CO2

The release of carbon dioxide into the atmosphere by the burning of fossil fuels is significantly altering the carbon cycle by adding to the amount of carbon in the atmosphere and in the more rapidly interacting portions of the biosphere and oceans. In order better to assess these changes, the basis for calculating global CO2 emissions is reviewed and new annual values are computed for the period 1800 through 1969. The world average fractions of carbon in coal and lignite, estimated from calorific data, are found to be lower than previously assumed. When account is taken of handling losses and partial diversion to produce petrochemicals, road asphalt, and other non-fuels, the calculated CO2 emissions are further reduced by several percent even after allowing that most unburned materials eventually oxidize to CO2 in the environment. On the other hand, the production of CO2 by kilning of limestone adds 1 to 2% to the annual totals. The cumulative increase in carbon in the short term carbon cycle, owing to man's industrial and domestic activities up to 1970, is estimated to be 1.12 + 0.14 × 1017 g (4.1 ± 0.5 × 1017 g CO2), or about 18% of the amount of CO2 in the atmosphere during the late nineteenth century.DOI: 10.1111/j.2153-3490.1973.tb01604.x

@article{doi103402tellusav25i29652,
    author = "Keeling, Charles D.",
    title = "Industrial production of carbon dioxide from fossil fuels and limestone",
    year = "1973",
    journal = "Tellus A Dynamic Meteorology and Oceanography",
    abstract = "The release of carbon dioxide into the atmosphere by the burning of fossil fuels is significantly altering the carbon cycle by adding to the amount of carbon in the atmosphere and in the more rapidly interacting portions of the biosphere and oceans. In order better to assess these changes, the basis for calculating global CO2 emissions is reviewed and new annual values are computed for the period 1800 through 1969. The world average fractions of carbon in coal and lignite, estimated from calorific data, are found to be lower than previously assumed. When account is taken of handling losses and partial diversion to produce petrochemicals, road asphalt, and other non-fuels, the calculated CO2 emissions are further reduced by several percent even after allowing that most unburned materials eventually oxidize to CO2 in the environment. On the other hand, the production of CO2 by kilning of limestone adds 1 to 2\% to the annual totals. The cumulative increase in carbon in the short term carbon cycle, owing to man's industrial and domestic activities up to 1970, is estimated to be 1.12 + 0.14 × 1017 g (4.1 ± 0.5 × 1017 g CO2), or about 18\% of the amount of CO2 in the atmosphere during the late nineteenth century.DOI: 10.1111/j.2153-3490.1973.tb01604.x",
    url = "https://doi.org/10.3402/tellusa.v25i2.9652",
    doi = "10.3402/tellusa.v25i2.9652",
    openalex = "W4246011515"
}

@article{adams1975wood,
    author = "Adams, J. A. S. and Lundell, L. L. and Mantovani, M. S. M.",
    title = "Wood Versus Fossil Fuel for Excess Carbon Dioxide",
    year = "1975",
    journal = "Science",
    url = "https://doi.org/10.1126/science.190.4220.1154",
    doi = "10.1126/science.190.4220.1154",
    number = "4220",
    openalex = "W2043874713",
    pages = "1154-1154",
    volume = "190",
    references = "doi101111j215334901957tb01848x"
}

Phenomena related to the natural carbon cycle as the 14C distribution between atmosphere and ocean and the atmospheric response to the input of fossil fuel CO 2 and of 14 C produced in nuclear weapon tests have been quantitatively discussed by other authors using box models. However the exchange coefficients derived from the natural 14 C distribution do not agree with those valid to describe the short-term phenomena. A model consisting of a well mixed atmospheric box coupled to a long-term biosphere, of an ocean surface box and a diffusive deep ocean is discussed. The dynamic parameters were derived from the preindustrial 14 C distribution in atmosphere and ocean. A consistent description of phenomena with completely different characteristic times is possible, because in the box diffusion model the flux from mixed layer to deep sea increases for decreasing time constants of the perturbations. This is in contrary to box models where it is essentially independent of the time constants if they are smaller than a few hundred years. Due to this fact our model is valid for predictions of the atmospheric CO 2 response to the various possible future CO 2 input time functions.

@article{doi103402tellusav27i29900,
    author = "Oeschger, H. and Siegenthaler, U. and Schotterer, U. and Gugelmann, A.",
    title = "A box diffusion model to study the carbon dioxide exchange in nature",
    year = "1975",
    journal = "Tellus A Dynamic Meteorology and Oceanography",
    abstract = "Phenomena related to the natural carbon cycle as the 14C distribution between atmosphere and ocean and the atmospheric response to the input of fossil fuel CO 2 and of 14 C produced in nuclear weapon tests have been quantitatively discussed by other authors using box models. However the exchange coefficients derived from the natural 14 C distribution do not agree with those valid to describe the short-term phenomena. A model consisting of a well mixed atmospheric box coupled to a long-term biosphere, of an ocean surface box and a diffusive deep ocean is discussed. The dynamic parameters were derived from the preindustrial 14 C distribution in atmosphere and ocean. A consistent description of phenomena with completely different characteristic times is possible, because in the box diffusion model the flux from mixed layer to deep sea increases for decreasing time constants of the perturbations. This is in contrary to box models where it is essentially independent of the time constants if they are smaller than a few hundred years. Due to this fact our model is valid for predictions of the atmospheric CO 2 response to the various possible future CO 2 input time functions.",
    url = "https://doi.org/10.3402/tellusa.v27i2.9900",
    doi = "10.3402/tellusa.v27i2.9900",
    openalex = "W2087582584",
    references = "doi101002qj49706427503, doi10100797814684198636, doi101029jc074i023p05491, doi101029jz065i009p02903, doi101029jz068i013p03899, doi101111j215334901957tb01848x, doi101126science1223166415a, doi103402tellusav12i29366, doi103402tellusav25i29652, doi103402tellusav9i19075"
}

@book{crossref1977the,
    title = "The Fate of Fossil Fuel CO2 in the Oceans",
    year = "1977",
    url = "https://doi.org/10.1007/978-1-4899-5016-1",
    doi = "10.1007/978-1-4899-5016-1",
    openalex = "W655165904"
}

If the amounts of wood consumed in deforestation to increase agricultural land and as firewood in underindustrialized countries are added to the amount consumed by the money economies as forest products, the estimates of the net amount of wood removed from the biosphere in this century should be revised upward. The per capita ratio of the weight of carbon from net wood burned to the weight of carbon from fossil fuel burned in this century has been at least 0.1 and may have approached 1.0.

@article{doi101126science196428554,
    author = "Adams, J. A. S. and Mantovani, Marco and Lundell, L. L.",
    title = "Wood Versus Fossil Fuel as a Source of Excess Carbon Dioxide in the Atmosphere: A Preliminary Report",
    year = "1977",
    journal = "Science",
    abstract = "If the amounts of wood consumed in deforestation to increase agricultural land and as firewood in underindustrialized countries are added to the amount consumed by the money economies as forest products, the estimates of the net amount of wood removed from the biosphere in this century should be revised upward. The per capita ratio of the weight of carbon from net wood burned to the weight of carbon from fossil fuel burned in this century has been at least 0.1 and may have approached 1.0.",
    url = "https://doi.org/10.1126/science.196.4285.54",
    doi = "10.1126/science.196.4285.54",
    openalex = "W2060675860",
    references = "adams1975wood"
}

@incollection{pytkowicz1977fossil,
    author = "Pytkowicz, R. M. and Small, L. F.",
    title = "Fossil Fuel Problem and Carbon Dioxide: an Overview",
    year = "1977",
    booktitle = "The Fate of Fossil Fuel CO2 in the Oceans",
    url = "https://doi.org/10.1007/978-1-4899-5016-1\_2",
    doi = "10.1007/978-1-4899-5016-1\_2",
    openalex = "W2492666150",
    pages = "7-31",
    references = "doi101016001600325290625x, doi1010160016703758900462, doi10106313067687, doi101111j215334901957tb01849x, doi101111j215334901975tb01671x, doi101126science15637801358, doi103402tellusav27i29900, doi103402tellusav9i19075, doi104319lo19731860897, openalexw1488584644"
}

Current knowledge of the world carbon budget is reviewed with special emphasis on the question of whether the biota is a source or a sink for CO/sub 2/. The analysis shows through convergent lines of evidence that the biota is not a sink and may be a source of CO/sub 2/ as large or larger than the fossil fuel source. The issue is important because of the potential that changes in the CO/sub 2/ content of air have for changing climate worldwide. Various analyses suggest that human activities in the near future could release large additional amounts of CO/sub 2/ into the atmosphere with results that are substantially unpredictable.

@article{doi101126science1994325141,
    author = "Woodwell, George M. and Whittaker, R. H. and Reiners, William A. and Likens, Gene E. and Delwiche, C. C. and Botkin, Daniel B.",
    title = "The Biota and the World Carbon Budget",
    year = "1978",
    journal = "Science",
    abstract = "Current knowledge of the world carbon budget is reviewed with special emphasis on the question of whether the biota is a source or a sink for CO/sub 2/. The analysis shows through convergent lines of evidence that the biota is not a sink and may be a source of CO/sub 2/ as large or larger than the fossil fuel source. The issue is important because of the potential that changes in the CO/sub 2/ content of air have for changing climate worldwide. Various analyses suggest that human activities in the near future could release large additional amounts of CO/sub 2/ into the atmosphere with results that are substantially unpredictable.",
    url = "https://doi.org/10.1126/science.199.4325.141",
    doi = "10.1126/science.199.4325.141",
    openalex = "W2025836562",
    references = "doi101007978940098514835, doi101029jz070i024p06053, doi101093icb8119, doi1010970001069419611100000024, doi101111j215334901976tb00701x, doi101126science1223166415a, doi101126science1223166415b, doi101146annureves08110177000411, doi103402tellusav27i29900, openalexw3022078416"
}

The fate of fossil fuel carbon dioxide released into the atmosphere depends on the exchange rates of carbon between the atmosphere and three major carbon reservoirs, namely, the oceans, shallow-water sediments, and the terrestrial biosphere. Various assumptions and models used to estimate the global carbon budget for the last 20 years are reviewed and evaluated. Several versions of recent atmosphere-ocean models appear to give reliable and mutually consistent estimates for carbon dioxide uptake by the oceans. On the other hand, there is no compelling evidence which establishes that the terrestrial biomass has decreased at a rate comparable to that of fossil fuel combustion over the last two decades, as has been recently claimed.

@article{broecker1979fate,
    author = "Broecker, W. S. and Takahashi, T. and Simpson, H. J. and Peng, T. -H.",
    title = "Fate of Fossil Fuel Carbon Dioxide and the Global Carbon Budget",
    year = "1979",
    journal = "Science",
    abstract = "The fate of fossil fuel carbon dioxide released into the atmosphere depends on the exchange rates of carbon between the atmosphere and three major carbon reservoirs, namely, the oceans, shallow-water sediments, and the terrestrial biosphere. Various assumptions and models used to estimate the global carbon budget for the last 20 years are reviewed and evaluated. Several versions of recent atmosphere-ocean models appear to give reliable and mutually consistent estimates for carbon dioxide uptake by the oceans. On the other hand, there is no compelling evidence which establishes that the terrestrial biomass has decreased at a rate comparable to that of fossil fuel combustion over the last two decades, as has been recently claimed.",
    url = "https://doi.org/10.1126/science.206.4417.409",
    doi = "10.1126/science.206.4417.409",
    number = "4417",
    openalex = "W2095051466",
    pages = "409-418",
    volume = "206",
    references = "crossref1977the, doi1010079783642809132, doi1010160304420374900152, doi101126science1223166415a, doi101126science1223166415b, doi101126science1994325141, doi101146annureves08110177000411, doi103402tellusav26i129733, doi103402tellusav27i29900, doi104319lo19731860897"
}

@misc{broecker1979fate1,
    author = "Broecker, W. S. and Takahashi, T. and Simpson, J. and Peng, T. H",
    title = "Fate of fossil fuel carbon dioxide and the global carbon budget",
    year = "1979",
    howpublished = "Science, v. 206, p. 409-418",
    note = "talkorigins\_source = {true}; raw\_reference = {Broecker, W. S., Takahashi, T., Simpson, J., and Peng, T. H., 1979, Fate of fossil fuel carbon dioxide and the global carbon budget: Science, v. 206, p. 409-418.}"
}

During the years 1975–1978 concern over the increase of CO 2 in the atmosphere expanded from the laboratory into the public policy arena. This was a period during which a profusion of international symposia, technical papers, and public‐policy‐oriented discussions drew wide attention to the potential dangers of unchecked growth of atmospheric CO 2 and man's alterations of the global carbon cycle. At the same time, the interdisciplinary interactions focused attention on the gaps in understanding, the uncertainties in the models, the inadequacies of the data, and the difficulties inherent in forecasting. Recognizing the social, political, and economic implications should fossil fuel burning be implicated as a cause of major [unfavorable] changes in climate, the scientists involved have called for increased understanding through stimulated scientific inquiry, and for flexibility in public policy options.

@article{doi101029rg017i007p01813,
    author = "Marland, Gregg and Rotty, Ralph M.",
    title = "Carbon dioxide and climate",
    year = "1979",
    journal = "Reviews of Geophysics",
    abstract = "During the years 1975–1978 concern over the increase of CO 2 in the atmosphere expanded from the laboratory into the public policy arena. This was a period during which a profusion of international symposia, technical papers, and public‐policy‐oriented discussions drew wide attention to the potential dangers of unchecked growth of atmospheric CO 2 and man's alterations of the global carbon cycle. At the same time, the interdisciplinary interactions focused attention on the gaps in understanding, the uncertainties in the models, the inadequacies of the data, and the difficulties inherent in forecasting. Recognizing the social, political, and economic implications should fossil fuel burning be implicated as a cause of major [unfavorable] changes in climate, the scientists involved have called for increased understanding through stimulated scientific inquiry, and for flexibility in public policy options.",
    url = "https://doi.org/10.1029/rg017i007p01813",
    doi = "10.1029/rg017i007p01813",
    openalex = "W2058634856",
    references = "pytkowicz1977fossil"
}

Past increase of atmospheric CO/sub 2/ involves significant ntributions from both fossil and nonfossil (biospheric) sources. A simulation model was used to reconstruct changes since 1860 and project four hypothetical future scenarios of CO/sub 2/ injection to 2460. Nineteen compartments and their exchanges of carbon were considered. Areal extent of tropical forests, other wooded ecosystems, and nonforests were incorporated into the model. Rapidly and slowly exchanging pools of carbon per unit area, and net primary production for each pool and exosystem group, were projected by integrating income-loss differential equations numerically using CSMP programming language. Estimated cumulative releases of CO/sub 2/ from fossil fuels (plus cement) near 120 Gtons of carbon (1 Gton = 10/sup 9/ metric tons) from 1860 to 1970 were assumed to equal prompt and delayed releases from forest clearing. Limits of exploitable forest area and biomass were evaluated and found to contribute much less future CO/sub 2/ than the usable coal, oil, gas, and oil shale. Ultimate release from the latter (7500 +- 2500 x 10/sup 9/ tons of C) could increase atmospheric CO/sub 2/ manyfold: doubling the assumed 1860 levels as early as (1) year 2025 for assumed nominal scenario (expanding releases slightly less rapidly than at present), (2) year 2033 for a delayed expansion scenario that would prolong use of fossil reserves (lowering peak carbon release rate from approx. 43 to approx. 28 Gtons/year), (3) year 2087 for a slow burner scenario (increasing very slowly from present levels), and (4) year 2290 for a combination scenario (which assumes low fossil-fuel use, high carbon storage, and high net primary production of forested exosystems).

@misc{doi1021726206754,
    author = "Chan, Y.‐H. and Olson, Jerry S. and Emanuel, William R.",
    title = "Simulation of land-use patterns affecting the global carbon cycle. [Reconstruction and projection of CO/sub 2/ scenarios from 1860 to 2460]",
    year = "1979",
    abstract = "Past increase of atmospheric CO/sub 2/ involves significant ntributions from both fossil and nonfossil (biospheric) sources. A simulation model was used to reconstruct changes since 1860 and project four hypothetical future scenarios of CO/sub 2/ injection to 2460. Nineteen compartments and their exchanges of carbon were considered. Areal extent of tropical forests, other wooded ecosystems, and nonforests were incorporated into the model. Rapidly and slowly exchanging pools of carbon per unit area, and net primary production for each pool and exosystem group, were projected by integrating income-loss differential equations numerically using CSMP programming language. Estimated cumulative releases of CO/sub 2/ from fossil fuels (plus cement) near 120 Gtons of carbon (1 Gton = 10/sup 9/ metric tons) from 1860 to 1970 were assumed to equal prompt and delayed releases from forest clearing. Limits of exploitable forest area and biomass were evaluated and found to contribute much less future CO/sub 2/ than the usable coal, oil, gas, and oil shale. Ultimate release from the latter (7500 +- 2500 x 10/sup 9/ tons of C) could increase atmospheric CO/sub 2/ manyfold: doubling the assumed 1860 levels as early as (1) year 2025 for assumed nominal scenario (expanding releases slightly less rapidly than at present), (2) year 2033 for a delayed expansion scenario that would prolong use of fossil reserves (lowering peak carbon release rate from approx. 43 to approx. 28 Gtons/year), (3) year 2087 for a slow burner scenario (increasing very slowly from present levels), and (4) year 2290 for a combination scenario (which assumes low fossil-fuel use, high carbon storage, and high net primary production of forested exosystems).",
    url = "https://doi.org/10.2172/6206754",
    doi = "10.2172/6206754",
    openalex = "W4231474868",
    references = "pytkowicz1977fossil"
}

@article{doi101007bf00386231,
    author = "Farquhar, Graham D. and von Caemmerer, Susanne and Berry, Joseph A.",
    title = "A biochemical model of photosynthetic CO2 assimilation in leaves of C3 species",
    year = "1980",
    journal = "Planta",
    url = "https://doi.org/10.1007/bf00386231",
    doi = "10.1007/bf00386231",
    openalex = "W2046857879",
    references = "doi1010160003986179900523, doi101016002251937790265x, doi101038275741a0, doi101086331469, doi101104pp545678, doi101104pp5561067, doi101104pp59186, doi101104pp595986, doi101104pp613411, openalexw2294308609"
}

Changes in land use over the past two centuries have caused a significant release of CO 2 to the atmosphere from the terrestrial biota and soils. An analysis of this release is based on amounts of organic carbon within an ecosystem following changes such as harvest of forests; it is also based on rates of changes, such as conversion of forest to agriculture, deduced from agricultural and forestry statistics. A model is used to calculate the net amount of carbon stored or released each year by the biota and soils of 69 regional ecosystems. Some of the changes, such as afforestation, the growth of harvested forests, and buildup of soil organic matter, result in a storage of carbon; others, such as harvest of forests and increase in pasture and agricultural areas, result in a loss of carbon to the atmosphere. According to this analysis, there has been a net release of carbon from terrestrial ecosystems worldwide since at least 1860. Until °1960, the annual release was greater than release of carbon from fossil fuels. The total net release of carbon from terrestrial ecosystems since 1860 is estimated to have been 180 x 10 1 5 g (a range of estimates is 135—228 x 10 1 5 g). The estimated net release of carbon in 1980 was 1.8—4.7 x 10 1 5 g; for the 22 yr since 1958 the release of C was 38—76 x 10 1 5 g. The ranges reflect the differences among various estimates of forest biomass, soil carbon, and agricultural clearing. Improvements in the data on the clearing of tropical forests alone would reduce the range of estimates for 1980 by almost 60%. Estimates of the other major terms in the global carbon budget, the atmospheric increase in CO 2, the fossil fuel release of CO 2, and the oceanic uptake of CO 2, are all subject to uncertainties. The combined errors in these estimates are large enough that the global carbon budget appears balanced if the low estimate for the biotic release of carbon given above is used (1.8 x 10 1 5 g released in 1980) with the higher estimates of oceanic uptake. If higher estimates for biotic release are used, then the carbon budget does not balance, and the estimates of oceanic uptake or of other factors require revision.

