Precipitation and soil water amplify the influence of climatic factors on global vegetation reversals

Satellite observations reveal significant changes in global terrestrial vegetation over the past four decades. However, the neglect of interactions among influencing factors has sparked intense debates regarding vegetation dynamics at regional and global scales. This study systematically evaluated the spatiotemporal evolution of global vegetation dynamics (1982–2020) and their complex driving mechanisms by integrating five remote sensing-derived vegetation products with climate and socio-economic data. The results showed that approximately 51.98% of the global terrestrial vegetation area experienced change reversals between 1995 and 2005, with vegetation “greenness” predominantly transitioning from increase to decrease. This percentage differs between different climate zones, ranging from 46.41% in cold zone to 54.99% in tropical zone. This phenomenon was primarily driven by the weakening (6% ± 4%) of interactive coupling among total precipitation (TP), soil water (SW), and other factors (e.g., temperature, vapor pressure deficit (VPD)), rather than being mainly attributed to VPD as reported in previous studies. The findings underscore the need to more explicitly consider the impact of interactions between water-related factors on regional and global vegetation in a warming climate.