change trends. Remote sensing data show that in 2010, 43% of all agricultural land globally had at least 10% tree cover and that this has increased by 2% over the previous ten years. Combining geographically and bioclimatically stratified Intergovernmental Panel on Climate Change (IPCC) Tier 1 default estimates of carbon storage with this tree cover analysis, we estimated 45.3 PgC on agricultural land globally, with trees contributing >75%. Between 2000 and 2010 tree cover increased by 3.7%, resulting in an increase of >2 PgC (or 4.6%) of biomass carbon. On average, globally, biomass carbon increased from 20.4 to 21.4 tC ha(-1). Regional and country-level variation in stocks and trends were mapped and tabulated globally, and for all countries. Brazil, Indonesia, China and India had the largest increases in biomass carbon stored on agricultural land, while Argentina, Myanmar, and Sierra Leone had the largest decreases.

Evolvement rules of basin flood risk under low-carbon mode. Part I: response of soil organic carbon to land use change and its influence on land use planning in the Haihe basin.

Science.gov (United States)

Li, Fawen; Wang, Liping; Zhao, Yong

2017-08-01

Soil organic carbon (SOC) plays an important role in the global carbon cycle. The aim of this study was to evaluate the response of SOC to land use change and its influence on land use planning in the Haihe basin, and provide planning land use pattern for basin flood risk assessment. Firstly, the areas of different land use types in 1980, 2008, and the planning year (2020) were counted by area statistics function of ArcGIS. Then, the transfer matrixes of land use were produced by spatial overlay analysis function. Lastly, based on the land use maps, soil type map and soil profile database, SOC storage of different land use types in three different periods were calculated. The results showed the patterns of land use have changed a lot from 1980 to 2008, among the 19,835 km 2 of grassland was transformed into forestland, which was the largest conversion landscape. And land use conversion brought the SOC storage changes. Total carbon source was 88.83 Tg, and total carbon sink was 85.49 Tg. So, the Haihe basin presented as a carbon source from 1980 to 2008. From 2008 to 2020, the changes of forestland and grassland are the biggest in Haihe basin, which cause the SOC pool change from a carbon source to a carbon sink. SOC storage will increase from 2420.5 Tg in 2008 to 2495.5 Tg in 2020. The changing trend is conducive to reducing atmospheric concentrations. Therefore, land use planning in Haihe basin is reasonable and can provide the underlying surface condition for flood risk assessment.

Seasonal effects of irrigation on land-atmosphere latent heat, sensible heat and carbon fluxes in semi-arid basin

Science.gov (United States)

Xie, Zhenghui; Zeng, Yujin

2017-04-01

Irrigation, which constitutes 70% of the total amount of fresh water consumed by the human population, is significantly impacting the land-atmosphere fluxes. In this study, using the improved Community Land Model version 4.5 (CLM 4.5) with an active crop model, two high resolution ( 1 km) simulations investigating the effects of irrigation on Latent Heat (LH), Sensible Heat (SH) and Carbon Fluxes (or net ecosystem exchange, NEE) from land to atmosphere on the Heihe River Basin in northwestern China were conducted using a high-quality irrigation dataset compiled from 1981 to 2013. The model output and measurements from remote sensing demonstrated the capacity and viability of the developed models to reproduce ecological and hydrological processes. The results revealed the effects of irrigation on LH and SH are strongest during summer with a LH increase of 100 W/m2 and a SH decrease of 60 W/m2 over intensely irrigated areas. However, the reactions are much weaker during spring and autumn when there is much less irrigation. When the irrigation rate below 5 mm/day, the LH generally increases, whereas the SH decreases with growing irrigation rates. However, when the irrigation threshold is in excess of 5 mm/day, there is no accrued effect of irrigation on the LH and SH. Irrigation produces opposite effects to the NEE during spring and summer. During the spring, irrigation yields more discharged carbon from the land to the atmosphere, increasing the NEE value by 0.4-0.8 gC/m2/day, while the summer irrigation favors crop fixing of carbon from atmospheric CO2, decreasing the NEE value by 0.8 gC/m2/day. The repercussions of irrigation on land-atmosphere fluxes are not solely linked to the irrigation amount, and other parameters (especially the temperature) also control the effects of irrigation on LH, SH and NEE. The study indicates that how a land surface model with high spatial resolution can represent crop growing and its effects over basin scale.

Seasonal effects of irrigation on land-atmosphere latent heat, sensible heat, and carbon fluxes in semiarid basin

Science.gov (United States)

Zeng, Yujin; Xie, Zhenghui; Liu, Shuang

2017-02-01

Irrigation, which constitutes ˜ 70 % of the total amount of freshwater consumed by the human population, is significantly impacting land-atmosphere fluxes. In this study, using the improved Community Land Model version 4.5 (CLM4.5) with an active crop model, two high-resolution (˜ 1 km) simulations investigating the effects of irrigation on latent heat (LH), sensible heat (SH), and carbon fluxes (or net ecosystem exchange, NEE) from land to atmosphere in the Heihe River basin in northwestern China were conducted using a high-quality irrigation dataset compiled from 1981 to 2013. The model output and measurements from remote sensing demonstrated the capacity of the developed models to reproduce ecological and hydrological processes. The results revealed that the effects of irrigation on LH and SH are strongest during summer, with a LH increase of ˜ 100 W m-2 and a SH decrease of ˜ 60 W m-2 over intensely irrigated areas. However, the reactions are much weaker during spring and autumn when there is much less irrigation. When the irrigation rate is below 5 mm day-1, the LH generally increases, whereas the SH decreases with growing irrigation rates. However, when the irrigation threshold is in excess of 5 mm day-1, there is no accrued effect of irrigation on the LH and SH. Irrigation produces opposite effects to the NEE during spring and summer. During the spring, irrigation yields more discharged carbon from the land to the atmosphere, increasing the NEE value by 0.4-0.8 gC m-2 day-1, while the summer irrigation favors crop fixing of carbon from atmospheric CO2, decreasing the NEE value by ˜ 0.8 gC m-2 day-1. The repercussions of irrigation on land-atmosphere fluxes are not solely linked to the irrigation amount, and other parameters (especially the temperature) also control the effects of irrigation on LH, SH, and NEE.

Wildland fire emissions, carbon, and climate: Seeing the forest and the trees - A cross-scale assessment of wildfire and carbon dynamics in fire-prone, forested ecosystems

Science.gov (United States)

Rachel A. Loehman; Elizabeth Reinhardt; Karin L. Riley

2014-01-01

Wildfires are an important component of the terrestrial carbon cycle and one of the main pathways for movement of carbon from the land surface to the atmosphere. Fires have received much attention in recent years as potential catalysts for shifting landscapes from carbon sinks to carbon sources. Unless structural or functional ecosystem shifts occur, net carbon balance...

Land Use and Climate Alter Carbon Dynamics in Watersheds of Chesapeake Bay

Science.gov (United States)

Kaushal, S.; Duan, S.; Grese, M.; Pennino, M. J.; Belt, K. T.; Findlay, S.; Groffman, P. M.; Mayer, P. M.; Murthy, S.; Blomquist, J.

2011-12-01

There have been long-term changes in the quantity of organic carbon in streams and rivers globally. Shifts in the quality of organic carbon due to environmental changes may also impact downstream ecosystem metabolism and fate and transport of contaminants. We investigated long-term impacts of land use and hydrologic variability on organic carbon transport in watersheds of the Baltimore Long-Term Ecological Research (LTER) site and large rivers of the Chesapeake Bay. In small and medium-sized watersheds of the Baltimore LTER site, urban land use increased organic carbon concentrations in streams several-fold compared to forest and agricultural watersheds. Enzymatic activities of stream microbes were significantly altered across watershed land use during a record wet year. During the wet year, short-term bioassays showed that bioavailable dissolved organic carbon varied seasonally, but comprised a substantial proportion of the dissolved organic carbon pool. Similarly, measurements of biochemical oxygen demand across hydrologic variability suggest that reactive organic carbon export from small and medium-sized urban watersheds during storms can be substantial. At a larger regional scale, major tributaries such as the Potomac, Susquehanna, Patuxent, and Choptank rivers also showed similar variability as smaller watersheds in quantity and quality of organic carbon based on land use and climate. There were distinct isotopic values of d13C of particulate organic matter and fluorescence excitation emission matrices for rivers influenced by different land uses. Stable isotopic values of d13C of particulate organic matter and fluorescence excitation emission matrices showed marked seasonal changes in organic matter quality during spring floods in the Potomac River at Washington D.C. Across watershed size, there appeared to be differences in seasonal cycles of organic carbon quality and this may have been based on the degree of hydrologic connectivity between watersheds and

Dynamics Analysis Of Land-Based Carbon Stock In The Region Of Samarinda East Kalimantan Province

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Zikri Azham

2017-10-01

Full Text Available This study aims to determine the potential dynamics of carbon stocks in various land cover classes in the city of Samarinda in the calculation of carbon stocks land cover only devided into three 3 Class Land Cover CLC is a secondary forest CLC CLC thickets and CLC shrubs. Research results show that the above ground carbon AGC stocks on Secondary Forest Land Cover Class average of 71.93 tonnesha the land cover classes thickets of 32.34 tonnes hectares and shrubs land cover classes of 19.66 tonnes hectare. The carbon stocks in 2009 amounted to 2589929 tonnes in 2012 there were 2347477 tons and in 2015 there were 2201005 tonnes. Estimated decrease in land-based stock carbon in the city of Samarinda during the period 2009-2015 amounted to 388943 tonnes or an average of 70170 tonnes per year or approximately 2.73year or the emissions in the field of land amounting to 254538 tonnes of CO2 equivalent.

Spatial scaling of net primary productivity using subpixel landcover information

Science.gov (United States)

Chen, X. F.; Chen, Jing M.; Ju, Wei M.; Ren, L. L.

2008-10-01

Gridding the land surface into coarse homogeneous pixels may cause important biases on ecosystem model estimations of carbon budget components at local, regional and global scales. These biases result from overlooking subpixel variability of land surface characteristics. Vegetation heterogeneity is an important factor introducing biases in regional ecological modeling, especially when the modeling is made on large grids. This study suggests a simple algorithm that uses subpixel information on the spatial variability of land cover type to correct net primary productivity (NPP) estimates, made at coarse spatial resolutions where the land surface is considered as homogeneous within each pixel. The algorithm operates in such a way that NPP obtained from calculations made at coarse spatial resolutions are multiplied by simple functions that attempt to reproduce the effects of subpixel variability of land cover type on NPP. Its application to a carbon-hydrology coupled model(BEPS-TerrainLab model) estimates made at a 1-km resolution over a watershed (named Baohe River Basin) located in the southwestern part of Qinling Mountains, Shaanxi Province, China, improved estimates of average NPP as well as its spatial variability.

Land Clearing and the Biofuel Carbon Debt

Science.gov (United States)

Fargione, Joseph; Hill, Jason; Tilman, David; Polasky, Stephen; Hawthorne, Peter

2008-02-01

Increasing energy use, climate change, and carbon dioxide (CO2) emissions from fossil fuels make switching to low-carbon fuels a high priority. Biofuels are a potential low-carbon energy source, but whether biofuels offer carbon savings depends on how they are produced. Converting rainforests, peatlands, savannas, or grasslands to produce food crop based biofuels in Brazil, Southeast Asia, and the United States creates a “biofuel carbon debt” by releasing 17 to 420 times more CO2 than the annual greenhouse gas (GHG) reductions that these biofuels would provide by displacing fossil fuels. In contrast, biofuels made from waste biomass or from biomass grown on degraded and abandoned agricultural lands planted with perennials incur little or no carbon debt and can offer immediate and sustained GHG advantages.

Estimating Terrestrial Wood Biomass from Observed Concentrations of Atmospheric Carbon Dioxide

NARCIS (Netherlands)

Schaefer, K. M.; Peters, W.; Carvalhais, N.; van der Werf, G.; Miller, J.

2008-01-01

We estimate terrestrial disequilibrium state and wood biomass from observed concentrations of atmospheric CO2 using the CarbonTracker system coupled to the SiBCASA biophysical model. Starting with a priori estimates of carbon flux from the land, ocean, and fossil fuels, CarbonTracker estimates net

A land-use and land-cover modeling strategy to support a national assessment of carbon stocks and fluxes

Science.gov (United States)

Sohl, Terry L.; Sleeter, Benjamin M.; Zhu, Zhi-Liang; Sayler, Kristi L.; Bennett, Stacie; Bouchard, Michelle; Reker, Ryan R.; Hawbaker, Todd; Wein, Anne; Liu, Shu-Guang; Kanengieter, Ronald; Acevedo, William

2012-01-01

Changes in land use, land cover, disturbance regimes, and land management have considerable influence on carbon and greenhouse gas (GHG) fluxes within ecosystems. Through targeted land-use and land-management activities, ecosystems can be managed to enhance carbon sequestration and mitigate fluxes of other GHGs. National-scale, comprehensive analyses of carbon sequestration potential by ecosystem are needed, with a consistent, nationally applicable land-use and land-cover (LULC) modeling framework a key component of such analyses. The U.S. Geological Survey has initiated a project to analyze current and projected future GHG fluxes by ecosystem and quantify potential mitigation strategies. We have developed a unique LULC modeling framework to support this work. Downscaled scenarios consistent with IPCC Special Report on Emissions Scenarios (SRES) were constructed for U.S. ecoregions, and the FORE-SCE model was used to spatially map the scenarios. Results for a prototype demonstrate our ability to model LULC change and inform a biogeochemical modeling framework for analysis of subsequent GHG fluxes. The methodology was then successfully used to model LULC change for four IPCC SRES scenarios for an ecoregion in the Great Plains. The scenario-based LULC projections are now being used to analyze potential GHG impacts of LULC change across the U.S.

Africa and the global carbon cycle

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Denning A Scott

2007-03-01

Full Text Available Abstract The African continent has a large and growing role in the global carbon cycle, with potentially important climate change implications. However, the sparse observation network in and around the African continent means that Africa is one of the weakest links in our understanding of the global carbon cycle. Here, we combine data from regional and global inventories as well as forward and inverse model analyses to appraise what is known about Africa's continental-scale carbon dynamics. With low fossil emissions and productivity that largely compensates respiration, land conversion is Africa's primary net carbon release, much of it through burning of forests. Savanna fire emissions, though large, represent a short-term source that is offset by ensuing regrowth. While current data suggest a near zero decadal-scale carbon balance, interannual climate fluctuations (especially drought induce sizeable variability in net ecosystem productivity and savanna fire emissions such that Africa is a major source of interannual variability in global atmospheric CO2. Considering the continent's sizeable carbon stocks, their seemingly high vulnerability to anticipated climate and land use change, as well as growing populations and industrialization, Africa's carbon emissions and their interannual variability are likely to undergo substantial increases through the 21st century.

PV water pumping for carbon sequestration in dry land agriculture

International Nuclear Information System (INIS)

Olsson, Alexander; Campana, Pietro Elia; Lind, Mårten; Yan, Jinyue

2015-01-01

Highlights: • A novel model for carbon sequestration in dry land agriculture is developed. • We consider the water-food-energy-climate nexus to assess carbon sequestration. • Using water for carbon sequestration should be assessed critically. • Co-benefits of carbon sequestration should be included in the assessment. • Moisture feedback is part of the nexus model. - Abstract: This paper suggests a novel model for analysing carbon sequestration activities in dry land agriculture considering the water-food-energy-climate nexus. The paper is based on our on-going studies on photovoltaic water pumping (PVWP) systems for irrigation of grasslands in China. Two carbon sequestration projects are analysed in terms of their water productivity and carbon sequestration potential. It is concluded that the economic water productivity, i.e. how much water that is needed to produce an amount of grass, of grassland restoration is low and that there is a need to include several of the other co-benefits to justify the use of water for climate change mitigation. The co-benefits are illustrated in a nexus model including (1) climate change mitigation, (2) water availability, (3) downstream water impact, (4) energy security, (5) food security and (6) moisture recycling. We argue for a broad approach when analysing water for carbon sequestration. The model includes energy security and food security together with local and global water concerns. This makes analyses of dry land carbon sequestration activities more relevant and accurate. Without the nexus approach, the co-benefits of grassland restoration tend to be diminished

Controls on declining carbon balance with leaf age among 10 woody species in Australian woodland: do leaves have zero daily net carbon balances when they die?

Science.gov (United States)

Reich, Peter B; Falster, Daniel S; Ellsworth, David S; Wright, Ian J; Westoby, Mark; Oleksyn, Jacek; Lee, Tali D

2009-01-01

* Here, we evaluated how increased shading and declining net photosynthetic capacity regulate the decline in net carbon balance with increasing leaf age for 10 Australian woodland species. We also asked whether leaves at the age of their mean life-span have carbon balances that are positive, zero or negative. * The net carbon balances of 2307 leaves on 53 branches of the 10 species were estimated. We assessed three-dimensional architecture, canopy openness, photosynthetic light response functions and dark respiration rate across leaf age sequences on all branches. We used YPLANT to estimate light interception and to model carbon balance along the leaf age sequences. * As leaf age increased to the mean life-span, increasing shading and declining photosynthetic capacity each separately reduced daytime carbon gain by approximately 39% on average across species. Together, they reduced daytime carbon gain by 64% on average across species. * At the age of their mean life-span, almost all leaves had positive daytime carbon balances. These per leaf carbon surpluses were of a similar magnitude to the estimated whole-plant respiratory costs per leaf. Thus, the results suggest that a whole-plant economic framework, including respiratory costs, may be useful in assessing controls on leaf longevity.

How does soil erosion influence the terrestrial carbon cycle and the impacts of land use and land cover change?

Science.gov (United States)

Naipal, V.; Wang, Y.; Ciais, P.; Guenet, B.; Lauerwald, R.

2017-12-01

The onset of agriculture has accelerated soil erosion rates significantly, mobilizing vast quantities of soil organic carbon (SOC) globally. Studies show that at timescales of decennia to millennia this mobilized SOC can significantly alter previously estimated carbon emissions from land use and land cover change (LULCC). However, a full understanding of the impact of soil erosion on land-atmosphere carbon exchange is still missing. The aim of our study is to better constrain the terrestrial carbon fluxes by developing methods, which are compatible with earth system models (ESMs), and explicitly represent the links between soil erosion and carbon dynamics. For this we use an emulator that represents the carbon cycle of ORCHIDEE, which is the land component of the IPSL ESM, in combination with an adjusted version of the Revised Universal Soil Loss Equation (RUSLE) model. We applied this modeling framework at the global scale to evaluate how soil erosion influenced the terrestrial carbon cycle in the presence of elevated CO2, regional climate change and land use change. Here, we focus on the effects of soil detachment by erosion only and do not consider sediment transport and deposition. We found that including soil erosion in the SOC dynamics-scheme resulted in two times more SOC being lost during the historical period (1850-2005 AD). LULCC is the main contributor to this SOC loss, whose impact on the SOC stocks is significantly amplified by erosion. Regionally, the influence of soil erosion varies significantly, depending on the magnitude of the perturbations to the carbon cycle and the effects of LULCC and climate change on soil erosion rates. We conclude that it is necessary to include soil erosion in assessments of LULCC, and to explicitly consider the effects of elevated CO2 and climate change on the carbon cycle and on soil erosion, for better quantification of past, present, and future LULCC carbon emissions.

Nutrient limitation reduces land carbon uptake in simulations with a model of combined carbon, nitrogen and phosphorus cycling

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D. S. Goll

2012-09-01

Full Text Available Terrestrial carbon (C cycle models applied for climate projections simulate a strong increase in net primary productivity (NPP due to elevated atmospheric CO₂ concentration during the 21st century. These models usually neglect the limited availability of nitrogen (N and phosphorus (P, nutrients that commonly limit plant growth and soil carbon turnover. To investigate how the projected C sequestration is altered when stoichiometric constraints on C cycling are considered, we incorporated a P cycle into the land surface model JSBACH (Jena Scheme for Biosphere–Atmosphere Coupling in Hamburg, which already includes representations of coupled C and N cycles.

The model reveals a distinct geographic pattern of P and N limitation. Under the SRES (Special Report on Emissions Scenarios A1B scenario, the accumulated land C uptake between 1860 and 2100 is 13% (particularly at high latitudes and 16% (particularly at low latitudes lower in simulations with N and P cycling, respectively, than in simulations without nutrient cycles. The combined effect of both nutrients reduces land C uptake by 25% compared to simulations without N or P cycling. Nutrient limitation in general may be biased by the model simplicity, but the ranking of limitations is robust against the parameterization and the inflexibility of stoichiometry. After 2100, increased temperature and high CO₂ concentration cause a shift from N to P limitation at high latitudes, while nutrient limitation in the tropics declines. The increase in P limitation at high-latitudes is induced by a strong increase in NPP and the low P sorption capacity of soils, while a decline in tropical NPP due to high autotrophic respiration rates alleviates N and P limitations. The quantification of P limitation remains challenging. The poorly constrained processes of soil P sorption and biochemical mineralization are identified as the main uncertainties in the strength of P limitation

Warmer temperatures reduce net carbon uptake, but not water use, in a mature southern Appalachian forest

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Increasing air temperature is expected to extend growing season length in temperate, broadleaf forests, leading to potential increases in evapotranspiration and net carbon uptake. However, other key processes affecting water and carbon cycles are also highly temperature-dependent...

Net Community Metabolism and Seawater Carbonate Chemistry Scale Non-intuitively with Coral Cover

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Heather N. Page

2017-05-01

Full Text Available Coral cover and reef health have been declining globally as reefs face local and global stressors including higher temperature and ocean acidification (OA. Ocean warming and acidification will alter rates of benthic reef metabolism (i.e., primary production, respiration, calcification, and CaCO3 dissolution, but our understanding of community and ecosystem level responses is limited in terms of functional, spatial, and temporal scales. Furthermore, dramatic changes in coral cover and benthic metabolism could alter seawater carbonate chemistry on coral reefs, locally alleviating or exacerbating OA. This study examines how benthic metabolic rates scale with changing coral cover (0–100%, and the subsequent influence of these coral communities on seawater carbonate chemistry based on mesocosm experiments in Bermuda and Hawaii. In Bermuda, no significant differences in benthic metabolism or seawater carbonate chemistry were observed for low (40% and high (80% coral cover due to large variability within treatments. In contrast, significant differences were detected between treatments in Hawaii with benthic metabolic rates increasing with increasing coral cover. Observed increases in daily net community calcification and nighttime net respiration scaled proportionally with coral cover. This was not true for daytime net community organic carbon production rates, which increased the most between 0 and 20% coral cover and then less so between 20 and 100%. Consequently, diel variability in seawater carbonate chemistry increased with increasing coral cover, but absolute values of pH, Ωa, and pCO2 were not significantly different during daytime. To place the results of the mesocosm experiments into a broader context, in situ seawater carbon dioxide (CO2 at three reef sites in Bermuda and Hawaii were also evaluated; reefs with higher coral cover experienced a greater range of diel CO2 levels, complementing the mesocosm results. The results from this study

North America's net terrestrial CO2 exchange with the atmosphere 1990–2009

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King, A.W.; Andres, R.J.; Davis, K.J.; Hafer, M.; Hayes, D.J.; Huntzinger, Deborah N.; de Jong, Bernardus; Kurz, W.A.; McGuire, A. David; Vargas, Rodrigo I.; Wei, Y.; West, Tristram O.; Woodall, Christopher W.

2015-01-01

Scientific understanding of the global carbon cycle is required for developing national and international policy to mitigate fossil fuel CO2 emissions by managing terrestrial carbon uptake. Toward that understanding and as a contribution to the REgional Carbon Cycle Assessment and Processes (RECCAP) project, this paper provides a synthesis of net land–atmosphere CO2 exchange for North America (Canada, United States, and Mexico) over the period 1990–2009. Only CO2 is considered, not methane or other greenhouse gases. This synthesis is based on results from three different methods: atmospheric inversion, inventory-based methods and terrestrial biosphere modeling. All methods indicate that the North American land surface was a sink for atmospheric CO2, with a net transfer from atmosphere to land. Estimates ranged from −890 to −280 Tg C yr−1, where the mean of atmospheric inversion estimates forms the lower bound of that range (a larger land sink) and the inventory-based estimate using the production approach the upper (a smaller land sink). This relatively large range is due in part to differences in how the approaches represent trade, fire and other disturbances and which ecosystems they include. Integrating across estimates, "best" estimates (i.e., measures of central tendency) are −472 ± 281 Tg C yr−1 based on the mean and standard deviation of the distribution and −360 Tg C yr−1 (with an interquartile range of −496 to −337) based on the median. Considering both the fossil fuel emissions source and the land sink, our analysis shows that North America was, however, a net contributor to the growth of CO2 in the atmosphere in the late 20th and early 21st century. With North America's mean annual fossil fuel CO2 emissions for the period 1990–2009 equal to 1720 Tg C yr−1 and assuming the estimate of −472 Tg C yr−1 as an approximation of the true terrestrial CO2 sink, the continent's source : sink ratio for this time period was

The Australian terrestrial carbon budget

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V. Haverd

2013-02-01

Full Text Available This paper reports a study of the full carbon (C-CO₂ budget of the Australian continent, focussing on 1990–2011 in the context of estimates over two centuries. The work is a contribution to the RECCAP (REgional Carbon Cycle Assessment and Processes project, as one of numerous regional studies. In constructing the budget, we estimate the following component carbon fluxes: net primary production (NPP; net ecosystem production (NEP; fire; land use change (LUC; riverine export; dust export; harvest (wood, crop and livestock and fossil fuel emissions (both territorial and non-territorial. Major biospheric fluxes were derived using BIOS2 (Haverd et al., 2012, a fine-spatial-resolution (0.05° offline modelling environment in which predictions of CABLE (Wang et al., 2011, a sophisticated land surface model with carbon cycle, are constrained by multiple observation types. The mean NEP reveals that climate variability and rising CO₂ contributed 12 ± 24 (1σ error on mean and 68 ± 15 TgC yr⁻¹, respectively. However these gains were partially offset by fire and LUC (along with other minor fluxes, which caused net losses of 26 ± 4 TgC yr⁻¹ and 18 ± 7 TgC yr⁻¹, respectively. The resultant net biome production (NBP is 36 ± 29 TgC yr⁻¹, in which the largest contributions to uncertainty are NEP, fire and LUC. This NBP offset fossil fuel emissions (95 ± 6 TgC yr⁻¹ by 38 ± 30%. The interannual variability (IAV in the Australian carbon budget exceeds Australia's total carbon emissions by fossil fuel combustion and is dominated by IAV in NEP. Territorial fossil fuel emissions are significantly smaller than the rapidly growing fossil fuel exports: in 2009–2010, Australia exported 2.5 times more carbon in fossil fuels than it emitted by burning fossil fuels.

Soil Organic Carbon Fractions and Stocks Respond to Restoration Measures in Degraded Lands by Water Erosion

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Nie, Xiaodong; Li, Zhongwu; Huang, Jinquan; Huang, Bin; Xiao, Haibing; Zeng, Guangming

2017-05-01

Assessing the degree to which degraded soils can be recovered is essential for evaluating the effects of adopted restoration measures. The objective of this study was to determine the restoration of soil organic carbon under the impact of terracing and reforestation. A small watershed with four typical restored plots (terracing and reforestation (four different local plants)) and two reference plots (slope land with natural forest (carbon-depleted) and abandoned depositional land (carbon-enriched)) in subtropical China was studied. The results showed that soil organic carbon, dissolved organic carbon and microbial biomass carbon concentrations in the surface soil (10 cm) of restored lands were close to that in abandoned depositional land and higher than that in natural forest land. There was no significant difference in soil organic carbon content among different topographic positions of the restored lands. Furthermore, the soil organic carbon stocks in the upper 60 cm soils of restored lands, which were varied between 50.08 and 62.21 Mg C ha-1, were higher than 45.90 Mg C ha-1 in natural forest land. Our results indicated that the terracing and reforestation could greatly increase carbon sequestration and accumulation and decrease carbon loss induced by water erosion. And the combination measures can accelerate the restoration of degraded soils when compared to natural forest only. Forest species almost have no impact on the total amount of soil organic carbon during restoration processes, but can significantly influence the activity and stability of soil organic carbon. Combination measures which can provide suitable topography and continuous soil organic carbon supply could be considered in treating degraded soils caused by water erosion.

Soil Organic Carbon Fractions and Stocks Respond to Restoration Measures in Degraded Lands by Water Erosion.

Science.gov (United States)

Nie, Xiaodong; Li, Zhongwu; Huang, Jinquan; Huang, Bin; Xiao, Haibing; Zeng, Guangming

2017-05-01

Assessing the degree to which degraded soils can be recovered is essential for evaluating the effects of adopted restoration measures. The objective of this study was to determine the restoration of soil organic carbon under the impact of terracing and reforestation. A small watershed with four typical restored plots (terracing and reforestation (four different local plants)) and two reference plots (slope land with natural forest (carbon-depleted) and abandoned depositional land (carbon-enriched)) in subtropical China was studied. The results showed that soil organic carbon, dissolved organic carbon and microbial biomass carbon concentrations in the surface soil (10 cm) of restored lands were close to that in abandoned depositional land and higher than that in natural forest land. There was no significant difference in soil organic carbon content among different topographic positions of the restored lands. Furthermore, the soil organic carbon stocks in the upper 60 cm soils of restored lands, which were varied between 50.08 and 62.21 Mg C ha -1 , were higher than 45.90 Mg C ha -1 in natural forest land. Our results indicated that the terracing and reforestation could greatly increase carbon sequestration and accumulation and decrease carbon loss induced by water erosion. And the combination measures can accelerate the restoration of degraded soils when compared to natural forest only. Forest species almost have no impact on the total amount of soil organic carbon during restoration processes, but can significantly influence the activity and stability of soil organic carbon. Combination measures which can provide suitable topography and continuous soil organic carbon supply could be considered in treating degraded soils caused by water erosion.

