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Philippe Ciais - One of the best experts on this subject based on the ideXlab platform.
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How have past fire disturbances contributed to the current Carbon Balance of boreal ecosystems?
Biogeosciences Discussions, 2016Co-Authors: C Yue, Philippe Ciais, D Zhu, T Wang, S. Peng, L. PiaoAbstract:Boreal fires have immediate effects on regional Carbon budgets by emitting CO 2 into the atmosphere at the time of burning, but they also have legacy effects by initiating a long-term Carbon sink during post-fire vegetation recovery. Quantifying these different effects on the current-day pan-boreal (44–84 • N) Carbon Balance and quantifying relative contributions of legacy sinks by past fires is important for understanding and predicting the Carbon dynamics in this region. Here we used the global dynamic vegetation model ORCHIDEE–SPITFIRE (Organising Carbon and Hydrology In Dynamic Ecosystems – SPread and InTensity of FIRE) to attribute the contributions by fires in different decades between 1850 and 2009 to the Carbon Balance of 2000–2009, taking into account the atmospheric CO 2 change and climate change since 1850. The fire module of ORCHIDEE– SPITFIRE was turned off for each decade in turn and was also turned off before and after the decade in question in order to model the legacy Carbon trajectory by fires in each past decade. We found that, unsurprisingly, fires that occurred in 2000–2009 are a Carbon source (−0.17 Pg C yr −1) for the Carbon Balance of 2000–2009, whereas fires in all decades before 2000 contribute Carbon sinks with a collective contribution of 0.23 Pg C yr −1. This leaves a net fire sink effect of 0.06 Pg C yr −1 , or 6.3 % of the simulated regional Carbon sink (0.95 Pg C yr −1). Further, fires with an age of 10–40 years (i.e., those that occurred during 1960–1999) contribute more than half of the total sink effect of fires. The small net sink effect of fires indicates that current-day fire emissions are roughly Balanced out by legacy sinks. The future role of fires in the regional Carbon Balance remains uncertain and will depend on whether changes in fires and associated Carbon emissions will exceed the enhanced sink effects of previous fires, both being strongly affected by global change.
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Nutrient availability as the key regulator of global forest Carbon Balance
Nature Climate Change, 2014Co-Authors: Marcos Fernández-martínez, Philippe Ciais, Yadvinder Malhi, Jordi Sardans, Ivan A. Janssens, Sara Vicca, Sebastiaan Luyssaert, Matteo Campioli, F. S. Chapin, Michael ObersteinerAbstract:A synthesis of findings from 92 forests in different climate zones reveals that nutrient availability plays a crucial role in determining forest Carbon Balance, primarily through its influence on respiration rates. These findings challenge the validity of assumptions used in most global coupled Carbon-cycle climate models.
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The Carbon Balance of terrestrial ecosystems in China
Nature, 2009Co-Authors: Shilong Piao, Philippe Peylin, Stephen Sitch, Jingyun Fang, Philippe Ciais, Yao Huang, Tao WangAbstract:Global terrestrial ecosystems absorbed Carbon at a rate of 1-4 Pg yr -1 during the 1980s and 1990s, offsetting 10-60 per cent of the fossil-fuel emissions. The regional patterns and causes of terrestrial Carbon sources and sinks, however, remain uncertain. With increasing scientific and political interest in regional aspects of the global Carbon cycle, there is a strong impetus to better understand the Carbon Balance of China. This is not only because China is the world's most populous country and the largest emitter of fossil-fuel CO 2 into the atmosphere, but also because it has experienced regionally distinct land-use histories and climate trends, which together control the Carbon budget of its ecosystems. Here we analyse the current terrestrial Carbon Balance of China and its driving mechanisms during the 1980s and 1990s using three different methods: biomass and soil Carbon inventories extrapolated by satellite greenness measurements, ecosystem models and atmospheric inversions. The three methods produce similar estimates of a net Carbon sink in the range of 0.19-0.26 Pg Carbon (PgC) per year, which is smaller than that in the conterminous United States but comparable to that in geographic Europe. We find that northeast China is a net source of CO 2 to the atmosphere owing to overharvesting and degradation of forests. By contrast, southern China accounts for more than 65 per cent of the Carbon sink, which can be attributed to regional climate change, large-scale plantation programmes active since the 1980s and shrub recovery. Shrub recovery is identified as the most uncertain factor contributing to the Carbon sink. Our data and model results together indicate that China's terrestrial ecosystems absorbed 28-37 per cent of its cumulated fossil Carbon emissions during the 1980s and 1990s.
