Global vegetation vulnerability to drought is underestimated due to the lagged effect

Abstract

Quantifying vegetation vulnerability plays a critical role in the field of impacts and risks of extreme weather and climate. However, vegetation vulnerability assessments remain facing challenges due to complexity, nonlinearity and spatiotemporal heterogeneity of the lagged effect. In this study, we develop a Drought Vulnerability Index (DVI) based dynamic of vegetation response during the lagged period using the Standardized Precipitation Evapotranspiration Index and the Normalized Differential Vegetation Index. We examine spatiotemporal pattern of vulnerability of global terrestrial vegetation to drought and explore related driving factors. Our findings reveal that 68.22 % of terrestrial vegetation exhibits a lagged effect, primarily at 1–3 lagged months. Vegetation vulnerability of terrestrial vegetation is underestimated without considering the lagged effect. The underestimation is particularly higher in regions with 1–3 lagged months. Vegetation has higher vulnerability to more severe drought. Approximately 56.15 % of global terrestrial vegetation experiences an elevated vulnerability to drought from 1982 to 2022. Our study introduces a new perspective for a systematic scientific assessment of drought impacts, aiding in the formulation of proactive adaptation measures to mitigate drought risks.