Integrated carbon analysis of biomass production on fallow agricultural land and product substitution in Sweden - Preliminary results

Energy Technology Data Exchange (ETDEWEB)

Dornburg, Veronika; Eggers, Thies; Gustavsson, Leif [Mid Sweden Univ., Oestersund (Sweden). Ecotechnology

2006-07-15

An important option in the Swedish context to reduce its net emissions of carbon dioxide (CO{sub 2}) is the increased use of biomass for energy and material substitution. On fallow agricultural land additional production of biomass would be possible. We analyse biomass production systems based on Norway spruce, hybrid poplar and willow hybrids and the use of this biomass to replace fossil energy and energy intensive material systems. The highest biomass production potential is for willow in southern Sweden. Fertilisation management of spruce could shorten the rotation lengths by about 17%. The fertilised production of Norway spruce with use of harvested timber for construction and use of remaining woody biomass for heat and power production gives the largest reductions of carbon emissions per hectare under the assumptions made. The use of willow for heat and power and of fertilised spruce for a wood product mix lead to the highest fossil primary energy savings in our scenarios. Spruce cultivations can achieve considerable carbon emission reductions in the long term, but willow and poplar might be a good option when fossil energy savings and carbon emission reductions should be achieved in the short term.

Carbon Sequestration in Colorado's Lands: A Spatial and Policy Analysis

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Brandt, N.; Brazeau, A.; Browning, K.; Meier, R.

2017-12-01

Managing landscapes to enhance terrestrial carbon sequestration has significant potential to mitigate climate change. While a previous carbon baseline assessment in Colorado has been published (Conant et al, 2007), our study pulls from the existing literature to conduct an updated baseline assessment of carbon stocks and a unique review of carbon policies in Colorado. Through a multi-level spatial analysis based in GIS and informed by a literature review, we established a carbon stock baseline and ran four land use and carbon stock projection scenarios using Monte Carlo simulations. We identified 11 key policy recommendations for improving Colorado's carbon stocks, and evaluated each using Bardach's policy matrix approach (Bardach, 2012). We utilized a series of case studies to support our policy recommendations. We found that Colorado's lands have a carbon stock of 3,334 MMT CO2eq, with Forests and Woodlands holding the largest stocks, at 1,490 and 774 MMT CO2eq respectively. Avoided conversion of all Grasslands, Forests, and Wetlands in Colorado projected over 40 years would increase carbon stocks by 32 MMT CO2eq, 1,053 MMT CO2eq, and 36 MMT CO2eq, respectively. Over the 40-year study period, Forests and Woodlands areas are projected to shrink while Shrublands and Developed areas are projected to grow. Those projections suggest sizable increases in area of future wildfires and development in Colorado. We found that numerous policy opportunities to sequester carbon exist at different jurisdictional levels and across land cover types. The largest opportunities were found in state-level policies and policies impacting Forests, Grasslands, and Wetlands. The passage of statewide emission reduction legislation has the highest potential to impact carbon sequestration, although political and administrative feasibility of this option are relatively low. This study contributes to the broader field of carbon sequestration literature by examining the nexus of carbon stocks

Managing Carbon on Federal Public Lands: Opportunities and Challenges in Southwestern Colorado

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Dilling, Lisa; Kelsey, Katharine C.; Fernandez, Daniel P.; Huang, Yin D.; Milford, Jana B.; Neff, Jason C.

2016-08-01

Federal lands in the United States have been identified as important areas where forests could be managed to enhance carbon storage and help mitigate climate change. However, there has been little work examining the context for decision making for carbon in a multiple-use public land environment, and how science can support decision making. This case study of the San Juan National Forest and the Bureau of Land Management Tres Rios Field Office in southwestern Colorado examines whether land managers in these offices have adequate tools, information, and management flexibility to practice effective carbon stewardship. To understand how carbon was distributed on the management landscape we added a newly developed carbon map for the SJNF-TRFO area based on Landsat TM texture information (Kelsey and Neff in Remote Sens 6:6407-6422. doi: 10.3390/rs6076407, 2014). We estimate that only about 22 % of the aboveground carbon in the SJNF-TRFO is in areas designated for active management, whereas about 38 % is in areas with limited management opportunities, and 29 % is in areas where natural processes should dominate. To project the effects of forest management actions on carbon storage, staff of the SJNF are expected to use the Forest Vegetation Simulator (FVS) and extensions. While identifying FVS as the best tool generally available for this purpose, the users and developers we interviewed highlighted the limitations of applying an empirically based model over long time horizons. Future research to improve information on carbon storage should focus on locations and types of vegetation where carbon management is feasible and aligns with other management priorities.

Estimate of total CO2 output from desertified sandy land in China

International Nuclear Information System (INIS)

Duan Zhenghu; Lanzhou University; Xiao Honglang; Dong Zhibao; He Xingdong; Wang Gang

2001-01-01

Soil is an important factor in regional and global carbon budgets because it serves as a reservoir of large amount of organic carbon. In our study, using remote sensing data of different periods we analyzed the development and reversion of desertification in China, calculated the variations of organic carbon contents of the desertified lands in China. The results showed that the total storage of organic carbon in 0-50cm soil layer of the desertified lands is 855Mt. In recent 40yr, the total CO 2 amount released by land desertification processes to the atmosphere was 150Mt, while the CO 2 amount sequestered by desertification reversing processes corresponded to 59MtC. Hence, the net CO 2 amount released from desertified lands of China corresponded to 91MtC, about 68.42% of the 133MtC of annual CO 2 release in the global temperate and frigid zones. Simultaneously, it indicated that CO 2 amount sequestered by desertification reversing processes in desertified land had greater potential than the other soils. (Author)

Simulating carbon sequestration using cellular automata and land use assessment for Karaj, Iran

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Khatibi, Ali; Pourebrahim, Sharareh; Mokhtar, Mazlin Bin

2018-06-01

Carbon sequestration has been proposed as a means of slowing the atmospheric and marine accumulation of greenhouse gases. This study used observed and simulated land use/cover changes to investigate and predict carbon sequestration rates in the city of Karaj. Karaj, a metropolis of Iran, has undergone rapid population expansion and associated changes in recent years, and these changes make it suitable for use as a case study for rapidly expanding urban areas. In particular, high quality agricultural space, green space and gardens have rapidly transformed into industrial, residential and urban service areas. Five classes of land use/cover (residential, agricultural, rangeland, forest and barren areas) were considered in the study; vegetation and soil samples were taken from 20 randomly selected locations. The level of carbon sequestration was determined for the vegetation samples by calculating the amount of organic carbon present using the dry plant weight method, and for soil samples by using the method of Walkley and Black. For each area class, average values of carbon sequestration in vegetation and soil samples were calculated to give a carbon sequestration index. A cellular automata approach was used to simulate changes in the classes. Finally, the carbon sequestration indices were combined with simulation results to calculate changes in carbon sequestration for each class. It is predicted that, in the 15 year period from 2014 to 2029, much agricultural land will be transformed into residential land, resulting in a severe reduction in the level of carbon sequestration. Results from this study indicate that expansion of forest areas in urban counties would be an effective means of increasing the levels of carbon sequestration. Finally, future opportunities to include carbon sequestration into the simulation of land use/cover changes are outlined.

Net soil respiration and greenhouse gas balance along a sequence of forest disturbance to smallholder rubber and oil palm plantations in Sumatra

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Khusyu Aini, Fitri; Hergoualc'h, Kristell; Smith, Jo; Verchot, Louis; Martius, Christopher

2017-04-01

The rapid increase in demand for land to establish oil palm and rubber plantations has led to the conversion of forests, with potential impacts on greenhouse gas emissions and on climate change. This study evaluates the net greenhouse gas balance following forest change to other land uses, i.e. one year rubber plantation, twenty-year rubber plantation and eight year oil palm plantation on Sumatran mineral soils. None of the plantations had ever been fertilized previously. During this study they were fertilized to provide nitrogen at the recommended rate used by farmers (33.3 kg N ha-1 y-1). The ecosystem stores carbon in litterfall, standing litter biomass (undergrowth vegetation, leaves, twigs, litter on the soil surface), soil organic matter, root biomass, and standing tree biomass. It releases carbon to the atmosphere through soil respiration fluxes, negative values indicating that carbon is stored by the land use change and positive values indicating emissions to the atmosphere. Net soil respiration was assessed using a mass balance approach: standing litter and tree biomass were measured once; the rate of carbon accumulation from standing litter and tree biomass was calculated by dividing the stock by the age of plantation or the time since logging started in the disturbed forest. The carbon accumulation in standing litter, tree biomass in the forest and soil organic matter for all land-uses was estimated from available in the literature. Root biomass for each land-use system was calculated using the root:shoot ratio. The net soil respiration of carbon dioxide from the forest, disturbed forest, one year rubber plantation, twenty-year rubber plantation and oil palm plantation were calculated to be -6 (± 5), 12 (± 6), 11 (± 15), 10 (± 5), 39 (± 7) Mg ha-1 y-1, respectively. Soil nitrous oxide, methane and litterfall were measured for 14 months and respiration fluxes were measured for 5 months across land uses and different seasons. The measured emissions of

Evaluation and uncertainty analysis of regional-scale CLM4.5 net carbon flux estimates

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Post, Hanna; Hendricks Franssen, Harrie-Jan; Han, Xujun; Baatz, Roland; Montzka, Carsten; Schmidt, Marius; Vereecken, Harry

2018-01-01

Modeling net ecosystem exchange (NEE) at the regional scale with land surface models (LSMs) is relevant for the estimation of regional carbon balances, but studies on it are very limited. Furthermore, it is essential to better understand and quantify the uncertainty of LSMs in order to improve them. An important key variable in this respect is the prognostic leaf area index (LAI), which is very sensitive to forcing data and strongly affects the modeled NEE. We applied the Community Land Model (CLM4.5-BGC) to the Rur catchment in western Germany and compared estimated and default ecological key parameters for modeling carbon fluxes and LAI. The parameter estimates were previously estimated with the Markov chain Monte Carlo (MCMC) approach DREAM(zs) for four of the most widespread plant functional types in the catchment. It was found that the catchment-scale annual NEE was strongly positive with default parameter values but negative (and closer to observations) with the estimated values. Thus, the estimation of CLM parameters with local NEE observations can be highly relevant when determining regional carbon balances. To obtain a more comprehensive picture of model uncertainty, CLM ensembles were set up with perturbed meteorological input and uncertain initial states in addition to uncertain parameters. C3 grass and C3 crops were particularly sensitive to the perturbed meteorological input, which resulted in a strong increase in the standard deviation of the annual NEE sum (σ ∑ NEE) for the different ensemble members from ˜ 2 to 3 g C m-2 yr-1 (with uncertain parameters) to ˜ 45 g C m-2 yr-1 (C3 grass) and ˜ 75 g C m-2 yr-1 (C3 crops) with perturbed forcings. This increase in uncertainty is related to the impact of the meteorological forcings on leaf onset and senescence, and enhanced/reduced drought stress related to perturbation of precipitation. The NEE uncertainty for the forest plant functional type (PFT) was considerably lower (σ ∑ NEE ˜ 4.0-13.5 g C

The LandCarbon Web Application: Advanced Geospatial Data Delivery and Visualization Tools for Communication about Ecosystem Carbon Sequestration and Greenhouse Gas Fluxes

Science.gov (United States)

Thomas, N.; Galey, B.; Zhu, Z.; Sleeter, B. M.; Lehmer, E.

2015-12-01

The LandCarbon web application (http://landcarbon.org) is a collaboration between the U.S. Geological Survey and U.C. Berkeley's Geospatial Innovation Facility (GIF). The LandCarbon project is a national assessment focused on improved understanding of carbon sequestration and greenhouse gas fluxes in and out of ecosystems related to land use, using scientific capabilities from USGS and other organizations. The national assessment is conducted at a regional scale, covers all 50 states, and incorporates data from remote sensing, land change studies, aquatic and wetland data, hydrological and biogeochemical modeling, and wildfire mapping to estimate baseline and future potential carbon storage and greenhouse gas fluxes. The LandCarbon web application is a geospatial portal that allows for a sophisticated data delivery system as well as a suite of engaging tools that showcase the LandCarbon data using interactive web based maps and charts. The web application was designed to be flexible and accessible to meet the needs of a variety of users. Casual users can explore the input data and results of the assessment for a particular area of interest in an intuitive and interactive map, without the need for specialized software. Users can view and interact with maps, charts, and statistics that summarize the baseline and future potential carbon storage and fluxes for U.S. Level 2 Ecoregions for 3 IPCC emissions scenarios. The application allows users to access the primary data sources and assessment results for viewing and download, and also to learn more about the assessment's objectives, methods, and uncertainties through published reports and documentation. The LandCarbon web application is built on free and open source libraries including Django and D3. The GIF has developed the Django-Spillway package, which facilitates interactive visualization and serialization of complex geospatial raster data. The underlying LandCarbon data is available through an open application

[Carbon sequestration in soil particle-sized fractions during reversion of desertification at Mu Us Sand land.

Science.gov (United States)

Ma, Jian Ye; Tong, Xiao Gang; Li, Zhan Bin; Fu, Guang Jun; Li, Jiao; Hasier

2016-11-18

The aim of this study was to investigate the effects of carbon sequestration in soil particle-sized fractions during reversion of desertification at Mu Us Sand Land, soil samples were collected from quicksand land, semifixed sand and fixed sand lands that were established by the shrub for 20-55 year-old and the arbor for 20-50 year-old at sand control region of Yulin in Northern Shaanxi Province. The dynamics and sequestration rate of soil organic carbon (SOC) associated with sand, silt and clay were measured by physical fractionation method. The results indicated that, compared with quicksand area, the carbon content in total SOC and all soil particle-sized fractions at bothsand-fixing sand forest lands showed a significant increasing trend, and the maximum carbon content was observed in the top layer of soils. From quicksand to fixed sand land with 55-year-old shrub and 50-year-old arbor, the annual sequestration rate of carbon stock in 0-5 cm soil depth was same in silt by 0.05 Mg·hm -2 ·a -1 . The increase rate of carbon sequestration in sand was 0.05 and 0.08 Mg·hm -2 ·a -1 , and in clay was 0.02 and 0.03 Mg·hm -2 ·a -1 at shrubs and arbors land, respectively. The increase rate of carbon sequestration in 0-20 cm soil layer for all the soil particles was averagely 2.1 times as that of 0-5 cm. At the annual increase rate of carbon, the stock of carbon in sand, silt and clay at the two fixed sand lands were increased by 6.7, 18.1 and 4.4 times after 50-55 year-old reversion of quicksand land to fixed sand. In addition, the average percentages that contributed to accumulation of total SOC by different particles in 0-20 cm soil were in the order of silt carbon (39.7%)≈sand carbon (34.6%) > clay carbon (25.6%). Generally, the soil particle-sized fractions had great carbon sequestration potential during reversion of desertification in Mu Us Sand Land, and the slit and sand were the main fractions for carbon sequestration at both fixed sand lands.

Scaling net ecosystem production and net biome production over a heterogeneous region in the western United States

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D. P. Turner

2007-08-01

Full Text Available Bottom-up scaling of net ecosystem production (NEP and net biome production (NBP was used to generate a carbon budget for a large heterogeneous region (the state of Oregon, 2.5×10⁵ km² in the western United States. Landsat resolution (30 m remote sensing provided the basis for mapping land cover and disturbance history, thus allowing us to account for all major fire and logging events over the last 30 years. For NEP, a 23-year record (1980–2002 of distributed meteorology (1 km resolution at the daily time step was used to drive a process-based carbon cycle model (Biome-BGC. For NBP, fire emissions were computed from remote sensing based estimates of area burned and our mapped biomass estimates. Our estimates for the contribution of logging and crop harvest removals to NBP were from the model simulations and were checked against public records of forest and crop harvesting. The predominately forested ecoregions within our study region had the highest NEP sinks, with ecoregion averages up to 197 gC m⁻² yr⁻¹. Agricultural ecoregions were also NEP sinks, reflecting the imbalance of NPP and decomposition of crop residues. For the period 1996–2000, mean NEP for the study area was 17.0 TgC yr⁻¹, with strong interannual variation (SD of 10.6. The sum of forest harvest removals, crop removals, and direct fire emissions amounted to 63% of NEP, leaving a mean NBP of 6.1 TgC yr⁻¹. Carbon sequestration was predominantly on public forestland, where the harvest rate has fallen dramatically in the recent years. Comparison of simulation results with estimates of carbon stocks, and changes in carbon stocks, based on forest inventory data showed generally good agreement. The carbon sequestered as NBP, plus accumulation of forest products in slow turnover pools, offset 51% of the annual emissions of fossil fuel CO₂ for the state. State-level NBP dropped below zero in 2002

Net carbon dioxide emissions from alternative firewood-production systems in Australia

International Nuclear Information System (INIS)

Paul, K.I.; Booth, T.H.; Jovanovic, T.; Polglase, P.J.; Elliott, A.; Kirschbaum, M.U.F.

2006-01-01

The use of firewood for domestic heating has the potential to reduce fossil-fuel use and associated CO 2 emissions. The level of possible reductions depends upon the extent to which firewood off-sets the use of fossil fuels, the efficiency with which wood is burnt, and use of fossil fuels for collection and transport of firewood. Plantations grown for firewood also have a cost of emissions associated with their establishment. Applying the FullCAM model and additional calculations, these factors were examined for various management scenarios under three contrasting firewood production systems (native woodland, sustainably managed native forest, and newly established plantations) in low-medium rainfall (600-800mm) regions of south-eastern Australia. Estimates of carbon dioxide emissions per unit of heat energy produced for all scenarios were lower than for non-renewable energy sources (which generally emit about 0.3-1.0kgCO 2 kWh -1 ). Amongst the scenarios, emissions were greatest when wood was periodically collected from dead wood in woodlands (0.11kgCO 2 kWh -1 ), and was much lower when obtained from harvest residues and dead wood in native forests ( 2 kWh -1 ). When wood was obtained from plantations established on previously cleared agricultural land, use of firewood led to carbon sequestration equivalent to -0.06kgCO 2 kWh -1 for firewood obtained from a coppiced plantation, and -0.17kgCO 2 kWh -1 for firewood collected from thinnings, slash and other residue in a plantation grown for sawlog production. An uncertainty analysis, where inputs and assumptions were varied in relation to a plausible range of management practices, identified the most important influencing factors and an expected range in predicted net amount of CO 2 emitted per unit of heat energy produced from burning firewood. (author)

The carbon cycle and global warming

International Nuclear Information System (INIS)

Anon.

1991-01-01

Five land-use-based approaches can be used to slow the buildup of CO 2 in the atmosphere: slowing or stopping the loss of existing forests, thus preserving current carbon reservoirs; adding to the planet's vegetative cover through reforestation or other means, thus enlarging living terrestrial carbon reservoirs; increasing the carbon stored in nonliving carbon reservoirs such as agricultural soils; increasing the carbon stored in artificial reservoirs, including timber products; and substituting sustainable biomass energy sources for fossil fuel consumption, thus reducing energy-related carbon emissions. These approaches are all based on the same basic premise: adding to the planet's net carbon stores in vegetative cover or soil, or preventing any net loss, will help moderate global warming by keeping atmospheric CO 2 levels lower than they would otherwise be. Because biotic policy options appear capable of contributing significantly to the mitigation of global warming while also furthering many other public policy objectives, their role deserves careful consideration on a country-by-country basis

Net emissions of carbon dioxide to the atmosphere when using forest residues for production of heat and electricity

International Nuclear Information System (INIS)

Zetterberg, L.; Hansen, O.

1998-05-01

This study estimates net emissions of carbon dioxide to the atmosphere from the use of forest residues for production of heat and electricity. In the report, the use of forest residues for energy production is called residue-usage. Our results show that for a turnover period of 80 years, the net emission of CO 2 to the atmosphere is 15.8 kg CO 2 -C/MWh (3.1-31.6 kg CO 2 -C/MWh), which represents 16% of the total carbon content in the wood fuel (3%-32%). Fossil fuel consumption is responsible for 3.1 kg CO 2 -C/MWh of this. Residue-usage may produce indirect emissions or uptake of carbon dioxide, e.g. through changes in production conditions, changes in the turnover of carbon in the humus layer or through a reduction of the amount of forest fires. Due to uncertainties in data it is hard to quantify these indirect effects. In some cases it is hard even to determine their signs. As a consequence of this, we have chosen not to include the indirect effects in our estimates of net emissions from residue-usage. Instead we discuss these effects in a qualitative manner. It may seem surprising that the biogenic part of the residue-usage produces a net emission of carbon dioxide considering that carbon has originated from the atmosphere. The explanation is that the residue-usage systematically leads to earlier emissions than would be the case if the residues were left on the ground. If forest residues are left to decay, in the long run a pool of carbon might be created in the ground. This does not happen with residue-usage 33 refs, 4 figs, 12 tabs

Evaluation of Terrestrial Carbon Cycle with the Land Use Harmonization Dataset

Science.gov (United States)

Sasai, T.; Nemani, R. R.

2017-12-01

CO2 emission by land use and land use change (LULUC) has still had a large uncertainty (±50%). We need to more accurately reveal a role of each LULUC process on terrestrial carbon cycle, and to develop more complicated land cover change model, leading to improve our understanding of the mechanism of global warming. The existing biosphere model studies do not necessarily have enough major LULUC process in the model description (e.g., clear cutting and residual soil carbon). The issue has the potential for causing an underestimation of the effect of LULUC on the global carbon exchange. In this study, the terrestrial biosphere model was modified with several LULUC processes according to the land use harmonization data set. The global mean LULUC emission from the year 1850 to 2000 was 137.2 (PgC 151year-1), and we found the noticeable trend in tropical region. As with the case of primary production in the existing studies, our results emphasized the role of tropical forest on wood productization and residual soil organic carbon by cutting. Global mean NEP was decreased by LULUC. NEP is largely affected by decreasing leaf biomass (photosynthesis) by deforestation process and increasing plant growth rate by regrowth process. We suggested that the model description related to deforestation, residual soil decomposition, wood productization and plant regrowth is important to develop a biosphere model for estimating long-term global carbon cycle.

Indirect land-use changes can overcome carbon savings from biofuels in Brazil

Science.gov (United States)

Lapola, David M.; Schaldach, Ruediger; Alcamo, Joseph; Bondeau, Alberte; Koch, Jennifer; Koelking, Christina; Priess, Joerg A.

2010-01-01

The planned expansion of biofuel plantations in Brazil could potentially cause both direct and indirect land-use changes (e.g., biofuel plantations replace rangelands, which replace forests). In this study, we use a spatially explicit model to project land-use changes caused by that expansion in 2020, assuming that ethanol (biodiesel) production increases by 35 (4) x 109 liter in the 2003-2020 period. Our simulations show that direct land-use changes will have a small impact on carbon emissions because most biofuel plantations would replace rangeland areas. However, indirect land-use changes, especially those pushing the rangeland frontier into the Amazonian forests, could offset the carbon savings from biofuels. Sugarcane ethanol and soybean biodiesel each contribute to nearly half of the projected indirect deforestation of 121,970 km2 by 2020, creating a carbon debt that would take about 250 years to be repaid using these biofuels instead of fossil fuels. We also tested different crops that could serve as feedstock to fulfill Brazil’s biodiesel demand and found that oil palm would cause the least land-use changes and associated carbon debt. The modeled livestock density increases by 0.09 head per hectare. But a higher increase of 0.13 head per hectare in the average livestock density throughout the country could avoid the indirect land-use changes caused by biofuels (even with soybean as the biodiesel feedstock), while still fulfilling all food and bioenergy demands. We suggest that a closer collaboration or strengthened institutional link between the biofuel and cattle-ranching sectors in the coming years is crucial for effective carbon savings from biofuels in Brazil. PMID:20142492

Protecting tropical forests from the rapid expansion of rubber using carbon payments

DEFF Research Database (Denmark)

Warren-Thomas, Eleanor M.; Edwards, David P.; Bebber, Daniel P.

2018-01-01

comprehensive Cambodian forest data, exploring scenarios of selective logging and conversion, and assuming land-use choice is based on net present value, we find that carbon prices of $30-$51 per tCO2 are needed to break even against costs, higher than those currently paid on carbon markets or through carbon...

Status and potential of terrestrial carbon sequestration in West Virginia

Science.gov (United States)

Benktesh D. Sharma; Jingxin. Wang

2011-01-01

Terrestrial ecosystem management offers cost-effective ways to enhance carbon (C) sequestration. This study utilized C stock and C sequestration in forest and agricultural lands, abandoned mine lands, and harvested wood products to estimate the net current annual C sequestration in West Virginia. Several management options within these components were simulated using a...

Carbon Sequestered, Carbon Displaced and the Kyoto Context

International Nuclear Information System (INIS)

Marland, G.; Schlamadinger, B.

1999-01-01

The integrated system that embraces forest management, forest products, and land-use change impacts the global carbon cycle - and hence the net emission of the greenhouse gas carbon dioxide - in four fundamental ways. Carbon is stored in living and dead biomass, carbon is stored in wood products and landfills, forest products substitute in the market place for products made from other materials, and forest harvests can be used wholly or partially to displace fossil fuels in the energy sector. Implementation of the Kyoto Protocol to the United Nations Framework Convention on Climate Change would result in the creation of international markets for carbon dioxide emissions credits, but the current Kyoto text does not treat all carbon identically. We have developed a carbon accounting model, GORCAM, to examine a variety of scenarios for land management and the production of forest products. In this paper we explore, for two simple scenarios of forest management, the carbon flows that occur and how these might be accounted for under the Kyoto text. The Kyoto protocol raises questions about what activities can result in emissions credits, which carbon reservoirs will be counted, who will receive the credits, and how much credit will be available? The Kyoto Protocol would sometimes give credits for carbon sequestered, but it would always give credits when fossil-fuel carbon dioxide emissions are displaced

Environmental impacts of alternative agricultural uses of poorly drained farm land in Ireland.

Science.gov (United States)

Sharma, Pooja; Humphreys, James; Holden, Nicholas M

2018-05-07

Abolition of the milk quota in the European Union and favourable market conditions have stimulated the expansion of the dairy sector in Ireland, causing more milk to be produced from poorly drained land. This work evaluated the environmental impacts of alternative agricultural uses for poorly drained farm land in Ireland using life cycle assessment (LCA). The avoided burden of the displaced product was used to calculate the net environmental consequences in the context of regional or global markets. The impact categories evaluated were climate change, eutrophication and acidification, all expressed per hectare of land for the alternative land uses, which were pasture-based milk, suckler beef and lowland sheep production and coniferous forestry. Beef had the lowest net climate change impact with global marginal and average product substitution while sheep had the lowest net climate change impact with European displaced product. For net eutrophication and acidification, dairy had the lowest impacts with European and global average displaced product. With global marginal displaced product, forestry had the lowest net eutrophication impact and sheep had the lowest net acidification impact. From an Irish perspective, forestry would generate the lowest environmental impacts and would also increase soil carbon stock, but this was not the best land use option from global perspective. Overall it can be concluded that a pasture based dairy or sheep system would have the greatest net global impact reduction (i.e. greatest global benefit) as land use options for farms with poorly drained soils. Prioritizing climate change, suckler beef system would perhaps be more favourable. It is clear that the choice of the displaced regional or global co-product from the market has a great influence on the results and there is a need to consider more detailed consumption modelling to better understand the substitution process. Copyright © 2018 Elsevier B.V. All rights reserved.

Impacts of historic and projected land-cover, land-use, and land-management change on carbon and water fluxes: The Land Use Model Intercomparison Project (LUMIP)

Science.gov (United States)

Lawrence, D. M.; Lombardozzi, D. L.; Lawrence, P.; Hurtt, G. C.

2017-12-01

Human land-use activities have resulted in large changes to the Earth surface, with resulting implications for climate. In the future, land-use activities are likely to intensify to meet growing demands for food, fiber, and energy. The Land Use Model Intercomparison Project (LUMIP) aims to further advance understanding of the broad question of impacts of land-use and land-cover change (LULCC) as well as more detailed science questions to get at process-level attribution, uncertainty, and data requirements in more depth and sophistication than possible in a multi-model context to date. LUMIP is multi-faceted and aims to advance our understanding of land-use change from several perspectives. In particular, LUMIP includes a factorial set of land-only simulations that differ from each other with respect to the specific treatment of land use or land management (e.g., irrigation active or not, crop fertilization active or not, wood harvest on or not), or in terms of prescribed climate. This factorial series of experiments serves several purposes and is designed to provide a detailed assessment of how the specification of land-cover change and land management affects the carbon, water, and energy cycle response to land-use change. The potential analyses that are possible through this set of experiments are vast. For example, comparing a control experiment with all land management active to an experiment with no irrigation allows a multi-model assessment of whether or not the increasing use of irrigation during the 20th century is likely to have significantly altered trends of regional water and energy fluxes (and therefore climate) and/or crop yield and carbon fluxes in agricultural regions. Here, we will present preliminary results from the factorial set of experiments utilizing the Community Land Model (CLM5). The analyses presented here will help guide multi-model analyses once the full set of LUMIP simulations are available.

Human-induced climate change: the impact of land-use change

Science.gov (United States)

Gries, Thomas; Redlin, Margarete; Ugarte, Juliette Espinosa

2018-02-01

For hundreds of years, human activity has modified the planet's surface through land-use practices. Policies and decisions on how land is managed and land-use changes due to replacement of forests by agricultural cropping and grazing lands affect greenhouse gas emissions. Agricultural management and agroforestry and the resulting changes to the land surface alter the global carbon cycle as well as the Earth's surface albedo, both of which in turn change the Earth's radiation balance. This makes land-use change the second anthropogenic source of climate change after fossil fuel burning. However, the scientific research community has so far not been able to identify the direction and magnitude of the global impact of land-use change. This paper examines the effects of net carbon flux from land-use change on temperature by applying Granger causality and error correction models. The results reveal a significant positive long-run equilibrium relationship between land-use change and the temperature series as well as an opposing short-term effect such that land-use change tends to lead to global warming; however, a rise in temperature causes a decline in land-use change.

Effect of land use and land cover changes on carbon sequestration in vegetation and soils between 1956 and 2007 (southern Spain)

Science.gov (United States)

Muñoz-Rojas, M.; Jordán, A.; Zavala, L. M.; de la Rosa, D.; Abd-Elmabod, S. K.; Anaya-Romero, M.

