Escalating drought sensitivity of a greening China.

Introduction: The sensitivity of vegetation to drought is a critical determinant of whether recurrent droughts will disrupt sustainable greening and climate change mitigation efforts. However, its potential spatiotemporal heterogeneity, shaped by both environmental and anthropogenic drivers, remains poorly understood. Methods: Here, we employed multiscalar Standardized Precipitation Evapotranspiration Index (SPEI) to unfold the spatiotemporal patterns of drought across China since the 1980s. We then examined the sensitivity of land surface greenness to drought and its changes across drainage basins, agricultural regions, and plant functional types. Results: China has experienced a notable aridification trend since the 1980s, primarily driven by intensified spring dryness across the northern drylands. Significant correlations between greenness variability and SPEI were observed across 29.09% to 44.37% of vegetated lands, with the spatial extent increasing along with the SPEI timescale (12 to 48 months). Critically, despite a widespread greening trend covering nearly 55% of vegetated lands, the sensitivity of greenness variability to multiscalar SPEI markedly escalated across 27.48%-39.67% of China. Discussion: Our findings suggest that increasing drought sensitivity poses a growing potential constraint to the sustainability of vegetation greening in China, highlighting the urgent need for adaptive water resource management and ecosystem restoration strategies under a warming climate.