Anthropogenic Aerosol Dominates the Decadal Change in Evapotranspiration over Southeastern China in the Past Four Decades

Evapotranspiration (ET) is vital for global water balance, energy cycle, and biological processes, representing a key component of Earth systems interactions. However, how human activities affect regional ET is still unknown. This study identified a decadal decrease in ET before 2000, followed by an increase over southeastern China in observations. Simulations from the coupled model intercomparison project phase 6 (CMIP6) models well reproduced the observed decadal ET change, with a lag of 10 years, which may be due to the spatial and temporal simplification of aerosol forcing data in CMIP6. Attribution analysis reveals that the change in anthropogenic aerosol emissions was the primary driver of the ET change, while the contribution of greenhouse gas was negligible. The Penman-Monteith framework identified that the net surface radiation contributed 77% of the ET trend change in the anthropogenic aerosol-only experiment. The increase and reduction in anthropogenic aerosol emissions reduce and increase the shortwave radiation reaching the Earth's surface, respectively, resulting in the different trends of energy sources for ET. Our findings underscore the critical role of aerosols in shaping surface energy balance and influencing regional hydrological cycles.