@article{doi1023071942531,
    author = "Houghton, R. A. and Hobbie, John E. and Melillo, Jerry M. and Moore, Berrien and Peterson, B. J. and Shaver, Gus and Woodwell, George M.",
    title = {Changes in the Carbon Content of Terrestrial Biota and Soils between 1860 and 1980: A Net Release of CO"2 to the Atmosphere},
    year = "1983",
    journal = "Ecological Monographs",
    abstract = "Changes in land use over the past two centuries have caused a significant release of CO 2 to the atmosphere from the terrestrial biota and soils. An analysis of this release is based on amounts of organic carbon within an ecosystem following changes such as harvest of forests; it is also based on rates of changes, such as conversion of forest to agriculture, deduced from agricultural and forestry statistics. A model is used to calculate the net amount of carbon stored or released each year by the biota and soils of 69 regional ecosystems. Some of the changes, such as afforestation, the growth of harvested forests, and buildup of soil organic matter, result in a storage of carbon; others, such as harvest of forests and increase in pasture and agricultural areas, result in a loss of carbon to the atmosphere. According to this analysis, there has been a net release of carbon from terrestrial ecosystems worldwide since at least 1860. Until °1960, the annual release was greater than release of carbon from fossil fuels. The total net release of carbon from terrestrial ecosystems since 1860 is estimated to have been 180 x 10 1 5 g (a range of estimates is 135—228 x 10 1 5 g). The estimated net release of carbon in 1980 was 1.8—4.7 x 10 1 5 g; for the 22 yr since 1958 the release of C was 38—76 x 10 1 5 g. The ranges reflect the differences among various estimates of forest biomass, soil carbon, and agricultural clearing. Improvements in the data on the clearing of tropical forests alone would reduce the range of estimates for 1980 by almost 60\%. Estimates of the other major terms in the global carbon budget, the atmospheric increase in CO 2, the fossil fuel release of CO 2, and the oceanic uptake of CO 2, are all subject to uncertainties. The combined errors in these estimates are large enough that the global carbon budget appears balanced if the low estimate for the biotic release of carbon given above is used (1.8 x 10 1 5 g released in 1980) with the higher estimates of oceanic uptake. If higher estimates for biotic release are used, then the carbon budget does not balance, and the estimates of oceanic uptake or of other factors require revision.",
    url = "https://doi.org/10.2307/1942531",
    doi = "10.2307/1942531",
    openalex = "W2084211992",
    references = "doi101126science1994325141"
}

With growing concern about climatic changes that could result from increased atmospheric carbon dioxide, it is appropriate to use the improved statistics on the production and use of fossil fuels which are now available and to review the CO2 discharges to the atmosphere from fossil fuel burning. Data on global fuel production and the chemical composition of these fuels have been re-examined and an attempt has been made to estimate the fraction of fuel which is used in the petrochemicals industry or otherwise not soon oxidized. Available statistics now permit more systematic treatment of natural gas liquids than in earlier calculations. Values used for combustion efficiency and non-fuel use on a global scale still require some estimation and extrapolation from United States data but can be bounded with sufficient precision that they add little uncertainty to the calculation of global CO2 emissions. Data now available permit the computation to be made with confidence that there are no major oversights. The differences from earlier calculations of CO2 emissions are minor, well within the uncertainty limits in the data available. The fundamental problems of assembling a data set on global fuel production limit the utility of striving for too much precision at other steps in the calculation. Annual CO2 emissions retain an uncertainty of 6-10%.Results of the calculations for 1980 through 1982 show decreases from 1979 CO2 emissions. This is the first time since the end of World War I1 that the emissions have decreased 3 years in succession. During the period following the 1973 escalation of fuel prices, the growth rate of emissions has been less than half what it was during the 1950s and 1960s (1.5%/year since 1973 as opposed to 4.5%/year through the 1950s and 1960s). Most of the change is a result of decreased growth in the use of oil.

@article{doi103402tellusbv36i414907,
    author = "Marland, Gregg and Rotty, Ralph M.",
    title = "Carbon dioxide emissions from fossil fuels: a procedure for estimation and results for 1950-1982",
    year = "1984",
    journal = "Tellus B",
    abstract = "With growing concern about climatic changes that could result from increased atmospheric carbon dioxide, it is appropriate to use the improved statistics on the production and use of fossil fuels which are now available and to review the CO2 discharges to the atmosphere from fossil fuel burning. Data on global fuel production and the chemical composition of these fuels have been re-examined and an attempt has been made to estimate the fraction of fuel which is used in the petrochemicals industry or otherwise not soon oxidized. Available statistics now permit more systematic treatment of natural gas liquids than in earlier calculations. Values used for combustion efficiency and non-fuel use on a global scale still require some estimation and extrapolation from United States data but can be bounded with sufficient precision that they add little uncertainty to the calculation of global CO2 emissions. Data now available permit the computation to be made with confidence that there are no major oversights. The differences from earlier calculations of CO2 emissions are minor, well within the uncertainty limits in the data available. The fundamental problems of assembling a data set on global fuel production limit the utility of striving for too much precision at other steps in the calculation. Annual CO2 emissions retain an uncertainty of 6-10\%.Results of the calculations for 1980 through 1982 show decreases from 1979 CO2 emissions. This is the first time since the end of World War I1 that the emissions have decreased 3 years in succession. During the period following the 1973 escalation of fuel prices, the growth rate of emissions has been less than half what it was during the 1950s and 1960s (1.5\%/year since 1973 as opposed to 4.5\%/year through the 1950s and 1960s). Most of the change is a result of decreased growth in the use of oil.",
    url = "https://doi.org/10.3402/tellusb.v36i4.14907",
    doi = "10.3402/tellusb.v36i4.14907",
    openalex = "W2066964481"
}

New data on the three major determinants of the carbon release from tropical forest clearing are used in a computer model that simulates land use change and its effects on the carbon content of vegetation and soil in order to calculate the net flux of carbon dioxide between tropical ecosystems and the atmosphere. The model also permits testing the sensitivity of the calculated flux to uncertainties in these data. The tropics were a net source of at least 0.4 x 10(15) grams but not more than 1.6 x 10(15) grams of carbon in 1980, considerably less than previous estimates. Decreases in soil organic matter were responsible for 0.1 x 10(15) to 0.3 x 10(15) grams of the release, while the burning and decay of cleared vegetation accounted for 0.3 x 10(15) to 1.3 x 10(15) grams. These estimates are lower than many previous ones because lower biomass estimates and slightly lower land clearing rates were used and because ecosystem recovery processes were included. These new estimates of the biotic release allow for the possibility of a balanced global budget given the large remaining uncertainties in the marine, terrestrial, and fossil fuel components of the carbon cycle.

@article{doi101126science239483542,
    author = "Detwiler, R. P. and Hall, Charles A. S.",
    title = "Tropical Forests and the Global Carbon Cycle",
    year = "1988",
    journal = "Science",
    abstract = "New data on the three major determinants of the carbon release from tropical forest clearing are used in a computer model that simulates land use change and its effects on the carbon content of vegetation and soil in order to calculate the net flux of carbon dioxide between tropical ecosystems and the atmosphere. The model also permits testing the sensitivity of the calculated flux to uncertainties in these data. The tropics were a net source of at least 0.4 x 10(15) grams but not more than 1.6 x 10(15) grams of carbon in 1980, considerably less than previous estimates. Decreases in soil organic matter were responsible for 0.1 x 10(15) to 0.3 x 10(15) grams of the release, while the burning and decay of cleared vegetation accounted for 0.3 x 10(15) to 1.3 x 10(15) grams. These estimates are lower than many previous ones because lower biomass estimates and slightly lower land clearing rates were used and because ecosystem recovery processes were included. These new estimates of the biotic release allow for the possibility of a balanced global budget given the large remaining uncertainties in the marine, terrestrial, and fossil fuel components of the carbon cycle.",
    url = "https://doi.org/10.1126/science.239.4835.42",
    doi = "10.1126/science.239.4835.42",
    openalex = "W1976873738"
}

Observed atmospheric concentrations of CO(2) and data on the partial pressures of CO(2) in surface ocean waters are combined to identify globally significant sources and sinks of CO(2). The atmospheric data are compared with boundary layer concentrations calculated with the transport fields generated by a general circulation model (GCM) for specified source-sink distributions. In the model the observed north-south atmospheric concentration gradient can be maintained only if sinks for CO(2) are greater in the Northern than in the Southern Hemisphere. The observed differences between the partial pressure of CO(2) in the surface waters of the Northern Hemisphere and the atmosphere are too small for the oceans to be the major sink of fossil fuel CO(2). Therefore, a large amount of the CO(2) is apparently absorbed on the continents by terrestrial ecosystems.

@article{doi101126science24749491431,
    author = "Tans, Pieter P. and Fung, Inez and Takahashi, Taro",
    title = "Observational Contrains on the Global Atmospheric Co 2 Budget",
    year = "1990",
    journal = "Science",
    abstract = "Observed atmospheric concentrations of CO(2) and data on the partial pressures of CO(2) in surface ocean waters are combined to identify globally significant sources and sinks of CO(2). The atmospheric data are compared with boundary layer concentrations calculated with the transport fields generated by a general circulation model (GCM) for specified source-sink distributions. In the model the observed north-south atmospheric concentration gradient can be maintained only if sinks for CO(2) are greater in the Northern than in the Southern Hemisphere. The observed differences between the partial pressure of CO(2) in the surface waters of the Northern Hemisphere and the atmosphere are too small for the oceans to be the major sink of fossil fuel CO(2). Therefore, a large amount of the CO(2) is apparently absorbed on the continents by terrestrial ecosystems.",
    url = "https://doi.org/10.1126/science.247.4949.1431",
    doi = "10.1126/science.247.4949.1431",
    openalex = "W2074247901",
    references = "broecker1979fate, doi101007bf01054491, doi101029jd093id08p09341, doi101038319109a0, doi101126science1994325141, doi101126science2064417409, doi101126science239483542, doi101126science2404850293, doi1011751520049319831110609etdgmf20co2, doi103402tellusav27i29900, doi103402tellusbv36i414907"
}

Abstract The terrestrial biosphere plays an important role in the global carbon cycle. In the 1994 Intergovernmental Panel Assessment on Climate Change (IPCC), an effort was made to improve the quantification of terrestrial exchanges and potential feedbacks from climate, changing CO 2, and other factors; this paper presents the key results from that assessment, together with expanded discussion. The carbon cycle is the fluxes of carbon among four main reservoirs: fossil carbon, the atmosphere, the oceans, and the terrestrial biosphere. Emissions of fossil carbon during the 1980s averaged 5.5 Gt y −1. During the same period, the atmosphere gained 3.2 Gt C y −1 and the oceans are believed to have absorbed 2.0 Gt C y −1. The regrowing forests of the Northern Hemisphere may have absorbed 0.5 Gt C y −1 during this period. Meanwhile, tropical deforestation is thought to have released an average 1.6 Gt C y −1 over the 1980s. While the fluxes among the four pools should balance, the average 198Ds values lead to a ‘missing sink’ of 1.4 Gt C y −1 Several processes, including forest regrowth, CO 2 fertilization of plant growth (c. 1.0 Gt C y −1), N deposition (c. 0.6 Gt C y −1), and their interactions, may account for the budget imbalance. However, it remains difficult to quantify the influences of these separate but interactive processes. Uncertainties in the individual numbers are large, and are themselves poorly quantified. This paper presents detail beyond the IPCC assessment on procedures used to approximate the flux uncertainties. Lack of knowledge about positive and negative feedbacks from the biosphere is a major limiting factor to credible simulations of future atmospheric CO 2 concentrations. Analyses of the atmospheric gradients of CO 2 and 13 CO 2 concentrations provide increasingly strong evidence for terrestrial sinks, potentially distributed between Northern Hemisphere and tropical regions, but conclusive detection in direct biomass and soil measurements remains elusive. Current regional‐to‐global terrestrial ecosystem models with coupled carbon and nitrogen cycles represent the effects of CO 2 fertilization differently, but all suggest longterm responses to CO 2 that are substantially smaller than potential leaf‐ or laboratory whole plant‐level responses. Analyses of emissions and biogeochemical fluxes consistent with eventual stabilization of atmospheric CO 2 concentrations are sensitive to the way in which biospheric feedbacks are modeled by c. 15%. Decisions about land use can have effects of 100s of Gt C over the next few centuries, with similarly significant effects on the atmosphere. Critical areas for future research are continued measurements and analyses of atmospheric data (CO 2 and 13 CO 2) to serve as large‐scale constraints, process studies of the scaling from the photosynthetic response to CO 2 to whole‐ecosystem carbon storage, and rigorous quantification of the effects of changing land use on carbon storage.

@article{doi101111j136524861995tb00008x,
    author = "Schimel, David",
    title = "Terrestrial ecosystems and the carbon cycle",
    year = "1995",
    journal = "Global Change Biology",
    abstract = "Abstract The terrestrial biosphere plays an important role in the global carbon cycle. In the 1994 Intergovernmental Panel Assessment on Climate Change (IPCC), an effort was made to improve the quantification of terrestrial exchanges and potential feedbacks from climate, changing CO 2, and other factors; this paper presents the key results from that assessment, together with expanded discussion. The carbon cycle is the fluxes of carbon among four main reservoirs: fossil carbon, the atmosphere, the oceans, and the terrestrial biosphere. Emissions of fossil carbon during the 1980s averaged 5.5 Gt y −1. During the same period, the atmosphere gained 3.2 Gt C y −1 and the oceans are believed to have absorbed 2.0 Gt C y −1. The regrowing forests of the Northern Hemisphere may have absorbed 0.5 Gt C y −1 during this period. Meanwhile, tropical deforestation is thought to have released an average 1.6 Gt C y −1 over the 1980s. While the fluxes among the four pools should balance, the average 198Ds values lead to a ‘missing sink’ of 1.4 Gt C y −1 Several processes, including forest regrowth, CO 2 fertilization of plant growth (c. 1.0 Gt C y −1), N deposition (c. 0.6 Gt C y −1), and their interactions, may account for the budget imbalance. However, it remains difficult to quantify the influences of these separate but interactive processes. Uncertainties in the individual numbers are large, and are themselves poorly quantified. This paper presents detail beyond the IPCC assessment on procedures used to approximate the flux uncertainties. Lack of knowledge about positive and negative feedbacks from the biosphere is a major limiting factor to credible simulations of future atmospheric CO 2 concentrations. Analyses of the atmospheric gradients of CO 2 and 13 CO 2 concentrations provide increasingly strong evidence for terrestrial sinks, potentially distributed between Northern Hemisphere and tropical regions, but conclusive detection in direct biomass and soil measurements remains elusive. Current regional‐to‐global terrestrial ecosystem models with coupled carbon and nitrogen cycles represent the effects of CO 2 fertilization differently, but all suggest longterm responses to CO 2 that are substantially smaller than potential leaf‐ or laboratory whole plant‐level responses. Analyses of emissions and biogeochemical fluxes consistent with eventual stabilization of atmospheric CO 2 concentrations are sensitive to the way in which biospheric feedbacks are modeled by c. 15\%. Decisions about land use can have effects of 100s of Gt C over the next few centuries, with similarly significant effects on the atmosphere. Critical areas for future research are continued measurements and analyses of atmospheric data (CO 2 and 13 CO 2) to serve as large‐scale constraints, process studies of the scaling from the photosynthetic response to CO 2 to whole‐ecosystem carbon storage, and rigorous quantification of the effects of changing land use on carbon storage.",
    url = "https://doi.org/10.1111/j.1365-2486.1995.tb00008.x",
    doi = "10.1111/j.1365-2486.1995.tb00008.x",
    openalex = "W1970527729",
    references = "broecker1979fate, doi101007bf00002772, doi10102991gb01778, doi10102993gb02725, doi101038361520a0, doi101038363234a0, doi101126science2064417409, doi101126science24749491431, doi101126science26051161905, doi101126science2635144185, doi102136sssaj199303615995005700010034x, doi1023071311067, openalexw1759145845"
}

@article{doi101016s0009254199000315,
    author = "Gaillardet, Jérôme and Dupré, Bernard and Louvat, Pascale and Allègre, Claude J.",
    title = "Global silicate weathering and CO2 consumption rates deduced from the chemistry of large rivers",
    year = "1999",
    journal = "Chemical Geology",
    url = "https://doi.org/10.1016/s0009-2541(99)00031-5",
    doi = "10.1016/s0009-2541(99)00031-5",
    openalex = "W2008587428",
    references = "doi1010160012821x88900131, doi101016001670379500078e, doi101016b0080437516071036, doi101029jc092ic08p08293, doi101086628741, doi101086629606, doi10113000917613198210516vosstp20co2, doi102475ajs2837641, doi102475ajs2875401, doi102475ajs294156, openalexw1624806571"
}

Long‐term atmospheric 14 CO 2 observations are used to quantify fossil fuel‐derived CO 2 concentrations at a regional polluted site, and at a continental mountain station in southwest Germany. Fossil fuel CO 2 emission rates for the relevant catchment areas are obtained by applying the Radon‐Tracer‐Method. They compare well with statistical emissions inventories but reveal a larger seasonality than earlier assumed, thus contributing significantly to the observed CO 2 seasonal cycle over Europe. Based on the present approach, emissions reductions on the order of 5–10% are detectable for catchment areas of several hundred kilometres radius, as anticipated within a five‐years commitment period of the Kyoto Protocol. Still, no significant change of fossil fuel CO 2 emissions is observed at the two sites over the last 16 years.

