Global Carbon Budget 2023

Background

“Global Carbon Budget 2023” extends this annual budget series with data up to 2022 and a projection for 2023, including for the first time explicit treatment of carbon dioxide removal (CDR) and new constraints from atmospheric oxygen measurements. Atmospheric CO2 averages 417.1 ± 0.1 ppm in 2022 and is projected to reach about 419.3 ppm in 2023, reflecting continued net accumulation despite temporary pandemic-related emission reductions.

Goals and Methods

This study quantifies fossil and industrial emissions (EFOS), land-use change emissions (ELUC), atmospheric growth (GATM), and land and ocean sinks (SLAND, SOCEAN). It introduces land/ocean net flux estimates from both Earth System Models (ESMs) and atmospheric O2 data, as well as CDR uptake. Preliminary 2023 fossil emissions are derived from near-real-time activity and energy data, combined with standard datasets. Land-use emissions are obtained from multiple bookkeeping models. Sinks are derived from global process models and additional observation-constrained approaches, with a budget imbalance term tracking

residual discrepancy.

Conclusions and Takeaways
This research reveals that global fossil fuel and industry emissions increased by 0.9 percent compared to the preceding year, reaching 9.9 ± 0.5 GtC per year, while emissions from land use change were estimated at 1.2 ± 0.7 GtC per year, resulting in total anthropogenic CO₂ emissions of 11.1 ± 0.8 GtC per year or 40.7 ± 3.2 GtCO₂ per year when accounting for the cement carbonation sink. Atmospheric CO₂ grew by 4.6 ± 0.2 GtC per year, equivalent to 2.18 ± 0.1 ppm per year, with oceans and terrestrial ecosystems absorbing 2.8 ± 0.4 GtC per year and 3.8 ± 0.8 GtC per year respectively, leaving a small budget imbalance of −0.1 GtC per year, while the global mean atmospheric CO₂ concentration reached 417.1 ± 0.1 ppm in 2022 and is estimated to have risen further to 419.3 ppm in 2023, about 51% above pre-industrial levels. Over the period 1959–2022, the global carbon budget shows internally consistent long-term trends with near-zero overall imbalance, but substantial uncertainties persist, particularly for land use change emissions, land carbon fluxes in the northern extra-tropics, and the strength of the ocean carbon sink over the past decade.