Quantitative evaluation of drought risk related to vegetation productivity in China

Quantitative assessment of vegetation drought risk is crucial for addressing drought problems and vegetation management under global warming. In this study, we employed a framework based on long-term (2001–2019) vegetation Gross Primary Productivity (GPP) and the Standardized Precipitation Evapotranspiration Index (SPEI) to quantify drought risk, considering vegetation vulnerability, exposure, and hazard to drought. The results revealed that vegetation drought risk was influenced by drought hazard (55.15%), exposure (24.46%), and vulnerability (20.39%). Approximately 48% of study pixels experienced moderate to high drought risk, primarily concentrated in northeastern to southwestern China. In terms of vegetation types, forest suffered the highest drought risk, followed by cropland, while grassland had the mildest drought risk. Notably, croplands in northern China experienced relatively high drought risk, posing a threat to food security. Therefore, it is imperative to consider appropriate crop management practices such as irrigation and crop rotation to mitigate the impact of droughts. Temperature and precipitation are key climatic factors affecting vegetation drought risk in moderate-to-high risk areas. Warming inhibited drought risk by promoting vegetation growth, but also consumed water to promote drought risk. Meanwhile, increased rainfall in parts of northern China may be caused by extreme weather events that intensify vegetation vulnerability, thus aggravating drought risk. Our research provided scientific guidance to understand and cope with drought risk induced by climate change on vegetation.