scholarly journals Towards a more complete quantification of the global carbon cycle

2018 ◽  
Author(s):  
Miko U. F. Kirschbaum ◽  
Guang Zeng ◽  
Fabiano Ximenes ◽  
Donna L. Giltrap ◽  
John R. Zeldis
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Co2 Emissions ◽  
Fossil Fuels ◽  
Dissolved Inorganic Carbon ◽  
Wood Products ◽  
Co2 Uptake ◽  
River Transport ◽  
Anthropogenic Co2 ◽  
Global Carbon

Abstract. The main components of global carbon budget calculations are the emissions from burning fossil fuels, cement production, and net land-use change, partly balanced by ocean CO2 uptake and CO2 increase in the atmosphere. The remaining difference between these terms is referred to as the residual sink, assumed to correspond to increasing carbon storage in the terrestrial biosphere (ΔB). It is often used to constrain carbon exchange in global earth-system models. More broadly, it guides expectations of autonomous changes in global carbon stocks in response to climatic changes, including increasing CO2, that may add to, or subtract from, anthropogenic CO2 emissions. However, a budget with only these terms omits some important additional fluxes that are important for correctly inferring ΔB. They are cement carbonation and fluxes into increasing pools of plastic, bitumen, harvested-wood products, and landfill deposition after disposal of these products, and carbon fluxes to the oceans via wind erosion and non-CO2 fluxes of the intermediate break-down products of methane and other volatile organic compounds. While the global budget includes river transport of dissolved inorganic carbon it omits river transport of dissolved and particulate organic carbon, and the deposition of carbon in inland water bodies. Each one of these terms is relatively small, but together they can constitute important additional fluxes that would significantly reduce the size of the inferred ΔB. We estimate here that inclusion of these fluxes would reduce ΔB from the currently reported 3.6 down to only about 2.1 GtC yr−1 (excluding losses from land-use change). The implicit reduction in the size of ΔB has important implications for the inferred magnitude of current-day biospheric net carbon uptake and the consequent potential of future biospheric feedbacks to amplify or negate net anthropogenic CO2 emissions.

scholarly journals Towards a more complete quantification of the global carbon cycle

2019 ◽  
Vol 16 (3) ◽  
pp. 831-846 ◽  
Author(s):  
Miko U. F. Kirschbaum ◽  
Guang Zeng ◽  
Fabiano Ximenes ◽  
Donna L. Giltrap ◽  
John R. Zeldis
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Co2 Emissions ◽  
Dissolved Inorganic Carbon ◽  
Wood Products ◽  
Plant Responses ◽  
Co2 Uptake ◽  
River Transport ◽  
Anthropogenic Co2 ◽  
Global Carbon

Abstract. The main components of global carbon budget calculations are the emissions from burning fossil fuels, cement production, and net land-use change, partly balanced by ocean CO2 uptake and CO2 increase in the atmosphere. The difference between these terms is referred to as the residual sink, assumed to correspond to increasing carbon storage in the terrestrial biosphere through physiological plant responses to changing conditions (ΔBphys). It is often used to constrain carbon exchange in global earth-system models. More broadly, it guides expectations of autonomous changes in global carbon stocks in response to climatic changes, including increasing CO2, that may add to, or subtract from, anthropogenic CO2 emissions. However, a budget with only these terms omits some important additional fluxes that are needed to correctly infer ΔBphys. They are cement carbonation and fluxes into increasing pools of plastic, bitumen, harvested-wood products, and landfill deposition after disposal of these products, and carbon fluxes to the oceans via wind erosion and non-CO2 fluxes of the intermediate breakdown products of methane and other volatile organic compounds. While the global budget includes river transport of dissolved inorganic carbon, it omits river transport of dissolved and particulate organic carbon, and the deposition of carbon in inland water bodies. Each one of these terms is relatively small, but together they can constitute important additional fluxes that would significantly reduce the size of the inferred ΔBphys. We estimate here that inclusion of these fluxes would reduce ΔBphys from the currently reported 3.6 GtC yr−1 down to about 2.1 GtC yr−1 (excluding losses from land-use change). The implicit reduction in the size of ΔBphys has important implications for the inferred magnitude of current-day biospheric net carbon uptake and the consequent potential of future biospheric feedbacks to amplify or negate net anthropogenic CO2 emissions.