@article{doi1010292003gl018477,
    author = "Levin, Ingeborg and Kromer, Bernd and Schmidt, Martina and Sartorius, H.",
    title = "A novel approach for independent budgeting of fossil fuel CO 2 over Europe by 14 CO 2 observations",
    year = "2003",
    journal = "Geophysical Research Letters",
    abstract = "Long‐term atmospheric 14 CO 2 observations are used to quantify fossil fuel‐derived CO 2 concentrations at a regional polluted site, and at a continental mountain station in southwest Germany. Fossil fuel CO 2 emission rates for the relevant catchment areas are obtained by applying the Radon‐Tracer‐Method. They compare well with statistical emissions inventories but reveal a larger seasonality than earlier assumed, thus contributing significantly to the observed CO 2 seasonal cycle over Europe. Based on the present approach, emissions reductions on the order of 5–10\% are detectable for catchment areas of several hundred kilometres radius, as anticipated within a five‐years commitment period of the Kyoto Protocol. Still, no significant change of fossil fuel CO 2 emissions is observed at the two sites over the last 16 years.",
    url = "https://doi.org/10.1029/2003gl018477",
    doi = "10.1029/2003gl018477",
    openalex = "W2148708766",
    references = "doi101126science1223166415b"
}

@article{doi101016jcemconres200401021,
    author = "Gartner, E.M.",
    title = "Industrially interesting approaches to “low-CO2” cements",
    year = "2004",
    journal = "Cement and Concrete Research",
    url = "https://doi.org/10.1016/j.cemconres.2004.01.021",
    doi = "10.1016/j.cemconres.2004.01.021",
    openalex = "W1993016649",
    references = "doi101007bf00355128, doi101016b9780080430188501508, doi101680adcr1994623109, doi101680adcr199911115, openalexw1570227906, openalexw1607401957"
}

The growth rate of atmospheric carbon dioxide (CO(2)), the largest human contributor to human-induced climate change, is increasing rapidly. Three processes contribute to this rapid increase. Two of these processes concern emissions. Recent growth of the world economy combined with an increase in its carbon intensity have led to rapid growth in fossil fuel CO(2) emissions since 2000: comparing the 1990s with 2000-2006, the emissions growth rate increased from 1.3% to 3.3% y(-1). The third process is indicated by increasing evidence (P = 0.89) for a long-term (50-year) increase in the airborne fraction (AF) of CO(2) emissions, implying a decline in the efficiency of CO(2) sinks on land and oceans in absorbing anthropogenic emissions. Since 2000, the contributions of these three factors to the increase in the atmospheric CO(2) growth rate have been approximately 65 +/- 16% from increasing global economic activity, 17 +/- 6% from the increasing carbon intensity of the global economy, and 18 +/- 15% from the increase in AF. An increasing AF is consistent with results of climate-carbon cycle models, but the magnitude of the observed signal appears larger than that estimated by models. All of these changes characterize a carbon cycle that is generating stronger-than-expected and sooner-than-expected climate forcing.

@article{doi101073pnas0702737104,
    author = "Canadell, Josep G. and Quéré, Corinne Le and Raupach, Michael and Field, Christopher B. and Buitenhuis, Erik T. and Ciais, Philippe and Conway, T. J. and Gillett, Nathan P. and Houghton, R. A. and Marland, Gregg",
    title = "Contributions to accelerating atmospheric CO 2 growth from economic activity, carbon intensity, and efficiency of natural sinks",
    year = "2007",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "The growth rate of atmospheric carbon dioxide (CO(2)), the largest human contributor to human-induced climate change, is increasing rapidly. Three processes contribute to this rapid increase. Two of these processes concern emissions. Recent growth of the world economy combined with an increase in its carbon intensity have led to rapid growth in fossil fuel CO(2) emissions since 2000: comparing the 1990s with 2000-2006, the emissions growth rate increased from 1.3\% to 3.3\% y(-1). The third process is indicated by increasing evidence (P = 0.89) for a long-term (50-year) increase in the airborne fraction (AF) of CO(2) emissions, implying a decline in the efficiency of CO(2) sinks on land and oceans in absorbing anthropogenic emissions. Since 2000, the contributions of these three factors to the increase in the atmospheric CO(2) growth rate have been approximately 65 +/- 16\% from increasing global economic activity, 17 +/- 6\% from the increasing carbon intensity of the global economy, and 18 +/- 15\% from the increase in AF. An increasing AF is consistent with results of climate-carbon cycle models, but the magnitude of the observed signal appears larger than that estimated by models. All of these changes characterize a carbon cycle that is generating stronger-than-expected and sooner-than-expected climate forcing.",
    url = "https://doi.org/10.1073/pnas.0702737104",
    doi = "10.1073/pnas.0702737104",
    openalex = "W2133920545",
    references = "doi10103820859, doi10103835021000, doi101038nature03972, doi101049ep19770180, doi101073pnas0505734102, doi101073pnas0700609104, doi101175jcli38001, doi10230720033020, doi1023073324639, openalexw2939474406"
}

The global carbon budget is, of course, balanced. The conservation of carbon and the first law of thermodynamics are intact. “Balancing the carbon budget” refers to the state of the science in evaluating the terms of the global carbon equation. The annual increases in the amount of carbon in the atmosphere, oceans, and land should balance the emissions of carbon from fossil fuels and deforestation. Balancing the carbon budget is not the real issue, however. The real issue is understanding the processes responsible for net sources and sinks of carbon. Such understanding should lead to more accurate predictions of future concentrations of CO 2 and more accurate predictions of the rate and extent of climatic change. The recent past may be insufficient for prediction, however. Oceanic and terrestrial sinks that have lessened the rate of growth in atmospheric CO 2 until now may diminish as feedbacks between the carbon cycle and climate become more prominent.

@article{doi101146annurevearth35031306140057,
    author = "Houghton, R. A.",
    title = "Balancing the Global Carbon Budget",
    year = "2007",
    journal = "Annual Review of Earth and Planetary Sciences",
    abstract = "The global carbon budget is, of course, balanced. The conservation of carbon and the first law of thermodynamics are intact. “Balancing the carbon budget” refers to the state of the science in evaluating the terms of the global carbon equation. The annual increases in the amount of carbon in the atmosphere, oceans, and land should balance the emissions of carbon from fossil fuels and deforestation. Balancing the carbon budget is not the real issue, however. The real issue is understanding the processes responsible for net sources and sinks of carbon. Such understanding should lead to more accurate predictions of future concentrations of CO 2 and more accurate predictions of the rate and extent of climatic change. The recent past may be insufficient for prediction, however. Oceanic and terrestrial sinks that have lessened the rate of growth in atmospheric CO 2 until now may diminish as feedbacks between the carbon cycle and climate become more prominent.",
    url = "https://doi.org/10.1146/annurev.earth.35.031306.140057",
    doi = "10.1146/annurev.earth.35.031306.140057",
    openalex = "W2148979610",
    references = "broecker1979fate, doi101038298156a0, doi10103835041539, doi101038386698a0, doi101038nature03972, doi101038nature04514, doi101126science1097403, doi101126science2064417409, doi101126science2815374200, doi101175jcli38001, doi101256004316502320517344, doi1018901051076120000100423tvdoso20co2"
}

@incollection{doi10100797803874948903,
    author = "Hori, Yoshio",
    title = "Electrochemical CO2 Reduction on Metal Electrodes",
    year = "2008",
    booktitle = "Modern aspects of electrochemistry",
    url = "https://doi.org/10.1007/978-0-387-49489-0\_3",
    doi = "10.1007/978-0-387-49489-0\_3",
    openalex = "W2202057872",
    references = "doi1012019781315139098, openalexw1573748297, openalexw294628349"
}

Nature's photosynthesis uses the sun's energy with chlorophyll in plants as a catalyst to recycle carbon dioxide and water into new plant life. Only given sufficient geological time can new fossil fuels be formed naturally. In contrast, chemical recycling of carbon dioxide from natural and industrial sources as well as varied human activities or even from the air itself to methanol or dimethyl ether (DME) and their varied products can be achieved via its capture and subsequent reductive hydrogenative conversion. The present Perspective reviews this new approach and our research in the field over the last 15 years. Carbon recycling represents a significant aspect of our proposed Methanol Economy. Any available energy source (alternative energies such as solar, wind, geothermal, and atomic energy) can be used for the production of needed hydrogen and chemical conversion of CO(2). Improved new methods for the efficient reductive conversion of CO(2) to methanol and/or DME that we have developed include bireforming with methane and ways of catalytic or electrochemical conversions. Liquid methanol is preferable to highly volatile and potentially explosive hydrogen for energy storage and transportation. Together with the derived DME, they are excellent transportation fuels for internal combustion engines (ICE) and fuel cells as well as convenient starting materials for synthetic hydrocarbons and their varied products. Carbon dioxide thus can be chemically transformed from a detrimental greenhouse gas causing global warming into a valuable, renewable and inexhaustible carbon source of the future allowing environmentally neutral use of carbon fuels and derived hydrocarbon products.

@article{doi101021jo801260f,
    author = "Olah, George A. and Goeppert, Alain and Prakash, G. K. Surya",
    title = "Chemical Recycling of Carbon Dioxide to Methanol and Dimethyl Ether: From Greenhouse Gas to Renewable, Environmentally Carbon Neutral Fuels and Synthetic Hydrocarbons",
    year = "2008",
    journal = "The Journal of Organic Chemistry",
    abstract = "Nature's photosynthesis uses the sun's energy with chlorophyll in plants as a catalyst to recycle carbon dioxide and water into new plant life. Only given sufficient geological time can new fossil fuels be formed naturally. In contrast, chemical recycling of carbon dioxide from natural and industrial sources as well as varied human activities or even from the air itself to methanol or dimethyl ether (DME) and their varied products can be achieved via its capture and subsequent reductive hydrogenative conversion. The present Perspective reviews this new approach and our research in the field over the last 15 years. Carbon recycling represents a significant aspect of our proposed Methanol Economy. Any available energy source (alternative energies such as solar, wind, geothermal, and atomic energy) can be used for the production of needed hydrogen and chemical conversion of CO(2). Improved new methods for the efficient reductive conversion of CO(2) to methanol and/or DME that we have developed include bireforming with methane and ways of catalytic or electrochemical conversions. Liquid methanol is preferable to highly volatile and potentially explosive hydrogen for energy storage and transportation. Together with the derived DME, they are excellent transportation fuels for internal combustion engines (ICE) and fuel cells as well as convenient starting materials for synthetic hydrocarbons and their varied products. Carbon dioxide thus can be chemically transformed from a detrimental greenhouse gas causing global warming into a valuable, renewable and inexhaustible carbon source of the future allowing environmentally neutral use of carbon fuels and derived hydrocarbon products.",
    url = "https://doi.org/10.1021/jo801260f",
    doi = "10.1021/jo801260f",
    openalex = "W2113086422",
    references = "doi1010179781316577226067, openalexw1573748297"
}

CO 2 released from combustion of fossil fuels equilibrates among the various carbon reservoirs of the atmosphere, the ocean, and the terrestrial biosphere on timescales of a few centuries. However, a sizeable fraction of the CO 2 remains in the atmosphere, awaiting a return to the solid earth by much slower weathering processes and deposition of CaCO 3. Common measures of the atmospheric lifetime of CO 2, including the e-folding time scale, disregard the long tail. Its neglect in the calculation of global warming potentials leads many to underestimate the longevity of anthropogenic global warming. Here, we review the past literature on the atmospheric lifetime of fossil fuel CO 2 and its impact on climate, and we present initial results from a model intercomparison project on this topic. The models agree that 20–35% of the CO 2 remains in the atmosphere after equilibration with the ocean (2–20 centuries). Neutralization by CaCO 3 draws the airborne fraction down further on timescales of 3 to 7 kyr.

@article{archer2009atmospheric,
    author = "Archer, David and Eby, Michael and Brovkin, Victor and Ridgwell, Andy and Cao, Long and Mikolajewicz, Uwe and Caldeira, Ken and Matsumoto, Katsumi and Munhoven, Guy and Montenegro, Alvaro and Tokos, Kathy",
    title = "Atmospheric Lifetime of Fossil Fuel Carbon Dioxide",
    year = "2009",
    journal = "Annual Review of Earth and Planetary Sciences",
    abstract = "CO 2 released from combustion of fossil fuels equilibrates among the various carbon reservoirs of the atmosphere, the ocean, and the terrestrial biosphere on timescales of a few centuries. However, a sizeable fraction of the CO 2 remains in the atmosphere, awaiting a return to the solid earth by much slower weathering processes and deposition of CaCO 3. Common measures of the atmospheric lifetime of CO 2, including the e-folding time scale, disregard the long tail. Its neglect in the calculation of global warming potentials leads many to underestimate the longevity of anthropogenic global warming. Here, we review the past literature on the atmospheric lifetime of fossil fuel CO 2 and its impact on climate, and we present initial results from a model intercomparison project on this topic. The models agree that 20–35\% of the CO 2 remains in the atmosphere after equilibration with the ocean (2–20 centuries). Neutralization by CaCO 3 draws the airborne fraction down further on timescales of 3 to 7 kyr.",
    url = "https://doi.org/10.1146/annurev.earth.031208.100206",
    doi = "10.1146/annurev.earth.031208.100206",
    number = "1",
    openalex = "W2149521176",
    pages = "117-134",
    volume = "37",
    references = "doi101016003101829290207l, doi101016s0038071703001238, doi101029jc086ic10p09776, doi10103834839, doi101038353225a0, doi101046j13652486200100383x, doi101046j13652486200300569x, doi101126science24749491431, doi101175jcli38001, doi1023071971875, doi102475ajs2837641, doi102475ajs294156, openalexw2939474406"
}

Since the time of the industrial revolution, the atmospheric CO(2) concentration has risen by nearly 35 % to its current level of 383 ppm. The increased carbon dioxide concentration in the atmosphere has been suggested to be a leading contributor to global climate change. To slow the increase, reductions in anthropogenic CO(2) emissions are necessary. Large emission point sources, such as fossil-fuel-based power generation facilities, are the first targets for these reductions. A benchmark, mature technology for the separation of dilute CO(2) from gas streams is via absorption with aqueous amines. However, the use of solid adsorbents is now being widely considered as an alternative, potentially less-energy-intensive separation technology. This Review describes the CO(2) adsorption behavior of several different classes of solid carbon dioxide adsorbents, including zeolites, activated carbons, calcium oxides, hydrotalcites, organic-inorganic hybrids, and metal-organic frameworks. These adsorbents are evaluated in terms of their equilibrium CO(2) capacities as well as other important parameters such as adsorption-desorption kinetics, operating windows, stability, and regenerability. The scope of currently available CO(2) adsorbents and their critical properties that will ultimately affect their incorporation into large-scale separation processes is presented.

@article{doi101002cssc200900036,
    author = "Choi, Sunho and Drese, Jeffrey H. and Jones, Christopher W.",
    title = "Adsorbent Materials for Carbon Dioxide Capture from Large Anthropogenic Point Sources",
    year = "2009",
    journal = "ChemSusChem",
    abstract = "Since the time of the industrial revolution, the atmospheric CO(2) concentration has risen by nearly 35 \% to its current level of 383 ppm. The increased carbon dioxide concentration in the atmosphere has been suggested to be a leading contributor to global climate change. To slow the increase, reductions in anthropogenic CO(2) emissions are necessary. Large emission point sources, such as fossil-fuel-based power generation facilities, are the first targets for these reductions. A benchmark, mature technology for the separation of dilute CO(2) from gas streams is via absorption with aqueous amines. However, the use of solid adsorbents is now being widely considered as an alternative, potentially less-energy-intensive separation technology. This Review describes the CO(2) adsorption behavior of several different classes of solid carbon dioxide adsorbents, including zeolites, activated carbons, calcium oxides, hydrotalcites, organic-inorganic hybrids, and metal-organic frameworks. These adsorbents are evaluated in terms of their equilibrium CO(2) capacities as well as other important parameters such as adsorption-desorption kinetics, operating windows, stability, and regenerability. The scope of currently available CO(2) adsorbents and their critical properties that will ultimately affect their incorporation into large-scale separation processes is presented.",
    url = "https://doi.org/10.1002/cssc.200900036",
    doi = "10.1002/cssc.200900036",
    openalex = "W2104943417"
}

In this paper, three of the leading options for large scale CO2 capture are reviewed from a technical perspective. We consider solvent-based chemisorption techniques, carbonate looping technology, and the so-called oxyfuel process. For each technology option, we give an overview of the technology, listing advantages and disadvantages. Subsequently, a discussion of the level of technological maturity is presented, and we conclude by identifying current gaps in knowledge and suggest areas with significant scope for future work. We then discuss the suitability of using ionic liquids as novel, environmentally benign solvents with which to capture CO2. In addition, we consider alternatives to simply sequestering CO2—we present a discussion on the possibility of recycling captured CO2 and exploiting it as a C1 building block for the sustainable manufacture of polymers, fine chemicals, and liquid fuels. Finally, we present a discussion of relevant systems engineering methodologies in carbon capture system design.

