Yongqiang Zhang

Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China

Abstract

The hydrological system has undergone significant changes over the last four decades, and it is anticipated to continue evolving in the future. One notable projection is that streamflow is expected to rise in response to increasing atmospheric CO₂ levels. This phenomenon is attributed to the reduction of stomatal conductance and subsequent decrease in land surface evapotranspiration caused by elevated CO₂ levels. Many global Earth System Models (ESMs) predict an augmentation in future streamflow. However, our approach, based on data-driven elasticity analysis, reveals that these ESMs tend to overestimate the expected increase in streamflow due to their heightened sensitivity to variations in evapotranspiration. Furthermore, our study incorporates historical data from the past four decades to corroborate our findings, which suggest that these global models overstate the CO₂-induced surge in streamflow. This raises concerns about the potential severity of a future water crisis, which may be more pronounced than initially anticipated.