Global Carbon Budget 2022
Authors: Friedlingstein Pierre , O'Sullivan Michael , Jones Matthew W. , Andrew Robbie M. , Gregor Luke , Hauck Judith , Le Quéré Corinne , Luijkx Ingrid T. , Olsen Are , Peters Glen P. , Peters Wouter , Pongratz Julia , Schwingshackl Clemens , Sitch Stephen , Canadell Josep G. , Ciais Philippe , Jackson Robert B. , Alin Simone R. , Alkama Ramdane , Arneth Almut , Arora Vivek K. , Bates Nicholas R. , Becker Meike , Bellouin Nicolas , Bittig Henry C. , Bopp Laurent , Chevallier Frédéric , Chini Louise P. , Cronin Margot , Evans Wiley , Falk Stefanie , Feely Richard A. , Gasser Thomas , Gehlen Marion , Gkritzalis Thanos , Gloege Lucas , Grassi Giacomo , Gruber Nicolas , Gürses Özgür , Harris Ian , Hefner Matthew , Houghton Richard A. , Hurtt George C. , Iida Yosuke , Ilyina Tatiana , Jain Atul K. , Jersild Annika , Kadono Koji , Kato Etsushi , Kennedy Daniel , Klein Goldewijk Kees , Knauer Jürgen , Korsbakken Jan Ivar , Landschützer Peter , Lefèvre Nathalie , Lindsay Keith , Liu Junjie , Liu Zhu , Marland Gregg , Mayot Nicolas , McGrath Matthew J. , Metzl Nicolas , Monacci Natalie M. , Munro David R. , Nakaoka Shin-Ichiro , Niwa Yosuke , O'Brien Kevin , Ono Tsuneo , Palmer Paul I. , Pan Naiqing , Pierrot Denis , Pocock Katie , Poulter Benjamin , Resplandy Laure , Robertson Eddy , Rödenbeck Christian , Rodriguez Carmen , Rosan Thais M. , Schwinger Jörg , Séférian Roland , Shutler Jamie D. , Skjelvan Ingunn , Steinhoff Tobias , Sun Qing , Sutton Adrienne J. , Sweeney Colm , Takao Shintaro , Tanhua Toste , Tans Pieter P. , Tian Xiangjun , Tian Hanqin , Tilbrook Bronte , Tsujino Hiroyuki , Tubiello Francesco , van der Werf Guido , Walker Anthony P. , Wanninkhof Rik , Whitehead Chris , Willstrand Wranne Anna , Wright Rebecca , Yuan Wenping , Yue Chao , Yue Xu , Zaehle Sönke , Zeng Jiye , Zheng Bo 
Published: September 2022

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 synthesise 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 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), ELUC was 1.1 ± 0.7 GtC yr-1, for a total anthropogenic CO2 emission of 11.1 ± 0.8 GtC yr-1 (40.8 ± 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. total estimated sources too low or sinks 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 +1.1 % (0 % to 1.7 %) globally, and atmospheric CO2 concentration reaching 417.3 ppm, more than 50 % above pre-industrial level. 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 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 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., 2022a; Friedlingstein et al., 2020; Friedlingstein et al., 2019; Le Quéré et al., 2018b, 2018a, 2016, 2015b, 2015a, 2014, 2013). The data presented in this work are available at https://doi.org/10.18160/GCP-2022 (Friedlingstein et al., 2022b).