@article{doi101039c004106h,
    author = "MacDowell, Niall and Florin, Nick and Buchard, Antoine and Hallett, Jason P. and Galindo, Amparo and Jackson, George and Adjiman, Claire S. and Williams, Charlotte K. and Shah, Nilay and Fennell, Paul S.",
    title = "An overview of CO2 capture technologies",
    year = "2010",
    journal = "Energy \& Environmental Science",
    abstract = "In this paper, three of the leading options for large scale CO2 capture are reviewed from a technical perspective. We consider solvent-based chemisorption techniques, carbonate looping technology, and the so-called oxyfuel process. For each technology option, we give an overview of the technology, listing advantages and disadvantages. Subsequently, a discussion of the level of technological maturity is presented, and we conclude by identifying current gaps in knowledge and suggest areas with significant scope for future work. We then discuss the suitability of using ionic liquids as novel, environmentally benign solvents with which to capture CO2. In addition, we consider alternatives to simply sequestering CO2—we present a discussion on the possibility of recycling captured CO2 and exploiting it as a C1 building block for the sustainable manufacture of polymers, fine chemicals, and liquid fuels. Finally, we present a discussion of relevant systems engineering methodologies in carbon capture system design.",
    url = "https://doi.org/10.1039/c004106h",
    doi = "10.1039/c004106h",
    openalex = "W2131379134",
    references = "doi1010160378381289803085, doi101016s1750583607000941, doi101021cr068357u, doi101021cr068363q, doi101021es0158861, doi101021ie00104a021, doi101038nature06900, doi101039b804323j, doi101126science1181761, openalexw600445240"
}

Density functional theory calculations explain copper's unique ability to convert CO2 into hydrocarbons, which may open up (photo-)electrochemical routes to fuels.

@article{doi101039c0ee00071j,
    author = "Peterson, Andrew A. and Abild‐Pedersen, Frank and Studt, Felix and Rossmeisl, Jan and Nørskov, Jens K.",
    title = "How copper catalyzes the electroreduction of carbon dioxide into hydrocarbon fuels",
    year = "2010",
    journal = "Energy \& Environmental Science",
    abstract = "Density functional theory calculations explain copper's unique ability to convert CO2 into hydrocarbons, which may open up (photo-)electrochemical routes to fuels.",
    url = "https://doi.org/10.1039/c0ee00071j",
    doi = "10.1039/c0ee00071j",
    openalex = "W2060023027"
}

Our present dependence on fossil fuels means that, as our demand for energy inevitably increases, so do emissions of greenhouse gases, most notably carbon dioxide (CO2). To avoid the obvious consequences on climate change, the concentration of such greenhouse gases in the atmosphere must be stabilized. But, as populations grow and economies develop, future demands now ensure that energy will be one of the defining issues of this century. This unique set of (coupled) challenges also means that science and engineering have a unique opportunity-and a burgeoning challenge-to apply their understanding to provide sustainable energy solutions. Integrated carbon capture and subsequent sequestration is generally advanced as the most promising option to tackle greenhouse gases in the short to medium term. Here, we provide a brief overview of an alternative mid- to long-term option, namely, the capture and conversion of CO2, to produce sustainable, synthetic hydrocarbon or carbonaceous fuels, most notably for transportation purposes. Basically, the approach centres on the concept of the large-scale re-use of CO2 released by human activity to produce synthetic fuels, and how this challenging approach could assume an important role in tackling the issue of global CO2 emissions. We highlight three possible strategies involving CO2 conversion by physico-chemical approaches: sustainable (or renewable) synthetic methanol, syngas production derived from flue gases from coal-, gas- or oil-fired electric power stations, and photochemical production of synthetic fuels. The use of CO2 to synthesize commodity chemicals is covered elsewhere (Arakawa et al. 2001 Chem. Rev. 101, 953-996); this review is focused on the possibilities for the conversion of CO2 to fuels. Although these three prototypical areas differ in their ultimate applications, the underpinning thermodynamic considerations centre on the conversion-and hence the utilization-of CO2. Here, we hope to illustrate that advances in the science and engineering of materials are critical for these new energy technologies, and specific examples are given for all three examples. With sufficient advances, and institutional and political support, such scientific and technological innovations could help to regulate/stabilize the CO2 levels in the atmosphere and thereby extend the use of fossil-fuel-derived feedstocks.

@article{doi101098rsta20100119,
    author = "Jiang, Zheng and Xiao, Tiancun and Кузнецов, В. Л. and Edwards, Peter P.",
    title = "Turning carbon dioxide into fuel",
    year = "2010",
    journal = "Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences",
    abstract = "Our present dependence on fossil fuels means that, as our demand for energy inevitably increases, so do emissions of greenhouse gases, most notably carbon dioxide (CO2). To avoid the obvious consequences on climate change, the concentration of such greenhouse gases in the atmosphere must be stabilized. But, as populations grow and economies develop, future demands now ensure that energy will be one of the defining issues of this century. This unique set of (coupled) challenges also means that science and engineering have a unique opportunity-and a burgeoning challenge-to apply their understanding to provide sustainable energy solutions. Integrated carbon capture and subsequent sequestration is generally advanced as the most promising option to tackle greenhouse gases in the short to medium term. Here, we provide a brief overview of an alternative mid- to long-term option, namely, the capture and conversion of CO2, to produce sustainable, synthetic hydrocarbon or carbonaceous fuels, most notably for transportation purposes. Basically, the approach centres on the concept of the large-scale re-use of CO2 released by human activity to produce synthetic fuels, and how this challenging approach could assume an important role in tackling the issue of global CO2 emissions. We highlight three possible strategies involving CO2 conversion by physico-chemical approaches: sustainable (or renewable) synthetic methanol, syngas production derived from flue gases from coal-, gas- or oil-fired electric power stations, and photochemical production of synthetic fuels. The use of CO2 to synthesize commodity chemicals is covered elsewhere (Arakawa et al. 2001 Chem. Rev. 101, 953-996); this review is focused on the possibilities for the conversion of CO2 to fuels. Although these three prototypical areas differ in their ultimate applications, the underpinning thermodynamic considerations centre on the conversion-and hence the utilization-of CO2. Here, we hope to illustrate that advances in the science and engineering of materials are critical for these new energy technologies, and specific examples are given for all three examples. With sufficient advances, and institutional and political support, such scientific and technological innovations could help to regulate/stabilize the CO2 levels in the atmosphere and thereby extend the use of fossil-fuel-derived feedstocks.",
    url = "https://doi.org/10.1098/rsta.2010.0119",
    doi = "10.1098/rsta.2010.0119",
    openalex = "W2091166143",
    references = "doi1012019781315139098"
}

Global warming resulting from the emission of greenhouse gases, especially CO2, has become a widespread concern in the recent years. Though various CO2 capture technologies have been proposed, chemical absorption and adsorption are currently believed to be the most suitable ones for post-combustion power plants. The operation of the chemical absorption process is reviewed in this work, together with the use of absorbents, such as the ionic liquid, alkanolamines and their blended aqueous solutions. The major concerns for this technology, including CO2 capture efficiency, absorption rate, energy required in regeneration, and volume of absorber, are addressed. For adsorption, in addition to physical adsorbents, various mesoporous solid adsorbents impregnated with polyamines and grafted with aminosilanes are reviewed in this work. The major concerns for selection of adsorbent, including cost, adsorption rate, CO2 adsorption capacity, and thermal stability, are compared and discussed. More effective and less energy-consuming regeneration techniques for CO2-loaded adsorbents are also proposed. Future works for both absorption and adsorption are suggested.

@article{doi104209aaqr2012050132,
    author = "Yu, Cheng‐Hsiu and Huang, Chih‐Hung and Tan, Chung‐Sung",
    title = "A Review of CO2 Capture by Absorption and Adsorption",
    year = "2012",
    journal = "Aerosol and Air Quality Research",
    abstract = "Global warming resulting from the emission of greenhouse gases, especially CO2, has become a widespread concern in the recent years. Though various CO2 capture technologies have been proposed, chemical absorption and adsorption are currently believed to be the most suitable ones for post-combustion power plants. The operation of the chemical absorption process is reviewed in this work, together with the use of absorbents, such as the ionic liquid, alkanolamines and their blended aqueous solutions. The major concerns for this technology, including CO2 capture efficiency, absorption rate, energy required in regeneration, and volume of absorber, are addressed. For adsorption, in addition to physical adsorbents, various mesoporous solid adsorbents impregnated with polyamines and grafted with aminosilanes are reviewed in this work. The major concerns for selection of adsorbent, including cost, adsorption rate, CO2 adsorption capacity, and thermal stability, are compared and discussed. More effective and less energy-consuming regeneration techniques for CO2-loaded adsorbents are also proposed. Future works for both absorption and adsorption are suggested.",
    url = "https://doi.org/10.4209/aaqr.2012.05.0132",
    doi = "10.4209/aaqr.2012.05.0132",
    openalex = "W2144754980",
    references = "doi101002anie201000431, doi101002cssc200900036, doi101016jccr201102012, doi101021ja017593d, doi101021ja0570032, doi101039b802426j, doi101126science1152516, doi101126science1172246, doi101126science1176731, doi101126science1192160"
}

Abstract Black carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black‐carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom‐up inventory methods are 7500 Gg yr −1 in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial‐era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W m −2 with 90% uncertainty bounds of (+0.08, +1.27) W m −2. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W m −2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial‐era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W m −2 with 90% uncertainty bounds of +0.17 to +2.1 W m −2. Thus, there is a very high probability that black carbon emissions, independent of co‐emitted species, have a positive forcing and warm the climate. We estimate that black carbon, with a total climate forcing of +1.1 W m −2, is the second most important human emission in terms of its climate forcing in the present‐day atmosphere; only carbon dioxide is estimated to have a greater forcing. Sources that emit black carbon also emit other short‐lived species that may either cool or warm climate. Climate forcings from co‐emitted species are estimated and used in the framework described herein. When the principal effects of short‐lived co‐emissions, including cooling agents such as sulfur dioxide, are included in net forcing, energy‐related sources (fossil fuel and biofuel) have an industrial‐era climate forcing of +0.22 (−0.50 to +1.08) W m −2 during the first year after emission. For a few of these sources, such as diesel engines and possibly residential biofuels, warming is strong enough that eliminating all short‐lived emissions from these sources would reduce net climate forcing (i.e., produce cooling). When open burning emissions, which emit high levels of organic matter, are included in the total, the best estimate of net industrial‐era climate forcing by all short‐lived species from black‐carbon‐rich sources becomes slightly negative (−0.06 W m −2 with 90% uncertainty bounds of −1.45 to +1.29 W m −2). The uncertainties in net climate forcing from black‐carbon‐rich sources are substantial, largely due to lack of knowledge about cloud interactions with both black carbon and co‐emitted organic carbon. In prioritizing potential black‐carbon mitigation actions, non‐science factors, such as technical feasibility, costs, policy design, and implementation feasibility play important roles. The major sources of black carbon are presently in different stages with regard to the feasibility for near‐term mitigation. This assessment, by evaluating the large number and complexity of the associated physical and radiative processes in black‐carbon climate forcing, sets a baseline from which to improve future climate forcing estimates.

@article{doi101002jgrd50171,
    author = "Bond, Tami C. and Doherty, Sarah J. and Fahey, D. W. and Forster, Piers and Berntsen, Terje K. and DeAngelo, B. J. and Flanner, M. and Ghan, S. J. and Kärcher, B. and Koch, D. and Kinne, S. and Kondo, Y. and Quinn, Patricia K. and Sarofim, Marcus C. and Schultz, Martin G. and Schulz, Michael and Venkataraman, Chandra and Zhang, H. and Zhang, Xiaofeng and Bellouin, Nicolas and Guttikunda, Sarath and Hopke, Philip K. and Jacobson, Mark Z. and Kaiser, Johannes W. and Klimont, Zbigniew and Lohmann, Ulrike and Schwarz, J. P. and Shindell, Drew and Storelvmo, Trude and Warren, Stephen G. and Zender, Charles S.",
    title = "Bounding the role of black carbon in the climate system: A scientific assessment",
    year = "2013",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "Abstract Black carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black‐carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom‐up inventory methods are 7500 Gg yr −1 in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial‐era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W m −2 with 90\% uncertainty bounds of (+0.08, +1.27) W m −2. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W m −2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial‐era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W m −2 with 90\% uncertainty bounds of +0.17 to +2.1 W m −2. Thus, there is a very high probability that black carbon emissions, independent of co‐emitted species, have a positive forcing and warm the climate. We estimate that black carbon, with a total climate forcing of +1.1 W m −2, is the second most important human emission in terms of its climate forcing in the present‐day atmosphere; only carbon dioxide is estimated to have a greater forcing. Sources that emit black carbon also emit other short‐lived species that may either cool or warm climate. Climate forcings from co‐emitted species are estimated and used in the framework described herein. When the principal effects of short‐lived co‐emissions, including cooling agents such as sulfur dioxide, are included in net forcing, energy‐related sources (fossil fuel and biofuel) have an industrial‐era climate forcing of +0.22 (−0.50 to +1.08) W m −2 during the first year after emission. For a few of these sources, such as diesel engines and possibly residential biofuels, warming is strong enough that eliminating all short‐lived emissions from these sources would reduce net climate forcing (i.e., produce cooling). When open burning emissions, which emit high levels of organic matter, are included in the total, the best estimate of net industrial‐era climate forcing by all short‐lived species from black‐carbon‐rich sources becomes slightly negative (−0.06 W m −2 with 90\% uncertainty bounds of −1.45 to +1.29 W m −2). The uncertainties in net climate forcing from black‐carbon‐rich sources are substantial, largely due to lack of knowledge about cloud interactions with both black carbon and co‐emitted organic carbon. In prioritizing potential black‐carbon mitigation actions, non‐science factors, such as technical feasibility, costs, policy design, and implementation feasibility play important roles. The major sources of black carbon are presently in different stages with regard to the feasibility for near‐term mitigation. This assessment, by evaluating the large number and complexity of the associated physical and radiative processes in black‐carbon climate forcing, sets a baseline from which to improve future climate forcing estimates.",
    url = "https://doi.org/10.1002/jgrd.50171",
    doi = "10.1002/jgrd.50171",
    openalex = "W1907369419",
    references = "doi1010160960168693901047, doi101016s0169743996000445, doi1010292005jd006653, doi10102993jd02916, doi101038nature08823, doi101126science22246301283, doi105194acp10117072010, doi105194acp119312011, openalexw2907110490, openalexw2939474406, openalexw617039848"
}

@article{doi101038nature11893,
    author = "Nugent, Patrick and Belmabkhout, Youssef and Burd, Stephen and Cairns, Amy and Luebke, Ryan and Forrest, Katherine A. and Pham, Tony and Ma, Shengqian and Space, Brian and Wojtas, Łukasz and Eddaoudi, Mohamed and Zaworotko, Michael J.",
    title = "Porous materials with optimal adsorption thermodynamics and kinetics for CO2 separation",
    year = "2013",
    journal = "Nature",
    url = "https://doi.org/10.1038/nature11893",
    doi = "10.1038/nature11893",
    openalex = "W2062904068",
    references = "doi101002aic690110125, doi101002anie200300610, doi101021cr2003272, doi101021cr9900432, doi101021ja3055639, doi101021ja8036096, doi101021la800227x, doi10103846248, doi101038nature01650, doi101126science1067208"
}

This paper reviews recent progress made in identifying electrocatalysts for carbon dioxide (CO2) reduction to produce low-carbon fuels, including CO, HCOOH/HCOO(-), CH2O, CH4, H2C2O4/HC2O4(-), C2H4, CH3OH, CH3CH2OH and others. The electrocatalysts are classified into several categories, including metals, metal alloys, metal oxides, metal complexes, polymers/clusters, enzymes and organic molecules. The catalyts' activity, product selectivity, Faradaic efficiency, catalytic stability and reduction mechanisms during CO2 electroreduction have received detailed treatment. In particular, we review the effects of electrode potential, solution-electrolyte type and composition, temperature, pressure, and other conditions on these catalyst properties. The challenges in achieving highly active and stable CO2 reduction electrocatalysts are analyzed, and several research directions for practical applications are proposed, with the aim of mitigating performance degradation, overcoming additional challenges, and facilitating research and development in this area.

@article{doi101039c3cs60323g,
    author = "Qiao, Jinli and Liu, Yuyu and Hong, Feng and Zhang, Jiujun",
    title = "A review of catalysts for the electroreduction of carbon dioxide to produce low-carbon fuels",
    year = "2013",
    journal = "Chemical Society Reviews",
    abstract = "This paper reviews recent progress made in identifying electrocatalysts for carbon dioxide (CO2) reduction to produce low-carbon fuels, including CO, HCOOH/HCOO(-), CH2O, CH4, H2C2O4/HC2O4(-), C2H4, CH3OH, CH3CH2OH and others. The electrocatalysts are classified into several categories, including metals, metal alloys, metal oxides, metal complexes, polymers/clusters, enzymes and organic molecules. The catalyts' activity, product selectivity, Faradaic efficiency, catalytic stability and reduction mechanisms during CO2 electroreduction have received detailed treatment. In particular, we review the effects of electrode potential, solution-electrolyte type and composition, temperature, pressure, and other conditions on these catalyst properties. The challenges in achieving highly active and stable CO2 reduction electrocatalysts are analyzed, and several research directions for practical applications are proposed, with the aim of mitigating performance degradation, overcoming additional challenges, and facilitating research and development in this area.",
    url = "https://doi.org/10.1039/c3cs60323g",
    doi = "10.1039/c3cs60323g",
    openalex = "W1992591486",
    references = "doi101039c2cs35360a"
}

In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO2 from reaching the atmosphere. Gas, coal (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO2 capture technologies, available in the short and long term, and their technological maturity, before discussing CO2 transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO2 from the air and CO2 reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.

