High-resolution carbon emission patterns in China driven by historical land use change from 1850 to 2015

Accurate quantification of historical carbon emissions from land use changes is essential for assessing carbon sequestration potential and informing carbon neutrality goals. Existing research has significant limitations: studies with long time spans often lack spatial resolution, while those with high spatial resolution cover shorter time periods. To bridge this gap, this study developed a spatially explicit bookkeeping model at a 0.25° × 0.25° resolution, providing high-resolution estimates of carbon emissions from historical land use changes in China from 1850 to 2015. Our results reveal that the total net carbon emissions were 5.3 Pg C from 1850 to 2015. Reclamation (7.2 Pg C) and deforestation (1.6 Pg C) were the primary sources of carbon emissions, while cropland abandonment was the major driver of carbon sequestration (3.7 Pg C). China's carbon sources were concentrated in three regions: (1) Northeast China and the Huang-Huai Plain (dominated by cropland reclamation); (2) the Sichuan Basin (cropland expansion); and (3) South China and Yunnan province (deforestation of subtropical forests). Significant carbon sinks are found in Northwest China, including the Hexi Corridor, Inner Mongolia, and Xinjiang. Precipitation was identified as the most influential driver for the spatial pattern of emissions, followed by topographic constraints and economic pressures. Our study underscores the role of the historical land use policies and social environments in influencing carbon emission. The LUC carbon emissions underwent a regime shift in 2012, transitioning from a source to a sink, which was attributable to the benefits of large-scale ecological projects. The research clarifies China's role in global carbon budgets over long history and provides spatially explicit guidance for land management aligned with carbon neutrality.