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footprint of temperature changes in the temperate and boreal forest Carbon Balance
Geophysical Research Letters, 2009Co-Authors: Shilong Piao, Biao Zhu, Philippe Peylin, Philippe Ciais, Pierre Friedlingstein, Markus ReichsteinAbstract:In this study, we use net ecosystem productivity (NEP) measurement data across several forest sites and a simple conceptual model to investigate the linkage between temperature and NEP by considering either temperature change in the recent past or current mean annual temperature (MAT) as a forcing. After removing the effect of stand age, forest NEP is only weakly correlated with MAT. However, temperature changes during the period of 1980-2002 do explain a very significant fraction of the current spatial patterns of NEP, although the response of the terrestrial Carbon Balance to temperature changes varies with season. Changes in spring temperature having the highest correlation with annual NEP. We also show that temperature changes before the 1970s had a limited influence on the current NEP, and that the impact of recent temperature changes within the last decade on NEP are not strong enough to be observable. Overall, our analysis indicates not only that temperature changes in the recent past is one of the important drivers of today's forest Carbon Balance in the Northern Hemisphere, but also that the ongoing global warming will contribute significantly to the near-future evolution of the Northern Hemisphere Carbon sink. A non-equilibrium framework must be taken into account when studying the impacts of temperature change on current or future forest net Carbon Balance.
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Variability and recent trends in the African terrestrial Carbon Balance
Biogeosciences, 2009Co-Authors: Philippe Ciais, S.-l. Piao, P. Cadule, Pierre Friedlingstein, Alain ChédinAbstract:We modeled the African terrestrial Carbon Balance over the past century using a spatially resolved process based vegetation model (ORCHIDEE). The model is forced by changing climate and by human-induced changes in land use. It includes a simple parameterization of natural fires, but the natural vegetation dynamics was ignored. The period analyzed is 1901-2002. Overall, we found that the African net terrestrial Carbon Balance (Net Biome Productivity , NBP) increased from a net CO 2 source to the atmosphere of 0.14 Pg C yr −1 in the 1980s to a net sink of 0.15 Pg C yr −1 in the 1990s. The land use flux alone is estimated to be a source of 0.13 Pg C yr −1 caused by deforestation. This implies that climatic trends (mainly increasing precipitation) and CO 2 increase (fertilization effect), are causing a sink of 0.28 Pg C yr −1 which offsets the land-use source. We found that the interannual variability of NBP is large, and mostly driven by photosynthesis variability. Over savannas, photo-synthesis changes from one year to the next are strongly correlated with rainfall changes (R 2 =0.77 in northern Africa, and R 2 =0.42 in southern African savannas). Over forests, such a control by rainfall is not found. The main spatial pattern of interannual variability in NBP and photosynthe-sis/ecosystem respiration fluxes is related with ENSO, with dryer conditions prevailing over savannas during El Niño and wetter conditions over forests. Climate induced variations in fire emissions respond to this ENSO forcing, but do not determine strongly the NBP interannual variability. Finally, we model that ecosystem respiration variations (mostly au-totrophic respiration) are correlated with those of photosyn-Correspondence to: P. Ciais (philippe.ciais@lsce.ipsl.fr) thesis, on interannual as well as on decadal time scales, but this result is uncertain given the potential for acclimation for autotrophic respiration processes.
Shilong Piao - One of the best experts on this subject based on the ideXlab platform.