@article{doi101039c3ee42350f,
    author = "Boot-Handford, Matthew E. and Abánades, J.C. and Anthony, Edward J. and Blunt, Martin J. and Brandani, Stefano and Dowell, Niall Mac and Fernández, José Ramón and Ferrari, Maria‐Chiara and Gross, Robert and Hallett, Jason P. and Haszeldine, R. Stuart and Heptonstall, Philip and Lyngfelt, Anders and Makuch, Zen and Mangano, Enzo and Porter, Richard and Pourkashanian, Mohamed and Rochelle, Gary T. and Shah, Nilay and Yao, Joseph G. and Fennell, Paul S.",
    title = "Carbon capture and storage update",
    year = "2013",
    journal = "Energy \& Environmental Science",
    abstract = "In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO2 from reaching the atmosphere. Gas, coal (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO2 capture technologies, available in the short and long term, and their technological maturity, before discussing CO2 transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO2 from the air and CO2 reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.",
    url = "https://doi.org/10.1039/c3ee42350f",
    doi = "10.1039/c3ee42350f",
    openalex = "W2156157987",
    references = "doi101016jpecs200507001, doi101039c004106h"
}

Starting with coal, followed by petroleum oil and natural gas, the utilization of fossil fuels has allowed the fast and unprecedented development of human society. However, the burning of these resources in ever increasing pace is accompanied by large amounts of anthropogenic CO2 emissions, which are outpacing the natural carbon cycle, causing adverse global environmental changes, the full extent of which is still unclear. Even through fossil fuels are still abundant, they are nevertheless limited and will, in time, be depleted. Chemical recycling of CO2 to renewable fuels and materials, primarily methanol, offers a powerful alternative to tackle both issues, that is, global climate change and fossil fuel depletion. The energy needed for the reduction of CO2 can come from any renewable energy source such as solar and wind. Methanol, the simplest C1 liquid product that can be easily obtained from any carbon source, including biomass and CO2, has been proposed as a key component of such an anthropogenic carbon cycle in the framework of a "Methanol Economy". Methanol itself is an excellent fuel for internal combustion engines, fuel cells, stoves, etc. It's dehydration product, dimethyl ether, is a diesel fuel and liquefied petroleum gas (LPG) substitute. Furthermore, methanol can be transformed to ethylene, propylene and most of the petrochemical products currently obtained from fossil fuels. The conversion of CO2 to methanol is discussed in detail in this review.

@article{doi101039c4cs00122b,
    author = "Goeppert, Alain and Czaun, Miklós and Jones, John‐Paul and Prakash, G. K. Surya and Olah, George A.",
    title = "Recycling of carbon dioxide to methanol and derived products – closing the loop",
    year = "2014",
    journal = "Chemical Society Reviews",
    abstract = {Starting with coal, followed by petroleum oil and natural gas, the utilization of fossil fuels has allowed the fast and unprecedented development of human society. However, the burning of these resources in ever increasing pace is accompanied by large amounts of anthropogenic CO2 emissions, which are outpacing the natural carbon cycle, causing adverse global environmental changes, the full extent of which is still unclear. Even through fossil fuels are still abundant, they are nevertheless limited and will, in time, be depleted. Chemical recycling of CO2 to renewable fuels and materials, primarily methanol, offers a powerful alternative to tackle both issues, that is, global climate change and fossil fuel depletion. The energy needed for the reduction of CO2 can come from any renewable energy source such as solar and wind. Methanol, the simplest C1 liquid product that can be easily obtained from any carbon source, including biomass and CO2, has been proposed as a key component of such an anthropogenic carbon cycle in the framework of a "Methanol Economy". Methanol itself is an excellent fuel for internal combustion engines, fuel cells, stoves, etc. It's dehydration product, dimethyl ether, is a diesel fuel and liquefied petroleum gas (LPG) substitute. Furthermore, methanol can be transformed to ethylene, propylene and most of the petrochemical products currently obtained from fossil fuels. The conversion of CO2 to methanol is discussed in detail in this review.},
    url = "https://doi.org/10.1039/c4cs00122b",
    doi = "10.1039/c4cs00122b",
    openalex = "W2051796629",
    references = "doi101039c004106h, openalexw1573748297"
}

Abstract. Soils and other unconsolidated deposits in the northern circumpolar permafrost region store large amounts of soil organic carbon (SOC). This SOC is potentially vulnerable to remobilization following soil warming and permafrost thaw, but SOC stock estimates were poorly constrained and quantitative error estimates were lacking. This study presents revised estimates of permafrost SOC stocks, including quantitative uncertainty estimates, in the 0–3 m depth range in soils as well as for sediments deeper than 3 m in deltaic deposits of major rivers and in the Yedoma region of Siberia and Alaska. Revised estimates are based on significantly larger databases compared to previous studies. Despite this there is evidence of significant remaining regional data gaps. Estimates remain particularly poorly constrained for soils in the High Arctic region and physiographic regions with thin sedimentary overburden (mountains, highlands and plateaus) as well as for deposits below 3 m depth in deltas and the Yedoma region. While some components of the revised SOC stocks are similar in magnitude to those previously reported for this region, there are substantial differences in other components, including the fraction of perennially frozen SOC. Upscaled based on regional soil maps, estimated permafrost region SOC stocks are 217 ± 12 and 472 ± 27 Pg for the 0–0.3 and 0–1 m soil depths, respectively (±95% confidence intervals). Storage of SOC in 0–3 m of soils is estimated to 1035 ± 150 Pg. Of this, 34 ± 16 Pg C is stored in poorly developed soils of the High Arctic. Based on generalized calculations, storage of SOC below 3 m of surface soils in deltaic alluvium of major Arctic rivers is estimated as 91 ± 52 Pg. In the Yedoma region, estimated SOC stocks below 3 m depth are 181 ± 54 Pg, of which 74 ± 20 Pg is stored in intact Yedoma (late Pleistocene ice- and organic-rich silty sediments) with the remainder in refrozen thermokarst deposits. Total estimated SOC storage for the permafrost region is ∼1300 Pg with an uncertainty range of ∼1100 to 1500 Pg. Of this, ∼500 Pg is in non-permafrost soils, seasonally thawed in the active layer or in deeper taliks, while ∼800 Pg is perennially frozen. This represents a substantial ∼300 Pg lowering of the estimated perennially frozen SOC stock compared to previous estimates.

@article{doi105194bg1165732014,
    author = "Hugelius, Gustaf and Strauß, Jens and Zubrzycki, Sebastian and Harden, J. W. and Schuur, Edward A. G. and Ping, Chien‐Lu and Schirrmeister, Lutz and Grosse, Guido and Michaelson, G. J. and Koven, Charles D. and O’Donnell, Jonathan A. and Elberling, Bo and Mishra, Umakant and Camill, Philip and Yu, Zicheng and Palmtag, Juri and Kuhry, Peter",
    title = "Estimated stocks of circumpolar permafrost carbon with quantified uncertainty ranges and identified data gaps",
    year = "2014",
    journal = "Biogeosciences",
    abstract = "Abstract. Soils and other unconsolidated deposits in the northern circumpolar permafrost region store large amounts of soil organic carbon (SOC). This SOC is potentially vulnerable to remobilization following soil warming and permafrost thaw, but SOC stock estimates were poorly constrained and quantitative error estimates were lacking. This study presents revised estimates of permafrost SOC stocks, including quantitative uncertainty estimates, in the 0–3 m depth range in soils as well as for sediments deeper than 3 m in deltaic deposits of major rivers and in the Yedoma region of Siberia and Alaska. Revised estimates are based on significantly larger databases compared to previous studies. Despite this there is evidence of significant remaining regional data gaps. Estimates remain particularly poorly constrained for soils in the High Arctic region and physiographic regions with thin sedimentary overburden (mountains, highlands and plateaus) as well as for deposits below 3 m depth in deltas and the Yedoma region. While some components of the revised SOC stocks are similar in magnitude to those previously reported for this region, there are substantial differences in other components, including the fraction of perennially frozen SOC. Upscaled based on regional soil maps, estimated permafrost region SOC stocks are 217 ± 12 and 472 ± 27 Pg for the 0–0.3 and 0–1 m soil depths, respectively (±95\% confidence intervals). Storage of SOC in 0–3 m of soils is estimated to 1035 ± 150 Pg. Of this, 34 ± 16 Pg C is stored in poorly developed soils of the High Arctic. Based on generalized calculations, storage of SOC below 3 m of surface soils in deltaic alluvium of major Arctic rivers is estimated as 91 ± 52 Pg. In the Yedoma region, estimated SOC stocks below 3 m depth are 181 ± 54 Pg, of which 74 ± 20 Pg is stored in intact Yedoma (late Pleistocene ice- and organic-rich silty sediments) with the remainder in refrozen thermokarst deposits. Total estimated SOC storage for the permafrost region is ∼1300 Pg with an uncertainty range of ∼1100 to 1500 Pg. Of this, ∼500 Pg is in non-permafrost soils, seasonally thawed in the active layer or in deeper taliks, while ∼800 Pg is perennially frozen. This represents a substantial ∼300 Pg lowering of the estimated perennially frozen SOC stock compared to previous estimates.",
    url = "https://doi.org/10.5194/bg-11-6573-2014",
    doi = "10.5194/bg-11-6573-2014",
    openalex = "W2098627306",
    references = "doi1010292006gl027484, doi1010292008gb003327, doi101146annurevearth35031306140057, doi101641b580807, openalexw2183707334"
}

@misc{canadell2016fossil,
    author = "Canadell, Pep and Peters, Glen and Jackson, Rob and Quéré, Corinne",
    title = "Fossil fuel emissions have stalled: Global Carbon Budget 2016",
    year = "2016",
    url = "https://doi.org/10.64628/aa.a35hdgvhk",
    doi = "10.64628/aa.a35hdgvhk",
    openalex = "W4413718775"
}

@misc{crossref2016the,
    title = "The Origin of Birds",
    year = "2016",
    booktitle = "Avian Evolution",
    url = "https://doi.org/10.1002/9781119020677.ch2",
    doi = "10.1002/9781119020677.ch2",
    pages = "18-42"
}

CO 2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chemicals and even to specialty products with biological activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined analysis of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochemical value chain. This analysis and discussion differs significantly from a viewpoint on CO 2 utilization as a measure for global CO 2 mitigation. Whereas the latter focuses on reducing the end-of-pipe problem "CO 2 emissions" from todays' industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future production. Thus, the motivation to develop CO 2 -based chemistry does not depend primarily on the absolute amount of CO 2 emissions that can be remediated by a single technology. Rather, CO 2 -based chemistry is stimulated by the significance of the relative improvement in carbon balance and other critical factors defining the environmental impact of chemical production in all relevant sectors in accord with the principles of green chemistry.

@article{doi101021acschemrev7b00435,
    author = "Artz, Jens and Müller, Thomas E. and Thenert, Katharina and Kleinekorte, Johanna and Meys, Raoul and Sternberg, André and Bardow, André and Leitner, Walter",
    title = "Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment",
    year = "2017",
    journal = "Chemical Reviews",
    abstract = {CO 2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chemicals and even to specialty products with biological activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined analysis of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochemical value chain. This analysis and discussion differs significantly from a viewpoint on CO 2 utilization as a measure for global CO 2 mitigation. Whereas the latter focuses on reducing the end-of-pipe problem "CO 2 emissions" from todays' industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future production. Thus, the motivation to develop CO 2 -based chemistry does not depend primarily on the absolute amount of CO 2 emissions that can be remediated by a single technology. Rather, CO 2 -based chemistry is stimulated by the significance of the relative improvement in carbon balance and other critical factors defining the environmental impact of chemical production in all relevant sectors in accord with the principles of green chemistry.},
    url = "https://doi.org/10.1021/acs.chemrev.7b00435",
    doi = "10.1021/acs.chemrev.7b00435",
    openalex = "W2771222095",
    references = "doi101038nrmicro1931, doi101039c004106h"
}

We describe a process for capturing CO2 from the atmosphere in an industrial plant. The design captures ∼1 Mt-CO2/year in a continuous process using an aqueous KOH sorbent coupled to a calcium caustic recovery loop. We describe the design rationale, summarize performance of the major unit operations, and provide a capital cost breakdown developed with an independent consulting engineering firm. We report results from a pilot plant that provides data on performance of the major unit operations. We summarize the energy and material balance computed using an Aspen process simulation. When CO2 is delivered at 15 MPa, the design requires either 8.81 GJ of natural gas, or 5.25 GJ of gas and 366 kWhr of electricity, per ton of CO2 captured. Depending on financial assumptions, energy costs, and the specific choice of inputs and outputs, the levelized cost per ton CO2 captured from the atmosphere ranges from 94 to 232 $/t-CO2.

@article{doi101016jjoule201805006,
    author = "Keith, David W. and Holmes, Geoffrey and Angelo, David St. and Heidel, Kenton",
    title = "A Process for Capturing CO2 from the Atmosphere",
    year = "2018",
    journal = "Joule",
    abstract = "We describe a process for capturing CO2 from the atmosphere in an industrial plant. The design captures ∼1 Mt-CO2/year in a continuous process using an aqueous KOH sorbent coupled to a calcium caustic recovery loop. We describe the design rationale, summarize performance of the major unit operations, and provide a capital cost breakdown developed with an independent consulting engineering firm. We report results from a pilot plant that provides data on performance of the major unit operations. We summarize the energy and material balance computed using an Aspen process simulation. When CO2 is delivered at 15 MPa, the design requires either 8.81 GJ of natural gas, or 5.25 GJ of gas and 366 kWhr of electricity, per ton of CO2 captured. Depending on financial assumptions, energy costs, and the specific choice of inputs and outputs, the levelized cost per ton CO2 captured from the atmosphere ranges from 94 to 232 $/t-CO2.",
    url = "https://doi.org/10.1016/j.joule.2018.05.006",
    doi = "10.1016/j.joule.2018.05.006",
    openalex = "W2806520197",
    references = "doi1010160009250988851595, doi101016jenpol201603038, doi101021acschemrev6b00173, doi101021es070874m, doi101021es702607w, doi101038nclimate2870, doi101073pnas1012253108, doi101073pnas1108765109, doi101140epjste2009011503, openalexw615468836"
}

@article{doi101038s4156001700788,
    author = "Yang, Hong Bin and Hung, Sung‐Fu and Liu, Song and Yuan, Kaidi and Miao, Shu and Zhang, Liping and Huang, Xiang and Wang, Hsin‐Yi and Cai, Weizheng and Chen, Rong and Gao, Jiajian and Yang, Xiaofeng and Chen, Wei and Huang, Yanqiang and Chen, Hao Ming and Li, Chang Ming and Zhang, Tao and Liu, Bin",
    title = "Atomically dispersed Ni(i) as the active site for electrochemical CO2 reduction",
    year = "2018",
    journal = "Nature Energy",
    url = "https://doi.org/10.1038/s41560-017-0078-8",
    doi = "10.1038/s41560-017-0078-8",
    openalex = "W2790507915",
    references = "doi101016jjelechem200605013, doi101021ja3010978, doi101021jp047349j, doi101038nature16455, doi101038nature19060, doi101038nchem1095, doi101103physrevb5411169, doi101103physrevb591758, doi101103physrevlett773865, doi101126science2855428687"
}

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 and 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 (2008–2017), EFF was 9.4±0.5 GtC yr−1, ELUC 1.5±0.7 GtC yr−1, GATM 4.7±0.02 GtC yr−1, SOCEAN 2.4±0.5 GtC yr−1, and SLAND 3.2±0.8 GtC yr−1, with a budget imbalance BIM of 0.5 GtC yr−1 indicating overestimated emissions and/or underestimated sinks. For the year 2017 alone, the growth in EFF was about 1.6 % and emissions increased to 9.9±0.5 GtC yr−1. Also for 2017, ELUC was 1.4±0.7 GtC yr−1, GATM was 4.6±0.2 GtC yr−1, SOCEAN was 2.5±0.5 GtC yr−1, and SLAND was 3.8±0.8 GtC yr−1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 405.0±0.1 ppm averaged over 2017. For 2018, preliminary data for the first 6–9 months indicate a renewed growth in EFF of +2.7 % (range of 1.8 % to 3.7 %) based on national emission projections for China, the US, 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. The analysis presented here shows that the mean and trend in the five components of the global carbon budget are consistently estimated over the period of 1959–2017, 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 show (1) no consensus in the mean and trend in land-use change emissions, (2) a persistent low agreement among 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, originating 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 the global carbon cycle compared with previous publications of this data set (Le Quéré et al., 2018, 2016, 2015a, b, 2014, 2013). All results presented here can be downloaded from https://doi.org/10.18160/GCP-2018.