2012-04-01

Land use has significantly changed during the last decades at global and local scale, while the importance of ecosystems as sources/sinks of C has been highlighted, emphasizing the global impact of land use changes. The aim of this research was to improve and test methodologies to assess land use and land cover change dynamics and temporal and spatial variability in C stored in soils and vegetation at a wide scale. A Mediterranean region (Andalusia, Southern Spain) was selected for this pilot study in the period 1956-2007. Land use changes were detected by comparison of data layers, and soil information was gathered from available spatial databases. Data from land use and land cover change were reclassified according to CORINE Land Cover legend, according to land cover flows reported in Europe. Carbon vegetation stocks for 1956 and 2007 were calculated by multiplying C density for each land cover class and area. Soil carbon stocks were determined for each combination of soil and land use type at different standard depths (0-25, 25-50 and 50-75 cm). Total current carbon stocks (2007) are 156.1 Tg in vegetation and 415 Tg in soils (in the first 75 cm). Southern Spain has supported intense land cover changes affecting more than one third of the study area, with significant consequences for C stocks. Vegetation carbon increased 17.24 Mt since 1956 after afforestation practices and intensification of agriculture. Soil C stock decreased mainly in Cambisols and Regosols (above 80%) after forest areas were transformed into agricultural areas. The methodologies and information generated in this project constitute a basis for modelling of C sequestration and analysis of potential scenarios, as a new component of MicroLEIS DSS. This study highlights the importance of land cover changes for C sequestration in Mediterranean areas, highlighting possible trends for management policies in Europe in order to mitigate climate change.

Management of carbon across sectors and scales: Insights from land use decision making

Science.gov (United States)

Dilling, L.; Failey, E. L.

2008-12-01

Carbon management is increasingly becoming a topic of interest among policy circles and business entrepreneurs alike. In the United States, while no binding regulatory framework exists, carbon management is nonetheless being pursued both by voluntary actions at a variety of levels, from the individual to the national level, and through mandatory policies at state and local levels. Controlling the amount of carbon dioxide in the atmosphere for climate purposes will ultimately require a form of governance that will ensure that the actions taken and being rewarded financially are indeed effective with respect to the global atmosphere on long time scales. Moreover, this new system of governance will need to interface with existing governance structures and decision criteria that have been established to arbitrate among various societal values and priorities. These existing institutions and expressed values will need to be examined against those proposed for effective carbon governance, such as the permanence of carbon storage, the additionality of credited activities, and the prevention of leakage, or displacement of prohibited activities to another region outside the governance boundary. The latter issue suggests that interactions among scales of decision making and governance will be extremely important in determining the ultimate success of any future system of carbon governance. The goal of our study is to understand the current context of land use decision making in different sectors and examine the potential for future carbon policy to be effective given this context. This study examined land use decision making in the U.S. state of Colorado from a variety of ownership perspectives, including US Federal land managers, individual private owners, and policy makers involved in land use at a number of different scales. This paper will report on the results of interviews with land managers and provide insight into the policy context for carbon management through land

Nitrogen deposition, land cover conversion, and contemporary carbon balance of Europe

Science.gov (United States)

Churkina, G.; Zaehle, S.; Hughes, J.; Viovy, N.; Jung, M.; Chen, Y.; Heimann, M.; Roedenbeck, C.; Jones, C.

2009-04-01

In Europe, atmospheric nitrogen deposition has more than doubled, forest cover was steadily increasing, and agricultural area was declining over the last 50 years. What effect have these changes had on the European carbon balance? In this study we estimate responses of the European land ecosystems to nitrogen deposition, land cover conversion and climate. We use results from four ecosystem process models such as BIOME-BGC, JULES, ORCHIDEE, and ORCHIDEE-CN to address this question. We discuss to which degree carbon balance of Europe has been altered by nitrogen deposition in comparison to other drivers and identify areas which carbon balance has been most effected by anthropogenic changes.

An approach to computing marginal land use change carbon intensities for bioenergy in policy applications

International Nuclear Information System (INIS)

Wise, Marshall; Hodson, Elke L.; Mignone, Bryan K.; Clarke, Leon; Waldhoff, Stephanie; Luckow, Patrick

2015-01-01

Accurately characterizing the emissions implications of bioenergy is increasingly important to the design of regional and global greenhouse gas mitigation policies. Market-based policies, in particular, often use information about carbon intensity to adjust relative deployment incentives for different energy sources. However, the carbon intensity of bioenergy is difficult to quantify because carbon emissions can occur when land use changes to expand production of bioenergy crops rather than simply when the fuel is consumed as for fossil fuels. Using a long-term, integrated assessment model, this paper develops an approach for computing the carbon intensity of bioenergy production that isolates the marginal impact of increasing production of a specific bioenergy crop in a specific region, taking into account economic competition among land uses. We explore several factors that affect emissions intensity and explain these results in the context of previous studies that use different approaches. Among the factors explored, our results suggest that the carbon intensity of bioenergy production from land use change (LUC) differs by a factor of two depending on the region in which the bioenergy crop is grown in the United States. Assumptions about international land use policies (such as those related to forest protection) and crop yields also significantly impact carbon intensity. Finally, we develop and demonstrate a generalized method for considering the varying time profile of LUC emissions from bioenergy production, taking into account the time path of future carbon prices, the discount rate and the time horizon. When evaluated in the context of power sector applications, we found electricity from bioenergy crops to be less carbon-intensive than conventional coal-fired electricity generation and often less carbon-intensive than natural-gas fired generation. - Highlights: • Modeling methodology for assessing land use change emissions from bioenergy • Use GCAM

Forest management for fixing and sequestering carbon

International Nuclear Information System (INIS)

Marland, G.; Dale, V.; Graham, R.; Luxmoore, R.; Marland, S.; McLaughlin, S.; Norby, R.; Post, W.M.; Tschaplinski, T.; Tuskan, J.; Wright, L.

1993-01-01

The concept of planting trees as part of a strategy to confront the possibility of global climate change is now widely accepted. As trees grow they remove CO 2 from the atmosphere and thus slow the atmospheric build-up of CO 2 , an important greenhouse gas. Within the global-climate-change context, there are two fundamental problems with managing trees to store carbon. First, the magnitude of fossil-fuel related emissions of CO 2 is so large, 6 billion metric tons of carbon per year that it takes very large areas of tree planting to make a significant impact. Second, as trees mature their rate of growth, and hence rate of net carbon uptake, declines. lie large demand on land area suggests that there is a limit to the fraction of total CO 2 emissions that we might reasonably expect to offset with growing trees. The ultimate maturation of forests suggests that there is a limit on the length of time over which offsets are feasible and that we need to ask what to do as the rate of C uptake declines. Acknowledging a that the availability of land will constrain the ability of tree planting to offset industrial emissions of CO 2 , we consider how the land which is available can be used most effectively. This report speculates on how much land might be available for a forest management strategy motivated (at least partially) by concerns about climate change, but our principal focus is on how a given land area can be best used to minimize net emissions of CO 2 and how much might be achieved on a unit of land. We do not suggest that carbon management should be the principal criteria for land management, but we discuss the implications if it were. Confronting global and local changes in climate will be one of many objectives in land management and we explore for the most effective strategy for pursuing this objective

[Impact of Land Utilization Pattern on Distributing Characters of Labile Organic Carbon in Soil Aggregates in Jinyun Mountain].

Science.gov (United States)

Li, Rui; Jiang, Chang-sheng; Hao, Qing-ju

2015-09-01

Four land utilization patterns were selected for this study in Jinyun mountain, including subtropical evergreen broad-leaved forest (abbreviation: forest), sloping farmland, orchard and abandoned land. Soil samples were taken every 10 cm in the depth of 60 cm soil and proportions of large macroaggregates (> 2 mm), small macroaggregates (0. 25-2 mm), microaggregates (0. 053 - 0. 25 mm) and silt + clay (organic carbon and labile organic carbon in each aggregate fraction and analyze impacts of land uses on organic carbon and labile organic carbon of soil aggregates. LOC content of four soil aggregates were significantly reduced with the increase of soil depth; in layers of 0-60 cm soil depth, our results showed that LOC contents of forest and abandoned land were higher than orchard and sloping farmland. Reserves of labile organic carbon were estimated by the same soil quality, it revealed that forest (3. 68 Mg.hm-2) > abandoned land (1. 73 Mg.hm-2) > orchard (1. 43 Mg.hm-2) >sloping farmland (0.54 Mg.hm-2) in large macroaggregates, abandoned land (7.77, 5. 01 Mg.hm-2) > forest (4. 96, 2.71 Mg.hm-2) > orchard (3. 33, 21. 10 Mg.hm-2) > sloping farmland (1. 68, 1. 35 Mg.hm-2) in small macroaggregates and microaggregates, and abandoned land(4. 32 Mg.hm-2) > orchard(4. 00 Mg.hm-2) > forest(3. 22 Mg.hm-2) > sloping farmland (2.37 Mg.hm-2) in silt + clay, forest and abandoned land were higher than orchard and sloping farmland in other three soil aggregates except silt + clay. It was observed that the level of organic carbon and labile organic carbon were decreased when bringing forest under cultivation to orchard or farmland, and augments on organic carbon and labile organic carbon were found after exchanging farmland to abandoned land. The most reverses of forest and abandoned land emerged in small macroaggregates, orchard and sloping farmland were in microaggregates. That was, during the transformations of land utilization pattern, soil aggregates with bigger size were

Influence of changes in wetland inundation extent on net fluxes of carbon dioxide and methane in northern high latitudes from 1993 to 2004

International Nuclear Information System (INIS)

Zhuang, Qianlai; Zhu, Xudong; He, Yujie; Prigent, Catherine; Melillo, Jerry M; Kicklighter, David W; David McGuire, A; Prinn, Ronald G

2015-01-01

Estimates of the seasonal and interannual exchanges of carbon dioxide (CO 2 ) and methane (CH 4 ) between land ecosystems north of 45°N and the atmosphere are poorly constrained, in part, because of uncertainty in the temporal variability of water-inundated land area. Here we apply a process-based biogeochemistry model to evaluate how interannual changes in wetland inundation extent might have influenced the overall carbon dynamics of the region during the time period 1993–2004. We find that consideration by our model of these interannual variations between 1993 and 2004, on average, results in regional estimates of net methane sources of 67.8 ± 6.2 Tg CH 4 yr −1 , which is intermediate to model estimates that use two static inundation extent datasets (51.3 ± 2.6 and 73.0 ± 3.6 Tg CH 4 yr −1 ). In contrast, consideration of interannual changes of wetland inundation extent result in regional estimates of the net CO 2 sink of −1.28 ± 0.03 Pg C yr −1 with a persistent wetland carbon sink from −0.38 to −0.41 Pg C yr −1 and a upland sink from −0.82 to −0.98 Pg C yr −1 . Taken together, despite the large methane emissions from wetlands, the region is a consistent greenhouse gas sink per global warming potential (GWP) calculations irrespective of the type of wetland datasets being used. However, the use of satellite-detected wetland inundation extent estimates a smaller regional GWP sink than that estimated using static wetland datasets. Our sensitivity analysis indicates that if wetland inundation extent increases or decreases by 10% in each wetland grid cell, the regional source of methane increases 13% or decreases 12%, respectively. In contrast, the regional CO 2 sink responds with only 7–9% changes to the changes in wetland inundation extent. Seasonally, the inundated area changes result in higher summer CH 4 emissions, but lower summer CO 2 sinks, leading to lower summer negative greenhouse gas forcing. Our analysis further

Carbonate system parameters of an algal-dominated reef along West Maui

Science.gov (United States)

Prouty, Nancy G.; Yates, Kimberly K.; Smiley, Nathan; Gallagher, Chris; Cheriton, Olivia; Storlazzi, Curt D.

2018-04-01

Constraining coral reef metabolism and carbon chemistry dynamics are fundamental for understanding and predicting reef vulnerability to rising coastal CO2 concentrations and decreasing seawater pH. However, few studies exist along reefs occupying densely inhabited shorelines with known input from land-based sources of pollution. The shallow coral reefs off Kahekili, West Maui, are exposed to nutrient-enriched, low-pH submarine groundwater discharge (SGD) and are particularly vulnerable to the compounding stressors from land-based sources of pollution and lower seawater pH. To constrain the carbonate chemistry system, nutrients and carbonate chemistry were measured along the Kahekili reef flat every 4 h over a 6-day sampling period in March 2016. Abiotic process - primarily SGD fluxes - controlled the carbonate chemistry adjacent to the primary SGD vent site, with nutrient-laden freshwater decreasing pH levels and favoring undersaturated aragonite saturation (Ωarag) conditions. In contrast, diurnal variability in the carbonate chemistry at other sites along the reef flat was driven by reef community metabolism. Superimposed on the diurnal signal was a transition during the second sampling period to a surplus of total alkalinity (TA) and dissolved inorganic carbon (DIC) compared to ocean endmember TA and DIC measurements. A shift from positive net community production and positive net community calcification to negative net community production and negative net community calcification was identified. This transition occurred during a period of increased SGD-driven nutrient loading, lower wave height, and reduced current speeds. This detailed study of carbon chemistry dynamics highlights the need to incorporate local effects of nearshore oceanographic processes into predictions of coral reef vulnerability and resilience.

Whole Watershed Quantification of Net Carbon Fluxes by Erosion and Deposition within the Christina River Basin Critical Zone Observatory

Science.gov (United States)

Aufdenkampe, A. K.; Karwan, D. L.; Aalto, R. E.; Marquard, J.; Yoo, K.; Wenell, B.; Chen, C.

2013-12-01

to organic carbon and nitrogen content with stable isotope (13C, 15N) and radiocarbon (14C) abundance to quantify OC/SA and organic carbon sources and mean age. We then use multivariate mixing model analysis to quantify the fractional contribution of each source end-member to each sample of suspended or deposited sediments. Last, we calculate a predicted OC/SA based on source end-member mixing and compare to the measured OC/SA to quantify net change in mineral complexed carbon. Aufdenkampe, A.K. et al. Riverine coupling of biogeochemical cycles between land, oceans, and atmosphere. Frontiers Ecol. Environ. 9, 53-60 (2011). Walling, D. E. Tracing suspended sediment sources in catchments and river systems. Sci. Total Environ. 34, 159-184 (2005).

Spatiotemporal Changes of Built-Up Land Expansion and Carbon Emissions Caused by the Chinese Construction Industry.

Science.gov (United States)

Chuai, Xiaowei; Huang, Xianjin; Lu, Qinli; Zhang, Mei; Zhao, Rongqin; Lu, Junyu

2015-11-03

China is undergoing rapid urbanization, enlarging the construction industry, greatly expanding built-up land, and generating substantial carbon emissions. We calculated both the direct and indirect carbon emissions from energy consumption (anthropogenic emissions) in the construction sector and analyzed built-up land expansion and carbon storage losses from the terrestrial ecosystem. According to our study, the total anthropogenic carbon emissions from the construction sector increased from 3,905×10(4) to 103,721.17×10(4) t from 1995 to 2010, representing 27.87%-34.31% of the total carbon emissions from energy consumption in China. Indirect carbon emissions from other industrial sectors induced by the construction sector represented approximately 97% of the total anthropogenic carbon emissions of the sector. These emissions were mainly concentrated in seven upstream industry sectors. Based on our assumptions, built-up land expansion caused 3704.84×10(4) t of carbon storage loss from vegetation between 1995 and 2010. Cropland was the main built-up land expansion type across all regions. The study shows great regional differences. Coastal regions showed dramatic built-up land expansion, greater carbon storage losses from vegetation, and greater anthropogenic carbon emissions. These regional differences were the most obvious in East China followed by Midsouth China. These regions are under pressure for strong carbon emissions reduction.

Carbon, land, and water footprint accounts for the European Union: consumption, production, and displacements through international trade.

Science.gov (United States)

Steen-Olsen, Kjartan; Weinzettel, Jan; Cranston, Gemma; Ercin, A Ertug; Hertwich, Edgar G

2012-10-16

A nation's consumption of goods and services causes various environmental pressures all over the world due to international trade. We use a multiregional input-output model to assess three kinds of environmental footprints for the member states of the European Union. Footprints are indicators that take the consumer responsibility approach to account for the total direct and indirect effects of a product or consumption activity. We quantify the total environmental pressures (greenhouse gas emissions: carbon footprint; appropriation of biologically productive land and water area: land footprint; and freshwater consumption: water footprint) caused by consumption in the EU. We find that the consumption activities by an average EU citizen in 2004 led to 13.3 tCO(2)e of induced greenhouse gas emissions, appropriation of 2.53 gha (hectares of land with global-average biological productivity), and consumption of 179 m(3) of blue water (ground and surface water). By comparison, the global averages were 5.7 tCO(2)e, 1.23 gha, and 163 m(3) blue water, respectively. Overall, the EU displaced all three types of environmental pressures to the rest of the world, through imports of products with embodied pressures. Looking at intra-EU displacements only, the UK was the most important displacer overall, while the largest net exporters of embodied environmental pressures were Poland (greenhouse gases), France (land), and Spain (freshwater).

Organic carbon sequestration under selected land use in Padang city, West Sumatra, Indonesia

Science.gov (United States)

Yulnafatmawita; Yasin, S.

2018-03-01

Organic carbon is a potential element to build biomass as well as emitting CO2 to the atmosphere and promotes global warming. This research was aimed to calculate the sequestered Carbon (C) within a 1-m soil depth under selected land use from 6 different sites in Padang city, Indonesia. Disturbed and undisturbed soil samples were taken from several horizons until 100 cm depth at each location. Soil parameters observed were organic carbon (OC), bulk density (BD), and soil texture. The result showed that soil OC content tended to decrease by the depth at all land use types, except under rice field in Kurao-Nanggalo which extremely increased at >65 cm soil depth with the highest carbon stock. The soil organic carbon sequestration from the highest to the lowest according to land use and the location is in the following order mix garden- Kayu Aro > mix garden- Aie Pacah > Rangeland- Parak Laweh >seasonal farming- Teluk Sirih > rice field- Kampuang Jua.

Carbon cycle dynamics within Oregon’s urban-suburban-forested-agricultural landscapes

Energy Technology Data Exchange (ETDEWEB)

Law, Beverly E. [Oregon State Univ., Corvallis, OR (United States); Still, Christopher Jason [Oregon State Univ., Corvallis, OR (United States); Schmidt, Andres [Oregon State Univ., Corvallis, OR (United States)

2017-06-15

Our overarching goal was to develop and utilize an observation-based analysis framework to assess interactions between climate and mosaics of land use, land cover and urbanization on regional carbon, water, and energy dynamics, and potential changes associated with land management and climate. Carbon, water and energy cycling was quantified for the range of current and potential land uses under present and future climates. The study region of Oregon has a strong climatic gradient from the coastal mesic forests (2500mm ppt) to the Willamette Valley, Cascade Mountains, and the Northern Great Basin semi-arid “cold desert” to the east (300 mm). The study was focused on the effects of (1) conversion of semi-arid sagebrush and Willamette Valley agricultural crops to bioenergy production; (2) afforestation of idle land and rangelands deemed suitable for forests or poplar crops under future climate conditions. We found that net ecosystem production (NEP), the net of ecosystem photosynthesis and respiration, was 10 times higher in the high biomass forests of the Coast Range compared with drier regions like sagebrush in the Northern Great Basin, which was nearly zero (Schmidt et al. 2016). The state total NEP averaged about 30 teragrams carbon (Tg C) per year for the years 2012 to 2014 using our model framework that we developed for predictions of current and future NEP, and compared well with our detailed inventory estimates (28 Tg C annual average for 2011-2015 for forests only; Law et al. 2017). Running our model framework until the year 2050, we found that climate alone only increased NEP by less than 1 Tg C per decade (~3%) using the current trajectory of carbon dioxide emissions, however, changes are expected to be more rapid in subsequent years. We evaluated the possibility of land use change from grass seed crops to poplar for bioenergy, which slightly increased NEP by 2050. The most important variable for carbon sequestration estimates (net carbon sources and

Long term estimation of carbon dynamic and sequestration for Iranian agro-ecosystem: I- Net primary productivity and annual carbon input for common agricultural crops

Directory of Open Access Journals (Sweden)

M Nassiri Mahalati

2016-05-01

Full Text Available Evaluation of carbon input is one of the most important factors for estimating soil carbon changes and potential for carbon sequestration. To evaluate the net primary productivity (NPP and soil carbon input in agricultural eco-systems of Iran, data for yield, cultivated area, harvest index (HI and shoot /root ratio in different crops including: wheat, barley, maize, cotton, rice, alfalfa and chickpea were obtained for different provinces. Then, allocated carbon to different organs of plant were calculated based on carbon allocation coefficients and finally, the net primary productivity based on carbon (NPPc was calculated. The ratio of NPPc that was annually returned to soil was considered as carbon annual input. The results showed that the maximum amount of NPPc for wheat, barely and alfalfa were obtained in Khazari climate for rice, chickpea and cotton was achieved in warm-wet climate and for maize was gained in warm-dry climate. In all regions of Iran, chickpea had the lowest effect on NPPc and consequently on carbon sequestration. The highest amount of carbon input per unit area among studied crops and different regions were observed in Khazari region for alfalfa whereas, the lowest carbon input per unit area was relation to chickpea in cold region. The lowest gap between actual and potential of carbon sequestration was observed in alfalfa whereas wheat, rice and cotton showed the most gap by 0.4, 0.38 and 0.37, respectively.

Moss and soil contributions to the annual net carbon flux of a maturing boreal forest

Science.gov (United States)

Harden, J.W.; O'Neill, K. P.; Trumbore, S.E.; Veldhuis, H.; Stocks, B.J.

1997-01-01

We used input and decomposition data from 14C studies of soils to determine rates of vertical accumulation of moss combined with carbon storage inventories on a sequence of burns to model how carbon accumulates in soils and moss after a stand-killing fire. We used soil drainage - moss associations and soil drainage maps of the old black spruce (OBS) site at the BOREAS northern study area (NSA) to areally weight the contributions of each moderately well drained, feathermoss areas; poorly drained sphagnum - feathermoss areas; and very poorly drained brown moss areas to the carbon storage and flux at the OBS NSA site. On this very old (117 years) complex of black spruce, sphagnum bog veneer, and fen systems we conclude that these systems are likely sequestering 0.01-0.03 kg C m-2 yr-' at OBS-NSA today. Soil drainage in boreal forests near Thompson, Manitoba, controls carbon storage and flux by controlling moss input and decomposition rates and by controlling through fire the amount and quality of carbon left after burning. On poorly drained soils rich in sphagnum moss, net accumulation and long-term storage of carbon is higher than on better drained soils colonized by feathermosses. The carbon flux of these contrasting ecosystems is best characterized by soil drainage class and stand age, where stands recently burned are net sources of CO2, and maturing stands become increasingly stronger sinks of atmospheric CO2. This approach to measuring carbon storage and flux presents a method of scaling to larger areas using soil drainage, moss cover, and stand age information.

Trailblazing the Carbon Cycle of Tropical Forests from Puerto Rico

Directory of Open Access Journals (Sweden)

Sandra Brown

2017-03-01

Full Text Available We review the literature that led to clarifying the role of tropical forests in the global carbon cycle from a time when they were considered sources of atmospheric carbon to the time when they were found to be atmospheric carbon sinks. This literature originates from work conducted by US Forest Service scientists in Puerto Rico and their collaborators. It involves the classification of forests by life zones, estimation of carbon density by forest type, assessing carbon storage changes with ecological succession and land use/land cover type, describing the details of the carbon cycle of forests at stand and landscape levels, assessing global land cover by forest type and the complexity of land use change in tropical regions, and assessing the ecological fluxes and storages that contribute to net carbon accumulation in tropical forests. We also review recent work that couples field inventory data, remote sensing technology such as LIDAR, and GIS analysis in order to more accurately determine the role of tropical forests in the global carbon cycle and point out new avenues of carbon research that address the responses of tropical forests to environmental change.

Global Land Carbon Uptake from Trait Distributions

Science.gov (United States)

Butler, E. E.; Datta, A.; Flores-Moreno, H.; Fazayeli, F.; Chen, M.; Wythers, K. R.; Banerjee, A.; Atkin, O. K.; Kattge, J.; Reich, P. B.

2016-12-01

Historically, functional diversity in land surface models has been represented through a range of plant functional types (PFTs), each of which has a single value for all of its functional traits. Here we expand the diversity of the land surface by using a distribution of trait values for each PFT. The data for these trait distributions is from a sub-set of the global database of plant traits, TRY, and this analysis uses three leaf traits: mass based nitrogen and phosphorus content and specific leaf area, which influence both photosynthesis and respiration. The data are extrapolated into continuous surfaces through two methodologies. The first, a categorical method, classifies the species observed in TRY into satellite estimates of their plant functional type abundances - analogous to how traits are currently assigned to PFTs in land surface models. Second, a Bayesian spatial method which additionally estimates how the distribution of a trait changes in accord with both climate and soil covariates. These two methods produce distinct patterns of diversity which are incorporated into a land surface model to estimate how the range of trait values affects the global land carbon budget.

Carbon and nitrogen balances for six shrublands across Europe

DEFF Research Database (Denmark)

Beier, Claus; Emmett, Bridget A.; Tietema, Albert

2009-01-01

,546 g C m−2, and the systems ranged from being net sinks (126 g C m−2 a−1) to being net sources (−536 g C m−2 a−1) of carbon with the largest storage and sink of carbon at wet and cold climatic conditions. The soil carbon store dominates the carbon budget at all sites and in particular at the site...... with a cold and wet climate where soil C constitutes 95% of the total carbon in the ecosystem. Respiration of carbon from the soil organic matter pool dominated the carbon loss at all sites while carbon loss from aboveground litter decomposition appeared less important. Total belowground carbon allocation...... that in the future a climate-driven land cover change between grasslands and shrublands in Europe will likely lead to increased ecosystem C where shrublands are promoted and less where grasses are promoted. However, it also emphasizes that if feedbacks on the global carbon cycle are to be predicted it is critically...

Assessment of model estimates of land-atmosphere CO2 exchange across northern Eurasia

Science.gov (United States)

Rawlins, M.A.; McGuire, A.D.; Kimball, J.S.; Dass, P.; Lawrence, D.; Burke, E.; Chen, X.; Delire, C.; Koven, C.; MacDougall, A.; Peng, S.; Rinke, A.; Saito, K.; Zhang, W.; Alkama, R.; Bohn, T. J.; Ciais, P.; Decharme, B.; Gouttevin, I.; Hajima, T.; Ji, D.; Krinner, G.; Lettenmaier, D.P.; Miller, P.; Moore, J.C.; Smith, B.; Sueyoshi, T.

2015-01-01

A warming climate is altering land-atmosphere exchanges of carbon, with a potential for increased vegetation productivity as well as the mobilization of permafrost soil carbon stores. Here we investigate land-atmosphere carbon dioxide (CO2) cycling through analysis of net ecosystem productivity (NEP) and its component fluxes of gross primary productivity (GPP) and ecosystem respiration (ER) and soil carbon residence time, simulated by a set of land surface models (LSMs) over a region spanning the drainage basin of Northern Eurasia. The retrospective simulations cover the period 1960–2009 at 0.5° resolution, which is a scale common among many global carbon and climate model simulations. Model performance benchmarks were drawn from comparisons against both observed CO2 fluxes derived from site-based eddy covariance measurements as well as regional-scale GPP estimates based on satellite remote-sensing data. The site-based comparisons depict a tendency for overestimates in GPP and ER for several of the models, particularly at the two sites to the south. For several models the spatial pattern in GPP explains less than half the variance in the MODIS MOD17 GPP product. Across the models NEP increases by as little as 0.01 to as much as 0.79 g C m−2 yr−2, equivalent to 3 to 340 % of the respective model means, over the analysis period. For the multimodel average the increase is 135 % of the mean from the first to last 10 years of record (1960–1969 vs. 2000–2009), with a weakening CO2 sink over the latter decades. Vegetation net primary productivity increased by 8 to 30 % from the first to last 10 years, contributing to soil carbon storage gains. The range in regional mean NEP among the group is twice the multimodel mean, indicative of the uncertainty in CO2 sink strength. The models simulate that inputs to the soil carbon pool exceeded losses, resulting in a net soil carbon gain amid a decrease in residence time. Our analysis points to improvements in model

Assessment of Land and Water Resource Implications of the UK 2050 Carbon Plan

Science.gov (United States)

Konadu, D. D.; Sobral Mourao, Z.; Skelton, S.; Lupton, R.

2015-12-01

The UK Carbon Plan presents four low-carbon energy system pathways that achieves 80% GHG emission targets by 2050, stipulated in the UK Climate Change Act (2008). However, some of the energy technologies prescribed under these pathways are land and water intensive; but would the increase demand for land and water under these pathways lead to increased competition and stress on agricultural land, and water resources in the UK? To answer the above question, this study uses an integrated modelling approach, ForeseerTM, which characterises the interdependencies and evaluates the land and water requirement for the pathways, based on scenarios of power plant location, and the energy crop yield projections. The outcome is compared with sustainable limits of resource appropriation to assess potential stresses and competition for water and land by other sectors of the economy. The results show the Carbon Plan pathways have low overall impacts on UK water resources, but agricultural land use and food production could be significantly impacted. The impact on agricultural land use is shown to be mainly driven by projections for transport decarbonisation via indigenously sourced biofuels. On the other hand, the impact on water resources is mainly associated with increased inland thermal electricity generation capacity, which would compete with other industrial and public water demands. The results highlight the need for a critical appraisal of UK's long term low-carbon energy system planning, in particular bioenergy sourcing strategy, and the siting of thermal power generation in order to avert potential resource stress and competition.

THE POTENTIAL OF RECLAIMED LANDS TO SEQUESTER CARBON AND MITIGATE THE GREENHOUSE EFFECT

Energy Technology Data Exchange (ETDEWEB)

Terry Brown; Song Jin

2006-05-01

Reclaimed mine lands have the potential to sequester carbon. The use of amendments to increase fertility and overall soil quality is encouraging. Waste amendments such as sewage sludge and clarifier sludge, as well as commercial compost were tested to determine their effects on carbon sequestration and humic acid formation in reclaimed mine lands. Sewage sludge and clarifier sludge have the potential to work as reclaimed mine lands amendments. C:N ratios need to be understood to determine probability of nutrient leaching and water contamination. Microbial activity on the humic acid fraction of sludge is directed toward the readily degradable constituents containing single chain functional groups. This finding indicate that amendments with lower molecular constituents such as aliphatic compounds are more amenable to microbial degradation, therefore serves as better nutrient sources to enhance the formation of vegetation in mine lands and leads to more efficient carbon sequestration.

Organic fertilizer application increases the soil respiration and net ecosystem carbon dioxide absorption of paddy fields under water-saving irrigation.

