Climate-regulated biomass burning rebound in China since 2021

Abstract

Biomass burning (BB) contributes significantly to atmospheric pollution and ecological degradation, with growing concern over its potential intensification under accelerating climate change. However, its recent fine-scale spatiotemporal dynamics in China remain poorly understood, obscured by the intertwined impacts of anthropogenic activity and climate variability. We analyzed BB patterns across China from 2016 to 2025 using an optimized hourly active fire dataset and quantified the contributions of climatic, vegetation, and anthropogenic factors. National BB activity showed substantial interannual variability, with an overall rebound after 2021. This rebound was concentrated in northern agricultural and southern forested areas, with pronounced daytime peaks. Interpretability analysis revealed pronounced land-use- and season-specific changes in variable importance, with moisture- and vegetation-related variables showing relatively greater importance during post-2021 period. Lagged analyses further identified regionally heterogeneous associations of vapor pressure deficit and soil moisture with subsequent BB activity. These findings underscore the need for region-specific and adaptive fire management strategies that address drought-enhanced fire susceptibility and evolving land-use patterns under increasing climate uncertainty.