@article{doi105194essd1021412018,
    author = "Quéré, Corinne Le and Andrew, Robbie M. and Friedlingstein, Pierre and Sitch, Stephen and Hauck, Judith and Pongratz, Julia and Pickers, Penelope A. and Korsbakken, Jan Ivar and Peters, Glen P. and Canadell, Josep G. and Arneth, Almut and Arora, Vivek K. and Barbero, Leticia and Bastos, Ana and Bopp, Laurent and Chevallier, Frédéric and Chini, Louise and Ciais, Philippe and Doney, Scott C. and Gkritzalis, Thanos and Goll, Daniel S. and Harris, Ian and Haverd, Vanessa and Hoffman, Forrest M. and Hoppema, Mario and Houghton, R. A. and Hurtt, G. C. and Ilyina, Tatiana and Jain, Atul K. and Johannessen, Truls and Jones, Chris and Kato, Etsushi and Keeling, Ralph F. and Goldewijk, Kees Klein and Landschützer, Peter and Lefèvre, Nathalie and Lienert, Sebastian and Liu, Zhu and Lombardozzi, Danica and Metzl, Nicolas and Munro, David R. and Nabel, Julia E. M. S. and Nakaoka, Shin‐Ichiro and Neill, Craig and Olsen, Are and Ono, Tsueno and Patra, Prabir K. and Peregon, Anna and Peters, Wouter and Peylin, Philippe and Pfeil, Benjamin and Pierrot, Denis and Poulter, Benjamin and Rehder, Gregor and Resplandy, Laure and Robertson, Eddy and Rocher, Matthias and Rödenbeck, Christian and Schuster, Ute and Schwinger, Jörg and Séférian, Roland and Skjelvan, Ingunn and Steinhoff, Tobias and Sutton, Adrienne J. and Tans, Pieter P. and Tian, Hanqin and Tilbrook, Bronte and Tubiello, Francesco N. and Luijkx, Ingrid T. and van der Werf, Guido R. and Viovy, Nicolas and Walker, Anthony P. and Wiltshire, A. and Wright, Rebecca and Zaehle, Sönke and Zheng, Bo",
    title = "Global Carbon Budget 2018",
    year = "2018",
    journal = "Earth system science data",
    abstract = "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 and 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 (2008–2017), EFF was 9.4±0.5 GtC yr−1, ELUC 1.5±0.7 GtC yr−1, GATM 4.7±0.02 GtC yr−1, SOCEAN 2.4±0.5 GtC yr−1, and SLAND 3.2±0.8 GtC yr−1, with a budget imbalance BIM of 0.5 GtC yr−1 indicating overestimated emissions and/or underestimated sinks. For the year 2017 alone, the growth in EFF was about 1.6 \% and emissions increased to 9.9±0.5 GtC yr−1. Also for 2017, ELUC was 1.4±0.7 GtC yr−1, GATM was 4.6±0.2 GtC yr−1, SOCEAN was 2.5±0.5 GtC yr−1, and SLAND was 3.8±0.8 GtC yr−1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 405.0±0.1 ppm averaged over 2017. For 2018, preliminary data for the first 6–9 months indicate a renewed growth in EFF of +2.7 \% (range of 1.8 \% to 3.7 \%) based on national emission projections for China, the US, 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. The analysis presented here shows that the mean and trend in the five components of the global carbon budget are consistently estimated over the period of 1959–2017, 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 show (1) no consensus in the mean and trend in land-use change emissions, (2) a persistent low agreement among 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, originating 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 the global carbon cycle compared with previous publications of this data set (Le Quéré et al., 2018, 2016, 2015a, b, 2014, 2013). All results presented here can be downloaded from https://doi.org/10.18160/GCP-2018.",
    url = "https://doi.org/10.5194/essd-10-2141-2018",
    doi = "10.5194/essd-10-2141-2018",
    openalex = "W2915336810",
    references = "andres2011monthly, archer2009atmospheric, doi101002joc3711, doi1010292003gb002199, doi101038nature09396, doi101038ngeo1955, doi101038ngeo689, doi101073pnas1019576108, doi102151jmsj2015001, doi1023073324639, doi105194acp10117072010, doi105194bg1066992013, doi105194essd96972017, doi105194essd99272017, myhre2009a"
}

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. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, respectively, while emissions from land-use change (ELUC), mainly deforestation, are based on land-cover change data and bookkeeping models. The global atmospheric CO2 concentration is measured directly and its rate of growth (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 (2007–2016), EFF was 9.4 ± 0.5 GtC yr−1, ELUC 1.3 ± 0.7 GtC yr−1, GATM 4.7 ± 0.1 GtC yr−1, SOCEAN 2.4 ± 0.5 GtC yr−1, and SLAND 3.0 ± 0.8 GtC yr−1, with a budget imbalance BIM of 0.6 GtC yr−1 indicating overestimated emissions and/or underestimated sinks. For year 2016 alone, the growth in EFF was approximately zero and emissions remained at 9.9 ± 0.5 GtC yr−1. Also for 2016, ELUC was 1.3 ± 0.7 GtC yr−1, GATM was 6.1 ± 0.2 GtC yr−1, SOCEAN was 2.6 ± 0.5 GtC yr−1, and SLAND was 2.7 ± 1.0 GtC yr−1, with a small BIM of −0.3 GtC. GATM continued to be higher in 2016 compared to the past decade (2007–2016), reflecting in part the high fossil emissions and the small SLAND consistent with El Niño conditions. The global atmospheric CO2 concentration reached 402.8 ± 0.1 ppm averaged over 2016. For 2017, preliminary data for the first 6–9 months indicate a renewed growth in EFF of +2.0 % (range of 0.8 to 3.0 %) based on national emissions projections for China, USA, and India, and projections of gross domestic product (GDP) corrected for recent changes in the carbon intensity of the economy for the rest of the world. This living data update documents changes in the methods and data sets used in this new global carbon budget compared with previous publications of this data set (Le Quéré et al., 2016, 2015b, a, 2014, 2013). All results presented here can be downloaded from https://doi.org/10.18160/GCP-2017 (GCP, 2017).

@article{doi105194essd104052018,
    author = "Quéré, Corinne Le and Andrew, Robbie M. and Friedlingstein, Pierre and Sitch, Stephen and Pongratz, Julia and Manning, Andrew C. and Korsbakken, Jan Ivar and Peters, Glen P. and Canadell, Josep G. and Jackson, Robert B. and Boden, Thomas A. and Tans, Pieter P. and Andrews, Oliver and Arora, Vivek K. and Bakker, Dorothée C. E. and Barbero, Leticia and Becker, Meike and Betts, Richard and Bopp, Laurent and Chevallier, Frédéric and Chini, Louise and Ciais, Philippe and Cosca, Catherine E and Cross, Jessica and Currie, Kim and Gasser, Thomas and Harris, Ian and Hauck, Judith and Haverd, Vanessa and Houghton, R. A. and Hunt, Christopher W and Hurtt, G. C. and Ilyina, Tatiana and Jain, Atul K. and Kato, Etsushi and Kautz, Markus and Keeling, Ralph F. and Goldewijk, Kees Klein and Körtzinger, Arne and Landschützer, Peter and Lefèvre, Nathalie and Lenton, Andrew and Lienert, Sebastian and Lima, Ivan D. and Lombardozzi, Danica and Metzl, Nicolas and Millero, Frank J. and Monteiro, Pedro M. S. and Munro, David R. and Nabel, Julia E. M. S. and Nakaoka, Shin‐Ichiro and Nojiri, Yukihiro and Padín, X. A. and Peregon, Anna and Pfeil, Benjamin and Pierrot, Denis and Poulter, Benjamin and Rehder, Gregor and Reimer, Janet J. and Rödenbeck, Christian and Schwinger, Jörg and Séférian, Roland and Skjelvan, Ingunn and Stocker, Benjamin D. and Tian, Hanqin and Tilbrook, Bronte and Tubiello, Francesco N. and Luijkx, Ingrid T. and van der Werf, Guido R. and van Heuven, Steven and Viovy, Nicolas and Vuichard, Nicolas and Walker, Anthony P. and Watson, Andrew and Wiltshire, A. and Zaehle, Sönke and Zhu, Dan",
    title = "Global Carbon Budget 2017",
    year = "2018",
    journal = "Earth system science data",
    abstract = "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. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, respectively, while emissions from land-use change (ELUC), mainly deforestation, are based on land-cover change data and bookkeeping models. The global atmospheric CO2 concentration is measured directly and its rate of growth (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 (2007–2016), EFF was 9.4 ± 0.5 GtC yr−1, ELUC 1.3 ± 0.7 GtC yr−1, GATM 4.7 ± 0.1 GtC yr−1, SOCEAN 2.4 ± 0.5 GtC yr−1, and SLAND 3.0 ± 0.8 GtC yr−1, with a budget imbalance BIM of 0.6 GtC yr−1 indicating overestimated emissions and/or underestimated sinks. For year 2016 alone, the growth in EFF was approximately zero and emissions remained at 9.9 ± 0.5 GtC yr−1. Also for 2016, ELUC was 1.3 ± 0.7 GtC yr−1, GATM was 6.1 ± 0.2 GtC yr−1, SOCEAN was 2.6 ± 0.5 GtC yr−1, and SLAND was 2.7 ± 1.0 GtC yr−1, with a small BIM of −0.3 GtC. GATM continued to be higher in 2016 compared to the past decade (2007–2016), reflecting in part the high fossil emissions and the small SLAND consistent with El Niño conditions. The global atmospheric CO2 concentration reached 402.8 ± 0.1 ppm averaged over 2016. For 2017, preliminary data for the first 6–9 months indicate a renewed growth in EFF of +2.0 \% (range of 0.8 to 3.0 \%) based on national emissions projections for China, USA, and India, and projections of gross domestic product (GDP) corrected for recent changes in the carbon intensity of the economy for the rest of the world. This living data update documents changes in the methods and data sets used in this new global carbon budget compared with previous publications of this data set (Le Quéré et al., 2016, 2015b, a, 2014, 2013). All results presented here can be downloaded from https://doi.org/10.18160/GCP-2017 (GCP, 2017).",
    url = "https://doi.org/10.5194/essd-10-405-2018",
    doi = "10.5194/essd-10-405-2018",
    openalex = "W2915841000",
    references = "archer2009atmospheric, myhre2009a"
}

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).

@article{doi105194essd1117832019,
    author = "Friedlingstein, Pierre and Jones, Matthew W. and O’Sullivan, Michael and Andrew, Robbie M. and Hauck, Judith and Peters, Glen P. and Peters, Wouter and Pongratz, Julia and Sitch, Stephen and Quéré, Corinne Le and Bakker, Dorothée C. E. and Canadell, Josep G. and Ciais, Philippe and Jackson, Robert B. and Anthoni, Peter and Barbero, Leticia and Bastos, Ana and Bastrikov, Vladislav and Becker, Meike and Bopp, Laurent and Buitenhuis, Erik T. and Chandra, Naveen and Chevallier, Frédéric and Chini, Louise and Currie, Kim and Feely, Richard A. and Gehlen, Marion and Gilfillan, Dennis and Gkritzalis, Thanos and Goll, Daniel S. and Gruber, Nicolas and Gutekunst, Sören and Harris, Ian and Haverd, Vanessa and Houghton, R. A. and Hurtt, G. C. and Ilyina, Tatiana and Jain, Atul K. and Joetzjer, Émilie and Kaplan, Jed O. and Kato, Etsushi and Goldewijk, Kees Klein and Korsbakken, Jan Ivar and Landschützer, Peter and Lauvset, Siv K. and Lefèvre, Nathalie and Lenton, Andrew and Lienert, Sebastian and Lombardozzi, Danica and Marland, Gregg and McGuire, Patrick and Melton, Joe R. and Metzl, Nicolas and Munro, David R. and Nabel, Julia E. M. S. and Nakaoka, Shin‐Ichiro and Neill, Craig and Omar, Abdirahman M and Ono, Tsuneo and Peregon, Anna and Pierrot, Denis and Poulter, Benjamin and Rehder, Gregor and Resplandy, Laure and Robertson, Eddy and Rödenbeck, Christian and Séférian, Roland and Schwinger, Jörg and Smith, Naomi and Tans, Pieter P. and Tian, Hanqin and Tilbrook, Bronte and Tubiello, Francesco N. and van der Werf, Guido R. and Wiltshire, A. and Zaehle, Sönke",
    title = "Global Carbon Budget 2019",
    year = "2019",
    journal = "Earth system science data",
    abstract = "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).",
    url = "https://doi.org/10.5194/essd-11-1783-2019",
    doi = "10.5194/essd-11-1783-2019",
    openalex = "W2979653715",
    references = "archer2009atmospheric, doi101002joc3711, doi1010292003gb002199, doi101073pnas1019576108, doi101126science1097403, doi101126science1244693, doi102151jmsj2015001, doi1023073324639, doi105194acp10117072010, doi105194bg1066992013, doi105194essd1021412018, doi105194essd1117832019, doi105194essd96972017, myhre2009a, openalexw2883478268"
}

The book considers innovative methods to curtail CO{sub 2} emissions. It collects the latest research and actual applied techniques for reducing carbon dioxide, and utilizing waste CO{sub 2} as a feedstock; outlines newer, more effective ways to separate CO{sub 2} from waste-stream gases; explores the utilization of fossil fuels with reduced CO{sub 2} emissions; and presents up-to-date research into CO{sub 2} capture, and disposal, storage and sequestration of pressurized CO{sub 2} in the ocean and underground aquifers.

@book{openalexw1573748297,
    author = "Halmann, M. and Steinberg, M.",
    title = "Greenhouse Gas Carbon Dioxide Mitigation: Science and Technology",
    year = "2019",
    journal = "Medical Entomology and Zoology",
    abstract = "The book considers innovative methods to curtail CO{sub 2} emissions. It collects the latest research and actual applied techniques for reducing carbon dioxide, and utilizing waste CO{sub 2} as a feedstock; outlines newer, more effective ways to separate CO{sub 2} from waste-stream gases; explores the utilization of fossil fuels with reduced CO{sub 2} emissions; and presents up-to-date research into CO{sub 2} capture, and disposal, storage and sequestration of pressurized CO{sub 2} in the ocean and underground aquifers.",
    openalex = "W1573748297"
}

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).

@article{doi105194essd1232692020,
    author = "Friedlingstein, Pierre and O’Sullivan, Michael and Jones, Matthew W. and Andrew, Robbie M. and Hauck, Judith and Olsen, Are and Peters, Glen P. and Peters, Wouter and Pongratz, Julia and Sitch, Stephen and Quéré, Corinne Le and Canadell, Josep G. and Ciais, Philippe and Jackson, Robert B. and Alin, Simone R. and Aragão, Luiz E. O. C. and Arneth, Almut and Arora, Vivek and Bates, Nicholas R. and Becker, Meike and Benoit-Cattin, Alice and Bittig, Henry C. and Bopp, Laurent and Bultan, Selma and Chandra, Naveen and Chevallier, Frédéric and Chini, Louise and Evans, Wiley and Florentie, Liesbeth and Forster, Piers and Gasser, Thomas and Gehlen, Marion and Gilfillan, Dennis and Gkritzalis, Thanos and Gregor, Luke and Gruber, Nicolas and Harris, Ian and Hartung, Kerstin and Haverd, Vanessa and Houghton, R. A. and Ilyina, Tatiana and Jain, Atul K. and Joetzjer, Émilie and Kadono, Koji and Kato, Etsushi and Kitidis, Vassilis and Korsbakken, Jan Ivar and Landschützer, Peter and Lefèvre, Nathalie and Lenton, Andrew and Lienert, Sebastian and Liu, Zhu and Lombardozzi, Danica and Marland, Gregg and Metzl, Nicolas and Munro, David R. and Nabel, Julia E. M. S. and Nakaoka, Shin‐Ichiro and Niwa, Yosuke and O’Brien, Kevin and Ono, Tsuneo and Palmer, Paul I. and Pierrot, Denis and Poulter, Benjamin and Resplandy, Laure and Robertson, Eddy and Rödenbeck, Christian and Schwinger, Jörg and Séférian, Roland and Skjelvan, Ingunn and Smith, Adam J. P. and Sutton, Adrienne J. and Tanhua, Toste and Tans, Pieter P. and Tian, Hanqin and Tilbrook, Bronte and van der Werf, Guido R. and Vuichard, Nicolas and Walker, Anthony P. and Wanninkhof, Rik and Watson, Andrew and Willis, David and Wiltshire, A. and Yuan, Wenping and Yue, Xu and Zaehle, Sönke",
    title = "Global Carbon Budget 2020",
    year = "2020",
    journal = "Earth system science data",
    abstract = "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).",
    url = "https://doi.org/10.5194/essd-12-3269-2020",
    doi = "10.5194/essd-12-3269-2020",
    openalex = "W3093432062",
    references = "archer2009atmospheric, doi101002joc3711, doi101016jdsr2200812009, doi1010292003gb002199, doi10102992jc00188, doi101038nature25138, doi101038ngeo689, doi101038s41467020189227, doi101038s415580200797x, doi101038s4159702004533, doi101073pnas0700609104, doi101073pnas1019576108, doi101126science1097403, doi101126science1244693, doi1011751520047719960770437tnyrp20co2, doi102151jmsj2015001, doi1023073324639, doi1025607obp1342, doi105194acp10117072010, doi105194essd1021412018, doi105194essd1117832019, doi105194essd119592019, doi105194essd1232692020, doi105194essd96972017, doi105194essd99272017, doi105194gmd919372016, myhre2009a, openalexw2883478268"
}

Global development has been heavily reliant on the overexploitation of natural resources since the Industrial Revolution. With the extensive use of fossil fuels, deforestation, and other forms of land-use change, anthropogenic activities have contributed to the ever-increasing concentrations of greenhouse gases (GHGs) in the atmosphere, causing global climate change. In response to the worsening global climate change, achieving carbon neutrality by 2050 is the most pressing task on the planet. To this end, it is of utmost importance and a significant challenge to reform the current production systems to reduce GHG emissions and promote the capture of CO2 from the atmosphere. Herein, we review innovative technologies that offer solutions achieving carbon (C) neutrality and sustainable development, including those for renewable energy production, food system transformation, waste valorization, C sink conservation, and C-negative manufacturing. The wealth of knowledge disseminated in this review could inspire the global community and drive the further development of innovative technologies to mitigate climate change and sustainably support human activities.