Science.gov (United States)

Yang, Shihong; Xiao, Ya Nan; Xu, Junzeng

2018-04-01

Quantifying carbon sequestration in paddy soil is necessary to understand the effect of agricultural practices on carbon cycles. The objective of this study was to assess the effect of organic fertilizer addition (MF) on the soil respiration and net ecosystem carbon dioxide (CO 2 ) absorption of paddy fields under water-saving irrigation (CI) in the Taihu Lake Region of China during the 2014 and 2015 rice-growing seasons. Compared with the traditional fertilizer and water management (FC), the joint regulation of CI and MF (CM) significantly increased the rice yields and irrigation water use efficiencies of paddy fields by 4.02~5.08 and 83.54~109.97% (p < 0.05). The effects of organic fertilizer addition on soil respiration and net ecosystem CO 2 absorption rates showed inter-annual differences. CM paddy fields showed a higher soil respiration and net CO 2 absorption rates during some periods of the rice growth stage in the first year and during most periods of the rice growth stage in the second year. These fields also had significantly higher total CO 2 emission through soil respiration (total R soil ) and total net CO 2 absorption compared with FC paddy fields (p < 0.05). The total R soil and net ecosystem CO 2 absorption of CM paddy fields were 67.39~91.55 and 129.41~113.75 mol m -2 , which were 27.66~135.52 and 12.96~31.66% higher than those of FC paddy fields. The interaction between water and fertilizer management had significant effects on total net ecosystem CO 2 absorption. The frequent alternate wet-dry cycles of CI paddy fields increased the soil respiration and reduced the net CO 2 absorption. Organic fertilizer promoted the soil respiration of paddy soil but also increased its net CO 2 absorption and organic carbon content. Therefore, the joint regulation of water-saving irrigation and organic fertilizer is an effective measure for maintaining yield, increasing irrigation water use efficiency, mitigating CO 2 emission, and promoting paddy

Beyond pure offsetting: Assessing options to generate Net-Mitigation-Effects in carbon market mechanisms

International Nuclear Information System (INIS)

Warnecke, Carsten; Wartmann, Sina; Höhne, Niklas; Blok, Kornelis

2014-01-01

The current project-based carbon market mechanisms such as the Clean Development Mechanism (CDM) and the Joint Implementation (JI) do not have a direct impact on global greenhouse gas emission levels, because they only replace or offset emissions. Nor do they contribute to host country's national greenhouse gas emission reduction targets. Contributions to net emission reductions in host countries is likely to become mandatory in new mechanisms under development such as in the framework for various approaches, a new market-based mechanism and even in a reformed JI. This research analysed the question if approaches for carbon market-based mechanisms exist that allow the generation of net emission reductions in host countries while keeping project initiation attractive. We present a criteria-based assessment method and apply it for four generic options in existing mechanisms and derive implications for future mechanism frameworks. We identified the application of “discounts” on the amount of avoided emissions for the issuance of carbon credits and “standardisation below business as usual” as most promising options over “limiting the crediting period” and “over-conservativeness”. We propose to apply these options differentiated over project types based on internal rate of return to ensure cost-efficiency and attractiveness. - Highlights: • Options for net emission reductions of market-based mechanisms are assessed. • Research combines past and current views for project and sector-based mechanisms. • Implementation ensures initiation of mitigation activities is not discouraged. • Important insights for methodological design of new market-based mechanisms. • Profitability-based approach for project-based mechanisms suggested

Complex forest dynamics indicate potential for slowing carbon accumulation in the southeastern United States.

Science.gov (United States)

Coulston, John W; Wear, David N; Vose, James M

2015-01-23

Over the past century forest regrowth in Europe and North America expanded forest carbon (C) sinks and offset C emissions but future C accumulation is uncertain. Policy makers need insights into forest C dynamics as they anticipate emissions futures and goals. We used land use and forest inventory data to estimate how forest C dynamics have changed in the southeastern United States and attribute changes to land use, management, and disturbance causes. From 2007-2012, forests yielded a net sink of C because of net land use change (+6.48 Tg C yr(-1)) and net biomass accumulation (+75.4 Tg C yr(-1)). Forests disturbed by weather, insect/disease, and fire show dampened yet positive forest C changes (+1.56, +1.4, +5.48 Tg C yr(-1), respectively). Forest cutting caused net decreases in C (-76.7 Tg C yr(-1)) but was offset by forest growth (+143.77 Tg C yr(-1)). Forest growth rates depend on age or stage of development and projected C stock changes indicate a gradual slowing of carbon accumulation with anticipated forest aging (a reduction of 9.5% over the next five years). Additionally, small shifts in land use transitions consistent with economic futures resulted in a 40.6% decrease in C accumulation.

Recent trends and drivers of regional sources and sinks of carbon dioxide

Science.gov (United States)

Sitch, S.; Friedlingstein, P.; Gruber, N.; Jones, S. D.; Murray-Tortarolo, G.; Ahlström, A.; Doney, S. C.; Graven, H.; Heinze, C.; Huntingford, C.; Levis, S.; Levy, P. E.; Lomas, M.; Poulter, B.; Viovy, N.; Zaehle, S.; Zeng, N.; Arneth, A.; Bonan, G.; Bopp, L.; Canadell, J. G.; Chevallier, F.; Ciais, P.; Ellis, R.; Gloor, M.; Peylin, P.; Piao, S. L.; Le Quéré, C.; Smith, B.; Zhu, Z.; Myneni, R.

2015-02-01

The land and ocean absorb on average just over half of the anthropogenic emissions of carbon dioxide (CO2) every year. These CO2 "sinks" are modulated by climate change and variability. Here we use a suite of nine dynamic global vegetation models (DGVMs) and four ocean biogeochemical general circulation models (OBGCMs) to estimate trends driven by global and regional climate and atmospheric CO2 in land and oceanic CO2 exchanges with the atmosphere over the period 1990-2009, to attribute these trends to underlying processes in the models, and to quantify the uncertainty and level of inter-model agreement. The models were forced with reconstructed climate fields and observed global atmospheric CO2; land use and land cover changes are not included for the DGVMs. Over the period 1990-2009, the DGVMs simulate a mean global land carbon sink of -2.4 ± 0.7 Pg C yr-1 with a small significant trend of -0.06 ± 0.03 Pg C yr-2 (increasing sink). Over the more limited period 1990-2004, the ocean models simulate a mean ocean sink of -2.2 ± 0.2 Pg C yr-1 with a trend in the net C uptake that is indistinguishable from zero (-0.01 ± 0.02 Pg C yr-2). The two ocean models that extended the simulations until 2009 suggest a slightly stronger, but still small, trend of -0.02 ± 0.01 Pg C yr-2. Trends from land and ocean models compare favourably to the land greenness trends from remote sensing, atmospheric inversion results, and the residual land sink required to close the global carbon budget. Trends in the land sink are driven by increasing net primary production (NPP), whose statistically significant trend of 0.22 ± 0.08 Pg C yr-2 exceeds a significant trend in heterotrophic respiration of 0.16 ± 0.05 Pg C yr-2 - primarily as a consequence of widespread CO2 fertilisation of plant production. Most of the land-based trend in simulated net carbon uptake originates from natural ecosystems in the tropics (-0.04 ± 0.01 Pg C yr-2), with almost no trend over the northern land region

Identifying key factors for mobilising under-utilised low carbon land resources : A case study on Kalimantan

NARCIS (Netherlands)

Goh, Chun Sheng; Junginger, Martin; Potter, Lesley; Faaij, André; Wicke, Birka

2018-01-01

Mobilising under-utilised low carbon (ULC) land for future agricultural expansion helps minimising further carbon stock loss. This study examined the regency cases in Kalimantan, a carbon loss hotspot, to understand the key factors for mobilising ULC land via narrative interviews with a range of

Terrestrial Carbon Cycle Variability [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Dennis Baldocchi

2016-09-01

Full Text Available A growing literature is reporting on how the terrestrial carbon cycle is experiencing year-to-year variability because of climate anomalies and trends caused by global change. As CO2 concentration records in the atmosphere exceed 50 years and as satellite records reach over 30 years in length, we are becoming better able to address carbon cycle variability and trends. Here we review how variable the carbon cycle is, how large the trends in its gross and net fluxes are, and how well the signal can be separated from noise. We explore mechanisms that explain year-to-year variability and trends by deconstructing the global carbon budget. The CO2 concentration record is detecting a significant increase in the seasonal amplitude between 1958 and now. Inferential methods provide a variety of explanations for this result, but a conclusive attribution remains elusive. Scientists have reported that this trend is a consequence of the greening of the biosphere, stronger northern latitude photosynthesis, more photosynthesis by semi-arid ecosystems, agriculture and the green revolution, tropical temperature anomalies, or increased winter respiration. At the global scale, variability in the terrestrial carbon cycle can be due to changes in constituent fluxes, gross primary productivity, plant respiration and heterotrophic (microbial respiration, and losses due to fire, land use change, soil erosion, or harvesting. It remains controversial whether or not there is a significant trend in global primary productivity (due to rising CO2, temperature, nitrogen deposition, changing land use, and preponderance of wet and dry regions. The degree to which year-to-year variability in temperature and precipitation anomalies affect global primary productivity also remains uncertain. For perspective, interannual variability in global gross primary productivity is relatively small (on the order of 2 Pg-C y-1 with respect to a large and uncertain background (123 +/- 4 Pg-C y-1

Gross changes in forest area shape the future carbon balance of tropical forests

Science.gov (United States)

Li, Wei; Ciais, Philippe; Yue, Chao; Gasser, Thomas; Peng, Shushi; Bastos, Ana

2018-01-01

Bookkeeping models are used to estimate land-use and land-cover change (LULCC) carbon fluxes (ELULCC). The uncertainty of bookkeeping models partly arises from data used to define response curves (usually from local data) and their representativeness for application to large regions. Here, we compare biomass recovery curves derived from a recent synthesis of secondary forest plots in Latin America by Poorter et al. (2016) with the curves used previously in bookkeeping models from Houghton (1999) and Hansis et al. (2015). We find that the two latter models overestimate the long-term (100 years) vegetation carbon density of secondary forest by about 25 %. We also use idealized LULCC scenarios combined with these three different response curves to demonstrate the importance of considering gross forest area changes instead of net forest area changes for estimating regional ELULCC. In the illustrative case of a net gain in forest area composed of a large gross loss and a large gross gain occurring during a single year, the initial gross loss has an important legacy effect on ELULCC so that the system can be a net source of CO2 to the atmosphere long after the initial forest area change. We show the existence of critical values of the ratio of gross area change over net area change (γAnetAgross), above which cumulative ELULCC is a net CO2 source rather than a sink for a given time horizon after the initial perturbation. These theoretical critical ratio values derived from simulations of a bookkeeping model are compared with observations from the 30 m resolution Landsat Thematic Mapper data of gross and net forest area change in the Amazon. This allows us to diagnose areas in which current forest gains with a large land turnover will still result in LULCC carbon emissions in 20, 50 and 100 years.

Global land carbon sink response to temperature and precipitation varies with ENSO phase

Energy Technology Data Exchange (ETDEWEB)

Fang, Yuanyuan; Michalak, Anna M.; Schwalm, Christopher R.; Huntzinger, Deborah N.; Berry, Joseph A.; Ciais, Philippe; Piao, Shilong; Poulter, Benjamin; Fisher, Joshua B.; Cook, Robert B.; Hayes, Daniel; Huang, Maoyi; Ito, Akihiko; Jain, Atul; Lei, Huimin; Lu, Chaoqun; Mao, Jiafu; Parazoo, Nicholas C.; Peng, Shushi; Ricciuto, Daniel M.; Shi, Xiaoying; Tao, Bo; Tian, Hanqin; Wang, Weile; Wei, Yaxing; Yang, Jia

2017-05-01

Climate variability associated with the El Niño-Southern Oscillation (ENSO) and its consequent impacts on land carbon sink interannual variability have been used as a basis for investigating carbon cycle responses to climate variability more broadly, and to inform the sensitivity of the tropical carbon budget to climate change. Past studies have presented opposing views about whether temperature or precipitation is the primary factor driving the response of the land carbon sink to ENSO. Here, we show that the dominant driver varies with ENSO phase. Whereas tropical temperature explains sink dynamics following El Niño conditions (r_TG,P=0.59, p<0.01), the post La Niña sink is driven largely by tropical precipitation (r_PG,T=-0.46, p=0.04). This finding points to an ENSO-phase-dependent interplay between water availability and temperature in controlling the carbon uptake response to climate variations in tropical ecosystems. We further find that none of a suite of ten contemporary terrestrial biosphere models captures these ENSO-phase-dependent responses, highlighting a key uncertainty in modeling climate impacts on the future of the global land carbon sink.

Evaluation of Net Primary Productivity and Carbon Allocation to Different Parts of Corn in Different Tillage and Nutrient Management Systems

Directory of Open Access Journals (Sweden)

esmat mohammadi

2017-09-01

Full Text Available Evaluation of net primary productivity and carbon allocation to different organs of corn under nutrient management and tillage systems Introduction Agriculture operations produce 10 to 20 percent of greenhouse gases. As a result of conventional operations of agriculture, greenhouse gases have been increased (Osborne et al., 2010. Therefor it is necessary to notice to carbon sequestration to reduce greenhouse gases emissions. In photosynthesis process, plants absorb CO2 and large amounts of organic carbon accumulate in their organs. Biochar is produced of pyrolysis of organic compounds. Biochar is an appropriate compound for improved of soil properties and carbon sequestration (Whitman and Lehmann, 2009; Smith et al., 2010. Conservation tillage has become an important technology in sustainable agriculture due to its benefits. So the aim of this study was to evaluate the effect of nutrient management and tillage systems on net primary production and carbon allocation to different organs of corn in Shahrood. Material and methods This study was conducted at the Shahrood University of Technology research farm. Experiment was done as split plot in randomized complete block design with three replications. Tillage systems with two levels (conventional tillage and minimum tillage were as the main factor and nutrient management in seven levels including (control, chemical fertilizer, manure, biochar, chemical fertilizer + manure, chemical fertilizer + biochar, manure + biochar were considered as sub plot. At the time of maturity of corn, was sampled from its aboveground and belowground biomasses. Carbon content of shoot, seed and root was considered almost 45 percent of yield of each of these biomasses and carbon in root exudates almost 65 percent of carbon in the root. Statistical analysis of the data was performed using SAS program. Comparison of means was conducted with LSD test at the 5% level. Results and discussion Effect of nutrient management was

Influence of land urbanization on carbon sequestration of urban vegetation: A temporal cooperativity analysis in Guangzhou as an example.

Science.gov (United States)

Xu, Qian; Dong, Yu-Xiang; Yang, Ren

2018-04-13

Land urbanization can affect carbon sequestration. In this study, the relationships between land urbanization and carbon sequestration of urban vegetation were studied for Guangzhou, China. The methodology was based on land use data from Thematic Mapper (TM) imagery, MODIS13Q1 data, and climate data, and the improved Carnegie-Ames-Stanford approach (CASA) model and linear system models were employed. Characteristics such as the amount of expansion, spatial agglomeration, spatial expansion intensity, and spatial growth of built-up land were analyzed, and the influence of land urbanization (built-up land expansion) on carbon sequestration of urban vegetation was elucidated by a temporal sequential cooperativity analysis. The main results were as follows. (1) Land urbanization had a clear influence on carbon sequestration of urban vegetation in Guangzhou, and the proportion and spatial agglomeration of built-up land showed significant negative correlations with this carbon sequestration; the correlation coefficients were -0.443 and -0.537, respectively, in 2014. (2) The spatial expansion intensity and spatial growth of built-up land showed small correlations with carbon sequestration, and the correlations from 2000 to 2005 were relatively larger than those at other times; this was because the built-up land expansion speed was the fastest during this period. (3) The temporal sequential cooperativity analysis revealed that carbon was lost as natural surfaces were transformed to artificial surfaces, and land urbanization effects on carbon sequestration showed no significant temporal lag. Carbon sequestration of urban vegetation in the city could be improved by adding urban green spaces; however, this would likely take some time as the system recovers. Copyright © 2018 Elsevier B.V. All rights reserved.

Economic approach to assess the forest carbon implications of biomass energy.

Science.gov (United States)

Daigneault, Adam; Sohngen, Brent; Sedjo, Roger

2012-06-05

There is widespread concern that biomass energy policy that promotes forests as a supply source will cause net carbon emissions. Most of the analyses that have been done to date, however, are biological, ignoring the effects of market adaptations through substitution, net imports, and timber investments. This paper uses a dynamic model of forest and land use management to estimate the impact of United States energy policies that emphasize the utilization of forest biomass on global timber production and carbon stocks over the next 50 years. We show that when market factors are included in the analysis, expanded demand for biomass energy increases timber prices and harvests, but reduces net global carbon emissions because higher wood prices lead to new investments in forest stocks. Estimates are sensitive to assumptions about whether harvest residues and new forestland can be used for biomass energy and the demand for biomass. Restricting biomass energy to being sourced only from roundwood on existing forestland can transform the policy from a net sink to a net source of emissions. These results illustrate the importance of capturing market adjustments and a large geographic scope when measuring the carbon implications of biomass energy policies.

Weakening temperature control on the interannual variations of spring carbon uptake across northern lands

Energy Technology Data Exchange (ETDEWEB)

Piao, Shilong [Chinese Academy of Sciences (CAS), Beijing (China); Peking Univ., Beijing (China); Liu, Zhuo [Peking Univ., Beijing (China); Wang, Tao [Chinese Academy of Sciences (CAS), Beijing (China); Peng, Shushi [Peking Univ., Beijing (China); Ciais, Philippe [Alternative Energies and Atomic Energy Commission (CEA), Gif-sur-Yvette (France); Huang, Mengtian [Peking Univ., Beijing (China); Ahlstrom, Anders [Stanford Univ., CA (United States); Burkhart, John F. [Univ. of Oslo (Norway); Chevallier, Frédéric [Alternative Energies and Atomic Energy Commission (CEA), Gif-sur-Yvette (France); Janssens, Ivan A. [Univ. of Antwerp, Wilrijk (Belgium); Jeong, Su-Jong [South Univ. of Science and Technology of China, Shenzhen (China); Lin, Xin [Alternative Energies and Atomic Energy Commission (CEA), Gif-sur-Yvette (France); Mao, Jiafu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Miller, John [National Oceanic and Atmospheric Administration Earth Systems Research Lab., Boulder, CO (United States); Univ. of Colorado, Boulder, CO (United States); Mohammat, Anwar [Chinese Academy of Sciences (CAS), Beijing (China); Myneni, Ranga B. [Boston Univ., MA (United States); Peñuelas, Josep [Centre for Ecological Research and Forestry Applications (CREAF), Barcelona (Spain); Shi, Xiaoying [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stohl, Andreas [Norwegian Institute for Air Research (NILU), Kjeller (Norway); Yao, Yitong [Peking Univ., Beijing (China); Zhu, Zaichun [Peking Univ., Beijing (China); Tans, Pieter P. [National Oceanic and Atmospheric Administration Earth Systems Research Lab., Boulder, CO (United States)

2017-04-24

Ongoing spring warming allows the growing season to begin earlier, enhancing carbon uptake in northern ecosystems. We use 34 years of atmospheric CO₂ concentration measurements at Barrow, Alaska (BRW, 71° N) to show that the interannual relationship between spring temperature and carbon uptake has recently shifted. Here, we use two indicators: the spring zero-crossing date of atmospheric CO₂ (SZC) and the magnitude of CO₂ drawdown between May and June (SCC). The previously reported strong correlation between SZC, SCC and spring land temperature (ST) was found in the first 17 years of measurements, but disappeared in the last 17 years. As a result, the sensitivity of both SZC and SCC to warming decreased. Simulations with an atmospheric transport model coupled to a terrestrial ecosystem model suggest that the weakened interannual correlation of SZC and SCC with ST in the last 17 years is attributable to the declining temperature response of spring net primary productivity (NPP) rather than to changes in heterotrophic respiration or in atmospheric transport patterns. Reduced chilling during dormancy and emerging light limitation are possible mechanisms that may have contributed to the loss of NPP response to ST. These results thus challenge the ‘warmer spring–bigger sink’ mechanism.

Payback time for soil carbon and sugar-cane ethanol

Science.gov (United States)

Mello, Francisco F. C.; Cerri, Carlos E. P.; Davies, Christian A.; Holbrook, N. Michele; Paustian, Keith; Maia, Stoécio M. F.; Galdos, Marcelo V.; Bernoux, Martial; Cerri, Carlos C.

2014-07-01

The effects of land-use change (LUC) on soil carbon (C) balance has to be taken into account in calculating the CO2 savings attributed to bioenergy crops. There have been few direct field measurements that quantify the effects of LUC on soil C for the most common land-use transitions into sugar cane in Brazil, the world's largest producer . We quantified the C balance for LUC as a net loss (carbon debt) or net gain (carbon credit) in soil C for sugar-cane expansion in Brazil. We sampled 135 field sites to 1 m depth, representing three major LUC scenarios. Our results demonstrate that soil C stocks decrease following LUC from native vegetation and pastures, and increase where cropland is converted to sugar cane. The payback time for the soil C debt was eight years for native vegetation and two to three years for pastures. With an increasing need for biofuels and the potential for Brazil to help meet global demand, our results will be invaluable for guiding expansion policies of sugar-cane production towards greater sustainability.

Taking climate, land use, and social economy into estimation of carbon budget in the Guanzhong-Tianshui Economic Region of China.

Science.gov (United States)

Li, Ting; Li, Jing; Zhou, Zixiang; Wang, Yanze; Yang, Xiaonan; Qin, Keyu; Liu, Jingya

2017-04-01

Carbon sequestration is an indispensable ecosystem service provided by soil and vegetation, so mapping and valuing the carbon budget by considering both ecological and social factors is an important trend in evaluating ecosystem services. In this work, we established multiple scenarios to evaluate the impacts of land use change, population growth, carbon emission per capita, and carbon markets on carbon budget. We quantified carbon sinks (aboveground and belowground) under different scenarios, using the Carnegie-Ames-Stanford Approach (CASA) model and an improved carbon cycle process model, and studied carbon sources caused by human activities by analyzing the spatial distribution of human population and carbon emission per capita. We also assessed the net present value (NPV) for carbon budgets under different carbon price and discount rate scenarios using NPV model. Our results indicate that the carbon budget of Guanzhong-Tianshui Economic Region is surplus: Carbon sinks range from 1.50 × 10 10 to 1.54 × 10 10  t, while carbon sources caused by human activities range from 2.76 × 10 5 to 7.60 × 10 5  t. And the NPV for carbon deficits range from 3.20 × 10 11 RMB to 1.52 × 10 12 RMB. From the perspective of ecological management, deforestation, urban sprawl, population growth, and excessive carbon consumption are considered as the main challenges in balancing carbon sources and sinks. Levying carbon tax would be a considerable option when decision maker develops carbon emission reduction policies. Our results provide a scientific and credible reference for harmonious and sustainable development in the Guanzhong-Tianshui Economic Region of China.

U.S. Geological Survey Methodology Development for Ecological Carbon Assessment and Monitoring

Science.gov (United States)

Zhu, Zhi-Liang; Stackpoole, S.M.

2009-01-01

Ecological carbon sequestration refers to transfer and storage of atmospheric carbon in vegetation, soils, and aquatic environments to help offset the net increase from carbon emissions. Understanding capacities, associated opportunities, and risks of vegetated ecosystems to sequester carbon provides science information to support formulation of policies governing climate change mitigation, adaptation, and land-management strategies. Section 712 of the Energy Independence and Security Act (EISA) of 2007 mandates the Department of the Interior to develop a methodology and assess the capacity of our nation's ecosystems for ecological carbon sequestration and greenhouse gas (GHG) flux mitigation. The U.S. Geological Survey (USGS) LandCarbon Project is responding to the Department of Interior's request to develop a methodology that meets specific EISA requirements.

Accounting for forest carbon pool dynamics in product carbon footprints: Challenges and opportunities

International Nuclear Information System (INIS)

Newell, Joshua P.; Vos, Robert O.

2012-01-01

Modification and loss of forests due to natural and anthropogenic disturbance contribute an estimated 20% of annual greenhouse gas (GHG) emissions worldwide. Although forest carbon pool modeling rarely suggests a ‘carbon neutral’ flux profile, the life cycle assessment community and associated product carbon footprint protocols have struggled to account for the GHG emissions associated with forestry, specifically, and land use generally. Principally, this is due to underdeveloped linkages between life cycle inventory (LCI) modeling for wood and forest carbon modeling for a full range of forest types and harvest practices, as well as a lack of transparency in globalized forest supply chains. In this paper, through a comparative study of U.S. and Chinese coated freesheet paper, we develop the initial foundations for a methodology that rescales IPCC methods from the national to the product level, with reference to the approaches in three international product carbon footprint protocols. Due to differences in geographic origin of the wood fiber, the results for two scenarios are highly divergent. This suggests that both wood LCI models and the protocols need further development to capture the range of spatial and temporal dimensions for supply chains (and the associated land use change and modification) for specific product systems. The paper concludes by outlining opportunities to measure and reduce uncertainty in accounting for net emissions of biogenic carbon from forestland, where timber is harvested for consumer products. - Highlights: ► Typical life cycle assessment practice for consumer products often excludes significant land use change emissions when estimating carbon footprints. ► The article provides a methodology to rescale IPCC guidelines for product-level carbon footprints. ► Life cycle inventories and product carbon footprint protocols need more comprehensive land use-related accounting. ► Interdisciplinary collaboration linking the LCA and

Multiple Observation Types Jointly Constrain Terrestrial Carbon and Water Cycles

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Raupach, M. R.; Haverd, V.; Briggs, P. R.; Canadell, J.; Davis, S. J.; Isaac, P. R.; Law, R.; Meyer, M.; Peters, G. P.; Pickett Heaps, C.; Roxburgh, S. H.; Sherman, B.; van Gorsel, E.; Viscarra Rossel, R.; Wang, Z.

2012-12-01

Information about the carbon cycle potentially constrains the water cycle, and vice versa. This paper explores the utility of multiple observation sets to constrain carbon and water fluxes and stores in a land surface model, and a resulting determination of the Australian terrestrial carbon budget. Observations include streamflow from 416 gauged catchments, measurements of evapotranspiration (ET) and net ecosystem production (NEP) from 12 eddy-flux sites, litterfall data, and data on carbon pools. The model is a version of CABLE (the Community Atmosphere-Biosphere-Land Exchange model), coupled with CASAcnp (a biogeochemical model) and SLI (Soil-Litter-Iso, a soil hydrology model including liquid and vapour water fluxes and the effects of litter). By projecting observation-prediction residuals onto model uncertainty, we find that eddy flux measurements provide a significantly tighter constraint on Australian continental net primary production (NPP) than the other data types. However, simultaneous constraint by multiple data types is important for mitigating bias from any single type. Results emerging from the multiply-constrained model are as follows (with all values applying over 1990-2011 and all ranges denoting ±1 standard error): (1) on the Australian continent, a predominantly semi-arid region, over half (0.64±0.05) of the water loss through ET occurs through soil evaporation and bypasses plants entirely; (2) mean Australian NPP is 2200±400 TgC/y, making the NPP/precipitation ratio about the same for Australia as the global land average; (3) annually cyclic ("grassy") vegetation and persistent ("woody") vegetation respectively account for 0.56±0.14 and 0.43±0.14 of NPP across Australia; (4) the average interannual variability of Australia's NEP (±180 TgC/y) is larger than Australia's total anthropogenic greenhouse gas emissions in 2011 (149 TgCeq/y), and is dominated by variability in desert and savannah regions. The mean carbon budget over 1990

Evaluating the Potential of Marginal Land for Cellulosic Feedstock Production and Carbon Sequestration in the United States.

Science.gov (United States)

Emery, Isaac; Mueller, Steffen; Qin, Zhangcai; Dunn, Jennifer B

2017-01-03

Land availability for growing feedstocks at scale is a crucial concern for the bioenergy industry. Feedstock production on land not well-suited to growing conventional crops, or marginal land, is often promoted as ideal, although there is a poor understanding of the qualities, quantity, and distribution of marginal lands in the United States. We examine the spatial distribution of land complying with several key marginal land definitions at the United States county, agro-ecological zone, and national scales, and compare the ability of both marginal land and land cover data sets to identify regions for feedstock production. We conclude that very few land parcels comply with multiple definitions of marginal land. Furthermore, to examine possible carbon-flow implications of feedstock production on land that could be considered marginal per multiple definitions, we model soil carbon changes upon transitions from marginal cropland, grassland, and cropland-pastureland to switchgrass production for three marginal land-rich counties. Our findings suggest that total soil organic carbon changes per county are small, and generally positive, and can influence life-cycle greenhouse gas emissions of switchgrass ethanol.

Increased power supplied to the shelf from land

International Nuclear Information System (INIS)

2002-01-01

The report analyses how increasing the power supply from land to the offshore installations will affect the emissions of carbon dioxide from the power production on land. For the time being the CO 2 emissions from the production in existing power plants outside Norway will increase. Since the power price also rises, this checks the rise in consumption. This means that the total emission of carbon dioxide does not increase as much as it would have done if the power supply to the shelf had been covered entirely by increased production in existing coal power plants. If in the long term new conventional gas power capacity can be developed commercially, then increased power supply to the shelf will cause the CO 2 emission from power production on land in Norway to increase. Should conventional gas power plants not be granted concession, then the effect will be to increase the power production in existing plants in other countries and to check the rise in consumption. The net rise in consumption increases the emission of carbon dioxide from production in coal, oil, or gas power plants in Denmark, Finland, Germany or Poland

Erosion of soil organic carbon: implications for carbon sequestration

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Van Oost, Kristof; Van Hemelryck, Hendrik; Harden, Jennifer W.; McPherson, B.J.; Sundquist, E.T.

2009-01-01

Agricultural activities have substantially increased rates of soil erosion and deposition, and these processes have a significant impact on carbon (C) mineralization and burial. Here, we present a synthesis of erosion effects on carbon dynamics and discuss the implications of soil erosion for carbon sequestration strategies. We demonstrate that for a range of data-based parameters from the literature, soil erosion results in increased C storage onto land, an effect that is heterogeneous on the landscape and is variable on various timescales. We argue that the magnitude of the erosion term and soil carbon residence time, both strongly influenced by soil management, largely control the strength of the erosion-induced sink. In order to evaluate fully the effects of soil management strategies that promote carbon sequestration, a full carbon account must be made that considers the impact of erosion-enhanced disequilibrium between carbon inputs and decomposition, including effects on net primary productivity and decomposition rates.