scholarly journals Global Carbon Budget 2019

2019 ◽  
Vol 11 (4) ◽  
pp. 1783-1838 ◽  
Author(s):  
Pierre Friedlingstein ◽  
Matthew W. Jones ◽  
Michael O'Sullivan ◽  
Robbie M. Andrew ◽  
Judith Hauck ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Carbon Cycle ◽  
Co2 Emissions ◽  
Carbon Budget ◽  
Co2 Concentration ◽  
Data Sets ◽  
Global Carbon Budget ◽  
The Mean ◽  
Global Carbon

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFF) are based on energy statistics and cement production data, while emissions from land use change (ELUC), mainly deforestation, are based on land use and land use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the last decade available (2009–2018), EFF was 9.5±0.5 GtC yr−1, ELUC 1.5±0.7 GtC yr−1, GATM 4.9±0.02 GtC yr−1 (2.3±0.01 ppm yr−1), SOCEAN 2.5±0.6 GtC yr−1, and SLAND 3.2±0.6 GtC yr−1, with a budget imbalance BIM of 0.4 GtC yr−1 indicating overestimated emissions and/or underestimated sinks. For the year 2018 alone, the growth in EFF was about 2.1 % and fossil emissions increased to 10.0±0.5 GtC yr−1, reaching 10 GtC yr−1 for the first time in history, ELUC was 1.5±0.7 GtC yr−1, for total anthropogenic CO2 emissions of 11.5±0.9 GtC yr−1 (42.5±3.3 GtCO2). Also for 2018, GATM was 5.1±0.2 GtC yr−1 (2.4±0.1 ppm yr−1), SOCEAN was 2.6±0.6 GtC yr−1, and SLAND was 3.5±0.7 GtC yr−1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 407.38±0.1 ppm averaged over 2018. For 2019, preliminary data for the first 6–10 months indicate a reduced growth in EFF of +0.6 % (range of −0.2 % to 1.5 %) based on national emissions projections for China, the USA, the EU, and India and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. Overall, the mean and trend in the five components of the global carbon budget are consistently estimated over the period 1959–2018, but discrepancies of up to 1 GtC yr−1 persist for the representation of semi-decadal variability in CO2 fluxes. A detailed comparison among individual estimates and the introduction of a broad range of observations shows (1) no consensus in the mean and trend in land use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent underestimation of the CO2 variability by ocean models outside the tropics. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Le Quéré et al., 2018a, b, 2016, 2015a, b, 2014, 2013). The data generated by this work are available at https://doi.org/10.18160/gcp-2019 (Friedlingstein et al., 2019).

scholarly journals Global Carbon Budget 2020

2020 ◽  
Vol 12 (4) ◽  
pp. 3269-3340
Author(s):  
Pierre Friedlingstein ◽  
Michael O'Sullivan ◽  
Matthew W. Jones ◽  
Robbie M. Andrew ◽  
Judith Hauck ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Carbon Cycle ◽  
Co2 Emissions ◽  
Carbon Budget ◽  
Co2 Concentration ◽  
Data Sets ◽  
Global Carbon Budget ◽  
The Mean ◽  
Global Carbon

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFOS) are based on energy statistics and cement production data, while emissions from land-use change (ELUC), mainly deforestation, are based on land use and land-use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the last decade available (2010–2019), EFOS was 9.6 ± 0.5 GtC yr−1 excluding the cement carbonation sink (9.4 ± 0.5 GtC yr−1 when the cement carbonation sink is included), and ELUC was 1.6 ± 0.7 GtC yr−1. For the same decade, GATM was 5.1 ± 0.02 GtC yr−1 (2.4 ± 0.01 ppm yr−1), SOCEAN 2.5 ±  0.6 GtC yr−1, and SLAND 3.4 ± 0.9 GtC yr−1, with a budget imbalance BIM of −0.1 GtC yr−1 indicating a near balance between estimated sources and sinks over the last decade. For the year 2019 alone, the growth in EFOS was only about 0.1 % with fossil emissions increasing to 9.9 ± 0.5 GtC yr−1 excluding the cement carbonation sink (9.7 ± 0.5 GtC yr−1 when cement carbonation sink is included), and ELUC was 1.8 ± 0.7 GtC yr−1, for total anthropogenic CO2 emissions of 11.5 ± 0.9 GtC yr−1 (42.2 ± 3.3 GtCO2). Also for 2019, GATM was 5.4 ± 0.2 GtC yr−1 (2.5 ± 0.1 ppm yr−1), SOCEAN was 2.6 ± 0.6 GtC yr−1, and SLAND was 3.1 ± 1.2 GtC yr−1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 409.85 ± 0.1 ppm averaged over 2019. Preliminary data for 2020, accounting for the COVID-19-induced changes in emissions, suggest a decrease in EFOS relative to 2019 of about −7 % (median estimate) based on individual estimates from four studies of −6 %, −7 %, −7 % (−3 % to −11 %), and −13 %. Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2019, but discrepancies of up to 1 GtC yr−1 persist for the representation of semi-decadal variability in CO2 fluxes. Comparison of estimates from diverse approaches and observations shows (1) no consensus in the mean and trend in land-use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent discrepancy between the different methods for the ocean sink outside the tropics, particularly in the Southern Ocean. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Friedlingstein et al., 2019; Le Quéré et al., 2018b, a, 2016, 2015b, a, 2014, 2013). The data presented in this work are available at https://doi.org/10.18160/gcp-2020 (Friedlingstein et al., 2020).