@article{doi101016jxinn2021100180,
    author = "Wang, Fang and Harindintwali, Jean Damascene and Yuan, Zhizhang and Wang, Min and Wang, Faming and Li, Sheng and Yin, Zhigang and Huang, Lei and Fu, Yuhao and Li, Lei and Chang, Scott X. and Zhang, Linjuan and Rinklebe, Jörg and Yuan, Zuoqiang and Zhu, Qinggong and Xiang, Leilei and Tsang, Daniel C.W. and Xu, Liang and Jiang, Xin and Liu, Jihua and Wei, Ning and Kästner, Matthias and Zou, Yang and Ok, Yong Sik and Shen, Jianlin and Peng, Dailiang and Zhang, Wei and Barceló, ‪Damià and Zhou, Yongjin J. and Bai, Zhaohai and Li, Boqiang and Zhang, Bin and Wei, Ke and Cao, Hujun and Tan, Zhiliang and Zhao, Liu‐Bin and He, Xiao and Zheng, Jinxing and Bolan, Nanthi and Liu, Xiaohong and Huang, Changping and Dietmann, Sabine and Luo, Ming and Sun, Nannan and Gong, Jirui and Gong, Yulie and Brahushi, Ferdi and Zhang, Tangtang and Xiao, Cunde and Li, Xianfeng and Chen, Wenfu and Jiao, Nianzhi and Lehmann, Johannes and Zhu, Yong‐Guan and Jin, Hongguang and Schäffer, Andreas and Tiedje, James M. and Chen, Jing M.",
    title = "Technologies and perspectives for achieving carbon neutrality",
    year = "2021",
    journal = "The Innovation",
    abstract = "Global development has been heavily reliant on the overexploitation of natural resources since the Industrial Revolution. With the extensive use of fossil fuels, deforestation, and other forms of land-use change, anthropogenic activities have contributed to the ever-increasing concentrations of greenhouse gases (GHGs) in the atmosphere, causing global climate change. In response to the worsening global climate change, achieving carbon neutrality by 2050 is the most pressing task on the planet. To this end, it is of utmost importance and a significant challenge to reform the current production systems to reduce GHG emissions and promote the capture of CO2 from the atmosphere. Herein, we review innovative technologies that offer solutions achieving carbon (C) neutrality and sustainable development, including those for renewable energy production, food system transformation, waste valorization, C sink conservation, and C-negative manufacturing. The wealth of knowledge disseminated in this review could inspire the global community and drive the further development of innovative technologies to mitigate climate change and sustainably support human activities.",
    url = "https://doi.org/10.1016/j.xinn.2021.100180",
    doi = "10.1016/j.xinn.2021.100180",
    openalex = "W3208259726",
    references = "doi101021acschemrev8b00705, doi101021cr300463y, doi101038s4146702020061y, doi101039d0cs00071j, doi101890110004, doi105194essd1232692020"
}

CHAP 1 - Introduction to the Guide CHAP 2 - Solution chemistry of carbon dioxide in sea water CHAP 3 - Quality assurance CHAP 4 - Recommended standard operating procedures (SOPs) SOP 1 - Water sampling for the parameters of the oceanic carbon dioxide system SOP 2 - Determination of total dissolved inorganic carbon in sea water SOP 3a - Determination of total alkalinity in sea water using a closed-cell titration SOP 3b - Determination of total alkalinity in sea water using an open-cell titration SOP 4 - Determination of p(CO2) in air that is in equilibrium with a discrete sample of sea water SOP 5 - Determination of p(CO2) in air that is in equilibrium with a continuous stream of sea water SOP 6a - Determination of the pH of sea water using a glass/reference electrode cell SOP 6b - Determination of the pH of sea water using the indicator dye m-cresol purple SOP 7 - Determination of dissolved organic carbon and total dissolved nitrogen in sea water SOP 7 en Espanol - Determinacion de carbono organico disuelto y nitrogeno total disuelto en agua de mar SOP 11 - Gravimetric calibration of the volume of a gas loop using water SOP 12 - Gravimetric calibration of volume delivered using water SOP 13 - Gravimetric calibration of volume contained using water SOP 14 - Procedure for preparing sodium carbonate solutions for the calibration of coulometric CT measurements SOP 21 - Applying air buoyancy corrections SOP 22 - Preparation of control charts SOP 23 - Statistical techniques used in quality assessment SOP 24 - Calculation of the fugacity of carbon dioxide in the pure gas or in air CHAP 5 - Physical and thermodynamic data Errata - to the hard copy of the Guide to best practices for ocean CO2 measurements

@book{doi1025607obp1342,
    author = "Dickson, Andrew G. and Sabine, Christopher L.",
    title = "Guide to best practices for ocean CO2 measurement.",
    year = "2021",
    booktitle = "IOC of UNESCO (Intergovernmental Oceanographic Commission)",
    abstract = "CHAP 1 - Introduction to the Guide CHAP 2 - Solution chemistry of carbon dioxide in sea water CHAP 3 - Quality assurance CHAP 4 - Recommended standard operating procedures (SOPs) SOP 1 - Water sampling for the parameters of the oceanic carbon dioxide system SOP 2 - Determination of total dissolved inorganic carbon in sea water SOP 3a - Determination of total alkalinity in sea water using a closed-cell titration SOP 3b - Determination of total alkalinity in sea water using an open-cell titration SOP 4 - Determination of p(CO2) in air that is in equilibrium with a discrete sample of sea water SOP 5 - Determination of p(CO2) in air that is in equilibrium with a continuous stream of sea water SOP 6a - Determination of the pH of sea water using a glass/reference electrode cell SOP 6b - Determination of the pH of sea water using the indicator dye m-cresol purple SOP 7 - Determination of dissolved organic carbon and total dissolved nitrogen in sea water SOP 7 en Espanol - Determinacion de carbono organico disuelto y nitrogeno total disuelto en agua de mar SOP 11 - Gravimetric calibration of the volume of a gas loop using water SOP 12 - Gravimetric calibration of volume delivered using water SOP 13 - Gravimetric calibration of volume contained using water SOP 14 - Procedure for preparing sodium carbonate solutions for the calibration of coulometric CT measurements SOP 21 - Applying air buoyancy corrections SOP 22 - Preparation of control charts SOP 23 - Statistical techniques used in quality assessment SOP 24 - Calculation of the fugacity of carbon dioxide in the pure gas or in air CHAP 5 - Physical and thermodynamic data Errata - to the hard copy of the Guide to best practices for ocean CO2 measurements",
    url = "https://doi.org/10.25607/obp-1342",
    doi = "10.25607/obp-1342",
    openalex = "W1501374473"
}

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize datasets 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) is estimated with global ocean biogeochemistry models and observation-based data products. The terrestrial CO2 sink (SLAND) is estimated with dynamic global vegetation models. 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 first time, an approach is shown to reconcile the difference in our ELUC estimate with the one from national greenhouse gas inventories, supporting the assessment of collective countries' climate progress. For the year 2020, EFOS declined by 5.4 % relative to 2019, with fossil emissions at 9.5 ± 0.5 GtC yr−1 (9.3 ± 0.5 GtC yr−1 when the cement carbonation sink is included), and ELUC was 0.9 ± 0.7 GtC yr−1, for a total anthropogenic CO2 emission of 10.2 ± 0.8 GtC yr−1 (37.4 ± 2.9 GtCO2). Also, for 2020, GATM was 5.0 ± 0.2 GtC yr−1 (2.4 ± 0.1 ppm yr−1), SOCEAN was 3.0 ± 0.4 GtC yr−1, and SLAND was 2.9 ± 1 GtC yr−1, with a BIM of −0.8 GtC yr−1. The global atmospheric CO2 concentration averaged over 2020 reached 412.45 ± 0.1 ppm. Preliminary data for 2021 suggest a rebound in EFOS relative to 2020 of +4.8 % (4.2 % to 5.4 %) globally. Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2020, but discrepancies of up to 1 GtC yr−1 persist for the representation of annual to semi-decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows (1) a persistent large uncertainty in the estimate of land-use changes emissions, (2) a low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) a discrepancy between the different methods on the strength of the ocean sink over the last decade. This living data update documents changes in the methods and datasets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this dataset (Friedlingstein et al., 2020, 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-2021 (Friedlingstein et al., 2021).

@article{doi105194essd1419172022,
    author = "Friedlingstein, Pierre and Jones, Matthew W. and O’Sullivan, Michael and Andrew, Robbie M. and Bakker, Dorothée C. E. and Hauck, Judith and Quéré, Corinne Le and Peters, Glen P. and Peters, Wouter and Pongratz, Julia and Sitch, Stephen and Canadell, Josep G. and Ciais, Philippe and Jackson, Robert B. and Alin, Simone R. and Anthoni, Peter and Bates, Nicholas R. and Becker, Meike and Bellouin, Nicolas and Bopp, Laurent and Chau, Thi Tuyet Trang and Chevallier, Frédéric and Chini, Louise and Cronin, Margot and Currie, Kim and Decharme, Bertrand and Djeutchouang, Laique and Dou, Xinyu and Evans, Wiley and Feely, Richard A. and Feng, Liang and Gasser, Thomas and Gilfillan, Dennis and Gkritzalis, Thanos and Grassi, Giacomo and Gregor, Luke and Gruber, Nicolas and Gürses, Özgür and Harris, Ian and Houghton, R. A. and Hurtt, G. C. and Iida, Yosuke and Ilyina, Tatiana and Luijkx, Ingrid T. and Jain, Atul K. and Jones, S. D. M. and Kato, Etsushi and Kennedy, Daniel and Goldewijk, Kees Klein and Knauer, Jürgen and Korsbakken, Jan Ivar and Körtzinger, Arne and Landschützer, Peter and Lauvset, Siv K. and Lefèvre, Nathalie and Lienert, Sebastian and Liu, Junjie and Marland, Gregg and McGuire, Patrick and Melton, Joe R. and Munro, David R. and Nabel, Julia E. M. S. and Nakaoka, Shin‐Ichiro and Niwa, Yosuke and Ono, Tsuneo and Pierrot, Denis and Poulter, Benjamin and Rehder, Gregor and Resplandy, Laure and Robertson, Eddy and Rödenbeck, Christian and Rosan, Thais M. and Schwinger, Jörg and Schwingshackl, Clemens and Séférian, Roland and Sutton, Adrienne J. and Sweeney, Colm and Tanhua, Toste and Tans, Pieter P. and Tian, Hanqin and Tilbrook, Bronte and Tubiello, Francesco N. and van der Werf, Guido R. and Vuichard, Nicolas and Wada, Chisato and Wanninkhof, Rik and Watson, Andrew and Willis, David and Wiltshire, A. and Yuan, Wenping and Yue, Chao and Yue, Xu and Zaehle, Sönke and Zeng, Jiye",
    title = "Global Carbon Budget 2021",
    year = "2022",
    journal = "Earth system science data",
    abstract = "Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize datasets 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) is estimated with global ocean biogeochemistry models and observation-based data products. The terrestrial CO2 sink (SLAND) is estimated with dynamic global vegetation models. 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 first time, an approach is shown to reconcile the difference in our ELUC estimate with the one from national greenhouse gas inventories, supporting the assessment of collective countries' climate progress. For the year 2020, EFOS declined by 5.4 \% relative to 2019, with fossil emissions at 9.5 ± 0.5 GtC yr−1 (9.3 ± 0.5 GtC yr−1 when the cement carbonation sink is included), and ELUC was 0.9 ± 0.7 GtC yr−1, for a total anthropogenic CO2 emission of 10.2 ± 0.8 GtC yr−1 (37.4 ± 2.9 GtCO2). Also, for 2020, GATM was 5.0 ± 0.2 GtC yr−1 (2.4 ± 0.1 ppm yr−1), SOCEAN was 3.0 ± 0.4 GtC yr−1, and SLAND was 2.9 ± 1 GtC yr−1, with a BIM of −0.8 GtC yr−1. The global atmospheric CO2 concentration averaged over 2020 reached 412.45 ± 0.1 ppm. Preliminary data for 2021 suggest a rebound in EFOS relative to 2020 of +4.8 \% (4.2 \% to 5.4 \%) globally. Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2020, but discrepancies of up to 1 GtC yr−1 persist for the representation of annual to semi-decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows (1) a persistent large uncertainty in the estimate of land-use changes emissions, (2) a low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) a discrepancy between the different methods on the strength of the ocean sink over the last decade. This living data update documents changes in the methods and datasets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this dataset (Friedlingstein et al., 2020, 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-2021 (Friedlingstein et al., 2021).",
    url = "https://doi.org/10.5194/essd-14-1917-2022",
    doi = "10.5194/essd-14-1917-2022",
    openalex = "W4225004802",
    references = "archer2009atmospheric, doi101002joc3711, doi1010160016703782901107, doi101016jdsr2200812009, doi1010292003gb002199, doi1010292006gb002784, doi10102992jc00188, doi101038nature14283, doi101038nature25138, doi101038s41467020189227, doi101038s4159702004533, doi101126science1097403, doi101126science1244693, doi102151jmsj2015001, doi1025607obp1342, doi104060ca9825en, doi105194acp10117072010, doi105194essd1021412018, doi105194essd1117832019, doi105194essd119592019, doi105194essd1232692020, doi105194essd1419172022, doi105194essd96972017, doi105194essd99272017, doi105194gmd919372016"
}

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical 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 methodologies 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) is estimated with global ocean biogeochemistry models and observation-based data products. The terrestrial CO2 sink (SLAND) is estimated with dynamic global vegetation models. 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 year 2021, EFOS increased by 5.1 % relative to 2020, with fossil emissions at 10.1 ± 0.5 GtC yr−1 (9.9 ± 0.5 GtC yr−1 when the cement carbonation sink is included), and ELUC was 1.1 ± 0.7 GtC yr−1, for a total anthropogenic CO2 emission (including the cement carbonation sink) of 10.9 ± 0.8 GtC yr−1 (40.0 ± 2.9 GtCO2). Also, for 2021, GATM was 5.2 ± 0.2 GtC yr−1 (2.5 ± 0.1 ppm yr−1), SOCEAN was 2.9 ± 0.4 GtC yr−1, and SLAND was 3.5 ± 0.9 GtC yr−1, with a BIM of −0.6 GtC yr−1 (i.e. the total estimated sources were too low or sinks were too high). The global atmospheric CO2 concentration averaged over 2021 reached 414.71 ± 0.1 ppm. Preliminary data for 2022 suggest an increase in EFOS relative to 2021 of +1.0 % (0.1 % to 1.9 %) globally and atmospheric CO2 concentration reaching 417.2 ppm, more than 50 % above pre-industrial levels (around 278 ppm). Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2021, but discrepancies of up to 1 GtC yr−1 persist for the representation of annual to semi-decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows (1) a persistent large uncertainty in the estimate of land-use change emissions, (2) a low agreement between the different methods on the magnitude of the land CO2 flux in the northern extratropics, and (3) a discrepancy between the different methods on the strength of the ocean sink over the last decade. 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. The data presented in this work are available at https://doi.org/10.18160/GCP-2022 (Friedlingstein et al., 2022b).

@article{doi105194essd1448112022,
    author = "Friedlingstein, Pierre and O’Sullivan, Michael and Jones, Matthew W. and Andrew, Robbie M. and Gregor, Luke and Hauck, Judith and Quéré, Corinne Le and Luijkx, Ingrid T. and Olsen, Are and Peters, Glen P. and Peters, Wouter and Pongratz, Julia and Schwingshackl, Clemens and Sitch, Stephen and Canadell, Josep G. and Ciais, Philippe and Jackson, Robert B. and Alin, Simone R. and Alkama, Ramdane and Arneth, Almut and Arora, Vivek and Bates, Nicholas R. and Becker, Meike and Bellouin, Nicolas and Bittig, Henry C. and Bopp, Laurent and Chevallier, Frédéric and Chini, Louise and Cronin, Margot and Evans, Wiley and Falk, Stefanie and Feely, Richard A. and Gasser, Thomas and Gehlen, Marion and Gkritzalis, Thanos and Gloege, Lucas and Grassi, Giacomo and Gruber, Nicolas and Gürses, Özgür and Harris, Ian and Hefner, Matthew and Houghton, R. A. and Hurtt, G. C. and Iida, Yosuke and Ilyina, Tatiana and Jain, Atul K. and Jersild, Annika and Kadono, Koji and Kato, Etsushi and Kennedy, Daniel and Goldewijk, Kees Klein and Knauer, Jürgen and Korsbakken, Jan Ivar and Landschützer, Peter and Lefèvre, Nathalie and Lindsay, Keith and Liu, Junjie and Liu, Zhu and Marland, Gregg and Mayot, Nicolas and McGrath, Matthew J. and Metzl, Nicolas and Monacci, Natalie and Munro, David R. and Nakaoka, Shin‐Ichiro and Niwa, Yosuke and O’Brien, Kevin and Ono, Tsuneo and Palmer, Paul I. and Pan, Naiqing and Pierrot, Denis and Pocock, Katie and Poulter, Benjamin and Resplandy, Laure and Robertson, Eddy and Rödenbeck, Christian and Rodríguez, Carmen Dolores Arbelo and Rosan, Thais M. and Schwinger, Jörg and Séférian, Roland and Shutler, Jamie D. and Skjelvan, Ingunn and Steinhoff, Tobias and Sun, Qing and Sutton, Adrienne J. and Sweeney, Colm and Takao, Shintaro and Tanhua, Toste and Tans, Pieter P. and Tian, Xiangjun and Tian, Hanqin and Tilbrook, Bronte and Tsujino, Hiroyuki and Tubiello, Francesco N. and van der Werf, Guido R. and Walker, Anthony P. and Wanninkhof, Rik and Whitehead, Chris and Wranne, Anna Willstrand and Wright, Rebecca",
    title = "Global Carbon Budget 2022",
    year = "2022",
    journal = "Earth system science data",
    abstract = "Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical 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 methodologies 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) is estimated with global ocean biogeochemistry models and observation-based data products. The terrestrial CO2 sink (SLAND) is estimated with dynamic global vegetation models. 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 year 2021, EFOS increased by 5.1 \% relative to 2020, with fossil emissions at 10.1 ± 0.5 GtC yr−1 (9.9 ± 0.5 GtC yr−1 when the cement carbonation sink is included), and ELUC was 1.1 ± 0.7 GtC yr−1, for a total anthropogenic CO2 emission (including the cement carbonation sink) of 10.9 ± 0.8 GtC yr−1 (40.0 ± 2.9 GtCO2). Also, for 2021, GATM was 5.2 ± 0.2 GtC yr−1 (2.5 ± 0.1 ppm yr−1), SOCEAN was 2.9 ± 0.4 GtC yr−1, and SLAND was 3.5 ± 0.9 GtC yr−1, with a BIM of −0.6 GtC yr−1 (i.e. the total estimated sources were too low or sinks were too high). The global atmospheric CO2 concentration averaged over 2021 reached 414.71 ± 0.1 ppm. Preliminary data for 2022 suggest an increase in EFOS relative to 2021 of +1.0 \% (0.1 \% to 1.9 \%) globally and atmospheric CO2 concentration reaching 417.2 ppm, more than 50 \% above pre-industrial levels (around 278 ppm). Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2021, but discrepancies of up to 1 GtC yr−1 persist for the representation of annual to semi-decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows (1) a persistent large uncertainty in the estimate of land-use change emissions, (2) a low agreement between the different methods on the magnitude of the land CO2 flux in the northern extratropics, and (3) a discrepancy between the different methods on the strength of the ocean sink over the last decade. 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. The data presented in this work are available at https://doi.org/10.18160/GCP-2022 (Friedlingstein et al., 2022b).",
    url = "https://doi.org/10.5194/essd-14-4811-2022",
    doi = "10.5194/essd-14-4811-2022",
    openalex = "W4308697725",
    references = "archer2009atmospheric, doi101002joc3711, doi1010160016703782901107, doi101016jdsr2200812009, doi1010179781009157896004, doi1010292003gb002199, doi10102992jc00188, doi101038nature14283, doi101038nature25138, doi101038s41467020189227, doi101038s4159702004533, doi101073pnas0700609104, doi101073pnas1019576108, doi101126science1244693, doi1011751520044220020151609aiisas20co2, doi102151jmsj2015001, doi1025607obp1342, doi104060ca9825en, doi105194acp10117072010, doi105194essd1021412018, doi105194essd1117832019, doi105194essd119592019, doi105194essd1232692020, doi105194essd1419172022, doi105194essd1448112022, doi105194essd96972017, doi105194essd99272017, doi105194gmd919372016"
}

storage capacity and technology adoption, diffusion, and path-dependencies. If CDR is constrained by limits derived from expert consensus, the respective modelled coal, oil, and gas reductions become 99%, 70%, and 84%. Our findings suggest the need to adopt unambiguous near- and long-term reduction benchmarks in coal, oil, and gas production and use alongside other climate mitigation targets.

