Global Carbon Budget and Land Carbon Sink

The role of terrestrial ecosystems in the global carbon cycle as a significant and growing sink of atmospheric CO₂ has been known for decades.  This sink has been largely attributed to the forest ecosystem uptake.  However, the magnitude of this sink, the location, and the cause of its interannual variability remain largely uncertain in the global carbon budget.  This uncertainty is due to the complexity of quantifying two main additive fluxes: first, the net flux of carbon from land use, land use change and forestry (LULUCF) that is estimated to be a source of carbon to the atmosphere, and second, the net flux of carbon driven by environmental changes (e.g. climate) and is estimated to be a sink of carbon.  Land use, Land-use change and forestry (LULUCF) accounts for 25% of emission reduction pledged by countries in their nationally determined contributions (NDCs), making it a crucial mechanism for mitigating climate change.  As the focus of climate policy shifts from pledges to implementation, there is a growing need to track progress on climate change mitigation at the country level, and particularly for the land-use sector.  Here, we estimated national and global CO₂ emissions and removals from land for the period of 2000-2023 using a combination of satellite and inventory data to provide the first global stocktake of land under the Paris Agreement.   Our estimates are disaggregated (forest and non-forest land, deforestation, degradation, and fire) to allow comparison with the data reported by countries to the United Nations Framework Convention on Climate Change (UNFCCC) and to balance the global carbon budget.    The results are shown for 185 countries separated for Annex I (AI) and Non-Annex I (NAI) parties and compared with data by inventory -based country reports and IPCC book-keeping models.