scholarly journals Anthropogenic CO<sub>2</sub> emissions in Africa

2009 ◽  
Vol 6 (3) ◽  
pp. 463-468 ◽  
Author(s):  
J. G. Canadell ◽  
M. R. Raupach ◽  
R. A. Houghton
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Co2 Emissions ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Global Average ◽  
The World ◽  
Per Capita ◽  
Global Emissions ◽  
Fossil Fuel Emissions

Abstract. An understanding of the regional contributions and trends of anthropogenic carbon dioxide (CO2) emissions is critical to design mitigation strategies aimed at stabilizing atmospheric greenhouse gases. Here we report CO2 emissions from the combustion of fossil fuels and land use change in Africa for various time periods. Africa was responsible for an average of 500 Tg C y−1 for the period 2000–2005. These emissions resulted from the combustion of fossil fuels (260 Tg C y−1) and land use change (240 Tg C y−1). Over this period, the African share of global emissions from land use change was 17%. For 2005, the last year reported in this study, African fossil fuel emissions were 285 Tg C accounting for 3.7% of the global emissions. The 2000–2005 growth rate in African fossil fuel emissions was 3.2% y−1, very close to the global average. Fossil fuel emissions per capita in Africa are among the lowest in the world, at 0.32 t C y−1 compared to the global average of 1.2 t C y−1. The average amount of carbon (C) emitted as CO2 to produce 1 US{$} of Gross Domestic Product (GDP) in Africa was 187 g C/$ in 2005, close to the world average of 199 g C/$. With the fastest population growth in the world and rising per capita GDP, Africa is likely to increase its share of global emissions over the coming decades although emissions from Africa will remain low compared to other continents.

scholarly journals Anthropogenic CO<sub>2</sub> emissions in Africa

2008 ◽  
Vol 5 (6) ◽  
pp. 4395-4411 ◽  
Author(s):  
J. G. Canadell ◽  
M. R. Raupach ◽  
R. A. Houghton
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Co2 Emissions ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Global Average ◽  
The World ◽  
Per Capita ◽  
Global Emissions ◽  
Fossil Fuel Emissions

Abstract. An understanding of the regional contributions and trends of anthropogenic carbon dioxide (CO2) emissions is critical to design mitigation strategies aimed at stabilizing atmospheric greenhouse gases. Here we report CO2 emissions from the combustion of fossil fuels and land use change in Africa for various time periods. Africa was responsible for an average of 500 TgC y−1 for the period 2000–2005. These emissions resulted from the combustion of fossil fuels (260 TgC y−1) and land use change (240 TgC y−1). Over this period, the African share of global emissions from land use change was 17%. For 2005, the last year reported in this study, African fossil fuel emissions were 285 TgC accounting for 3.7% of the global emissions. The 2000–2005 growth rate in African fossil fuel emissions was 3.2% y−1, very close to the global average. Fossil fuel emissions per capita in Africa are among the lowest in the world, at 0.32 tC y−1 compared to the global average of 1.2 tC y−1. The average amount of carbon (C) emitted as CO2 to produce 1 US $ of Gross Domestic Product (GDP) in Africa in 2005 was 187 gC/$, close to the world average of 199 gC/$. With the fastest population growth in the world and rising per capita GDP, Africa is likely to increase its share of global emissions over the coming decades although emissions from Africa will remain low compared to other continents.

scholarly journals CO2 Valorization and Its Subsequent Valorization

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 500
Author(s):  
Juan Antonio Cecilia ◽  
Daniel Ballesteros Plata ◽  
Enrique Vilarrasa García
Keyword(s):  
Co2 Emissions ◽  
Fossil Fuels ◽  
Industrial Revolution ◽  
World Population ◽  
Anthropogenic Co2 ◽  
The World ◽  
Co2 Valorization

After the industrial revolution, the increase in the world population and the consumption of fossil fuels has led to an increase in anthropogenic CO2 emissions [...]