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The Carbon Balance of Africa: synthesis of recent research studies
Philosophical transactions. Series A Mathematical physical and engineering sciences, 2011Co-Authors: P. Ciais, Shilong Piao, A. Bombelli, M. Henry, Mathew Williams, Jérôme Chave, Casey M. Ryan, P. Brender, Riccardo ValentiniAbstract:The African continent contributes one of the largest uncertainties to the global CO 2 budget, because very few long-term measurements are carried out in this region. The contribution of Africa to the global Carbon cycle is characterized by its low fossil fuel emissions, a rapidly increasing population causing cropland expansion, and degradation and deforestation risk to extensive dryland and savannah ecosystems and to tropical forests in Central Africa. A synthesis of the Carbon Balance of African ecosystems is provided at different scales, including observations of land–atmosphere CO 2 flux and soil Carbon and biomass Carbon stocks. A review of the most recent estimates of the net long-term Carbon Balance of African ecosystems is provided, including losses from fire disturbance, based upon observations, giving a sink of the order of 0.2 Pg C yr −1 with a large uncertainty around this number. By comparison, fossil fuel emissions are only of the order of 0.2 Pg C yr −1 and land-use emissions are of the order of 0.24 Pg C yr −1 . The sources of year-to-year variations in the ecosystem Carbon-Balance are also discussed. Recommendations for the deployment of a coordinated Carbon-monitoring system for African ecosystems are given.
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The Carbon Balance of terrestrial ecosystems in China
Nature, 2009Co-Authors: Shilong Piao, Philippe Peylin, Stephen Sitch, Jingyun Fang, Philippe Ciais, Yao Huang, Tao WangAbstract:Global terrestrial ecosystems absorbed Carbon at a rate of 1-4 Pg yr -1 during the 1980s and 1990s, offsetting 10-60 per cent of the fossil-fuel emissions. The regional patterns and causes of terrestrial Carbon sources and sinks, however, remain uncertain. With increasing scientific and political interest in regional aspects of the global Carbon cycle, there is a strong impetus to better understand the Carbon Balance of China. This is not only because China is the world's most populous country and the largest emitter of fossil-fuel CO 2 into the atmosphere, but also because it has experienced regionally distinct land-use histories and climate trends, which together control the Carbon budget of its ecosystems. Here we analyse the current terrestrial Carbon Balance of China and its driving mechanisms during the 1980s and 1990s using three different methods: biomass and soil Carbon inventories extrapolated by satellite greenness measurements, ecosystem models and atmospheric inversions. The three methods produce similar estimates of a net Carbon sink in the range of 0.19-0.26 Pg Carbon (PgC) per year, which is smaller than that in the conterminous United States but comparable to that in geographic Europe. We find that northeast China is a net source of CO 2 to the atmosphere owing to overharvesting and degradation of forests. By contrast, southern China accounts for more than 65 per cent of the Carbon sink, which can be attributed to regional climate change, large-scale plantation programmes active since the 1980s and shrub recovery. Shrub recovery is identified as the most uncertain factor contributing to the Carbon sink. Our data and model results together indicate that China's terrestrial ecosystems absorbed 28-37 per cent of its cumulated fossil Carbon emissions during the 1980s and 1990s.
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footprint of temperature changes in the temperate and boreal forest Carbon Balance
Geophysical Research Letters, 2009Co-Authors: Shilong Piao, Biao Zhu, Philippe Peylin, Philippe Ciais, Pierre Friedlingstein, Markus ReichsteinAbstract:In this study, we use net ecosystem productivity (NEP) measurement data across several forest sites and a simple conceptual model to investigate the linkage between temperature and NEP by considering either temperature change in the recent past or current mean annual temperature (MAT) as a forcing. After removing the effect of stand age, forest NEP is only weakly correlated with MAT. However, temperature changes during the period of 1980-2002 do explain a very significant fraction of the current spatial patterns of NEP, although the response of the terrestrial Carbon Balance to temperature changes varies with season. Changes in spring temperature having the highest correlation with annual NEP. We also show that temperature changes before the 1970s had a limited influence on the current NEP, and that the impact of recent temperature changes within the last decade on NEP are not strong enough to be observable. Overall, our analysis indicates not only that temperature changes in the recent past is one of the important drivers of today's forest Carbon Balance in the Northern Hemisphere, but also that the ongoing global warming will contribute significantly to the near-future evolution of the Northern Hemisphere Carbon sink. A non-equilibrium framework must be taken into account when studying the impacts of temperature change on current or future forest net Carbon Balance.
