Rising rainfall variability amplifies hydroclimate extremes in eastern China

Abstract Global warming drives increased rainfall variability, fundamentally because of enlarged moisture holding capacity of the atmosphere. But what does this increase mean in practical terms for rainfall spectrum? Here, we explore the link between changes in rainfall variability and rainfall spectrum and project hydroclimate volatility changes over eastern China, using a combination of long-term observed daily precipitation records and multiple decadal convection-permitting climate simulations. The increase in rainfall variability is reflected in a shift in the rainfall spectrum—from light to more intense precipitation—indicating heightened hazards of both droughts and flash floods. These wider swings between wet and dry extremes are driven by more frequent occurrences of high daily convective available potential energy and convective inhibition values, and intensified by stronger East Asian summer monsoon circulations. Using a combined measure of precipitation intensity and dry spell duration, we project a 29.4% increase in the precipitation volatility index by the end of the 21st century under a high emissions scenario. Our findings highlight the growing importance of rainfall variability in shaping regional hydroclimate volatility and underscore the need to accelerate a shift in water management strategies toward integrated drought and flood risk management.