Global Carbon Budget 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 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).