Biofuels That Cause Land-Use Change May Have Much Larger Non-GHG Air Quality Emissions Than Fossil Fuels

2012 ◽  
Vol 46 (19) ◽  
pp. 10835-10841 ◽  
Author(s):  
C.-C. Tsao ◽  
J. E. Campbell ◽  
M. Mena-Carrasco ◽  
S. N. Spak ◽  
G. R. Carmichael ◽  
...  
Keyword(s):  
Land Use ◽  
Air Quality ◽  
Land Use Change ◽  
Fossil Fuels

scholarly journals A theoretical framework for the net land-to-atmosphere CO<sub>2</sub> flux and its implications in the definition of "emissions from land-use change"

2013 ◽  
Vol 4 (1) ◽  
pp. 179-217 ◽  
Author(s):  
T. Gasser ◽  
P. Ciais
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Co2 Flux ◽  
Theoretical Framework ◽  
Elevated Atmospheric Co2 ◽  
Mathematical Expressions ◽  
Terrestrial Carbon Cycle ◽  
Definition Of ◽  
Mathematical Definitions ◽  
Global Carbon

Abstract. We develop a theoretical framework and analysis of the net land-to-atmosphere CO2 flux in order to discuss possible definitions of "emissions from land-use change". The terrestrial biosphere is affected by two perturbations: the perturbation of the global Carbon-Climate-Nitrogen system (CCN) with elevated atmospheric CO2, climate change and nitrogen deposition; and the Land-Use Change perturbation (LUC). Here, we progressively establish mathematical definitions of four generic components of the net land-to-atmosphere CO2 flux. The two first components are the fluxes that would be observed if only one perturbation occurred. The two other components are due to the coupling of the CCN and LUC perturbations, which shows the non-linear response of the terrestrial carbon cycle. Thanks to these four components, we introduce three possible definitions of "emissions from land-use change", that are indeed used in the scientific literature, often without clear distinctions, and we draw conclusions as for their absolute and relative behaviors. Thanks to the OSCAR v2 model, we provide quantitative estimates of the differences between the three definitions, and we find that comparing results from studies that do not use the same definition can lead to a bias of up to 20% between estimates of those emissions. After discussion of the limitations of the framework, we conclude on the three major points of this study that should help the community to reconcile modeling and observation of emissions from land-use change. The Appendix mainly provides more detailed mathematical expressions of the four components of the net land-to-atmosphere CO2 flux.

scholarly journals A synthesis of carbon in international trade

2012 ◽  
Vol 9 (3) ◽  
pp. 3949-4023 ◽  
Author(s):  
G. P. Peters ◽  
S. J. Davis ◽  
R. M. Andrew
Keyword(s):  
International Trade ◽  
Co2 Emissions ◽  
Fossil Fuels ◽  
Wood Products ◽  
Total Production ◽  
Goods And Services ◽  
Traded Goods ◽  
Harvested Wood Products ◽  
Global Emissions ◽  
Embodied Co2 Emissions

Abstract. In a globalised world, the transfer of carbon between regions, either physically or embodied in production, represents a substantial fraction of global carbon emissions. The resulting emission transfers are important for balancing regional carbon budgets and for understanding the drivers of regional emissions. In this paper we synthesise current understanding in two parts: (1) embodied CO2 emissions from the production of goods and services produced in one country but consumed in others, (2) physical carbon flows in fossil fuels, petroleum-derived products, harvested wood products, crops, and livestock. We describe the key differences between studies and provide a consistent set of estimates using the same definitions, modelling framework, and consistent data. We find the largest trade flows of carbon in international trade in 2004 were fossil fuels (2673 MtC, 37% of global emissions), CO2 embodied in traded goods and services (1661 MtC, 22% of global emissions), livestock (651 MtC, 20% of total livestock carbon), crops (522 MtC, 31% of total harvested crop carbon), petroleum-based products (183 MtC, 50% of their total production), and harvested wood products (149 MtC, 40% of total roundwood extraction). We find that for embodied CO2 emissions estimates from independent studies are robust. We found that differences between individual studies is not representative of the uncertainty in consumption-based estimates as different studies use different production-based emission estimates as input and different definitions of allocating emissions to international trade. After adjusting for these issues, results across independent studies converge to give less uncertainty than previously assumed. For physical carbon flows there are relatively few studies to be synthesised, but differences between existing studies are due to the method of allocating to international trade with some studies using "apparent consumption" as opposed to "final consumption" in more comprehensive approaches. While results across studies are robust to be used in further applications, more research is needed to understand the differences between methods and to harmonise definitions for particular applications.

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