Unifying Dynamic Prognostic Phenology, Heterogeneous Soil and Vegetation Fluxes, and Ecosystem Biomass and Carbon Stocks To Predict the Terrestrial Carbon Cycle and Land-Atmosphere Exchanges in the Simple Biosphere Model (SiB4)

Science.gov (United States)

Haynes, K. D.; Baker, I. T.; Denning, S.

2016-12-01

Future climate projections require process-based models that incorporate the mechanisms and feedbacks controlling the carbon cycle. Over the past three decades, land surface models have been key contributors to Earth system models, evolving from predicting latent (LE) and sensible (SH) heat fluxes to energy and water budgets, momentum transfer, and terrestrial carbon exchange and storage. This study presents the latest version of the Simple Biosphere Model (SiB4), which builds on a compilation of previous versions and adds a new mechanistic-based scheme that fully predicts the terrestrial carbon cycle. The main SiB4 updates can be summarized as follows: (i) Incorporation of carbon pools that use new respiration and transfer methods, (ii) Creation of a new dynamic phenology scheme that uses mechanistic-based seasonal stages, and (iii) Unification of carbon pools, phenology and disturbance to close the carbon cycle. SiB4 removes the dependence on satellite-based vegetation indices, and instead uses a single mathematical framework to prognose self-consistent land-atmosphere exchanges of carbon, water, energy, radiation, and momentum, as well as carbon storage. Since grasslands cover 30% of land and are highly seasonal, we investigated forty grass sites. Diurnal cycles of gross primary productivity (GPP), ecosystem respiration (RE), net ecosystem exchange (NEE), LE and SH have third-quartile root mean squared (RMS) errors less than 2.0 µmol m-2 s-1, 1.9 µmol m-2 s-1, 2.0 µmol m-2 s-1, 42 W m-2, and 78 W m-2, respectively. On the synoptic timeframe, all sites have significant LE correlation coefficients of non-seasonal daily data; and all but one have significant SH correlations. Mean seasonal cycles for leaf area index (LAI), GPP, RE, LE, and SH have third-quartile normalized RMS errors less than 32%, 25%, 28%, 16%, and 48%, respectively. On multi-year timescales, daily correlations of LAI, GPP, RE, and LE are all statistically significant, with third-quartile RMS

The CarbonTracker Data Assimilation Shell (CTDAS) v1.0: implementation and global carbon balance 2001-2015

Science.gov (United States)

van der Laan-Luijkx, Ingrid T.; van der Velde, Ivar R.; van der Veen, Emma; Tsuruta, Aki; Stanislawska, Karolina; Babenhauserheide, Arne; Zhang, Hui Fang; Liu, Yu; He, Wei; Chen, Huilin; Masarie, Kenneth A.; Krol, Maarten C.; Peters, Wouter

2017-07-01

Data assimilation systems are used increasingly to constrain the budgets of reactive and long-lived gases measured in the atmosphere. Each trace gas has its own lifetime, dominant sources and sinks, and observational network (from flask sampling and in situ measurements to space-based remote sensing) and therefore comes with its own optimal configuration of the data assimilation. The CarbonTracker Europe data assimilation system for CO2 estimates global carbon sources and sinks, and updates are released annually and used in carbon cycle studies. CarbonTracker Europe simulations are performed using the new modular implementation of the data assimilation system: the CarbonTracker Data Assimilation Shell (CTDAS). Here, we present and document this redesign of the data assimilation code that forms the heart of CarbonTracker, specifically meant to enable easy extension and modification of the data assimilation system. This paper also presents the setup of the latest version of CarbonTracker Europe (CTE2016), including the use of the gridded state vector, and shows the resulting carbon flux estimates. We present the distribution of the carbon sinks over the hemispheres and between the land biosphere and the oceans. We show that with equal fossil fuel emissions, 2015 has a higher atmospheric CO2 growth rate compared to 2014, due to reduced net land carbon uptake in later year. The European carbon sink is especially present in the forests, and the average net uptake over 2001-2015 was 0. 17 ± 0. 11 PgC yr-1 with reductions to zero during drought years. Finally, we also demonstrate the versatility of CTDAS by presenting an overview of the wide range of applications for which it has been used so far.

Bioenergy and the importance of land use policy in a carbon-constrained world

Energy Technology Data Exchange (ETDEWEB)

Calvin, Katherine V.; Edmonds, James A.; Wise, Marshall A.

2010-06-01

Policies aimed at limiting anthropogenic climate change would result in significant transformations of the energy and land-use systems. However, increasing the demand for bioenergy could have a tremendous impact on land use, and can result in land clearing and deforestation. Wise et al. (2009a,b) analyzed an idealized policy to limit the indirect land use change emissions from bioenergy. The policy, while effective, would be difficult, if not impossible, to implement in the real world. In this paper, we consider several different land use policies that deviate from this first-best, using the Joint Global Change Research Institute’s Global Change Assessment Model (GCAM). Specifically, these new frameworks are (1) a policy that focuses on just the above-ground or vegetative terrestrial carbon rather than the total carbon, (2) policies that focus exclusively on incentivizing and protecting forestland, and (3) policies that apply an economic penalty on the use of biomass as a proxy to limit indirect land use change emissions. For each policy, we examine its impact on land use, land-use change emissions, atmospheric CO2 concentrations, agricultural supply, and food prices.

Historical carbon emissions and uptake from the agricultural frontier of the Brazilian Amazon.

Science.gov (United States)

Galford, Gillian L; Melillo, Jerry M; Kicklighter, David W; Mustard, John F; Cronin, Timothy W; Cerri, Carlos E P; Cerri, Carlos C

2011-04-01

Tropical ecosystems play a large and complex role in the global carbon cycle. Clearing of natural ecosystems for agriculture leads to large pulses of CO2 to the atmosphere from terrestrial biomass. Concurrently, the remaining intact ecosystems, especially tropical forests, may be sequestering a large amount of carbon from the atmosphere in response to global environmental changes including climate changes and an increase in atmospheric CO2. Here we use an approach that integrates census-based historical land use reconstructions, remote-sensing-based contemporary land use change analyses, and simulation modeling of terrestrial biogeochemistry to estimate the net carbon balance over the period 1901-2006 for the state of Mato Grosso, Brazil, which is one of the most rapidly changing agricultural frontiers in the world. By the end of this period, we estimate that of the state's 925 225 km2, 221 092 km2 have been converted to pastures and 89 533 km2 have been converted to croplands, with forest-to-pasture conversions being the dominant land use trajectory but with recent transitions to croplands increasing rapidly in the last decade. These conversions have led to a cumulative release of 4.8 Pg C to the atmosphere, with 80% from forest clearing and 20% from the clearing of cerrado. Over the same period, we estimate that the residual undisturbed ecosystems accumulated 0.3 Pg C in response to CO2 fertilization. Therefore, the net emissions of carbon from Mato Grosso over this period were 4.5 Pg C. Net carbon emissions from Mato Grosso since 2000 averaged 146 Tg C/yr, on the order of Brazil's fossil fuel emissions during this period. These emissions were associated with the expansion of croplands to grow soybeans. While alternative management regimes in croplands, including tillage, fertilization, and cropping patterns promote carbon storage in ecosystems, they remain a small portion of the net carbon balance for the region. This detailed accounting of a region's carbon

Carbon fluxes on North American rangelands

Science.gov (United States)

Tony Svejcar; Raymond Angell; James A. Bradford; William Dugas; William Emmerich; Albert B. Frank; Tagir Gilmanov; Marshall Haferkamp; Douglas A. Johnson; Herman Mayeux; Pat Mielnick; Jack Morgan; Nicanor Z. Saliendra; Gerald E. Schuman; Phillip L. Sims; Kereith Snyder

2008-01-01

Rangelands account for almost half of the earth's land surface and may play an important role in the global carbon (C) cycle. We studied net ecosystem exchange (NEE) of C on eight North American rangeland sites over a 6-yr period. Management practices and disturbance regimes can influence NEE; for consistency, we compared ungrazed and undisturbed rangelands...

Quantitative Estimation of Soil Carbon Sequestration in Three Land Use Types (Orchard, Paddy Rice and Forest in a Part of Ramsar Lands, Northern Iran

Directory of Open Access Journals (Sweden)

zakieh pahlavan yali

2017-02-01

Full Text Available Introduction: The increasing Greenhouse Gases in atmosphere is the main cause of climate and ecosystems changes. The most important greenhouse gas is CO2 that causes global warming or the greenhouse effect. One of the known solutions that reduces atmospheric carbon and helps to improve the situation, is carbon sequestration in vegetation cover and soil. Carbon sequestration refers to the change in atmospheric CO2 into organic carbon compounds by plants and capture it for a certain time . However, the ecosystems with different vegetation have Impressive Influence on soil carbon sequestration (SCS. Soil as the main component of these ecosystems is a world-wide indicator which has been known to play an important role in global balance of carbon sequestration. Furthermore, carbon sequestration can be a standard world trade and becomes guaranteed. Costs of transfer of CO2 (carbon transfer From the atmosphere into the soil based on the negative effects of increased CO2 on Weather is always increasing, This issue can be faced by developing countries to create a new industry, especially when conservation and restoration of rangeland to follow. This research was regarded due to estimation of SCS in three land use types (orchard, paddy rice and forest in a Part of Ramsar Lands, Northern Iran. Materials and Methods: Ramsar city with an area of about 729/7 km2 is located in the western part of Mazandaran province. Its height above sea level is 20 meters. Ramsar city is situated in a temperate and humid climate. Land area covered by forest, orchard and paddy rice. After field inspection of the area, detailed topographic maps of the specified zone on the study were also tested. In each of the three land types, 500 hectares in the every growing and totally 1,500 hectares as study area were selected .For evaluation the sequestration of carbon in different vegetation systems,15 soil profile selected and sampling from depth of 0 to 100 centimetres of each profile

Alluvial Mountain Meadow Source-Sink Dynamics: Land-Cover Effects on Water and Fluvial Carbon Export

Science.gov (United States)

Weiss, T.; Covino, T. P.; Wohl, E.; Rhoades, C.; Fegel, T.; Clow, D. W.

2017-12-01

Fluvial networks of historically glaciated mountain landscapes alternate between confined and unconfined valley segments. In low-gradient unconfined reaches, river-connected wet meadows commonly establish, and have been recognized as important locations of long-term water, carbon, and nutrient storage. Among connected meadow floodplains, sink-source behavior shifts as a function of flow state; storing water at high flows (snowmelt) and contributing toward higher late-season baseflows. Despite these benefits, historical and contemporary land-use practices often result in the simplification of wet meadow systems, leading to reduced river-floodplain connectivity, lower water-tables and reductions in hydrologic buffering capacity. In this study, we are exploring hydrologic-carbon relationships across a gradient of valley confinement and river-floodplain connectivity (connected, n=3; disconnected, n=4) within the Colorado Rockies. Our approach includes hydrologic analysis, fluorometric assays, water chemistry, instream metabolic measures, and land-cover assessment to examine patterns between land-form, carbon quantity and quality, and stream ecosystem productivity. Between different meadow types, preliminary results suggest differences between instream productivity, carbon qualities, and hydrologic-carbon sink-source dynamics across the season. These data and analyses will provide insight into water, carbon and nutrient flux dynamics as a function of land-cover in mountain headwaters.

Modelling carbon dynamics from urban land conversion: fundamental model of city in relation to a local carbon cycle

Directory of Open Access Journals (Sweden)

Schellnhuber Hans-Joachim

2006-08-01

Full Text Available Abstract Background The main task is to estimate the qualitative and quantitative contribution of urban territories and precisely of the process of urbanization to the Global Carbon Cycle (GCC. Note that, on the contrary to many investigations that have considered direct anthropogenic emission of CO2(urbanized territories produce ca. 96–98% of it, we are interested in more subtle, and up until the present time, weaker processes associated with the conversion of the surrounding natural ecosystems and landscapes into urban lands. Such conversion inevitably takes place when cities are sprawling and additional "natural" lands are becoming "urbanized". Results In order to fulfil this task, we first develop a fundamental model of urban space, since the type of land cover within a city makes a difference for a local carbon cycle. Hence, a city is sub-divided by built-up, „green" (parks, etc. and informal settlements (favelas fractions. Another aspect is a sub-division of the additional two regions, which makes the total number reaching eight regions, while the UN divides the world by six. Next, the basic model of the local carbon cycle for urbanized territories is built. We consider two processes: carbon emissions as a result of conversion of natural lands caused by urbanization; and the transformation of carbon flows by "urbanized" ecosystems; when carbon, accumulated by urban vegetation, is exported to the neighbouring territories. The total carbon flow in the model depends, in general, on two groups of parameters. The first includes the NPP, and the sum of living biomass and dead organic matter of ecosystems involved in the process of urbanization, and namely them we calculate here, using a new more realistic approach and taking into account the difference in regional cities' evolution. Conclusion There is also another group of parameters, dealing with the areas of urban territories, and their annual increments. A method of dynamic forecasting

[Effects of land use type on the distribution of organic carbon in different sized soil particles effects of land use type on the distribution of organic carbon in different sized soil particles and its relationships to herb biomass in hilly red soil region of South China].

Science.gov (United States)

Li, Zhong-Wu; Guo, Wang; Wang, Xiao-Yan; Shen, Wei-Ping; Zhang, Xue; Chen, Xiao-Lin; Zhang, Yue-Nan

2012-04-01

The changes in organic carbon content in different sized soil particles under different land use patterns partly reflect the variation of soil carbon, being of significance in revealing the process of soil organic carbon cycle. Based on the long-term monitoring of soil erosion, and by the methods of soil particle size fractionation, this paper studied the effects of different land use types (wasteland, pinewood land, and grassland) on the distribution of organic carbon content in different sized soil particles and its relationships to the herb biomass. Land use type and slope position had obvious effects on the organic carbon content in different sized soil particles, and the organic carbon content was in the order of grassland > pinewood land > wasteland. The proportion of the organic carbon in different sized soil particles was mainly depended on the land use type, and had little relationships with slope position. According to the analysis of the ratio of particle-associated organic carbon to mineral-associated organic carbon (POC/MOC), the soil organic carbon in grassland was easily to be mineralized, whereas that in wasteland and pinewood land was relatively stable. On the slopes mainly in hilly red soil region, the soil organic carbon in sand fraction had great effects on herb biomass.

Mars MetNet Mission Status

Science.gov (United States)

Harri, Ari-Matti; Aleksashkin, Sergei; Arruego, Ignacio; Schmidt, Walter; Genzer, Maria; Vazquez, Luis; Haukka, Harri

2015-04-01

New kind of planetary exploration mission for Mars is under development in collaboration between the Finnish Meteorological Institute (FMI), Lavochkin Association (LA), Space Research Institute (IKI) and Institutio Nacional de Tecnica Aerospacial (INTA). The Mars MetNet mission is based on a new semi-hard landing vehicle called MetNet Lander (MNL). The scientific payload of the Mars MetNet Precursor [1] mission is divided into three categories: Atmospheric instruments, Optical devices and Composition and structure devices. Each of the payload instruments will provide significant insights in to the Martian atmospheric behavior. The key technologies of the MetNet Lander have been qualified and the electrical qualification model (EQM) of the payload bay has been built and successfully tested. 1. MetNet Lander The MetNet landing vehicles are using an inflatable entry and descent system instead of rigid heat shields and parachutes as earlier semi-hard landing devices have used. This way the ratio of the payload mass to the overall mass is optimized. The landing impact will burrow the payload container into the Martian soil providing a more favorable thermal environment for the electronics and a suitable orientation of the telescopic boom with external sensors and the radio link antenna. It is planned to deploy several tens of MNLs on the Martian surface operating at least partly at the same time to allow meteorological network science. 2. Scientific Payload The payload of the two MNL precursor models includes the following instruments: Atmospheric instruments: 1. MetBaro Pressure device 2. MetHumi Humidity device 3. MetTemp Temperature sensors Optical devices: 1. PanCam Panoramic 2. MetSIS Solar irradiance sensor with OWLS optical wireless system for data transfer 3. DS Dust sensor The descent processes dynamic properties are monitored by a special 3-axis accelerometer combined with a 3-axis gyrometer. The data will be sent via auxiliary beacon antenna throughout the

Effects of long-term land use change on dissolved carbon characteristics in the permafrost streams of northeast China.

Science.gov (United States)

Guo, Yuedong; Song, Changchun; Wan, Zhongmei; Tan, Wenwen; Lu, Yongzheng; Qiao, Tianhua

2014-11-01

Permafrost soils act as large sinks of organic carbon but are highly sensitive to interference such as changes in land use, which can greatly influence dissolved carbon loads in streams. This study examines the effects of long-term land reclamation on seasonal concentrations of dissolved carbons in the upper reaches of the Nenjiang River, northeast China. A comparison of streams in natural and agricultural systems shows that the dissolved organic carbon (DOC) concentration is much lower in the agricultural stream (AG) than in the two natural streams (WAF, wetland dominated; FR, forest dominated), suggesting that land use change is associated with reduced DOC exporting capacity. Moreover, the fluorescence indexes and the ratio of dissolved carbon to nitrogen also differ greatly between the natural and agricultural streams, indicating that the chemical characteristics and the origin of the DOC released from the whole reaches are also altered to some extent. Importantly, the exporting concentration of dissolved inorganic carbon (DIC) and its proportion of total dissolved carbon (TDC) substantially increase following land reclamation, which would largely alter the carbon cycling processes in the downstream fluvial system. Although the strong association between the stream discharge and the DOC concentration was unchanged, the reduction in total soil organic carbon following land reclamation led to remarkable decline of the total flux and exporting coefficient of the dissolved carbons. The results suggest that dissolved carbons in permafrost streams have been greatly affected by changes in land use since the 1970s, and the changes in the concentration and chemical characteristics of dissolved carbons will last until the alteration in both the traditional agriculture pattern and the persistent reclamation activities.

Land Cover Land Use Change and Soil Organic Carbon under Climate Variability in the Semi-Arid West African Sahel (1960-2050)

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Dieye, Amadou M.

2016-01-01

Land Cover Land Use (LCLU) change affects land surface processes recognized to influence climate change at local, national and global levels. Soil organic carbon is a key component for the functioning of agro-ecosystems and has a direct effect on the physical, chemical and biological characteristics of the soil. The capacity to model and project…

An initial SPARROW model of land use and in-stream controls on total organic carbon in streams of the conterminous United States

Science.gov (United States)

Shih, Jhih-Shyang; Alexander, Richard B.; Smith, Richard A.; Boyer, Elizabeth W.; Shwarz, Grogory E.; Chung, Susie

2010-01-01

Watersheds play many important roles in the carbon cycle: (1) they are a site for both terrestrial and aquatic carbon dioxide (CO2) removal through photosynthesis; (2) they transport living and decomposing organic carbon in streams and groundwater; and (3) they store organic carbon for widely varying lengths of time as a function of many biogeochemical factors. Using the U.S. Geological Survey (USGS) Spatially Referenced Regression on Watershed Attributes (SPARROW) model, along with long-term monitoring data on total organic carbon (TOC), this research quantitatively estimates the sources, transport, and fate of the long-term mean annual load of TOC in streams of the conterminous United States. The model simulations use surrogate measures of the major terrestrial and aquatic sources of organic carbon to estimate the long-term mean annual load of TOC in streams. The estimated carbon sources in the model are associated with four land uses (urban, cultivated, forest, and wetlands) and autochthonous fixation of carbon (stream photosynthesis). Stream photosynthesis is determined by reach-level application of an empirical model of stream chlorophyll based on total phosphorus concentration, and a mechanistic model of photosynthetic rate based on chlorophyll, average daily solar irradiance, water column light attenuation, and reach dimensions. It was found that the estimate of in-stream photosynthesis is a major contributor to the mean annual TOC load per unit of drainage area (that is, yield) in large streams, with a median share of about 60 percent of the total mean annual carbon load in streams with mean flows above 500 cubic feet per second. The interquartile range of the model predictions of TOC from in-stream photosynthesis is from 0.1 to 0.4 grams (g) carbon (C) per square meter (m-2) per day (day-1) for the approximately 62,000 stream reaches in the continental United States, which compares favorably with the reported literature range for net carbon fixation by

Multiple Observation Types Jointly Constrain Australian Terrestrial Carbon and Water Cycles

Science.gov (United States)

Haverd, Vanessa; Raupach, Michael; Briggs, Peter; Canadell, Pep; Davis, Steven; Isaac, Peter; Law, Rachel; Meyer, Mick; Peters, Glenn; Pickett-Heaps, Christopher; Roxburgh, Stephen; Sherman, Bradford; van Gorsel, Eva; Viscarra Rossel, Raphael; Wang, Ziyuan

2013-04-01

Information about the carbon cycle potentially constrains the water cycle, and vice versa. This paper explores the utility of multiple observation sets to constrain carbon and water fluxes and stores in a land surface model, and a resulting determination of the Australian terrestrial carbon budget. Observations include streamflow from 416 gauged catchments, measurements of evapotranspiration (ET) and net ecosystem production (NEP) from 12 eddy-flux sites, litterfall data, and data on carbon pools. The model is a version of CABLE (the Community Atmosphere-Biosphere-Land Exchange model), coupled with CASAcnp (a biogeochemical model) and SLI (Soil-Litter-Iso, a soil hydrology model including liquid and vapour water fluxes and the effects of litter). By projecting observation-prediction residuals onto model uncertainty, we find that eddy flux measurements provide a significantly tighter constraint on Australian continental net primary production (NPP) than the other data types. However, simultaneous constraint by multiple data types is important for mitigating bias from any single type. Results emerging from the multiply-constrained model are as follows (with all values applying over 1990-2011 and all ranges denoting ±1 standard error): (1) on the Australian continent, a predominantly semi-arid region, over half (0.64±0.05) of the water loss through ET occurs through soil evaporation and bypasses plants entirely; (2) mean Australian NPP is 2200±400 TgC/y, making the NPP/precipitation ratio about the same for Australia as the global land average; (3) annually cyclic ("grassy") vegetation and persistent ("woody") vegetation respectively account for 0.56±0.14 and 0.43±0.14 of NPP across Australia; (4) the average interannual variability of Australia's NEP (±180 TgC/y) is larger than Australia's total anthropogenic greenhouse gas emissions in 2011 (149 TgCeq/y), and is dominated by variability in desert and savannah regions. The mean carbon budget over 1990

Closing the Knowledge Gap: Effects of Land Use Conversion on Belowground Carbon near the 100th Meridian

Science.gov (United States)

Waldron, S. E.; Phillips, R. L.; Dell, R.; Suddick, E. C.

2012-12-01

Native prairie of the northern Great Plains near the 100th meridian is currently under land use conversion pressure due to high commodity prices. From 2002 to 2007, approximately 303,515 hectares of prairie were converted to crop production in the Prairie Pothole Region (PPR) from Montana to the Dakotas. The spatiotemporal effects of land-use conversion on soil organic matter are still unclear for the PPR. Effects will vary with management, soil properties and time, making regional experiments and simulation modeling necessary. Grassland conservationists are interested in soil carbon data and soil carbon simulation models to inform potential voluntary carbon credit programs. These programs require quantification of changes in soil carbon associated with land-use conversion and management. We addressed this issue by 1) designing a regional-scale experiment, 2) collecting and analyzing soil data, and 3) interviewing producers about land management practices, as required for regional, process-based biogeochemical models. We selected farms at random within a 29,000 km2 area of interest and measured soil properties at multiple depths for native prairie and adjacent annual crop fields. The cores were processed at six different depths (between 0 and 100 cm) for bulk density, pH, texture, total carbon, inorganic carbon, and total nitrogen. We found that the largest difference in soil organic carbon occurred at the 0-10 cm depth, but the magnitude of the effect of land use varied with soil properties and land management. Results from this project, coupled with regional model simulations (Denitrification-Decomposition, DNDC) represent the baseline data needed for future voluntary carbon credit programs and long-term carbon monitoring networks. Enrollment in such programs could help ranchers and farmers realize a new income stream from maintaining their native prairie and the carbon stored beneath it.

Altered belowground carbon cycling following land use change to perennial bioenergy crops

Science.gov (United States)

Belowground carbon (C) dynamics of terrestrial ecosystems play an important role in the global C cycle and thereby in climate regulation, yet remain poorly understood. Globally, land use change is a major driver of changes in belowground C storage; in general, land clearing and tillage for agricult...

Global patterns of land-atmosphere fluxes of carbon dioxide, latent heat, and sensible heat derived from eddy covariance, satellite, and meteorological observations

Science.gov (United States)

Martin, J.; Reichstein, M.

2012-12-01

We upscaled FLUXNET observations of carbon dioxide, water and energy fluxes to the global scale using the machine learning technique, Model Tree Ensembles (MTE). We trained MTE to predict site-level gross primary productivity (GPP), terrestrial ecosystem respiration (TER), net ecosystem exchange (NEE), latent energy (LE), and sensible heat (H) based on remote sensing indices, climate and meteorological data, and information on land use. We applied the trained MTEs to generate global flux fields at a 0.5° x 0.5o spatial resolution and a monthly temporal resolution from 1982-2008. Cross-validation analyses revealed good performance of MTE in predicting among-site flux variability with modeling efficiencies (MEf) between 0.64 and 0.84, except for NEE (MEf = 0.32). Performance was also good for predicting seasonal patterns (MEf between 0.84 and 0.89, except for NEE (0.64)). By comparison, predictions of monthly anomalies were weak. Our products are increasingly used to evaluate global land surface models. However, depending on the flux of interest (e.g. gross primary production, terrestrial ecosystem respiration, net ecosystem exchange, evapotranspiration) and the pattern of interest (mean annual map, seasonal cycles, interannual variability, trends) the robustness and uncertainty of these products varies considerably. To avoid pitfalls, this talk also aims at providing an overview of uncertainties associated with these products, and to provide recommendations on the usage for land surface model evaluations. Finally, we present FLUXCOM - an ongoing activity that aims at generating an ensemble of data-driven FLUXNET based products based on diverse approaches.

Federal land management, carbon sequestration, and climate change in the Southeastern U.S.: a case study with fort benning

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Zhao, S.; Liu, S.; Li, Z.; Sohl, Terry L.

2010-01-01

Land use activities can have a major impact on the temporal trendsandspatialpatternsofregionalland-atmosphereexchange of carbon. Federal lands generally have substantially different land management strategies from surrounding areas, and the carbon consequences have rarely been quantified and assessed. Using the Fort Benning Installation as a case study, we used the General Ensemble biogeochemical Modeling System (GEMS) to simulate and compare ecosystem carbon sequestration between the U.S. Army's Fort Benning and surrounding areas from 1992 to 2050. Our results indicate that the military installation sequestered more carbon than surrounding areas from 1992 to 2007 (76.7 vs 18.5 g C m-2 yr-1), and is projected to continue sequestering more carbon from 2008 to 2050 (75.7 vs 25.6 g C m-2 yr-1), mostly because of the proactive management approaches adopted on military training lands. Our results suggest that federal lands might play a positive and important role in sequestering and conserving atmospheric carbon because some anthropogenic disturbances (e.g., urbanization, forest harvesting, and agriculture) can be minimized or prevented on federal lands

The potential for reducing atmospheric carbon by large-scale afforestation in China and related cost/benefit analysis

International Nuclear Information System (INIS)

Deying Xu

1995-01-01

In this paper, the amount of carbon sequestered through large-scale afforestation and related costs and benefits are calculated, assuming that the forests are managed in perpetual rotations. Based on land availability for afforestation, 20 cases are identified in five suitable regions in China. The least expensive way of developing forests for the purpose of sequestering carbon emissions is the case of Pinus massoniana from the initial investment point of view, and then Spruce. The cases of open forest management are relatively less expensive options because of their low initial investment and long rotations, although their annual wood increments are low. Some less productive tree species have higher net costs for carbon sequestering. For most of the agroforestry systems the net costs are low, especially in the south, the southwest, and the north of China, though their initial investments are high. If the total land available is afforested, the net carbon sequestering will be about 9.7 billion tons under perpetual rotations, amounting to 16.3 times the total industrial carbon release in 1988 in China, and the total initial cost for such a programme is estimated at 19.3 billion US$. Some hindrances in developing forests in China are discussed. (Author)

Giving Credit where Credit is Due. A Practical Method to Distinguish between Human and Natural Factors in Carbon Accounting

International Nuclear Information System (INIS)

Kirschbaum, M.U.F.; Cowie, A.L.

2004-01-01

Net carbon emissions from the biosphere differ from fossil-fuel based emissions in that: (1) a large proportion of biospheric carbon exchange is not under direct human control; (2) land-use decisions often have only a small short-term effect on net emissions, but a large long-term effect; and (3) biospheric carbon exchange is potentially reversible. Because of these differences, carbon accounting approaches also need to be different for fossil-fuel and biosphere-based emissions. Recognising that, the international negotiators at COP 7 adopted a range of guiding principles for accounting for biospheric carbon exchange, including: that accounting excludes removals resulting from (a) elevated carbon dioxide concentrations above pre-industrial level; (b) indirect nitrogen deposition; and (c) the dynamic effects of age structure resulting from activities and practices before the reference year. In this paper, we highlight some of the challenges in biospheric carbon accounting for Canada, the U.S.A, New Zealand and Australia, four nations for which biospheric net carbon exchange is large relative to fossil-fuel based emissions. We discuss an accounting scheme that is based on assessing changes in average carbon stocks due to changes in land use. That scheme is tailored to the special needs of biospheric carbon management and is consistent with the accounting principles adopted at COP 7. The paper shows how the accounting scheme would resolve many of the biospheric carbon accounting anomalies identified for the four nations we studied

Nitrogen deposition, land cover conversion, climate, and contemporary carbon balance of Europe (Invited)

Science.gov (United States)

Churkina, G.; Zahle, S.; Hughes, J.; Viovy, N.; Chen, Y.; Jung, M.; Ramankutty, N.; Roedenbeck, C.; Heimann, M.; Jones, C.

