A consistent budgeting of terrestrial carbon fluxes.
Where this comes from
- Record sourced from PubMed, PMID 39198386.
- Also identified by DOI 10.1038/s41467-024-51126-x and PMC identifier 11358497.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Accurate estimates of CO<sub>2</sub> emissions from anthropogenic land-use change (E<sub>LUC</sub>) and of the natural terrestrial CO<sub>2</sub> sink (S<sub>LAND</sub>) are crucial to precisely know how much CO<sub>2</sub> can still be emitted to meet the goals of the Paris Agreement. In current carbon budgets, E<sub>LUC</sub> and S<sub>LAND</sub> stem from two model families that differ in how CO<sub>2</sub> fluxes are attributed to environmental and land-use changes, making their estimates conceptually inconsistent. Here we provide consistent estimates of E<sub>LUC</sub> and S<sub>LAND</sub> by integrating environmental effects on land carbon into a spatially explicit bookkeeping model. We find that state-of-the-art process-based models overestimate S<sub>LAND</sub> by 23% (min: 8%, max: 33%) in 2012-2021, as they include hypothetical sinks that in reality are lost through historical ecosystem degradation. Additionally, E<sub>LUC</sub> increases by 14% (8%, 23%) in 2012-2021 when considering environmental effects. Altogether, we find a weaker net land sink, which makes reaching carbon neutrality even more ambitious. These results highlight that a consistent estimation of terrestrial carbon fluxes is essential to assess the progress of net-zero emission commitments and the remaining carbon budget.