A. Bombelli - One of the best experts on this subject based on the ideXlab platform.
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The Carbon Balance of Africa: synthesis of recent research studies
Philosophical transactions. Series A Mathematical physical and engineering sciences, 2011Co-Authors: P. Ciais, Shilong Piao, A. Bombelli, M. Henry, Mathew Williams, Jérôme Chave, Casey M. Ryan, P. Brender, Riccardo ValentiniAbstract:The African continent contributes one of the largest uncertainties to the global CO 2 budget, because very few long-term measurements are carried out in this region. The contribution of Africa to the global Carbon cycle is characterized by its low fossil fuel emissions, a rapidly increasing population causing cropland expansion, and degradation and deforestation risk to extensive dryland and savannah ecosystems and to tropical forests in Central Africa. A synthesis of the Carbon Balance of African ecosystems is provided at different scales, including observations of land–atmosphere CO 2 flux and soil Carbon and biomass Carbon stocks. A review of the most recent estimates of the net long-term Carbon Balance of African ecosystems is provided, including losses from fire disturbance, based upon observations, giving a sink of the order of 0.2 Pg C yr −1 with a large uncertainty around this number. By comparison, fossil fuel emissions are only of the order of 0.2 Pg C yr −1 and land-use emissions are of the order of 0.24 Pg C yr −1 . The sources of year-to-year variations in the ecosystem Carbon-Balance are also discussed. Recommendations for the deployment of a coordinated Carbon-monitoring system for African ecosystems are given.
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An outlook on the Sub-Saharan Africa Carbon Balance
Biogeosciences, 2009Co-Authors: A. Bombelli, M. Henry, S. Castaldi, S. Adu-bredu, A. Arneth, A. De Grandcourt, E. Grieco, W. L. Kutsch, V. Lehsten, A. RasileAbstract:Abstract. This study gives an outlook on the Carbon Balance of Sub-Saharan Africa (SSA) by presenting a summary of currently available results from the project CarboAfrica (namely net ecosystem productivity and emissions from fires, deforestation and forest degradation, by field and model estimates) supplemented by bibliographic data and compared with a new synthesis of the data from national communications to UNFCCC. According to these preliminary estimates the biogenic Carbon Balance of SSA varies from 0.16 Pg C y−1 to a much higher sink of 1.00 Pg C y−1 (depending on the source data). Models estimates would give an unrealistic sink of 3.23 Pg C y−1, confirming their current inadequacy when applied to Africa. The Carbon uptake by forests and savannas (0.34 and 1.89 Pg C y−1, respectively,) are the main contributors to the resulting sink. Fires (0.72 Pg C y−1) and deforestation (0.25 Pg C y−1) are the main contributors to the SSA Carbon emissions, while the agricultural sector and forest degradation contributes only with 0.12 and 0.08 Pg C y−1, respectively. Savannas play a major role in shaping the SSA Carbon Balance, due to their large extension, their fire regime, and their strong interannual NEP variability, but they are also a major uncertainty in the overall budget. Even if fossil fuel emissions from SSA are relative low, they can be crucial in defining the sign of the overall SSA Carbon Balance by reducing the natural sink potential, especially in the future. This paper shows that Africa plays a key role in the global Carbon cycle system and probably could have a potential for Carbon sequestration higher than expected, even if still highly uncertain. Further investigations are needed, particularly to better address the role of savannas and tropical forests and to improve biogeochemical models. The CarboAfrica network of Carbon measurements could provide future unique data sets for better estimating the African Carbon Balance.
