Global Carbon Budget 2021

Friedlingstein, Pierre, Jones, Matthew W. ORCID: https://orcid.org/0000-0003-3480-7980, O'Sullivan, Michael, Andrew, Robbie M., Bakker, Dorothee C. E. ORCID: https://orcid.org/0000-0001-9234-5337, Hauck, Judith, Le Quéré, Corinne ORCID: https://orcid.org/0000-0003-2319-0452, Peters, Glen P., Peters, Wouter, Pongratz, Julia, Sitch, Stephen, Canadell, Josep G., Ciais, Philippe, Jackson, Robert B., Alin, Simone R., Anthoni, Peter, Bates, Nicholas R., Becker, Meike, Bellouin, Nicolas, Bopp, Laurent, Chau, Thi Tuyet Trang, Chevallier, Frédéric, Chini, Louise P., Cronin, Margot, Currie, Kim I., Decharme, Bertrand, Djeutchouang, Laique, Dou, Xinyu, Evans, Wiley, Feely, Richard A., Feng, Liang, Gasser, Thomas, Gilfillan, Dennis, Gkritzalis, Thanos, Grassi, Giacomo, Gregor, Luke, Gruber, Nicolas, Gürses, Özgür, Harris, Ian, Houghton, Richard A., Hurtt, George C., Iida, Yosuke, Ilyina, Tatiana, van der Laan-Luijkx, Ingrid T., Jain, Atul K., Jones, Steve D., Kato, Etsushi, Kennedy, Daniel, Klein Goldewijk, Kees, Knauer, Jürgen, Korsbakken, Jan Ivar, Körtzinger, Arne, Landschützer, Peter, Lauvset, Siv K., Lefèvre, Nathalie, Lienert, Sebastian, Liu, Junjie, Marland, Gregg, McGuire, Patrick C., Melton, Joe R., Munro, David R., Nabel, Julia E. M. S., Nakaoka, Shin-Ichiro, Niwa, Yosuke, Ono, Tsuneo, Pierrot, Denis, Poulter, Benjamin, Rehder, Gregor, Resplandy, Laure, Robertson, Eddy, Rödenbeck, Christian, Rosan, Thais M., Schwinger, Jörg, Schwingshackl, Clemens, Seferian, Roland, Sutton, Adrienne J., Sweeney, Colm, Tanhua, Toste, Tans, Pieter P., Tian, Hanqin, Tilbrook, Bronte, Tubiello, Francesco N., van der Werf, Guido R., Vuichard, Nicolas, Wada, Chisato, Wanninkhof, Rik, Watson, Andrew, Willis, David, Wiltshire, Andrew J., Yuan, Wenping, Yue, Chao, Yue, Xu, Zaehle, Sönke and Zeng, Jiye (2022) Global Carbon Budget 2021. Earth System Science Data, 14 (4). 1917–2005. ISSN 1866-3516

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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±0.5GtCyr-1 (9.3±0.5GtCyr-1 when the cement carbonation sink is included), and ELUC was 0.9±0.7GtCyr-1, for a total anthropogenic CO2 emission of 10.2±0.8GtCyr-1 (37.4±2.9GtCO2). Also, for 2020, GATM was 5.0±0.2GtCyr-1 (2.4±0.1ppmyr-1), SOCEAN was 3.0±0.4GtCyr-1, and SLAND was 2.9±1GtCyr-1, with a BIM of -0.8GtCyr-1. The global atmospheric CO2 concentration averaged over 2020 reached 412.45±0.1ppm. 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 1GtCyr-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 10.18160/gcp-2021 (Friedlingstein et al., 2021).

Item Type: Article
Uncontrolled Keywords: earth and planetary sciences(all),sdg 15 - life on land,sdg 13 - climate action ,/dk/atira/pure/subjectarea/asjc/1900
Faculty \ School: Faculty of Science > School of Environmental Sciences
University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups: University of East Anglia Schools > Faculty of Science > Tyndall Centre for Climate Change Research
Faculty of Science > Research Centres > Tyndall Centre for Climate Change Research
Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences
Faculty of Science > Research Groups > Climatic Research Unit
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Depositing User: LivePure Connector
Date Deposited: 18 Nov 2021 01:59
Last Modified: 15 Jun 2023 02:35
URI: https://ueaeprints.uea.ac.uk/id/eprint/82143
DOI: 10.5194/essd-2021-386

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