Shifted trend in drought sensitivity of vegetation productivity from 1982 to 2020

Abstract

Drought has imposed severe effects on vegetation productivity, and such impacts will continue to increase under ongoing climate change. However, long-term changes in vegetation sensitivity to drought (S_dro) remain poorly understood. Here, with satellite-based vegetation indexes (kNDVI and LAI) and soil moisture dataset, we investigated the spatiotemporal patterns of S_dro across the global land during 1982–2020. We found that S_dro was higher in dry regions in comparison to humid regions, and grasslands showed the highest S_dro while forests showed the lowest one. Temporally, the overall S_dro increased first and then decreased over past four decades. More than 55 % of global vegetated areas experienced a conversion from an increased trend to a declined trend in S_dro, which concentrated in humid regions. The potential driving mechanisms of these converted S_dro trends were mostly related to climate changes and varied regionally, with VPD in northern Europe, temperature in middle Africa, and precipitation in western America and northern India. Our findings underscore a shifted trend in vulnerability of terrestrial ecosystems to drought especially in global humid regions.