Global bookkeeping models provide one approach to measuring CO2 emissions from land use, land-use change and forestry (LULUCF).
Direct human activities (e.g., deforestation or reforestation), indirect human activities (e.g., more frequent and severe climate impacts like wildfires or increasing CO2 fertilization) and natural effects (e.g., climate variability due to El Niño and La Niña) that contribute to emissions and removals across the world’s land. Scientists have developed several approaches — including those employed by global bookkeeping models, dynamic global vegetation models and national greenhouse gas inventories — to try to distinguish human-caused emissions and removals from those that occur naturally. But each approach disentangles these fluxes differently. Global bookkeeping models, for example, consider CO2 fluxes from direct human activities on managed lands only when estimating net anthropogenic emissions from LULUCF, while dynamic global vegetation models account for fluxes from indirect human activities and natural effects on both managed and unmanaged lands when quantifying the world’s land sink. Both approaches contribute to the annual Global Carbon Budget, which reports these human-caused and natural fluxes separately. National greenhouse gas inventories, in contrast, approximate net anthropogenic CO2 emissions from LULUCF as CO2 fluxes from direct and indirect human activities, as well as natural effects, on managed lands. Consequently, national greenhouse gas inventories include a greater share of the land sink in their estimates of net anthropogenic CO2 emissions from LULUCF than global bookkeeping models.
This platform relies on global bookkeeping models, with supplementary data on emissions from peat drainage and burning, to estimate net anthropogenic CO2 emissions from LULUCF. While no method is inherently preferable to another, this section follows the precedent set by the “Summary for Policymakers” in Working Group III’s Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change in reporting estimates of net anthropogenic LULUCF emissions from global bookkeeping models, which aligns with the suggested approach in Grassi et al. 2023 that analyses focused on mitigation efforts at the global level and relative to modeled emissions pathways present estimates of net anthropogenic LULUCF emissions from global bookkeeping models used in Friedlingstein et al. 2026.