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The Sub-Saharan Africa Carbon Balance, an overview
2009Co-Authors: A. Bombelli, M. Henry, S. Castaldi, S. Adu-bredu, A. Arneth, A. De Grandcourt, E. Grieco, W. L. Kutsch, V. Lehsten, A. RasileAbstract:Abstract. This study presents a summary overview of the Carbon Balance of Sub-Saharan Africa (SSA) by synthesizing the available data from national communications to UNFCCC and first results from the project CarboAfrica (net ecosystem productivity and emissions from fires, deforestation and forest degradation, by field and model estimates). According to these preliminary estimates the overall Carbon Balance of SSA varies from 0.43 Pg C y−1 (using in situ measurements for savanna NEP) to a much higher sink of 2.53 Pg C y−1 (using model estimates for savanna NEP). UNFCCC estimates lead to a moderate Carbon sink of 0.58 Pg C y−1. Excluding anthropogenic disturbance and intrinsic episodic events, the Carbon uptake by forests (0.98 Pg C y−1) and savannas (from 1.38 to 3.48 Pg C y−1, depending on the used methodology) are the main components of the SSA sink effect. Fires (0.72 Pg C y−1), deforestation (0.25 Pg C y−1) and forest degradation (0.77 Pg C y−1) are the main contributors to the SSA Carbon emissions, while the agricultural sector contributes only with 0.12 Pg C y−1. Notably, the impact of forest degradation is higher than that caused by deforestation, and the SSA forest net Carbon Balance is close to equilibrium. Savannas play a major role in shaping the SSA Carbon Balance, due to their large areal extent, their fire regime, and their strong interannual NEP variability, but they are also a major uncertainty in the overall budget. This paper shows that Africa plays a key role in the global Carbon cycle system and probably could have a potential for Carbon sequestration higher than expected, even if still highly uncertain. Further investigations are needed, particularly to better address the role of savannas and tropical forests. The current CarboAfrica network of Carbon measurements could provide future unique data sets for better estimating the African Carbon Balance.
A. Rasile - One of the best experts on this subject based on the ideXlab platform.
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An outlook on the Sub-Saharan Africa Carbon Balance
Biogeosciences, 2009Co-Authors: A. Bombelli, M. Henry, S. Castaldi, S. Adu-bredu, A. Arneth, A. De Grandcourt, E. Grieco, W. L. Kutsch, V. Lehsten, A. RasileAbstract:Abstract. This study gives an outlook on the Carbon Balance of Sub-Saharan Africa (SSA) by presenting a summary of currently available results from the project CarboAfrica (namely net ecosystem productivity and emissions from fires, deforestation and forest degradation, by field and model estimates) supplemented by bibliographic data and compared with a new synthesis of the data from national communications to UNFCCC. According to these preliminary estimates the biogenic Carbon Balance of SSA varies from 0.16 Pg C y−1 to a much higher sink of 1.00 Pg C y−1 (depending on the source data). Models estimates would give an unrealistic sink of 3.23 Pg C y−1, confirming their current inadequacy when applied to Africa. The Carbon uptake by forests and savannas (0.34 and 1.89 Pg C y−1, respectively,) are the main contributors to the resulting sink. Fires (0.72 Pg C y−1) and deforestation (0.25 Pg C y−1) are the main contributors to the SSA Carbon emissions, while the agricultural sector and forest degradation contributes only with 0.12 and 0.08 Pg C y−1, respectively. Savannas play a major role in shaping the SSA Carbon Balance, due to their large extension, their fire regime, and their strong interannual NEP variability, but they are also a major uncertainty in the overall budget. Even if fossil fuel emissions from SSA are relative low, they can be crucial in defining the sign of the overall SSA Carbon Balance by reducing the natural sink potential, especially in the future. This paper shows that Africa plays a key role in the global Carbon cycle system and probably could have a potential for Carbon sequestration higher than expected, even if still highly uncertain. Further investigations are needed, particularly to better address the role of savannas and tropical forests and to improve biogeochemical models. The CarboAfrica network of Carbon measurements could provide future unique data sets for better estimating the African Carbon Balance.