2009-12-01

In Europe, atmospheric nitrogen deposition has more than doubled, air temperature was rising, forest cover was steadily increasing, while agricultural area was declining over the last 50 years. What effect have these changes had on the European carbon balance? In this study we estimate responses of the European land ecosystems to nitrogen deposition, rising CO2, land cover conversion and climate change. We use results from three ecosystem process models such as BIOME-BGC, JULES, and ORCHIDEE (-CN) to address this question. We discuss to which degree carbon balance of Europe has been altered by nitrogen deposition in comparison to other drivers and identify areas which carbon balance has been affected by anthropogenic changes the most. We also analyze ecosystems carbon pools which were affected by the abovementioned environmental changes.

Estimating carbon flux phenology with satellite-derived land surface phenology and climate drivers for different biomes: a synthesis of AmeriFlux observations.

Directory of Open Access Journals (Sweden)

Wenquan Zhu

Full Text Available Carbon Flux Phenology (CFP can affect the interannual variation in Net Ecosystem Exchange (NEE of carbon between terrestrial ecosystems and the atmosphere. In this study, we proposed a methodology to estimate CFP metrics with satellite-derived Land Surface Phenology (LSP metrics and climate drivers for 4 biomes (i.e., deciduous broadleaf forest, evergreen needleleaf forest, grasslands and croplands, using 159 site-years of NEE and climate data from 32 AmeriFlux sites and MODIS vegetation index time-series data. LSP metrics combined with optimal climate drivers can explain the variability in Start of Carbon Uptake (SCU by more than 70% and End of Carbon Uptake (ECU by more than 60%. The Root Mean Square Error (RMSE of the estimations was within 8.5 days for both SCU and ECU. The estimation performance for this methodology was primarily dependent on the optimal combination of the LSP retrieval methods, the explanatory climate drivers, the biome types, and the specific CFP metric. This methodology has a potential for allowing extrapolation of CFP metrics for biomes with a distinct and detectable seasonal cycle over large areas, based on synoptic multi-temporal optical satellite data and climate data.

Advances in Estimating Current and Future Effects of Climate and Management on Forest Ecosystem Carbon and Water Dynamics at Multiple Scales

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Law, B. E.; Still, C. J.; Hudiburg, T. W.; Buotte, P.; Hanson, C. V.

2017-12-01

As we examine the integrated effects of climate variability, atmospheric CO2, and land management actions on terrestrial carbon and water processes within regions, and evaluate mitigation and adaptation options, we want our analysis to be as accurate as possible to reduce the risk of negative impacts from management decisions. The use of global land models at regional scales requires modifications for realistic projections. Model evaluation reveals knowledge and data gaps in species sensitivities to climate extremes and responses to land use change and management actions such as restoration. For example, a combination of sapflux and AmeriFlux tower measurements identifies seasonal shifts in the proportion of water vapor exchange that is due to tree transpiration, as well as changes in tree water-use efficiency associated with climate variation. Thermal measurements from an unmanned aerial system quantify canopy temperatures reached during extreme heat events, as well as tree-to-tree thermal variations, which can be related to transpiration dynamics. Diagnosis of land model performance across climate/vegetation gradients includes the combination of atmospheric CO2/CO/H2O observations from aircraft, a tall tower network, and a mobile platform, combined with inverse modeling. This approach identified an ecoregion where the Community Land Model (CLM4.5) underestimated net ecosystem production by 28%, suggesting model challenges in high productivity forests with high soil nitrogen and deep organic soils. We use land-model output of net ecosystem production, harvest and fire emissions to estimate net ecosystem carbon balance, which is input to a Life-Cycle Assessment of wood product use to estimate net carbon emissions to the atmosphere for harvest scenarios and bioenergy production. Such robust and interdisciplinary approaches are needed to more accurately quantify impacts on ecosystems and "what the atmosphere sees" in terms of greenhouse gas sources and impacts on

Updated estimate of carbon balance on Russian territory

Energy Technology Data Exchange (ETDEWEB)

Kurganova, I. N.; Kudeyarov, V. N.; Gerenyu, V. O. Lopes de (Institute of Physicochemical and Biological Problems in Soil Science, RAS, Pushchino (Russian Federation)), e-mail: ikurg@mail.ru

2010-11-15

The land use system in Russia changed considerably after 1990: 30.2 million ha of croplands were abandoned. Based on the own field investigations that were carried out in abandoned lands of different age (Luvic Phaeozems, deciduous forest zone; Moscow region, 54 deg 50' N, 37 deg 37' E), it has been shown that after 4.5 yr of abandonment, the former croplands acted as a stable sink of CO{sub 2}. The net ecosystem production (NEP) in the post-agrogenic ecosystems averaged 245 +- 73gCm-2 yr-1 for the first 15 yr after land use change that corresponds to an estimated 74 +- 22 Tg C yr-1 for the total area of abandoned lands in Russian Federation. Currently, the Russian territory acts as an absolute sink of atmospheric CO{sub 2} at a rate about 0.90 Pg C yr-1. Using three different approaches, it was demonstrated that after 1990, the carbon sequestration in Russian soils (0.20 cm layer) has averaged 34 +- 2.2 Tg C yr-1. This soil C forms net biome production (NBP) where carbon lifetime is much longer than in 'Kyoto forests'. Thus, the post-agrogenic ecosystems in Russia provide with the additional CO{sub 2} sink in NEP and NBP that could annually compensate about 25% of the current fossil fuel emissions in the Russian Federation

Gross changes in forest area shape the future carbon balance of tropical forests

Directory of Open Access Journals (Sweden)

W. Li

2018-01-01

Full Text Available Bookkeeping models are used to estimate land-use and land-cover change (LULCC carbon fluxes (ELULCC. The uncertainty of bookkeeping models partly arises from data used to define response curves (usually from local data and their representativeness for application to large regions. Here, we compare biomass recovery curves derived from a recent synthesis of secondary forest plots in Latin America by Poorter et al. (2016 with the curves used previously in bookkeeping models from Houghton (1999 and Hansis et al. (2015. We find that the two latter models overestimate the long-term (100 years vegetation carbon density of secondary forest by about 25 %. We also use idealized LULCC scenarios combined with these three different response curves to demonstrate the importance of considering gross forest area changes instead of net forest area changes for estimating regional ELULCC. In the illustrative case of a net gain in forest area composed of a large gross loss and a large gross gain occurring during a single year, the initial gross loss has an important legacy effect on ELULCC so that the system can be a net source of CO2 to the atmosphere long after the initial forest area change. We show the existence of critical values of the ratio of gross area change over net area change (γAnetAgross, above which cumulative ELULCC is a net CO2 source rather than a sink for a given time horizon after the initial perturbation. These theoretical critical ratio values derived from simulations of a bookkeeping model are compared with observations from the 30 m resolution Landsat Thematic Mapper data of gross and net forest area change in the Amazon. This allows us to diagnose areas in which current forest gains with a large land turnover will still result in LULCC carbon emissions in 20, 50 and 100 years.

Effects of endogenous factors on regional land-use carbon emissions based on the Grossman decomposition model: a case study of Zhejiang Province, China.

Science.gov (United States)

Wu, Cifang; Li, Guan; Yue, Wenze; Lu, Rucheng; Lu, Zhangwei; You, Heyuan

2015-02-01

The impact of land-use change on greenhouse gas emissions has become a core issue in current studies on global change and carbon cycle. However, a comprehensive evaluation of the effects of land-use changes on carbon emissions is very necessary. This paper attempted to apply the Grossman decomposition model to estimate the scale, structural, and management effects of land-use carbon emissions based on final energy consumption by establishing the relationship between the types of land use and carbon emissions in energy consumption. It was shown that land-use carbon emissions increase from 169.5624 million tons in 2000 to 637.0984 million tons in 2010, with an annual average growth rate of 14.15%. Meanwhile, land-use carbon intensity increased from 17.59 t/ha in 2000 to 64.42 t/ha in 2010, with an average annual growth rate of 13.86%. The results indicated that rapid industrialization and urbanization in Zhejiang Province promptly increased urban land and industrial land, which consequently affected land-use extensive emissions. The structural and management effects did not mitigate land-use carbon emissions. By contrast, both factors evidently affected the growth of carbon emissions because of the rigid demands of energy-intensive land-use types and the absence of land management. Results called for the policy implications of optimizing land-use structures and strengthening land-use management.

Effects of Endogenous Factors on Regional Land-Use Carbon Emissions Based on the Grossman Decomposition Model: A Case Study of Zhejiang Province, China

Science.gov (United States)

Wu, Cifang; Li, Guan; Yue, Wenze; Lu, Rucheng; Lu, Zhangwei; You, Heyuan

2015-02-01

The impact of land-use change on greenhouse gas emissions has become a core issue in current studies on global change and carbon cycle. However, a comprehensive evaluation of the effects of land-use changes on carbon emissions is very necessary. This paper attempted to apply the Grossman decomposition model to estimate the scale, structural, and management effects of land-use carbon emissions based on final energy consumption by establishing the relationship between the types of land use and carbon emissions in energy consumption. It was shown that land-use carbon emissions increase from 169.5624 million tons in 2000 to 637.0984 million tons in 2010, with an annual average growth rate of 14.15 %. Meanwhile, land-use carbon intensity increased from 17.59 t/ha in 2000 to 64.42 t/ha in 2010, with an average annual growth rate of 13.86 %. The results indicated that rapid industrialization and urbanization in Zhejiang Province promptly increased urban land and industrial land, which consequently affected land-use extensive emissions. The structural and management effects did not mitigate land-use carbon emissions. By contrast, both factors evidently affected the growth of carbon emissions because of the rigid demands of energy-intensive land-use types and the absence of land management. Results called for the policy implications of optimizing land-use structures and strengthening land-use management.

Multicentury changes in ocean and land contributions to the climate-carbon feedback

Science.gov (United States)

Randerson, J. T.; Lindsay, K.; Munoz, E.; Fu, W.; Moore, J. K.; Hoffman, F. M.; Mahowald, N. M.; Doney, S. C.

2015-06-01

Improved constraints on carbon cycle responses to climate change are needed to inform mitigation policy, yet our understanding of how these responses may evolve after 2100 remains highly uncertain. Using the Community Earth System Model (v1.0), we quantified climate-carbon feedbacks from 1850 to 2300 for the Representative Concentration Pathway 8.5 and its extension. In three simulations, land and ocean biogeochemical processes experienced the same trajectory of increasing atmospheric CO2. Each simulation had a different degree of radiative coupling for CO2 and other greenhouse gases and aerosols, enabling diagnosis of feedbacks. In a fully coupled simulation, global mean surface air temperature increased by 9.3 K from 1850 to 2300, with 4.4 K of this warming occurring after 2100. Excluding CO2, warming from other greenhouse gases and aerosols was 1.6 K by 2300, near a 2 K target needed to avoid dangerous anthropogenic interference with the climate system. Ocean contributions to the climate-carbon feedback increased considerably over time and exceeded contributions from land after 2100. The sensitivity of ocean carbon to climate change was found to be proportional to changes in ocean heat content, as a consequence of this heat modifying transport pathways for anthropogenic CO2 inflow and solubility of dissolved inorganic carbon. By 2300, climate change reduced cumulative ocean uptake by 330 Pg C, from 1410 Pg C to 1080 Pg C. Land fluxes similarly diverged over time, with climate change reducing stocks by 232 Pg C. Regional influence of climate change on carbon stocks was largest in the North Atlantic Ocean and tropical forests of South America. Our analysis suggests that after 2100, oceans may become as important as terrestrial ecosystems in regulating the magnitude of the climate-carbon feedback.

Eddy covariance measurements of net C exchange in the CAM bioenergy crop, Agave tequiliana

Science.gov (United States)

Owen, Nick A.; Choncubhair, Órlaith Ní; Males, Jamie; del Real Laborde, José Ignacio; Rubio-Cortés, Ramón; Griffiths, Howard; Lanigan, Gary

2016-04-01

Bioenergy crop cultivation may focus more on low grade and marginal lands in order to avoid competition with food production for land and water resources. However, in many regions, this would require improvements in plant water-use efficiency that are beyond the physiological capacity of most C3 and C4 bioenergy crop candidates. Crassulacean acid metabolism (CAM) plants, such as Agave tequiliana, can combine high above-ground productivity with as little as 20% of the water demand of C3 and C4 crops. This is achieved through temporal separation of carboxylase activities, with stomata opening at night to allow gas exchange and minimise transpirational losses. Previous studies have employed 'bottom-up' methodologies to investigate carbon (C) accumulation and productivity in Agave, by scaling leaf-level gas exchange and titratable acidity (TA) with leaf area index or maximum productivity. We used the eddy covariance (EC) technique to quantify ecosystem-scale gas exchange over an Agave plantation in Mexico ('top-down' approach). Measurements were made over 252 days, including the transition from wet to dry periods. Results were cross-validated against diel changes in titratable acidity, leaf-unfurling rates, energy exchange fluxes and reported biomass yields. Net ecosystem exchange of CO2 displayed a CAM rhythm that alternated from a net C sink at night to a net C source during the day and partitioned canopy fluxes (gross C assimilation, FA,EC) showed a characteristic four-phase CO2 exchange pattern. The projected ecosystem C balance indicated that the site was a net sink of -333 ± 24 g C m-2 y-1, comprising cumulative soil respiration of 692 ± 7 g C m-2 y-1 and FA,EC of -1025 ± 25 g C m-2 y-1. EC-estimated biomass yield was 20.1 Mg ha-1 y-1. Average integrated daily FA,EC was -234 ± 5 mmol CO2 m-2 d-1 and persisted almost unchanged after 70 days of drought conditions. Our results suggest that the carbon acquisition strategy of drought avoidance employed by Agave

Carbon sequestration potential of forest land: Management for products and bioenergy versus preservation

International Nuclear Information System (INIS)

Van Deusen, P.

2010-01-01

A 40 year projection of potential carbon sequestration is based on USDA Forest Service Forest Inventory and Analysis (FIA) data from the state of Georgia. The objective is to compare carbon sequestration under a sustainable management strategy versus a preservation strategy. FIA plots are projected ahead in time with hotdeck matching. This matches each subject plot with another plot from the database that represents the subject plot at a future time. The matched plot sequences are used to provide input data to a harvest scheduling program to generate a management strategy for the state. The sequestration from the management strategy is compared with a preservation strategy that involves no harvesting. Harvested wood is assumed to go into products with various half life decay rates. Carbon sequestration is increased as increasing proportions go into wood for energy, which is treated like a product with an infinite half life. Therefore, the harvested carbon does not return immediately to the atmosphere. Public land and land close to cities is assumed to be unavailable, and all other private land is assumed to be accessible. The results are presented as gigatonnes of CO 2 equivalent to make them directly comparable to US annual carbon emissions. The conclusion is that forest management will sequester more above-ground carbon than preservation over a 40 year period if the wood is used for products with an average half life greater than 5 years.

Vegetation greenness and land carbon-flux anomalies associated with climate variations: a focus on the year 2015

Directory of Open Access Journals (Sweden)

C. Yue

2017-11-01

Full Text Available Understanding the variations in global land carbon uptake, and their driving mechanisms, is essential if we are to predict future carbon-cycle feedbacks on global environmental changes. Satellite observations of vegetation greenness have shown consistent greening across the globe over the past three decades. Such greening has driven the increasing land carbon sink, especially over the growing season in northern latitudes. On the other hand, interannual variations in land carbon uptake are strongly influenced by El Niño–Southern Oscillation (ENSO climate variations. Marked reductions in land uptake and strong positive anomalies in the atmospheric CO2 growth rates occur during El Niño events. Here we use the year 2015 as a natural experiment to examine the possible response of land ecosystems to a combination of vegetation greening and an El Niño event. The year 2015 was the greenest year since 2000 according to satellite observations, but a record atmospheric CO2 growth rate also occurred due to a weaker than usual land carbon sink. Two atmospheric inversions indicate that the year 2015 had a higher than usual northern land carbon uptake in boreal spring and summer, consistent with the positive greening anomaly and strong warming. This strong uptake was, however, followed by a larger source of CO2 in the autumn. For the year 2015, enhanced autumn carbon release clearly offset the extra uptake associated with greening during the summer. This finding leads us to speculate that a long-term greening trend may foster more uptakes during the growing season, but no large increase in annual carbon sequestration. For the tropics and Southern Hemisphere, a strong transition towards a large carbon source for the last 3 months of 2015 is discovered, concomitant with El Niño development. This transition of terrestrial tropical CO2 fluxes between two consecutive seasons is the largest ever found in the inversion records. The strong transition to a

Vegetation greenness and land carbon-flux anomalies associated with climate variations: a focus on the year 2015

Science.gov (United States)

Yue, Chao; Ciais, Philippe; Bastos, Ana; Chevallier, Frederic; Yin, Yi; Rödenbeck, Christian; Park, Taejin

2017-11-01

Understanding the variations in global land carbon uptake, and their driving mechanisms, is essential if we are to predict future carbon-cycle feedbacks on global environmental changes. Satellite observations of vegetation greenness have shown consistent greening across the globe over the past three decades. Such greening has driven the increasing land carbon sink, especially over the growing season in northern latitudes. On the other hand, interannual variations in land carbon uptake are strongly influenced by El Niño-Southern Oscillation (ENSO) climate variations. Marked reductions in land uptake and strong positive anomalies in the atmospheric CO2 growth rates occur during El Niño events. Here we use the year 2015 as a natural experiment to examine the possible response of land ecosystems to a combination of vegetation greening and an El Niño event. The year 2015 was the greenest year since 2000 according to satellite observations, but a record atmospheric CO2 growth rate also occurred due to a weaker than usual land carbon sink. Two atmospheric inversions indicate that the year 2015 had a higher than usual northern land carbon uptake in boreal spring and summer, consistent with the positive greening anomaly and strong warming. This strong uptake was, however, followed by a larger source of CO2 in the autumn. For the year 2015, enhanced autumn carbon release clearly offset the extra uptake associated with greening during the summer. This finding leads us to speculate that a long-term greening trend may foster more uptakes during the growing season, but no large increase in annual carbon sequestration. For the tropics and Southern Hemisphere, a strong transition towards a large carbon source for the last 3 months of 2015 is discovered, concomitant with El Niño development. This transition of terrestrial tropical CO2 fluxes between two consecutive seasons is the largest ever found in the inversion records. The strong transition to a carbon source in the

The terrestrial biosphere as a net source of greenhouse gases to the atmosphere.

Science.gov (United States)

Tian, Hanqin; Lu, Chaoqun; Ciais, Philippe; Michalak, Anna M; Canadell, Josep G; Saikawa, Eri; Huntzinger, Deborah N; Gurney, Kevin R; Sitch, Stephen; Zhang, Bowen; Yang, Jia; Bousquet, Philippe; Bruhwiler, Lori; Chen, Guangsheng; Dlugokencky, Edward; Friedlingstein, Pierre; Melillo, Jerry; Pan, Shufen; Poulter, Benjamin; Prinn, Ronald; Saunois, Marielle; Schwalm, Christopher R; Wofsy, Steven C

2016-03-10

The terrestrial biosphere can release or absorb the greenhouse gases, carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), and therefore has an important role in regulating atmospheric composition and climate. Anthropogenic activities such as land-use change, agriculture and waste management have altered terrestrial biogenic greenhouse gas fluxes, and the resulting increases in methane and nitrous oxide emissions in particular can contribute to climate change. The terrestrial biogenic fluxes of individual greenhouse gases have been studied extensively, but the net biogenic greenhouse gas balance resulting from anthropogenic activities and its effect on the climate system remains uncertain. Here we use bottom-up (inventory, statistical extrapolation of local flux measurements, and process-based modelling) and top-down (atmospheric inversions) approaches to quantify the global net biogenic greenhouse gas balance between 1981 and 2010 resulting from anthropogenic activities and its effect on the climate system. We find that the cumulative warming capacity of concurrent biogenic methane and nitrous oxide emissions is a factor of about two larger than the cooling effect resulting from the global land carbon dioxide uptake from 2001 to 2010. This results in a net positive cumulative impact of the three greenhouse gases on the planetary energy budget, with a best estimate (in petagrams of CO2 equivalent per year) of 3.9 ± 3.8 (top down) and 5.4 ± 4.8 (bottom up) based on the GWP100 metric (global warming potential on a 100-year time horizon). Our findings suggest that a reduction in agricultural methane and nitrous oxide emissions, particularly in Southern Asia, may help mitigate climate change.

Energy consumption and net CO2 sequestration of aqueous mineral carbonation

International Nuclear Information System (INIS)

Huijgen, W.J.J.; Ruijg, G.J.; Comans, R.N.J.; Witkamp, G.J.

2006-12-01

Aqueous mineral carbonation is a potentially attractive sequestration technology to reduce CO2 emissions. The energy consumption of this technology, however, reduces the net amount of CO2 sequestered. Therefore, the energetic CO2 sequestration efficiency of aqueous mineral carbonation was studied in dependence of various process variables using either wollastonite (CaSiO3) or steel slag as feedstock. For wollastonite, the maximum energetic CO2 sequestration efficiency within the ranges of process conditions studied was 75% at 200C, 20 bar CO2, and a particle size of <38μm. The main energy-consuming process steps were the grinding of the feedstock and the compression of the CO2 feed. At these process conditions, a significantly lower efficiency was determined for steel slag (69%), mainly because of the lower Ca content of the feedstock. The CO2 sequestration efficiency might be improved substantially for both types of feedstock by, e.g., reducing the amount of process water applied and further grinding of the feedstock. The calculated energetic efficiencies warrant a further assessment of the (energetic) feasibility of CO2 sequestration by aqueous mineral carbonation on the basis of a pilot-scale process

Black carbon reduction will weaken the aerosol net cooling effect

Science.gov (United States)

Wang, Z. L.; Zhang, H.; Zhang, X. Y.

2014-12-01

Black carbon (BC), a distinct type of carbonaceous material formed from the incomplete combustion of fossil and biomass based fuels under certain conditions, can interact with solar radiation and clouds through its strong light-absorption ability, thereby warming the Earth's climate system. Some studies have even suggested that global warming could be slowed down in a short term by eliminating BC emission due to its short lifetime. In this study, we estimate the influence of removing some sources of BC and other co-emitted species on the aerosol radiative effect by using an aerosol-climate coupled model BCC_AGCM2.0.1_CUACE/Aero, in combination with the aerosol emissions from the Representative Concentration Pathways (RCPs) scenarios. We find that the global annual mean aerosol net cooling effect at the top of the atmosphere (TOA) will be enhanced by 0.12 W m-2 compared with present-day conditions if the BC emission is reduced exclusively to the level projected for 2100 based on the RCP2.6 scenario. This will be beneficial for the mitigation of global warming. However, the global annual mean aerosol net cooling effect at the TOA will be weakened by 1.7-2.0 W m-2 relative to present-day conditions if emissions of BC and co-emitted sulfur dioxide and organic carbon are simultaneously reduced as the most close conditions to the actual situation to the level projected for 2100 in different ways based on the RCP2.6, RCP4.5, and RCP8.5 scenarios. Because there are no effective ways to remove the BC exclusively without influencing the other co-emitted components, our results therefore indicate that a reduction in BC emission can lead to an unexpected warming on the Earth's climate system in the future.

Carbon changes in conterminous US forests associated with growth and major disturbances: 1992-2001

International Nuclear Information System (INIS)

Zheng Daolan; Ducey, Mark J; Heath, Linda S; Smith, James E

2011-01-01

We estimated forest area and carbon changes in the conterminous United States using a remote sensing based land cover change map, forest fire data from the Monitoring Trends in Burn Severity program, and forest growth and harvest data from the USDA Forest Service, Forest Inventory and Analysis Program. Natural and human-associated disturbances reduced the forest ecosystems' carbon sink by 36% from 1992 to 2001, compared to that without disturbances in the 48 states. Among the three identified disturbances, forest-related land cover change contributed 33% of the total effect in reducing the forest carbon potential sink, while harvests and fires accounted for 63% and 4% of the total effect, respectively. The nation's forests sequestered 1.6 ± 0.1 Pg (10 15 petagram) carbon during the period, or 0.18 Pg C yr -1 , with substantial regional variation. The southern region of the United States was a small net carbon source whereas the greater Pacific Northwest region was a strong net sink. Results of the approach fit reasonably well at an aggregate level with other related estimates of the current forest US greenhouse gas inventory, suggesting that further research using this approach is warranted.

Dynamics of soil carbon stocks due to large-scale land use changes across the former Soviet Union during the 20th century

Science.gov (United States)

Kurganova, Irina; Prishchepov, Alexander V.; Schierhorn, Florian; Lopes de Gerenyu, Valentin; Müller, Daniel; Kuzyakov, Yakov

2016-04-01

Land use change is a major driver of land-atmosphere carbon (C) fluxes. The largest net C fluxes caused by LUC are attributed to the conversion of native unmanaged ecosystems to croplands and vice versa. Here, we present the changes of soil organic carbon (SOC) stocks in response to large-scale land use changes in the former Soviet Union from 1953-2012. Widespread and rapid conversion of native ecosystems to croplands occurred in the course of the Virgin Lands Campaign (VLC) between 1954 to 1963 in the Soviet Union, when more than 45 million hectares (Mha) were ploughed in south-eastern Russia and northern Kazakhstan in order to expand domestic food production. After 1991, the collapse of the Soviet Union triggered the abandonment of around 75 Mha across the post-Soviet states. To assess SOC dynamics, we generated a static cropland mask for 2009 based on three global cropland maps. We used the cropland mask to spatially disaggregate annual sown area statistics at province level based on the suitability of each plot for crop production, which yielded land use maps for each year from 1954 to 2012 for all post-Soviet states. To estimate the SOC-dynamics due to the VLC and post-Soviet croplands abandonment, we used available experimental data, own field measurements, and soil maps. A bookkeeping approach was applied to assess the total changes in SOC-stocks in response to large-scale land use changes in the former Soviet Union. The massive croplands expansion during VLC resulted in a substantial loss of SOC - 611±47 Mt C and 241±11 Mt C for the upper 0-50 cm soil layer during the first 20 years of cultivation for Russia and Kazakhstan, respectively. These magnitudes are similar to C losses due to the plowing up of the prairies in USA in the mid-1930s. The total SOC sequestration due to post-Soviet croplands abandonment was estimated at 72.2±6.0 Mt C per year from 1991 to 2010. This amount of carbon equals about 40% of the current fossil fuel emission for this

[Impact of land use type on stability and organic carbon of soil aggregates in Jinyun Mountain].

Science.gov (United States)

Li, Jian-Lin; Jiang, Chang-Sheng; Hao, Qing-Ju

2014-12-01

Soil aggregates have the important effect on soil fertility, soil quality and the sustainable utilization of soil, and they are the mass bases of water and fertilizer retention ability of soil and the supply or release of soil nutrients. In this paper, in order to study the impact of land use type on stability and organic carbon of soil aggregates in Jinyun Mountain, we separated four land use types of soil, which are woodland, abandoned land, orchard and sloping farmland by wet sieving method, then we got the proportion of large macroaggregates (> 2 mm), small macroaggregates (0.25-2 mm), microaggregates (53 μm-0.25 mm) and silt + clay (soil depth of 0-60 cm and calculated the total content of organic carbon of all aggregates fraction in each soil. The results showed that reclamation of woodland will lead to fragmentation of macroaggregates and deterioration of soil structure, and the proportion of macroaggrgates (> 0.25 mm) were 44.62% and 32.28% respectively in the soils of orchard and sloping farmland, which reduced 38.58% (P soil fraction from silt + clay to large macroaggregates and small macroaggregates, so it will improve the soil structure. MWD (mean weight diameter) and GMD (geometric mean diameter) are important indicators of evaluating the stability of soil aggregates. We found the MWD and GWD in soil depth of 0-60 cm in orchards and sloping farmland were significantly lower than those in woodland (P soil aggregates, and they will be separated more easily by water. However, after changing the sloping farmland to abandoned land will enhance the stability of soil aggregates, and improve the ability of soil to resist external damage. The organic carbon content in each soil aggregate of four land use types decreased with the increase of soil depth. In soil depth of 0-60 cm, the storage of organic carbon of large macroaggregates in each soil are in orders of woodland (14.98 Mg x hm(-2)) > abandoned land (8.71 Mg x hm(-2)) > orchard (5.82 Mg x hm(-2

Net ecosystem exchange of carbon dioxide and water of far eastern Siberian Larch (Larix cajanderii on permafrost

Directory of Open Access Journals (Sweden)

A. J. Dolman

2004-01-01

Full Text Available Observations of the net ecosystem exchange of water and CO2 were made during two seasons in 2000 and 2001 above a Larch forest in Far East Siberia (Yakutsk. The measurements were obtained by eddy correlation. There is a very sharply pronounced growing season of 100 days when the forest is leaved. Maximum half hourly uptake rates are 18 µmol m-2 s-1; maximum respiration rates are 5 µmol m-2 s-1. Net annual sequestration of carbon was estimated at 160 gCm-2 in 2001. Applying no correction for low friction velocities added 60 g C m-2. The net carbon exchange of the forest was extremely sensitive to small changes in weather that may switch the forest easily from a sink to a source, even in summer. June was the month with highest uptake in 2001. The average evaporation rate of the forest approached 1.46 mm day-1 during the growing season, with peak values of 3 mm day-1 with an estimated annual evaporation of 213 mm, closely approaching the average annual rainfall amount. 2001 was a drier year than 2000 and this is reflected in lower evaporation rates in 2001 than in 2000. The surface conductance of the forest shows a marked response to increasing atmospheric humidity deficits. This affects the CO2 uptake and evaporation in a different manner, with the CO2 uptake being more affected. There appears to be no change in the relation between surface conductance and net ecosystem uptake normalized by the atmospheric humidity deficit at the monthly time scale. The response to atmospheric humidity deficit is an efficient mechanism to prevent severe water loss during the short intense growing season. The associated cost to the sequestration of carbon may be another explanation for the slow growth of these forests in this environment.

Catchment-Wide Atmospheric Greenhouse Gas Exchange as Influenced by Land Use Diversity

DEFF Research Database (Denmark)

Herbst, Mathias; Friborg, Thomas; Ringgaard, Rasmus

2011-01-01

The turbulent fl uxes of carbon dioxide between the land surface and the atmosphere were measured with the eddy covariance technique above three contrasO ng land use types in the Skjern River catchment in western Denmark, namely an agricultural area, a forest plantation, and a wet grassland...... of the site by one-third. At the agricultural site this sink strength was reduced by 9% through the N2O emissions. Scaled up to the catchment, the observed net uptake of CO2 by the land surface was reduced by roughly one-tenth, in terms of CO2 equivalents, due to the emission of CH4 and N2O....

