Global Carbon Budget 2022

[摘要] Accurate assessment of anthropogenic carbon dioxide (CO 2 ) emissions andtheir redistribution among the atmosphere, ocean, and terrestrial biospherein a changing climate is critical to better understand the global carboncycle, support the development of climate policies, and project futureclimate change. Here we describe and synthesize data sets and methodologies toquantify the five major components of the global carbon budget and theiruncertainties. Fossil CO 2 emissions ( E FOS ) are based on energystatistics and cement production data, while emissions from land-use change( E LUC ), mainly deforestation, are based on land use and land-use changedata and bookkeeping models. Atmospheric CO 2 concentration is measureddirectly, and its growth rate ( G ATM ) is computed from the annualchanges in concentration. The ocean CO 2 sink ( S OCEAN ) is estimatedwith global ocean biogeochemistry models and observation-baseddata products. The terrestrial CO 2 sink ( S LAND ) is estimated withdynamic global vegetation models. The resulting carbon budget imbalance( B IM ), the difference between the estimated total emissions and theestimated changes in the atmosphere, ocean, and terrestrial biosphere, is ameasure of imperfect data and understanding of the contemporary carboncycle. All uncertainties are reported as ± 1 σ . For the year 2021, E FOS increased by 5.1 % relative to 2020, withfossil emissions at 10.1  ±  0.5 GtC yr −1 (9.9  ±  0.5 GtC yr −1 when the cement carbonation sink is included), and E LUC was 1.1  ±  0.7 GtC yr −1 , for a total anthropogenic CO 2 emission(including the cement carbonation sink) of 10.9  ±  0.8 GtC yr −1 (40.0  ±  2.9 GtCO 2 ). Also, for 2021, G ATM was 5.2  ±  0.2 GtC yr −1 (2.5  ±  0.1 ppm yr −1 ), S OCEAN was 2.9   ±  0.4 GtC yr −1 , and S LAND was 3.5  ±  0.9 GtC yr −1 , with a B IM of − 0.6 GtC yr −1 (i.e. the total estimated sources were too low orsinks were too high). The global atmospheric CO 2 concentration averaged over2021 reached 414.71  ±  0.1 ppm. Preliminary data for 2022 suggest anincrease in E FOS relative to 2021 of + 1.0 % (0.1 % to 1.9 %)globally and atmospheric CO 2 concentration reaching 417.2 ppm, morethan 50 % above pre-industrial levels (around 278 ppm). Overall, the meanand trend in the components of the global carbon budget are consistentlyestimated over the period 1959–2021, but discrepancies of up to 1 GtC yr −1 persist for the representation of annual to semi-decadalvariability in CO 2 fluxes. Comparison of estimates from multipleapproaches and observations shows (1) a persistent large uncertainty in theestimate of land-use change emissions, (2) a low agreement between thedifferent methods on the magnitude of the land CO 2 flux in the northernextratropics, and (3) a discrepancy between the different methods on thestrength of the ocean sink over the last decade. This living data updatedocuments changes in the methods and data sets used in this new globalcarbon budget and the progress in understanding of the global carbon cyclecompared with previous publications of this data set. The data presented inthis work are available at https://doi.org/10.18160/GCP-2022 (Friedlingstein et al., 2022b).

[学科分类] 眼科学