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The Sub-Saharan Africa Carbon Balance, an overview
2009Co-Authors: A. Bombelli, M. Henry, S. Castaldi, S. Adu-bredu, A. Arneth, A. De Grandcourt, E. Grieco, W. L. Kutsch, V. Lehsten, A. RasileAbstract:Abstract. This study presents a summary overview of the Carbon Balance of Sub-Saharan Africa (SSA) by synthesizing the available data from national communications to UNFCCC and first results from the project CarboAfrica (net ecosystem productivity and emissions from fires, deforestation and forest degradation, by field and model estimates). According to these preliminary estimates the overall Carbon Balance of SSA varies from 0.43 Pg C y−1 (using in situ measurements for savanna NEP) to a much higher sink of 2.53 Pg C y−1 (using model estimates for savanna NEP). UNFCCC estimates lead to a moderate Carbon sink of 0.58 Pg C y−1. Excluding anthropogenic disturbance and intrinsic episodic events, the Carbon uptake by forests (0.98 Pg C y−1) and savannas (from 1.38 to 3.48 Pg C y−1, depending on the used methodology) are the main components of the SSA sink effect. Fires (0.72 Pg C y−1), deforestation (0.25 Pg C y−1) and forest degradation (0.77 Pg C y−1) are the main contributors to the SSA Carbon emissions, while the agricultural sector contributes only with 0.12 Pg C y−1. Notably, the impact of forest degradation is higher than that caused by deforestation, and the SSA forest net Carbon Balance is close to equilibrium. Savannas play a major role in shaping the SSA Carbon Balance, due to their large areal extent, their fire regime, and their strong interannual NEP variability, but they are also a major uncertainty in the overall budget. This paper shows that Africa plays a key role in the global Carbon cycle system and probably could have a potential for Carbon sequestration higher than expected, even if still highly uncertain. Further investigations are needed, particularly to better address the role of savannas and tropical forests. The current CarboAfrica network of Carbon measurements could provide future unique data sets for better estimating the African Carbon Balance.
M. Henry - One of the best experts on this subject based on the ideXlab platform.
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The Carbon Balance of Africa: synthesis of recent research studies
Philosophical transactions. Series A Mathematical physical and engineering sciences, 2011Co-Authors: P. Ciais, Shilong Piao, A. Bombelli, M. Henry, Mathew Williams, Jérôme Chave, Casey M. Ryan, P. Brender, Riccardo ValentiniAbstract:The African continent contributes one of the largest uncertainties to the global CO 2 budget, because very few long-term measurements are carried out in this region. The contribution of Africa to the global Carbon cycle is characterized by its low fossil fuel emissions, a rapidly increasing population causing cropland expansion, and degradation and deforestation risk to extensive dryland and savannah ecosystems and to tropical forests in Central Africa. A synthesis of the Carbon Balance of African ecosystems is provided at different scales, including observations of land–atmosphere CO 2 flux and soil Carbon and biomass Carbon stocks. A review of the most recent estimates of the net long-term Carbon Balance of African ecosystems is provided, including losses from fire disturbance, based upon observations, giving a sink of the order of 0.2 Pg C yr −1 with a large uncertainty around this number. By comparison, fossil fuel emissions are only of the order of 0.2 Pg C yr −1 and land-use emissions are of the order of 0.24 Pg C yr −1 . The sources of year-to-year variations in the ecosystem Carbon-Balance are also discussed. Recommendations for the deployment of a coordinated Carbon-monitoring system for African ecosystems are given.