Estimating carbon sequestration in the piedmont ecoregion of the United States from 1971 to 2010

Science.gov (United States)

Liu, Jinxun; Sleeter, Benjamin M.; Zhu, Zhiliang; Heath, Linda S.; Tan, Zhengxi; Wilson, Tamara; Sherba, Jason T.; Zhou, Decheng

2016-01-01

Background: Human activities have diverse and profound impacts on ecosystem carbon cycles. The Piedmont ecoregion in the eastern United States has undergone significant land use and land cover change in the past few decades. The purpose of this study was to use newly available land use and land cover change data to quantify carbon changes within the ecoregion. Land use and land cover change data (60-m spatial resolution) derived from sequential remotely sensed Landsat imagery were used to generate 960-m resolution land cover change maps for the Piedmont ecoregion. These maps were used in the Integrated Biosphere Simulator (IBIS) to simulate ecosystem carbon stock and flux changes from 1971 to 2010. Results: Results show that land use change, especially urbanization and forest harvest had significant impacts on carbon sources and sinks. From 1971 to 2010, forest ecosystems sequestered 0.25 Mg C ha−1 yr−1, while agricultural ecosystems sequestered 0.03 Mg C ha−1 yr−1. The total ecosystem C stock increased from 2271 Tg C in 1971 to 2402 Tg C in 2010, with an annual average increase of 3.3 Tg C yr−1. Conclusions: Terrestrial lands in the Piedmont ecoregion were estimated to be weak net carbon sink during the study period. The major factors contributing to the carbon sink were forest growth and afforestation; the major factors contributing to terrestrial emissions were human induced land cover change, especially urbanization and forest harvest. An additional amount of carbon continues to be stored in harvested wood products. If this pool were included the carbon sink would be stronger. Keywords: Land-use change, Carbon change, Piedmont ecoregion, IBIS model

Scientific arguments for net carbon increase in soil organic matter in Dutch forests

NARCIS (Netherlands)

Mol, J.P.; Wyngaert, van den I.J.J.; Vries, de W.

2012-01-01

If reporting of emissions associated with Forest Management becomes obligatory in the next commitment period, the Netherlands will try to apply the 'not-a-source' principle to carbon emissions from litter and soil in land under Forest Management. To give a scientific basis for the principle of

Carbon stock projection in North Sumatera using multi objective land allocation approach

Science.gov (United States)

Ichwani, S. N.; Wulandari, R.; Ramachandra, A.

2018-05-01

Nowadays, GHG emission is a critical issue for environmental management due to the large scale of land cover change, especially forest cover. This study provides a protection development strategy for North Sumatera as one way to manage the area. By using Multi Objective Land Allocation (MOLA), we evaluated two GHG emission scenarios, including a Business As Usual (BAU) scenario and Protection scenario. The result shows that the province will lose the carbon stock up to 24 million tons in the year of 2035 by using a BAU scenario. On the other hand, by implementing the Protection scenario, total carbon stock that is lost in the same period is about 5 millions tons solely. It proves that protection scenario is a good scenario and effective to reduce the carbon loss. Furthermore, this scenario can be an alternative for North Sumatera spatial plan.

Implications of Deep Decarbonization for Carbon Cycle Science

Science.gov (United States)

Jones, A. D.; Williams, J.; Torn, M. S.

2016-12-01

The energy-system transformations required to achieve deep decarbonization in the United States, defined as a reduction of greenhouse gas emissions of 80% or more below 1990 levels by 2050, have profound implications for carbon cycle science, particularly with respect to 4 key objectives: understanding and enhancing the terrestrial carbon sink, using bioenergy sustainably, controlling non-CO2 GHGs, and emissions monitoring and verification. (1) As a source of mitigation, the terrestrial carbon sink is pivotal but uncertain, and changes in the expected sink may significantly affect the overall cost of mitigation. Yet the dynamics of the sink under changing climatic conditions, and the potential to protect and enhance the sink through land management, are poorly understood. Policy urgently requires an integrative research program that links basic science knowledge to land management practices. (2) Biomass resources can fill critical energy needs in a deeply decarbonized system, but current understanding of sustainability and lifecycle carbon aspects is limited. Mitigation policy needs better understanding of the sustainable amount, types, and cost of bioenergy feedstocks, their interactions with other land uses, and more efficient and reliable monitoring of embedded carbon. (3) As CO2 emissions from energy decrease under deep decarbonization, the relative share of non-CO2 GHGs grows larger and their mitigation more important. Because the sources tend to be distributed, variable, and uncertain, they have been under-researched. Policy needs a better understanding of mitigation priorities and costs, informed by deeper research in key areas such as fugitive CH4, fertilizer-derived N2O, and industrial F-gases. (4) The M&V challenge under deep decarbonization changes with a steep decrease in the combustion CO2 sources due to widespread electrification, while a greater share of CO2 releases is net-carbon-neutral. Similarly, gas pipelines may carry an increasing share of

Towards understanding of carbon stocks and stabilization in volcanic ash soils in natural Andean ecosystems of northern Ecuador

NARCIS (Netherlands)

Tonneijck, F.H.; Jansen, B.; Nierop, K.G.J.; Verstraten, J.M.; Sevink, J.; de Lange, L.

2010-01-01

Volcanic ash soils contain very large stocks of soil organic matter (SOM) per unit area. Consequently, they constitute potential sources or sinks for the greenhouse gas carbon dioxide. Whether soils become a net carbon source or sink with climate and/or land-use change depends on the stability of

Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) Users’ Manual and Technical Documentation

Energy Technology Data Exchange (ETDEWEB)

Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Qin, Zhangcai [Argonne National Lab. (ANL), Argonne, IL (United States); Mueller, Steffen [Univ. of Illinois, Chicago, IL (United States); Kwon, Ho-young [International Food Policy Research Inst., Washington, DC (United States); Wander, Michelle M. [Univ. of Illinois, Urbana-Champaign, IL (United States); Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-12-01

The Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) calculates carbon emissions from land use change (LUC) for four different ethanol production pathways including corn grain ethanol and cellulosic ethanol from corn stover, Miscanthus, and switchgrass, and a soy biodiesel pathway. This document discusses the version of CCLUB released September 30, 2017 which includes five ethanol LUC scenarios and four soy biodiesel LUC scenarios.

How closely does stem growth of adult beech (Fagus sylvatica) relate to net carbon gain under experimentally enhanced ozone stress?

International Nuclear Information System (INIS)

Kitao, Mitsutoshi; Winkler, J. Barbro; Löw, Markus; Nunn, Angela J.; Kuptz, Daniel; Häberle, Karl-Heinz; Reiter, Ilja M.; Matyssek, Rainer

2012-01-01

The hypothesis was tested that O 3 -induced changes in leaf-level photosynthetic parameters have the capacity of limiting the seasonal photosynthetic carbon gain of adult beech trees. To this end, canopy-level photosynthetic carbon gain and respiratory carbon loss were assessed in European beech (Fagus sylvatica) by using a physiologically based model, integrating environmental and photosynthetic parameters. The latter were derived from leaves at various canopy positions under the ambient O 3 regime, as prevailing at the forest site (control), or under an experimental twice-ambient O 3 regime (elevated O 3 ), as released through a free-air canopy O 3 fumigation system. Gross carbon gain at the canopy-level declined by 1.7%, while respiratory carbon loss increased by 4.6% under elevated O 3 . As this outcome only partly accounts for the decline in stem growth, O 3 -induced changes in allocation are referred to and discussed as crucial in quantitatively linking carbon gain with stem growth. - Highlights: ► We model O 3 -induced changes in the photosynthetic carbon gain of adult beech trees. ► Elevated O 3 decreases gross carbon gain but increases respiratory carbon loss. ► Reduction in net carbon gain only partly accounts for the decline in stem growth. ► O 3 effects on the whole-tree allocation is crucial in addition to carbon gains. - Reduction in net carbon gain at the canopy level only partly accounts for the decline in stem growth under elevated ozone.

Assessing the impact of urbanization on regional net primary productivity in Jiangyin County, China.

Science.gov (United States)

Xu, C; Liu, M; An, S; Chen, J M; Yan, P

2007-11-01

Urbanization is one of the most important aspects of global change. The process of urbanization has a significant impact on the terrestrial ecosystem carbon cycle. The Yangtze Delta region has one of the highest rates of urbanization in China. In this study, carried out in Jiangyin County as a representative region within the Yangtze Delta, land use and land cover changes were estimated using Landsat TM and ETM+ imagery. With these satellite data and the BEPS process model (Boreal Ecosystem Productivity Simulator), the impacts of urbanization on regional net primary productivity (NPP) and annual net primary production were assessed for 1991 and 2002. Landsat-based land cover maps in 1991 and 2002 showed that urban development encroached large areas of cropland and forest. Expansion of residential areas and reduction of vegetated areas were the major forms of land transformation in Jiangyin County during this period. Mean NPP of the total area decreased from 818 to 699 gCm(-2)yr(-1) during the period of 1991 to 2002. NPP of cropland was only reduced by 2.7% while forest NPP was reduced by 9.3%. Regional annual primary production decreased from 808 GgC in 1991 to 691 GgC in 2002, a reduction of 14.5%. Land cover changes reduced regional NPP directly, and the increasing intensity and frequency of human-induced disturbance in the urbanized areas could be the main reason for the decrease in forest NPP.

Land use and carbon dynamics in the southeastern United States from 1992 to 2050

International Nuclear Information System (INIS)

Zhao, Shuqing; Liu, Shuguang; Sohl, Terry; Werner, Jeremy; Young, Claudia

2013-01-01

Land use and land cover change (LUCC) plays an important role in determining the spatial distribution, magnitude, and temporal change of terrestrial carbon sources and sinks. However, the impacts of LUCC are not well understood and quantified over large areas. The goal of this study was to quantify the spatial and temporal patterns of carbon dynamics in various terrestrial ecosystems in the southeastern United States from 1992 to 2050 using a process-based modeling system and then to investigate the impacts of LUCC. Spatial LUCC information was reconstructed and projected using the FOREcasting SCEnarios of future land cover (FORE-SCE) model according to information derived from Landsat observations and other sources. Results indicated that urban expansion (from 3.7% in 1992 to 9.2% in 2050) was expected to be the primary driver for other land cover changes in the region, leading to various declines in forest, cropland, and hay/pasture. The region was projected to be a carbon sink of 60.4 gC m −2  yr −1 on average during the study period, primarily due to the legacy impacts of large-scale conversion of cropland to forest that happened since the 1950s. Nevertheless, the regional carbon sequestration rate was expected to decline because of the slowing down of carbon accumulation in aging forests and the decline of forest area. (letter)

Ecosystem function and the net benefit of services provided by three land-use types under variable management in northwestern Virginia

Science.gov (United States)

Huelsman, K. S.; Epstein, H. E.

2017-12-01

The concept of Ecosystem Services (ES) has become more interdisciplinary and influential in policy decision-making, but there are two major shortcomings in recent ES conversations: the resource inputs required by highly managed systems in order to provide material goods are not widely considered, and the distinction between ecosystem function and service is not always made. Supporting and regulating ES were examined for three land-use types with variable human management within the same mesoclimate: farmland, native prairie, and non-native early successional field. In situ soil moisture readings and soil nitrogen (N) transformation incubations, biodiversity surveys, vegetation harvesting, and soil sampling in each land-use type were used to determine the following ES: habitat, productivity, soil fertility, nutrient cycling, and water retention. If the provision of a particular ES required human inputs or interference, its overall value was reduced by the environmental cost of management. Non-native early successional field is not valued for the provision of any particular ES, as native prairie and farmland are, but it provides supporting and regulating ES without the requirement of human intervention, making it valuable in different ways. Likewise, any ecosystem functions with negative ecological side effects were considered ecosystem disservices and reduced the overall value of ES provided by the system. For example, the function of net nitrogen mineralization, generally defined as a service, is a disservice under N-saturated conditions, as additional N could be lost via leaching or gaseous forms. This research is valuable in the context of the current trend of increasing farmland abandonment and land use conversions. By considering the cost of human management for the provision of certain ES, as well as potential disservices associated with function, the overall net benefits of these three land-use types can be compared to improve land-use decision-making.

Exploring long-term trends in land use change and aboveground human appropriation of net primary production in nine European countries

DEFF Research Database (Denmark)

Gingrich, Simone; Niedertscheider, Maria; Kastner, Thomas

2015-01-01

Profound changes in land use occurred during the last century in Europe, driven by growing population, changes in affluence, and technological innovation. To capture and understand these changes, we compiled a consistent dataset on the distribution of land-use types and biomass extraction for nine...... primary production" (HANPP) framework for the nine countries and for the sum of all countries on a yearly basis from 1902 to 2003. We find that cropland and grazing land contracted in all countries except Albania in the observed period, while forestland increased. Crop yields increased in all countries......, most strongly during the second half of the 20th century. In some countries, biomass extraction on grazing lands increased to a similar extent. Overall, HANPP was high but declined slightly from 63% of the net primary production of potential vegetation in 1902 to 55% in 2003. This is the result...

Contributions of secondary forest and nitrogen dynamics to terrestrial carbon uptake

Directory of Open Access Journals (Sweden)

X. Yang

2010-10-01

Full Text Available We use a terrestrial carbon-nitrogen cycle component of the Integrated Science Assessment Model (ISAM to investigate the impacts of nitrogen dynamics on regrowing secondary forests over the 20th century. We further examine what the impacts of nitrogen deposition and land use change history are on terrestrial carbon uptake since preindustrial time. Our results suggest that global total net land use emissions for the 1990s associated with changes in cropland, pastureland, and wood harvest are 1.22 GtC/yr. Without considering the secondary forest regrowth, the estimated net global total land use emissions are 1.58 GtC/yr or about 0.36 GtC/yr higher than if secondary forest regrowth is considered. Results also show that without considering the nitrogen dynamics and deposition, the estimated global total secondary forest sink for the 1990s is 0.90 GtC/yr or about 0.54 GtC/yr higher than estimates that include the impacts of nitrogen dynamics and deposition. Nitrogen deposition alone is responsible for about 0.13 GtC/yr of the total secondary forest sink. While nitrogen is not a limiting nutrient in the intact primary forests in tropical regions, our study suggests that nitrogen becomes a limiting nutrient for regrowing secondary forests of the tropical regions, in particular Latin America and Tropical Africa. This is because land use change activities, especially wood harvest, removes large amounts of nitrogen from the system when slash is burnt or wood is removed for harvest. However, our model results show that carbon uptake is enhanced in the tropical secondary forests of the Indian region. We argue that this may be due to enhanced nitrogen mineralization and increased nitrogen availability following land use change in the Indian tropical forest ecosystems. Results also demonstrate that there is a significant amount of carbon accumulating in the Northern Hemisphere where most land use changes and forest regrowth has occurred in recent decades

Convergent evolution towards high net carbon gain efficiency contributes to the shade tolerance of palms (Arecaceae)

NARCIS (Netherlands)

Ma, Ren Yi; Zhang, Jiao Lin; Cavaleri, Molly A.; Sterck, Frank; Strijk, J.S.; Cao, Kun Fang

2015-01-01

Most palm species occur in the shaded lower strata of tropical rain forests, but how their traits relate to shade adaptation is poorly understood. We hypothesized that palms are adapted to the shade of their native habitats by convergent evolution towards high net carbon gain efficiency (CGEn),

Land-cover effects on soil organic carbon stocks in a European city.

Science.gov (United States)

Edmondson, Jill L; Davies, Zoe G; McCormack, Sarah A; Gaston, Kevin J; Leake, Jonathan R

2014-02-15

Soil is the vital foundation of terrestrial ecosystems storing water, nutrients, and almost three-quarters of the organic carbon stocks of the Earth's biomes. Soil organic carbon (SOC) stocks vary with land-cover and land-use change, with significant losses occurring through disturbance and cultivation. Although urbanisation is a growing contributor to land-use change globally, the effects of urban land-cover types on SOC stocks have not been studied for densely built cities. Additionally, there is a need to resolve the direction and extent to which greenspace management such as tree planting impacts on SOC concentrations. Here, we analyse the effect of land-cover (herbaceous, shrub or tree cover), on SOC stocks in domestic gardens and non-domestic greenspaces across a typical mid-sized U.K. city (Leicester, 73 km(2), 56% greenspace), and map citywide distribution of this ecosystem service. SOC was measured in topsoil and compared to surrounding extra-urban agricultural land. Average SOC storage in the city's greenspace was 9.9 kg m(-2), to 21 cm depth. SOC concentrations under trees and shrubs in domestic gardens were greater than all other land-covers, with total median storage of 13.5 kg m(-2) to 21 cm depth, more than 3 kg m(-2) greater than any other land-cover class in domestic and non-domestic greenspace and 5 kg m(-2) greater than in arable land. Land-cover did not significantly affect SOC concentrations in non-domestic greenspace, but values beneath trees were higher than under both pasture and arable land, whereas concentrations under shrub and herbaceous land-covers were only higher than arable fields. We conclude that although differences in greenspace management affect SOC stocks, trees only marginally increase these stocks in non-domestic greenspaces, but may enhance them in domestic gardens, and greenspace topsoils hold substantial SOC stores that require protection from further expansion of artificial surfaces e.g. patios and driveways. Copyright �

Integrating Ecosystem Carbon Dynamics into State-and-Transition Simulation Models of Land Use/Land Cover Change

Science.gov (United States)

Sleeter, B. M.; Daniel, C.; Frid, L.; Fortin, M. J.

2016-12-01

State-and-transition simulation models (STSMs) provide a general approach for incorporating uncertainty into forecasts of landscape change. Using a Monte Carlo approach, STSMs generate spatially-explicit projections of the state of a landscape based upon probabilistic transitions defined between states. While STSMs are based on the basic principles of Markov chains, they have additional properties that make them applicable to a wide range of questions and types of landscapes. A current limitation of STSMs is that they are only able to track the fate of discrete state variables, such as land use/land cover (LULC) classes. There are some landscape modelling questions, however, for which continuous state variables - for example carbon biomass - are also required. Here we present a new approach for integrating continuous state variables into spatially-explicit STSMs. Specifically we allow any number of continuous state variables to be defined for each spatial cell in our simulations; the value of each continuous variable is then simulated forward in discrete time as a stochastic process based upon defined rates of change between variables. These rates can be defined as a function of the realized states and transitions of each cell in the STSM, thus providing a connection between the continuous variables and the dynamics of the landscape. We demonstrate this new approach by (1) developing a simple IPCC Tier 3 compliant model of ecosystem carbon biomass, where the continuous state variables are defined as terrestrial carbon biomass pools and the rates of change as carbon fluxes between pools, and (2) integrating this carbon model with an existing LULC change model for the state of Hawaii, USA.

Land Cover Land Use change and soil organic carbon under climate variability in the semi-arid West African Sahel (1960-2050)

Science.gov (United States)

Dieye, Amadou M.

Land Cover Land Use (LCLU) change affects land surface processes recognized to influence climate change at local, national and global levels. Soil organic carbon is a key component for the functioning of agro-ecosystems and has a direct effect on the physical, chemical and biological characteristics of the soil. The capacity to model and project LCLU change is of considerable interest for mitigation and adaptation measures in response to climate change. A combination of remote sensing analyses, qualitative social survey techniques, and biogeochemical modeling was used to study the relationships between climate change, LCLU change and soil organic carbon in the semi-arid rural zone of Senegal between 1960 and 2050. For this purpose, four research hypotheses were addressed. This research aims to contribute to an understanding of future land cover land use change in the semi-arid West African Sahel with respect to climate variability and human activities. Its findings may provide insights to enable policy makers at local to national levels to formulate environmentally and economically adapted policy decisions. This dissertation research has to date resulted in two published and one submitted paper.

Carbon Impacts of Fire- and Bark Beetle-Caused Tree Mortality across the Western US using the Community Land Model (Invited)

Science.gov (United States)

Meddens, A. J.; Hicke, J. A.; Edburg, S. L.; Lawrence, D. M.

2013-12-01

Wildfires and bark beetle outbreaks cause major forest disturbances in the western US, affecting ecosystem productivity and thereby impacting forest carbon cycling and future climate. Despite the large spatial extent of tree mortality, quantifying carbon flux dynamics following fires and bark beetles over larger areas is challenging because of forest heterogeneity, varying disturbance severities, and field observation limitations. The objective of our study is to estimate these dynamics across the western US using the Community Land Model (version CLM4.5-BGC). CLM4.5-BGC is a land ecosystem model that mechanistically represents the exchanges of energy, water, carbon, and nitrogen with the atmosphere. The most recent iteration of the model has been expanded to include vertically resolved soil biogeochemistry and includes improved nitrogen cycle representations including nitrification and denitrification and biological fixation as well as improved canopy processes including photosynthesis. Prior to conducting simulations, we modified CLM4.5-BGC to include the effects of bark beetle-caused tree mortality on carbon and nitrogen stocks and fluxes. Once modified, we conducted paired simulations (with and without) fire- and bark beetle-caused tree mortality by using regional data sets of observed mortality as inputs. Bark beetle-caused tree mortality was prescribed from a data set derived from US Forest Service aerial surveys from 1997 to 2010. Annual tree mortality area was produced from observed tree mortality caused by bark beetles and was adjusted for underestimation. Fires were prescribed using the Monitoring Trends in Burn Severity (MTBS) database from 1984 to 2010. Annual tree mortality area was produced from forest cover maps and inclusion of moderate- and high-severity burned areas. Simulations show that maximum yearly reduction of net ecosystem productivity (NEP) caused by bark beetles is approximately 20 Tg C for the western US. Fires cause similar reductions

Soil Respiration in Semiarid Temperate Grasslands under Various Land Management.

Directory of Open Access Journals (Sweden)

Zhen Wang

Full Text Available Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17 μmol.m(-2.s(-1 and clipping (2.06 μmol.m(-2.s(-1 than under grazing (1.65 μmol.m-(2.s(-1 over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP. Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content and biotic (ANPP and BNPP factors regulate soil respiration in the semiarid temperate grassland of northern China.

Soil Respiration in Semiarid Temperate Grasslands under Various Land Management.

Science.gov (United States)

Wang, Zhen; Ji, Lei; Hou, Xiangyang; Schellenberg, Michael P

2016-01-01

Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures) on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17 μmol.m(-2).s(-1)) and clipping (2.06 μmol.m(-2).s(-1)) than under grazing (1.65 μmol.m-(2).s(-1)) over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP). Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP) and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content) and biotic (ANPP and BNPP) factors regulate soil respiration in the semiarid temperate grassland of northern China.

Global Surface Net-Radiation at 5 km from MODIS Terra

Directory of Open Access Journals (Sweden)

Manish Verma

2016-09-01

Full Text Available Reliable and fine resolution estimates of surface net-radiation are required for estimating latent and sensible heat fluxes between the land surface and the atmosphere. However, currently, fine resolution estimates of net-radiation are not available and consequently it is challenging to develop multi-year estimates of evapotranspiration at scales that can capture land surface heterogeneity and are relevant for policy and decision-making. We developed and evaluated a global net-radiation product at 5 km and 8-day resolution by combining mutually consistent atmosphere and land data from the Moderate Resolution Imaging Spectroradiometer (MODIS on board Terra. Comparison with net-radiation measurements from 154 globally distributed sites (414 site-years from the FLUXNET and Surface Radiation budget network (SURFRAD showed that the net-radiation product agreed well with measurements across seasons and climate types in the extratropics (Wilmott’s index ranged from 0.74 for boreal to 0.63 for Mediterranean sites. Mean absolute deviation between the MODIS and measured net-radiation ranged from 38.0 ± 1.8 W∙m−2 in boreal to 72.0 ± 4.1 W∙m−2 in the tropical climates. The mean bias was small and constituted only 11%, 0.7%, 8.4%, 4.2%, 13.3%, and 5.4% of the mean absolute error in daytime net-radiation in boreal, Mediterranean, temperate-continental, temperate, semi-arid, and tropical climate, respectively. To assess the accuracy of the broader spatiotemporal patterns, we upscaled error-quantified MODIS net-radiation and compared it with the net-radiation estimates from the coarse spatial (1° × 1° but high temporal resolution gridded net-radiation product from the Clouds and Earth’s Radiant Energy System (CERES. Our estimates agreed closely with the net-radiation estimates from the CERES. Difference between the two was less than 10 W·m−2 in 94% of the total land area. MODIS net-radiation product will be a valuable resource for the

Representing anthropogenic gross land use change, wood harvest, and forest age dynamics in a global vegetation model ORCHIDEE-MICT v8.4.2

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Yue, Chao; Ciais, Philippe; Luyssaert, Sebastiaan; Li, Wei; McGrath, Matthew J.; Chang, Jinfeng; Peng, Shushi

2018-01-01

Land use change (LUC) is among the main anthropogenic disturbances in the global carbon cycle. Here we present the model developments in a global dynamic vegetation model ORCHIDEE-MICT v8.4.2 for a more realistic representation of LUC processes. First, we included gross land use change (primarily shifting cultivation) and forest wood harvest in addition to net land use change. Second, we included sub-grid evenly aged land cohorts to represent secondary forests and to keep track of the transient stage of agricultural lands since LUC. Combination of these two features allows the simulation of shifting cultivation with a rotation length involving mainly secondary forests instead of primary ones. Furthermore, a set of decision rules regarding the land cohorts to be targeted in different LUC processes have been implemented. Idealized site-scale simulation has been performed for miombo woodlands in southern Africa assuming an annual land turnover rate of 5 % grid cell area between forest and cropland. The result shows that the model can correctly represent forest recovery and cohort aging arising from agricultural abandonment. Such a land turnover process, even though without a net change in land cover, yields carbon emissions largely due to the imbalance between the fast release from forest clearing and the slow uptake from agricultural abandonment. The simulation with sub-grid land cohorts gives lower emissions than without, mainly because the cleared secondary forests have a lower biomass carbon stock than the mature forests that are otherwise cleared when sub-grid land cohorts are not considered. Over the region of southern Africa, the model is able to account for changes in different forest cohort areas along with the historical changes in different LUC activities, including regrowth of old forests when LUC area decreases. Our developments provide possibilities to account for continental or global forest demographic change resulting from past anthropogenic and

CARBON SEQUESTRATION ON SURFACE MINE LANDS

Energy Technology Data Exchange (ETDEWEB)

Donald H. Graves; Christopher Barton; Richard Sweigard; Richard Warner

2005-06-22

An area planted in 2004 on Bent Mountain in Pike County was shifted to the Department of Energy project to centralize an area to become a demonstration site. An additional 98.3 acres were planted on Peabody lands in western Kentucky and Bent Mountain to bring the total area under study by this project to 556.5 acres as indicated in Table 2. Major efforts this quarter include the implementation of new plots that will examine the influence of differing geologic material on tree growth and survival, water quality and quantity and carbon sequestration. Normal monitoring and maintenance was conducted and additional instrumentation was installed to monitor the new areas planted.

Carbon Calculator for Land Use Change from Biofuels Production (CCLUB). Users' Manual and Technical Documentation

Energy Technology Data Exchange (ETDEWEB)

Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Qin, Zhangcai [Argonne National Lab. (ANL), Argonne, IL (United States); Mueller, Steffen [Univ. of Illinois at Chicago, Chicago, IL (United States); Kwon, Ho-young [International Food Policy Research Institute (IFPRI), Washington, DC (United States); Wander, Michelle M. [Univ. of Illinois, Urbana-Champaign, IL (United States); Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States)

2014-09-01

The Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) calculates carbon emissions from land use change (LUC) for four different ethanol production pathways including corn grain ethanol and cellulosic ethanol from corn stover, Miscanthus, and switchgrass. This document discusses the version of CCLUB released September 30, 2014 which includes corn and three cellulosic feedstocks: corn stover, Miscanthus, and switchgrass.

Estimating carbon sequestration in the piedmont ecoregion of the United States from 1971 to 2010

Directory of Open Access Journals (Sweden)

Jinxun Liu

2016-06-01

Full Text Available Abstract Background Human activities have diverse and profound impacts on ecosystem carbon cycles. The Piedmont ecoregion in the eastern United States has undergone significant land use and land cover change in the past few decades. The purpose of this study was to use newly available land use and land cover change data to quantify carbon changes within the ecoregion. Land use and land cover change data (60-m spatial resolution derived from sequential remotely sensed Landsat imagery were used to generate 960-m resolution land cover change maps for the Piedmont ecoregion. These maps were used in the Integrated Biosphere Simulator (IBIS to simulate ecosystem carbon stock and flux changes from 1971 to 2010. Results Results show that land use change, especially urbanization and forest harvest had significant impacts on carbon sources and sinks. From 1971 to 2010, forest ecosystems sequestered 0.25 Mg C ha−1 yr−1, while agricultural ecosystems sequestered 0.03 Mg C ha−1 yr−1. The total ecosystem C stock increased from 2271 Tg C in 1971 to 2402 Tg C in 2010, with an annual average increase of 3.3 Tg C yr−1. Conclusions Terrestrial lands in the Piedmont ecoregion were estimated to be weak net carbon sink during the study period. The major factors contributing to the carbon sink were forest growth and afforestation; the major factors contributing to terrestrial emissions were human induced land cover change, especially urbanization and forest harvest. An additional amount of carbon continues to be stored in harvested wood products. If this pool were included the carbon sink would be stronger.