@article{doi101038s4146702341105z,
    author = "Achakulwisut, Ploy and Erickson, Peter and Guivarch, Céline and Schaeffer, Roberto and Brutschin, Elina and Pye, Steve",
    title = "Global fossil fuel reduction pathways under different climate mitigation strategies and ambitions",
    year = "2023",
    journal = "Nature Communications",
    abstract = "storage capacity and technology adoption, diffusion, and path-dependencies. If CDR is constrained by limits derived from expert consensus, the respective modelled coal, oil, and gas reductions become 99\%, 70\%, and 84\%. Our findings suggest the need to adopt unambiguous near- and long-term reduction benchmarks in coal, oil, and gas production and use alongside other climate mitigation targets.",
    url = "https://doi.org/10.1038/s41467-023-41105-z",
    doi = "10.1038/s41467-023-41105-z",
    openalex = "W4386715594",
    references = "doi105194essd1448112022"
}

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical 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) is estimated with global ocean biogeochemistry models and observation-based fCO2 products. The terrestrial CO2 sink (SLAND) is estimated with dynamic global vegetation models. Additional lines of evidence on land and ocean sinks are provided by atmospheric inversions, atmospheric oxygen measurements, and Earth system models. 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 incomplete understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the year 2022, EFOS increased by 0.9 % relative to 2021, with fossil emissions at 9.9±0.5 Gt C yr−1 (10.2±0.5 Gt C yr−1 when the cement carbonation sink is not included), and ELUC was 1.2±0.7 Gt C yr−1, for a total anthropogenic CO2 emission (including the cement carbonation sink) of 11.1±0.8 Gt C yr−1 (40.7±3.2 Gt CO2 yr−1). Also, for 2022, GATM was 4.6±0.2 Gt C yr−1 (2.18±0.1 ppm yr−1; ppm denotes parts per million), SOCEAN was 2.8±0.4 Gt C yr−1, and SLAND was 3.8±0.8 Gt C yr−1, with a BIM of −0.1 Gt C yr−1 (i.e. total estimated sources marginally too low or sinks marginally too high). The global atmospheric CO2 concentration averaged over 2022 reached 417.1±0.1 ppm. Preliminary data for 2023 suggest an increase in EFOS relative to 2022 of +1.1 % (0.0 % to 2.1 %) globally and atmospheric CO2 concentration reaching 419.3 ppm, 51 % above the pre-industrial level (around 278 ppm in 1750). Overall, the mean of and trend in the components of the global carbon budget are consistently estimated over the period 1959–2022, with a near-zero overall budget imbalance, although discrepancies of up to around 1 Gt C yr−1 persist for the representation of annual to semi-decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows the following: (1) a persistent large uncertainty in the estimate of land-use changes emissions, (2) a low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) a discrepancy between the different methods on the strength of the ocean sink over the last decade. This living-data update documents changes in methods and data sets applied to this most recent global carbon budget as well as evolving community understanding of the global carbon cycle. The data presented in this work are available at https://doi.org/10.18160/GCP-2023 (Friedlingstein et al., 2023).

@article{doi105194essd1553012023,
    author = "Friedlingstein, Pierre and O’Sullivan, Michael and Jones, Matthew W. and Andrew, Robbie M. and Bakker, Dorothée C. E. and Hauck, Judith and Landschützer, Peter and Quéré, Corinne Le and Luijkx, Ingrid T. and Peters, Glen P. and Peters, Wouter and Pongratz, Julia and Schwingshackl, Clemens and Sitch, Stephen and Canadell, Josep G. and Ciais, Philippe and Jackson, Robert B. and Alin, Simone R. and Anthoni, Peter and Barbero, Leticia and Bates, Nicholas R. and Becker, Meike and Bellouin, Nicolas and Decharme, Bertrand and Bopp, Laurent and Brasika, Ida Bagus Mandhara and Cadule, Patricia and Chamberlain, Matthew A. and Chandra, Naveen and Chau, Thi Tuyet Trang and Chevallier, Frédéric and Chini, Louise and Cronin, Margot and Dou, Xinyu and Enyo, Kazutaka and Evans, Wiley and Falk, Stefanie and Feely, Richard A. and Feng, Liang and Ford, Daniel J. and Gasser, Thomas and Ghattas, Joséfine and Gkritzalis, Thanos and Grassi, Giacomo and Gregor, Luke and Gruber, Nicolas and Gürses, Özgür and Harris, Ian and Hefner, Matthew and Heinke, Jens and Houghton, R. A. and Hurtt, G. C. and Iida, Yosuke and Ilyina, Tatiana and Jacobson, A. R. and Jain, Atul K. and Jarníková, Tereza and Jersild, Annika and Jiang, Fei and Jin, Zhe and Joos, Fortunat and Kato, Etsushi and Keeling, Ralph F. and Kennedy, Daniel and Goldewijk, Kees Klein and Knauer, Jürgen and Korsbakken, Jan Ivar and Körtzinger, Arne and Lan, Xin and Lefèvre, Nathalie and Li, Hongmei and Liu, Junjie and Liu, Zhiqiang and Ma, Lei and Marland, G. and Mayot, Nicolas and McGuire, Patrick and McKinley, Galen A. and Meyer, Gesa and Morgan, Eric J. and Munro, David R. and Nakaoka, Shin‐Ichiro and Niwa, Yosuke and O'Brien, Kevin M. and Olsen, Are and Omar, Abdirahman M and Ono, Tsuneo and Paulsen, Melf and Pierrot, Denis and Pocock, Katie and Poulter, Benjamin and Powis, Carter M. and Rehder, Gregor and Resplandy, Laure and Robertson, Eddy and Rödenbeck, Christian and Rosan, Thais M. and Schwinger, Jörg and Séférian, Roland and Smallman, T. Luke",
    title = "Global Carbon Budget 2023",
    year = "2023",
    journal = "Earth system science data",
    abstract = "Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical 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) is estimated with global ocean biogeochemistry models and observation-based fCO2 products. The terrestrial CO2 sink (SLAND) is estimated with dynamic global vegetation models. Additional lines of evidence on land and ocean sinks are provided by atmospheric inversions, atmospheric oxygen measurements, and Earth system models. 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 incomplete understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the year 2022, EFOS increased by 0.9 \% relative to 2021, with fossil emissions at 9.9±0.5 Gt C yr−1 (10.2±0.5 Gt C yr−1 when the cement carbonation sink is not included), and ELUC was 1.2±0.7 Gt C yr−1, for a total anthropogenic CO2 emission (including the cement carbonation sink) of 11.1±0.8 Gt C yr−1 (40.7±3.2 Gt CO2 yr−1). Also, for 2022, GATM was 4.6±0.2 Gt C yr−1 (2.18±0.1 ppm yr−1; ppm denotes parts per million), SOCEAN was 2.8±0.4 Gt C yr−1, and SLAND was 3.8±0.8 Gt C yr−1, with a BIM of −0.1 Gt C yr−1 (i.e. total estimated sources marginally too low or sinks marginally too high). The global atmospheric CO2 concentration averaged over 2022 reached 417.1±0.1 ppm. Preliminary data for 2023 suggest an increase in EFOS relative to 2022 of +1.1 \% (0.0 \% to 2.1 \%) globally and atmospheric CO2 concentration reaching 419.3 ppm, 51 \% above the pre-industrial level (around 278 ppm in 1750). Overall, the mean of and trend in the components of the global carbon budget are consistently estimated over the period 1959–2022, with a near-zero overall budget imbalance, although discrepancies of up to around 1 Gt C yr−1 persist for the representation of annual to semi-decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows the following: (1) a persistent large uncertainty in the estimate of land-use changes emissions, (2) a low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) a discrepancy between the different methods on the strength of the ocean sink over the last decade. This living-data update documents changes in methods and data sets applied to this most recent global carbon budget as well as evolving community understanding of the global carbon cycle. The data presented in this work are available at https://doi.org/10.18160/GCP-2023 (Friedlingstein et al., 2023).",
    url = "https://doi.org/10.5194/essd-15-5301-2023",
    doi = "10.5194/essd-15-5301-2023",
    openalex = "W4389195056",
    references = "archer2009atmospheric, doi101016jdsr2200812009, doi1010179781009157896004, doi1010292003gb002199, doi1010292010jd015139, doi1010292019ms002010, doi101038nature14283, doi101038nature25138, doi101038ngeo689, doi101073pnas0702737104, doi105194acp10117072010, doi105194essd1021412018, doi105194essd1117832019, doi105194essd119592019, doi105194essd1232692020, doi105194essd1419172022, doi105194essd1448112022, doi105194essd1553012023, doi105194essd96972017, doi105194gmd113692018, doi105194gmd919372016"
}

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize datasets and methodologies 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) 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 global net uptake of CO2 by the ocean (SOCEAN, called the ocean sink) is estimated with global ocean biogeochemistry models and observation-based fCO2 products (fCO2 is the fugacity of CO2). The global net uptake of CO2 by the land (SLAND, called the land sink) is estimated with dynamic global vegetation models. Additional lines of evidence on land and ocean sinks are provided by atmospheric inversions, atmospheric oxygen measurements, and Earth system models. The sum of all sources and sinks results in the carbon budget imbalance (BIM), a measure of imperfect data and incomplete understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the year 2023, EFOS increased by 1.3 % relative to 2022, with fossil emissions at 10.1 ± 0.5 GtC yr−1 (10.3 ± 0.5 GtC yr−1 when the cement carbonation sink is not included), and ELUC was 1.0 ± 0.7 GtC yr−1, for a total anthropogenic CO2 emission (including the cement carbonation sink) of 11.1 ± 0.9 GtC yr−1 (40.6 ± 3.2 GtCO2 yr−1). Also, for 2023, GATM was 5.9 ± 0.2 GtC yr−1 (2.79 ± 0.1 ppm yr−1; ppm denotes parts per million), SOCEAN was 2.9 ± 0.4 GtC yr−1, and SLAND was 2.3 ± 1.0 GtC yr−1, with a near-zero BIM (−0.02 GtC yr−1). The global atmospheric CO2 concentration averaged over 2023 reached 419.31 ± 0.1 ppm. Preliminary data for 2024 suggest an increase in EFOS relative to 2023 of +0.8 % (−0.2 % to 1.7 %) globally and an atmospheric CO2 concentration increase by 2.87 ppm, reaching 422.45 ppm, 52 % above the pre-industrial level (around 278 ppm in 1750). Overall, the mean of and trend in the components of the global carbon budget are consistently estimated over the period 1959–2023, with a near-zero overall budget imbalance, although discrepancies of up to around 1 GtC yr−1 persist for the representation of annual to semi-decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows the following: (1) a persistent large uncertainty in the estimate of land-use change emissions, (2) low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) a discrepancy between the different methods on the mean ocean sink. This living-data update documents changes in methods and datasets applied to this most recent global carbon budget as well as evolving community understanding of the global carbon cycle. The data presented in this work are available at https://doi.org/10.18160/GCP-2024 (Friedlingstein et al., 2024).

@article{doi105194essd179652025,
    author = "Friedlingstein, Pierre and O’Sullivan, Michael and Jones, Matthew W. and Andrew, Robbie M. and Hauck, Judith and Landschützer, Peter and Quéré, Corinne Le and Li, Hongmei and Luijkx, Ingrid T. and Olsen, Are and Peters, Glen P. and Peters, Wouter and Pongratz, Julia and Schwingshackl, Clemens and Sitch, Stephen and Canadell, Josep G. and Ciais, Philippe and Jackson, Robert B. and Alin, Simone R. and Arneth, Almut and Arora, Vivek K. and Bates, Nicholas R. and Becker, Meike and Bellouin, Nicolas and Berghoff, Carla F. and Bittig, Henry C. and Bopp, Laurent and Cadule, Patricia and Campbell, Katie and Chamberlain, Matthew A. and Chandra, Naveen and Chevallier, Frédéric and Chini, Louise and Colligan, Thomas and Decayeux, Jeanne and Djeutchouang, Laique and Dou, Xinyu and Rojas, Maria Carolina Duran and Enyo, Kazutaka and Evans, Wiley and Fay, Amanda R. and Feely, Richard A. and Ford, Daniel J. and Foster, Adrianna and Gasser, Thomas and Gehlen, Marion and Gkritzalis, Thanos and Grassi, Giacomo and Gregor, Luke and Gruber, Nicolas and Gürses, Özgür and Harris, Ian A. and Hefner, Matthew and Heinke, Jens and Hurtt, G. C. and Iida, Yosuke and Ilyina, Tatiana and Jacobson, A. R. and Jain, Atul K. and Jarníková, Tereza and Jersild, Annika and Jiang, Fei and Jin, Zhe and Kato, Etsushi and Keeling, Ralph F. and Goldewijk, Kees Klein and Knauer, Jürgen and Korsbakken, Jan Ivar and Lan, Xin and Lauvset, Siv K. and Lefèvre, Nathalie and Liu, Zhu and Liu, Junjie and Ma, Lei and Maksyutov, Shamil and Marland, Gregg and Mayot, Nicolas and McGuire, Patrick and Metzl, Nicolas and Monacci, Natalie and Morgan, Eric J. and Nakaoka, Shin‐Ichiro and Neill, Craig and Niwa, Yosuke and Nützel, Tobias and Olivier, Léa and Ono, Tsuneo and Palmer, Paul I. and Pierrot, Denis and Qin, Zhangcai and Resplandy, Laure and Roobaert, Alizée and Rosan, Thais M. and Rödenbeck, Christian and Schwinger, Jörg and Smallman, T. Luke and Smith, Stephen M. and Sospedra‐Alfonso, Reinel and Steinhoff, Tobias and Sun, Qing",
    title = "Global Carbon Budget 2024",
    year = "2025",
    journal = "Earth system science data",
    abstract = "Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize datasets and methodologies 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) 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 global net uptake of CO2 by the ocean (SOCEAN, called the ocean sink) is estimated with global ocean biogeochemistry models and observation-based fCO2 products (fCO2 is the fugacity of CO2). The global net uptake of CO2 by the land (SLAND, called the land sink) is estimated with dynamic global vegetation models. Additional lines of evidence on land and ocean sinks are provided by atmospheric inversions, atmospheric oxygen measurements, and Earth system models. The sum of all sources and sinks results in the carbon budget imbalance (BIM), a measure of imperfect data and incomplete understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the year 2023, EFOS increased by 1.3 \% relative to 2022, with fossil emissions at 10.1 ± 0.5 GtC yr−1 (10.3 ± 0.5 GtC yr−1 when the cement carbonation sink is not included), and ELUC was 1.0 ± 0.7 GtC yr−1, for a total anthropogenic CO2 emission (including the cement carbonation sink) of 11.1 ± 0.9 GtC yr−1 (40.6 ± 3.2 GtCO2 yr−1). Also, for 2023, GATM was 5.9 ± 0.2 GtC yr−1 (2.79 ± 0.1 ppm yr−1; ppm denotes parts per million), SOCEAN was 2.9 ± 0.4 GtC yr−1, and SLAND was 2.3 ± 1.0 GtC yr−1, with a near-zero BIM (−0.02 GtC yr−1). The global atmospheric CO2 concentration averaged over 2023 reached 419.31 ± 0.1 ppm. Preliminary data for 2024 suggest an increase in EFOS relative to 2023 of +0.8 \% (−0.2 \% to 1.7 \%) globally and an atmospheric CO2 concentration increase by 2.87 ppm, reaching 422.45 ppm, 52 \% above the pre-industrial level (around 278 ppm in 1750). Overall, the mean of and trend in the components of the global carbon budget are consistently estimated over the period 1959–2023, with a near-zero overall budget imbalance, although discrepancies of up to around 1 GtC yr−1 persist for the representation of annual to semi-decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows the following: (1) a persistent large uncertainty in the estimate of land-use change emissions, (2) low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) a discrepancy between the different methods on the mean ocean sink. This living-data update documents changes in methods and datasets applied to this most recent global carbon budget as well as evolving community understanding of the global carbon cycle. The data presented in this work are available at https://doi.org/10.18160/GCP-2024 (Friedlingstein et al., 2024).",
    url = "https://doi.org/10.5194/essd-17-965-2025",
    doi = "10.5194/essd-17-965-2025",
    openalex = "W4408460092",
    references = "doi1010179781009157896004, doi1010292019ms002010, doi105194essd1419172022, doi105194essd1448112022, doi105194essd1553012023"
}