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An outlook on the Sub-Saharan Africa Carbon Balance
Biogeosciences, 2009Co-Authors: A. Bombelli, M. Henry, S. Castaldi, S. Adu-bredu, A. Arneth, A. De Grandcourt, E. Grieco, W. L. Kutsch, V. Lehsten, A. RasileAbstract:Abstract. This study gives an outlook on the Carbon Balance of Sub-Saharan Africa (SSA) by presenting a summary of currently available results from the project CarboAfrica (namely net ecosystem productivity and emissions from fires, deforestation and forest degradation, by field and model estimates) supplemented by bibliographic data and compared with a new synthesis of the data from national communications to UNFCCC. According to these preliminary estimates the biogenic Carbon Balance of SSA varies from 0.16 Pg C y−1 to a much higher sink of 1.00 Pg C y−1 (depending on the source data). Models estimates would give an unrealistic sink of 3.23 Pg C y−1, confirming their current inadequacy when applied to Africa. The Carbon uptake by forests and savannas (0.34 and 1.89 Pg C y−1, respectively,) are the main contributors to the resulting sink. Fires (0.72 Pg C y−1) and deforestation (0.25 Pg C y−1) are the main contributors to the SSA Carbon emissions, while the agricultural sector and forest degradation contributes only with 0.12 and 0.08 Pg C y−1, respectively. Savannas play a major role in shaping the SSA Carbon Balance, due to their large extension, their fire regime, and their strong interannual NEP variability, but they are also a major uncertainty in the overall budget. Even if fossil fuel emissions from SSA are relative low, they can be crucial in defining the sign of the overall SSA Carbon Balance by reducing the natural sink potential, especially in the future. This paper shows that Africa plays a key role in the global Carbon cycle system and probably could have a potential for Carbon sequestration higher than expected, even if still highly uncertain. Further investigations are needed, particularly to better address the role of savannas and tropical forests and to improve biogeochemical models. The CarboAfrica network of Carbon measurements could provide future unique data sets for better estimating the African Carbon Balance.
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The Sub-Saharan Africa Carbon Balance, an overview
2009Co-Authors: A. Bombelli, M. Henry, S. Castaldi, S. Adu-bredu, A. Arneth, A. De Grandcourt, E. Grieco, W. L. Kutsch, V. Lehsten, A. RasileAbstract:Abstract. This study presents a summary overview of the Carbon Balance of Sub-Saharan Africa (SSA) by synthesizing the available data from national communications to UNFCCC and first results from the project CarboAfrica (net ecosystem productivity and emissions from fires, deforestation and forest degradation, by field and model estimates). According to these preliminary estimates the overall Carbon Balance of SSA varies from 0.43 Pg C y−1 (using in situ measurements for savanna NEP) to a much higher sink of 2.53 Pg C y−1 (using model estimates for savanna NEP). UNFCCC estimates lead to a moderate Carbon sink of 0.58 Pg C y−1. Excluding anthropogenic disturbance and intrinsic episodic events, the Carbon uptake by forests (0.98 Pg C y−1) and savannas (from 1.38 to 3.48 Pg C y−1, depending on the used methodology) are the main components of the SSA sink effect. Fires (0.72 Pg C y−1), deforestation (0.25 Pg C y−1) and forest degradation (0.77 Pg C y−1) are the main contributors to the SSA Carbon emissions, while the agricultural sector contributes only with 0.12 Pg C y−1. Notably, the impact of forest degradation is higher than that caused by deforestation, and the SSA forest net Carbon Balance is close to equilibrium. Savannas play a major role in shaping the SSA Carbon Balance, due to their large areal extent, their fire regime, and their strong interannual NEP variability, but they are also a major uncertainty in the overall budget. This paper shows that Africa plays a key role in the global Carbon cycle system and probably could have a potential for Carbon sequestration higher than expected, even if still highly uncertain. Further investigations are needed, particularly to better address the role of savannas and tropical forests. The current CarboAfrica network of Carbon measurements could provide future unique data sets for better estimating the African Carbon Balance.