Modeling the grazing effect on dry grassland carbon cycling with modified Biome-BGC grazing model

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Luo, Geping; Han, Qifei; Li, Chaofan; Yang, Liao

2014-05-01

Identifying the factors that determine the carbon source/sink strength of ecosystems is important for reducing uncertainty in the global carbon cycle. Arid grassland ecosystems are a widely distributed biome type in Xinjiang, Northwest China, covering approximately one-fourth the country's land surface. These grasslands are the habitat for many endemic and rare plant and animal species and are also used as pastoral land for livestock. Using the modified Biome-BGC grazing model, we modeled carbon dynamics in Xinjiang for grasslands that varied in grazing intensity. In general, this regional simulation estimated that the grassland ecosystems in Xinjiang acted as a net carbon source, with a value of 0.38 Pg C over the period 1979-2007. There were significant effects of grazing on carbon dynamics. An over-compensatory effect in net primary productivity (NPP) and vegetation carbon (C) stock was observed when grazing intensity was lower than 0.40 head/ha. Grazing resulted in a net carbon source of 23.45 g C m-2 yr-1, which equaled 0.37 Pg in Xinjiang in the last 29 years. In general, grazing decreased vegetation C stock, while an increasing trend was observed with low grazing intensity. The soil C increased significantly (17%) with long-term grazing, while the soil C stock exhibited a steady trend without grazing. These findings have implications for grassland ecosystem management as it relates to carbon sequestration and climate change mitigation, e.g., removal of grazing should be considered in strategies that aim to increase terrestrial carbon sequestrations at local and regional scales. One of the greatest limitations in quantifying the effects of herbivores on carbon cycling is identifying the grazing systems and intensities within a given region. We hope our study emphasizes the need for large-scale assessments of how grazing impacts carbon cycling. Most terrestrial ecosystems in Xinjiang have been affected by disturbances to a greater or lesser extent in the past

Carbon Calculator for Land Use Change from Biofuels Production (CCLUB). Users' manual and technical documentation.

Energy Technology Data Exchange (ETDEWEB)

Mueller, S; Dunn, JB; Wang, M (Energy Systems); (Univ. of Illinois at Chicago)

2012-06-07

The Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) calculates carbon emissions from land use change (LUC) for four different ethanol production pathways including corn grain ethanol and cellulosic ethanol from corn stover, miscanthus, and switchgrass. This document discusses the version of CCLUB released May 31, 2012 which includes corn, as did the previous CCLUB version, and three cellulosic feedstocks: corn stover, miscanthus, and switchgrass. CCLUB calculations are based upon two data sets: land change areas and above- and below-ground carbon content. Table 1 identifies where these data are stored and used within the CCLUB model, which is built in MS Excel. Land change area data is from Purdue University's Global Trade Analysis Project (GTAP) model, a computable general equilibrium (CGE) economic model. Section 2 describes the GTAP data CCLUB uses and how these data were modified to reflect shrubland transitions. Feedstock- and spatially-explicit below-ground carbon content data for the United States were generated with a surrogate model for CENTURY's soil organic carbon sub-model (Kwon and Hudson 2010) as described in Section 3. CENTURY is a soil organic matter model developed by Parton et al. (1987). The previous CCLUB version used more coarse domestic carbon emission factors. Above-ground non-soil carbon content data for forest ecosystems was sourced from the USDA/NCIAS Carbon Online Estimator (COLE) as explained in Section 4. We discuss emission factors used for calculation of international greenhouse gas (GHG) emissions in Section 5. Temporal issues associated with modeling LUC emissions are the topic of Section 6. Finally, in Section 7 we provide a step-by-step guide to using CCLUB and obtaining results.

SOIL ORGANIC CARBON LEVELS IN SOILS OF CONTRASTING LAND USES IN SOUTHEASTERN NIGERIA

Directory of Open Access Journals (Sweden)

Chinyere Blessing Okebalama

2017-12-01

Full Text Available Land use change affects soil organic carbon (SOC storage in tropical soils, but information on the influence of land use change on segmental topsoil organic carbon stock is lacking. The study investigated SOC levels in Awgu (L, Okigwe (CL, Nsukka I (SL, and Nsukka II (SCL locations in southeastern Nigeria. Land uses considered in each location were the cultivated (manually-tilled and the adjacent uncultivated (4-5 year bush-fallow soils from which samples at 0-10, 10-20, and 20-30 cm topsoil depth were assessed. The SOC level decreased with topsoil depth in both land uses. Overall, the SOC level at 0-30 cm was between 285.44 and 805.05 Mg ha-1 amongst the soils.  The uncultivated sites stored more SOC than its adjacent cultivated counterpart at 0-10 and 10-20 cm depth, except in Nsukka II soils, which had significantly higher SOC levels in the cultivated than the uncultivated site. Nonetheless, at 20-30 cm depth, the SOC pool across the fallowed soils was statistically similar when parts of the same soil utilization type were tilled and cultivated. Therefore, while 4 to 5 years fallow may be a useful strategy for SOC stabilization within 20-30 cm topsoil depth in the geographical domain, segmental computation of topsoil organic carbon pool is critical.

MMPM - Mars MetNet Precursor Mission

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Harri, A.-M.; Schmidt, W.; Pichkhadze, K.; Linkin, V.; Vazquez, L.; Uspensky, M.; Polkko, J.; Genzer, M.; Lipatov, A.; Guerrero, H.; Alexashkin, S.; Haukka, H.; Savijarvi, H.; Kauhanen, J.

2008-09-01

We are developing a new kind of planetary exploration mission for Mars - MetNet in situ observation network based on a new semi-hard landing vehicle called the Met-Net Lander (MNL). The eventual scope of the MetNet Mission is to deploy some 20 MNLs on the Martian surface using inflatable descent system structures, which will be supported by observations from the orbit around Mars. Currently we are working on the MetNet Mars Precursor Mission (MMPM) to deploy one MetNet Lander to Mars in the 2009/2011 launch window as a technology and science demonstration mission. The MNL will have a versatile science payload focused on the atmospheric science of Mars. Detailed characterization of the Martian atmospheric circulation patterns, boundary layer phenomena, and climatology cycles, require simultaneous in-situ measurements by a network of observation posts on the Martian surface. The scientific payload of the MetNet Mission encompasses separate instrument packages for the atmospheric entry and descent phase and for the surface operation phase. The MetNet mission concept and key probe technologies have been developed and the critical subsystems have been qualified to meet the Martian environmental and functional conditions. Prototyping of the payload instrumentation with final dimensions was carried out in 2003-2006.This huge development effort has been fulfilled in collaboration between the Finnish Meteorological Institute (FMI), the Russian Lavoschkin Association (LA) and the Russian Space Research Institute (IKI) since August 2001. Currently the INTA (Instituto Nacional de Técnica Aeroespacial) from Spain is also participating in the MetNet payload development. To understand the behavior and dynamics of the Martian atmosphere, a wealth of simultaneous in situ observations are needed on varying types of Martian orography, terrain and altitude spanning all latitudes and longitudes. This will be performed by the Mars MetNet Mission. In addition to the science aspects the

Net ecosystem production and organic carbon balance of U.S. East Coast estuaries: A synthesis approach

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Herrmann, Maria; Najjar, Raymond G.; Kemp, W. Michael; Alexander, Richard B.; Boyer, Elizabeth W.; Cai, Wei-Jun; Griffith, Peter C.; Kroeger, Kevin D.; McCallister, S. Leigh; Smith, Richard A.

2015-01-01

Net ecosystem production (NEP) and the overall organic carbon budget for the estuaries along the East Coast of the United States are estimated. We focus on the open estuarine waters, excluding the fringing wetlands. We developed empirical models relating NEP to loading ratios of dissolved inorganic nitrogen to total organic carbon, and carbon burial in the sediment to estuarine water residence time and total nitrogen input across the landward boundary. Output from a data-constrained water quality model was used to estimate inputs of total nitrogen and organic carbon to the estuaries across the landward boundary, including fluvial and tidal-wetland sources. Organic carbon export from the estuaries to the continental shelf was computed by difference, assuming steady state. Uncertainties in the budget were estimated by allowing uncertainties in the supporting model relations. Collectively, U.S. East Coast estuaries are net heterotrophic, with the area-integrated NEP of −1.5 (−2.8, −1.0) Tg C yr−1 (best estimate and 95% confidence interval) and area-normalized NEP of −3.2 (−6.1, −2.3) mol C m−2 yr−1. East Coast estuaries serve as a source of organic carbon to the shelf, exporting 3.4 (2.0, 4.3) Tg C yr−1 or 7.6 (4.4, 9.5) mol C m−2 yr−1. Organic carbon inputs from fluvial and tidal-wetland sources for the region are estimated at 5.4 (4.6, 6.5) Tg C yr−1 or 12 (10, 14) mol C m−2 yr−1 and carbon burial in the open estuarine waters at 0.50 (0.33, 0.78) Tg C yr−1 or 1.1 (0.73, 1.7) mol C m−2 yr−1. Our results highlight the importance of estuarine systems in the overall coastal budget of organic carbon, suggesting that in the aggregate, U.S. East Coast estuaries assimilate (via respiration and burial) ~40% of organic carbon inputs from fluvial and tidal-wetland sources and allow ~60% to be exported to the shelf.

Quantifying Carbon Consequences of Recent Land Management and Disturbances in the Greater Yellowstone Ecosystems (GYE) by linking inventory data, remote sensing and carbon modeling

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Zhao, F.; Huang, C.; Healey, S. P.; McCarter, J. B.; Garrard, C.; Zhu, Z.

2015-12-01

Natural disturbances and land management directly change C stored in biomass and soil pools, and can have indirect impacts on long-term C balance. The Greater Yellowstone Ecosystem (GYE), located in Central Rocky Mountains of United States, is of different land ownerships within similar environmental settings, making it an ideal site to examine the impacts of management and disturbances on regional carbon dynamics. Recent advances in the remote sensing of vegetation condition and change, along with new techniques linking remote sensing with inventory records, have allowed investigations that are much more tightly constrained to actual landscape environment, instead of hypothetical or generalized conditions. These new capabilities are built into the Forest Carbon Management Framework (ForCaMF), which is being used by the National Forest System to not only model, but to monitor across very specific management units, the impact of different kinds of disturbance on carbon storage. In this study, we used the ForCaMF approach to evaluate carbon effects of natural disturbances (e.g. wildfire) and land management (e.g. harvests) in GYE National Parks, Wilderness Area and National Forests. As might be expected, wildfire has been the dominant disturbance factor in the carbon cycle of GYE's administratively protected areas since the mid-1980s, while harvests have dominated storage trends on the managed land in the region's National Forests. Moving beyond this monitoring result but maintaining the same fidelity to historical vegetation patterns, we are also able to simulate alternative disturbance scenarios to provide landscape-specific insights to forest managers. We can estimate likely carbon storage impacts in GYE protected areas, for example, if more active fire suppression had been pursued since the mid-1980s. Likewise, we can identify differences in current carbon storage on managed lands if high harvest rates during the same period had been moderated. We discuss

Effect of Land Use Change on Soil Carbon Storage over the Last 40 Years in the Shi Yang River Basin, China

Directory of Open Access Journals (Sweden)

Shurong Yang

2018-01-01

Full Text Available Accounting for one quarter of China’s land area, the endorheic Shiyang River basin is a vast semi-arid to arid region in China’s northwest. Exploring the impact of changes in land use on this arid area’s carbon budget under global warming is a key component to global climate change research. Variation in the region’s soil carbon storage due to land use changes occurring between 1973 and 2012 was estimated. The results show that land use change has a significant impact on the soil carbon budget, with soil carbon storage having decreased by 3.89 Tg between 1973 and 2012. Grassland stored the greatest amount of soil carbon (114.34 Mg ha−1, whereas considerably lower carbon storage occurred in woodland (58.53 Mg ha−1, cropland (26.75 Mg ha−1 and unused land (13.47 Mg ha−1. Grasslands transformed into cropland, and woodlands degraded into grassland have substantially reduced soil carbon storage, suggesting that measures should be adopted to reverse this trend to improve soil productivity.

Decadal change of forest biomass carbon stocks and tree demography in the Delaware River Basin

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Bing Xu; Yude Pan; Alain F. Plante; Arthur Johnson; Jason Cole; Richard Birdsey

2016-01-01

Quantifying forest biomass carbon (C) stock change is important for understanding forest dynamics and their feedbacks with climate change. Forests in the northeastern U.S. have been a net carbon sink in recent decades, but C accumulation in some northern hardwood forests has been halted due to the impact of emerging stresses such as invasive pests, land use change and...

The influence of land-use and land-management on Soil Organic Carbon concentrations: Limitations of making predictions using only soil order data

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Bell, M. J.; Worrall, F.

2009-04-01

In light of recent concern over the extent of global warming and the role of soil carbon as a potential store of atmospheric carbon, there is increasing demand for regions to estimate their current soil organic carbon (SOC) stocks with the greatest possible accuracy. Several previous attempts at calculating SOC baselines at global, national or regional scale have used mean values for soil orders and multiplied these values by the mapped areas of the soils they represent. Other methods have approached the task from a land cover point of view, making estimates using only land-use, or soil order/land-use combinations and others have included variables such as altitude, climate and soil texture. This study aimed to assess the major controls on SOC concentrations (%SOC) at the National Trust Wallington estate in Northumberland, NE England (area = 55km2) where an extensive soil sampling campaign was used to test what level of accuracy could be achieved in modelling the %SOC values on the Estate. Mapped %SOC values were compared to the values predicted from The National Soils Resources Institute (NSRI) representative soil profile data for major soil group, soil series and land-use corrected soil series values, as well as land-use/major soil group combinations from the Countryside Survey database. The results of this study can be summarised as follows: When only soil series or land-use were used as predictors only 48% and 44% of the variation in the dataset were explained. When soil series/land-use combinations were used explanatory power increased to 57% both altitude and soil pH are major controls on %SOC and including these variables gave an improvement to 59% A further improvement from 59% to 66% in the ability to predict %SOC levels at point locations when farm tenancy was included indicates that differences in land-management practices between farm tenancies explained more of the variation than either soil series or land-use in %SOC. Further work will involve a

Land-Based Mitigation Strategies under the Mid-Term Carbon Reduction Targets in Indonesia

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Tomoko Hasegawa

2016-12-01

Full Text Available We investigated the key mitigation options for achieving the mid-term target for carbon emission reduction in Indonesia. A computable general equilibrium model coupled with a land-based mitigation technology model was used to evaluate specific mitigation options within the whole economic framework. The results revealed three primary findings: (1 If no climate policy were implemented, Indonesia’s total greenhouse gas emissions would reach 3.0 GtCO2eq by 2030; (2 To reduce carbon emissions to meet the latest Intended Nationally-Determined Contributions (INDC target, ~58% of total reductions should come from the agriculture, forestry and other land use sectors by implementing forest protection, afforestation and plantation efforts; (3 A higher carbon price in 2020 suggests that meeting the 2020 target would be economically challenging, whereas the INDC target for 2030 would be more economically realistic in Indonesia.

How do soil properties and soil carbon stocks change after land abandonment in Mediterranean mountain areas?

Science.gov (United States)

Nadal Romero, Estela; Cammeraat, Erik; Pérez Cardiel, Estela; Lasanta, Teodoro

2016-04-01

Land abandonment and subsequent revegetation processes (due to secondary succession and afforestation practices) are global issues with important implications in Mediterranean mountain areas. Moreover, the effects of land use changes on soil carbon stocks are a matter of concern stated in international policy agendas on the mitigation of greenhouse emissions, and afforestation practices are increasingly viewed as an environmental restorative land use change prescription and are considered one of the most efficient carbon sequestration strategies currently available. The MED-AFFOREST project aims to gain more insight into the discussion by exploring the following central research questions: (i) what is the impact of land abandonment on soil properties? and (ii) how do soil organic carbon change after land abandonment? The main objective of this study is to assess the effects of land abandonment, land use change and afforestation practices on soil properties and soil organic carbon (SOC) dynamics. For this aim, five different land covers (bare soil, meadows, secondary succession, Pinus sylvestris (PS) and Pinus nigra (PN) afforestation), in the Central Spanish Pyrenees were analysed. Results showed that changes in soil properties after land abandonment were limited, even if afforestation practices were carried out and no differences were observed between natural succession and afforestation. The results on SOC dynamics showed that: (i) SOC contents were higher in the PN sites in the topsoil (10 cm), (ii) when all the profile was considered no significant differences were observed between meadows and PN, (iii) SOC accumulation under secondary succession is a slow process, and (iv) meadows should also be considered due to the relative importance in SOC stocks. The first step of SOC stabilization after afforestation is the formation of macro-aggregates promoted by large inputs of SOC, with a high contribution of labile organic matter. However, our respiration

Exploring Global Patterns in Human Appropriation of Net Primary Production Using Earth Observation Satellites and Statistical Data

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Imhoff, M.; Bounoua, L.

2004-12-01

A unique combination of satellite and socio-economic data were used to explore the relationship between human consumption and the carbon cycle. Biophysical models were applied to consumption data to estimate the annual amount of Earth's terrestrial net primary production humans require for food, fiber and fuel using the same modeling architecture as satellite-supported NPP measurements. The amount of Earth's NPP required to support human activities is a powerful measure of the aggregate human impacts on the biosphere and indicator of societal vulnerability to climate change. Equations were developed estimating the amount of landscape-level NPP required to generate all the products consumed by 230 countries including; vegetal foods, meat, milk, eggs, wood, fuel-wood, paper and fiber. The amount of NPP required was calculated on a per capita basis and projected onto a global map of population to create a spatially explicit map of NPP-carbon demand in units of elemental carbon. NPP demand was compared to a map of Earth's average annual net primary production or supply created using 17 years (1982-1998) of AVHRR vegetation index to produce a geographically accurate balance sheet of terrestrial NPP-carbon supply and demand. Globally, humans consume 20 percent of Earth's total net primary production on land. Regionally the NPP-carbon balance percentage varies from 6 to over 70 percent and locally from near 0 to over 30,000 percent in major urban areas. The uneven distribution of NPP-carbon supply and demand, indicate the degree to which various human populations rely on NPP imports, are vulnerable to climate change and suggest policy options for slowing future growth in NPP demand.

Satellite Based Cropland Carbon Monitoring System

Science.gov (United States)

Bandaru, V.; Jones, C. D.; Sedano, F.; Sahajpal, R.; Jin, H.; Skakun, S.; Pnvr, K.; Kommareddy, A.; Reddy, A.; Hurtt, G. C.; Izaurralde, R. C.

2017-12-01

Agricultural croplands act as both sources and sinks of atmospheric carbon dioxide (CO2); absorbing CO2 through photosynthesis, releasing CO2 through autotrophic and heterotrophic respiration, and sequestering CO2 in vegetation and soils. Part of the carbon captured in vegetation can be transported and utilized elsewhere through the activities of food, fiber, and energy production. As well, a portion of carbon in soils can be exported somewhere else by wind, water, and tillage erosion. Thus, it is important to quantify how land use and land management practices affect the net carbon balance of croplands. To monitor the impacts of various agricultural activities on carbon balance and to develop management strategies to make croplands to behave as net carbon sinks, it is of paramount importance to develop consistent and high resolution cropland carbon flux estimates. Croplands are typically characterized by fine scale heterogeneity; therefore, for accurate carbon flux estimates, it is necessary to account for the contribution of each crop type and their spatial distribution. As part of NASA CMS funded project, a satellite based Cropland Carbon Monitoring System (CCMS) was developed to estimate spatially resolved crop specific carbon fluxes over large regions. This modeling framework uses remote sensing version of Environmental Policy Integrated Climate Model and satellite derived crop parameters (e.g. leaf area index (LAI)) to determine vertical and lateral carbon fluxes. The crop type LAI product was developed based on the inversion of PRO-SAIL radiative transfer model and downscaled MODIS reflectance. The crop emergence and harvesting dates were estimated based on MODIS NDVI and crop growing degree days. To evaluate the performance of CCMS framework, it was implemented over croplands of Nebraska, and estimated carbon fluxes for major crops (i.e. corn, soybean, winter wheat, grain sorghum, alfalfa) grown in 2015. Key findings of the CCMS framework will be presented

Carbon cost of plant nitrogen acquisition: global carbon cycle impact from an improved plant nitrogen cycle in the Community Land Model.

Science.gov (United States)

Shi, Mingjie; Fisher, Joshua B; Brzostek, Edward R; Phillips, Richard P

2016-03-01

Plants typically expend a significant portion of their available carbon (C) on nutrient acquisition - C that could otherwise support growth. However, given that most global terrestrial biosphere models (TBMs) do not include the C cost of nutrient acquisition, these models fail to represent current and future constraints to the land C sink. Here, we integrated a plant productivity-optimized nutrient acquisition model - the Fixation and Uptake of Nitrogen Model - into one of the most widely used TBMs, the Community Land Model. Global plant nitrogen (N) uptake is dynamically simulated in the coupled model based on the C costs of N acquisition from mycorrhizal roots, nonmycorrhizal roots, N-fixing microbes, and retranslocation (from senescing leaves). We find that at the global scale, plants spend 2.4 Pg C yr(-1) to acquire 1.0 Pg N yr(-1) , and that the C cost of N acquisition leads to a downregulation of global net primary production (NPP) by 13%. Mycorrhizal uptake represented the dominant pathway by which N is acquired, accounting for ~66% of the N uptake by plants. Notably, roots associating with arbuscular mycorrhizal (AM) fungi - generally considered for their role in phosphorus (P) acquisition - are estimated to be the primary source of global plant N uptake owing to the dominance of AM-associated plants in mid- and low-latitude biomes. Overall, our coupled model improves the representations of NPP downregulation globally and generates spatially explicit patterns of belowground C allocation, soil N uptake, and N retranslocation at the global scale. Such model improvements are critical for predicting how plant responses to altered N availability (owing to N deposition, rising atmospheric CO2 , and warming temperatures) may impact the land C sink. © 2015 John Wiley & Sons Ltd.

Mars MetNet Mission Status

Science.gov (United States)

Harri, A.-M.; Aleksashkin, S.; Arruego, I.; Schmidt, W.; Genzer, M.; Vazquez, L.; Haukka, H.; Palin, M.; Nikkanen, T.

2015-10-01

New kind of planetary exploration mission for Mars is under development in collaboration between the Finnish Meteorological Institute (FMI), Lavochkin Association (LA), Space Research Institute (IKI) and Institutio Nacional de Tecnica Aerospacial (INTA). The Mars MetNet mission is based on a new semihard landing vehicle called MetNet Lander (MNL). The scientific payload of the Mars MetNet Precursor [1] mission is divided into three categories: Atmospheric instruments, Optical devices and Composition and structure devices. Each of the payload instruments will provide significant insights in to the Martian atmospheric behavior. The key technologies of the MetNet Lander have been qualified and the electrical qualification model (EQM) of the payload bay has been built and successfully tested.

Drivers of land use change and carbon mapping in the savannah area of Ghana

Directory of Open Access Journals (Sweden)

Koranteng Addo

2017-12-01

Full Text Available Land-use and land-cover change in both forest reserves and off-reserves is a critical issue in sub Saharan Africa. Deforestation and conversion of forest land to agricultural land continue to be one of the major environmental problems in Africa, and for that matter, Ghana cannot be exceptional; and its resultant effect is the loss in the ecological integrity and the quality of forests, resulting in carbon loss and the resultant climate change effects (FAO 2016. The study area covers the Community Resource Management Areas (CREMA of the Mole National Park in Ghana, and this study reveals that the area is well endowed with a diverse composition and structure of woodland including dense, open and riverine stretches, which – under the national definition of forest – qualifies as forest. The results reveal that there had been an annual deforestation rate of 0.11% over the period of review. It was concluded from the study that woodland had high carbon stocks with an average carbon of 80 tC/ha, the highest being 194 tC/ha and the lowest being 7 tC/ha, which was recorded in the dense woodland and grassland respectively. The fluxes within the land sector in the study area are moderate and the potential of the area to qualify for as REDD+ is very high. However, the drivers of deforestation, especially bush fires and illegal timber harvesting, are challenges that need to be addressed.

Uncertainty of forest carbon stock changes. Implications to the total uncertainty of GHG inventory of Finland

International Nuclear Information System (INIS)

Monni, S.; Savolainen, I.; Peltoniemi, M.; Lehtonen, A.; Makipaa, R.; Palosuo, T.

2007-01-01

Uncertainty analysis facilitates identification of the most important categories affecting greenhouse gas (GHG) inventory uncertainty and helps in prioritisation of the efforts needed for development of the inventory. This paper presents an uncertainty analysis of GHG emissions of all Kyoto sectors and gases for Finland consolidated with estimates of emissions/removals from LULUCF categories. In Finland, net GHG emissions in 2003 were around 69 Tg (±15 Tg) CO2 equivalents. The uncertainties in forest carbon sink estimates in 2003 were larger than in most other emission categories, but of the same order of magnitude as in carbon stock change estimates in other land use, land-use change and forestry (LULUCF) categories, and in N2O emissions from agricultural soils. Uncertainties in sink estimates of 1990 were lower, due to better availability of data. Results of this study indicate that inclusion of the forest carbon sink to GHG inventories reported to the UNFCCC increases uncertainties in net emissions notably. However, the decrease in precision is accompanied by an increase in the accuracy of the overall net GHG emissions due to improved completeness of the inventory. The results of this study can be utilised when planning future GHG mitigation protocols and emission trading schemes and when analysing environmental benefits of climate conventions

CO2 supersaturation and net heterotrophy in a tropical estuary (Cochin, India): Influence of anthropogenic effect - Carbon dynamics in tropical estuary

Digital Repository Service at National Institute of Oceanography (India)

Gupta, G.V.M.; Thottathil, S.D.; Balachandran, K.K.; Madhu, N.V.; Madeswaran, P.; Nair, S.

of pCO sub(2) (up to 6000 mu atm) and CO sub(2) effluxes (up to 274 mmolC m sup(-2) d sup(-1)) especially during monsoon. A first-order estimate of the carbon mass balance shows that net production of dissolved inorganic carbon is an order of magnitude...

Remote SST Forcing and Local Land-Atmosphere Moisture Coupling as Drivers of Amazon Temperature and Carbon Cycle Variability

Science.gov (United States)

Levine, P. A.; Xu, M.; Chen, Y.; Randerson, J. T.; Hoffman, F. M.

2017-12-01

Interannual variability of climatic conditions in the Amazon rainforest is associated with El Niño-Southern Oscillation (ENSO) and ocean-atmosphere interactions in the North Atlantic. Sea surface temperature (SST) anomalies in these remote ocean regions drive teleconnections with Amazonian surface air temperature (T), precipitation (P), and net ecosystem production (NEP). While SST-driven NEP anomalies have been primarily linked to T anomalies, it is unclear how much the T anomalies result directly from SST forcing of atmospheric circulation, and how much result indirectly from decreases in precipitation that, in turn, influence surface energy fluxes. Interannual variability of P associated with SST anomalies lead to variability in soil moisture (SM), which would indirectly affect T via partitioning of turbulent heat fluxes between the land surface and the atmosphere. To separate the direct and indirect influence of the SST signal on T and NEP, we performed a mechanism-denial experiment to decouple SST and SM anomalies. We used the Accelerated Climate Modeling for Energy (ACMEv0.3), with version 5 of the Community Atmosphere Model and version 4.5 of the Community Land Model. We forced the model with observed SSTs from 1982-2016. We found that SST and SM variability both contribute to T and NEP anomalies in the Amazon, with relative contributions depending on lag time and location within the Amazon basin. SST anomalies associated with ENSO drive most of the T variability at shorter lag times, while the ENSO-driven SM anomalies contribute more to T variability at longer lag times. SM variability and the resulting influence on T anomalies are much stronger in the eastern Amazon than in the west. Comparing modeled T with observations demonstrate that SST alone is sufficient for simulating the correct timing of T variability, but SM anomalies are necessary for simulating the correct magnitude of the T variability. Modeled NEP indicated that variability in carbon fluxes

Soil Carbon Mapping in Low Relief Areas with Combined Land Use Types and Percentages

Science.gov (United States)

Liu, Y. L.; Wu, Z. H.; Chen, Y. Y.; Wang, B. Z.

2018-05-01

Accurate mapping of soil carbon in low relief areas is of great challenge because of the defect of conventional "soil-landscape" model. Efforts have been made to integrate the land use information in the modelling and mapping of soil organic carbon (SOC), in which the spatial context was ignored. With 256 topsoil samples collected from Jianghan Plain, we aim to (i) explore the land-use dependency of SOC via one-way ANOVA; (ii) investigate the "spillover effect" of land use on SOC content; (iii) examine the feasibility of land use types and percentages (obtained with a 200-meter buffer) for soil mapping via regression Kriging (RK) models. Results showed that the SOC of paddy fields was higher than that of woodlands and irrigated lands. The land use type could explain 20.5 % variation of the SOC, and the value increased to 24.7 % when the land use percentages were considered. SOC was positively correlated with the percentage of water area and irrigation canals. Further research indicated that SOC of irrigated lands was significantly correlated with the percentage of water area and irrigation canals, while paddy fields and woodlands did not show similar trends. RK model that combined land use types and percentages outperformed the other models with the lowest values of RMSEC (5.644 g/kg) and RMSEP (6.229 g/kg), and the highest R2C (0.193) and R2P (0.197). In conclusions, land use types and percentages serve as efficient indicators for the SOC mapping in plain areas. Additionally, irrigation facilities contributed to the farmland SOC sequestration especially in irrigated lands.

Quantifying terrestrial ecosystem carbon dynamics in the Jinsha watershed, Upper Yangtze, China from 1975 to 2000

Science.gov (United States)

Zhao, Shuqing; Liu, Shuguang; Yin, Runsheng; Li, Zhengpeng; Deng, Yulin; Tan, Kun; Deng, Xiangzheng; Rothstein, David; Qi, Jiaguo

2010-01-01

Quantifying the spatial and temporal dynamics of carbon stocks in terrestrial ecosystems and carbon fluxes between the terrestrial biosphere and the atmosphere is critical to our understanding of regional patterns of carbon budgets. Here we use the General Ensemble biogeochemical Modeling System to simulate the terrestrial ecosystem carbon dynamics in the Jinsha watershed of China’s upper Yangtze basin from 1975 to 2000, based on unique combinations of spatial and temporal dynamics of major driving forces, such as climate, soil properties, nitrogen deposition, and land use and land cover changes. Our analysis demonstrates that the Jinsha watershed ecosystems acted as a carbon sink during the period of 1975–2000, with an average rate of 0.36 Mg/ha/yr, primarily resulting from regional climate variation and local land use and land cover change. Vegetation biomass accumulation accounted for 90.6% of the sink, while soil organic carbon loss before 1992 led to a lower net gain of carbon in the watershed, and after that soils became a small sink. Ecosystem carbon sink/source patterns showed a high degree of spatial heterogeneity. Carbon sinks were associated with forest areas without disturbances, whereas carbon sources were primarily caused by stand-replacing disturbances. It is critical to adequately represent the detailed fast-changing dynamics of land use activities in regional biogeochemical models to determine the spatial and temporal evolution of regional carbon sink/source patterns.

South African carbon observations: CO2 measurements for land, atmosphere and ocean