Water availability regulates abrupt shifts in global terrestrial vegetation productivity by reducing resilience

Abrupt shifts in vegetation productivity induced by environmental change profoundly affect ecosystem functions and services, such as carbon sequestration, biodiversity maintenance and climate regulation, yet their long-term global patterns and underlying drivers remain insufficiently understood. In this study, abrupt shifts in vegetation productivity were identified using two independent long-term satellite datasets, and early warning signals were assessed through ecosystem resilience. The main drivers of resilience decline were further examined across land-cover, climate and human-activity dimensions. The results showed that negative abrupt shifts were predominantly concentrated in high northern latitudes and equatorial regions, and that both negative and positive abrupt shifts displayed distinct increasing trends after 2002. A sharp decline in ecosystem resilience was also detected during the 4 years preceding abrupt shifts. Changes in water availability were identified as the primary factor contributing to the reduced resilience of global ecosystems, as evidenced by the driver trajectory, generalized additive models and convergent cross-mapping methods. This study provides insight into the pervasive occurrence of abrupt shifts in vegetation productivity and the discernible impact of climate change. When projecting vegetation dynamics under future climate change, it is essential to consider the significant uncertainties associated with abrupt shifts.