A wetter yet drier world: the role of intensified precipitation unevenness

Abstract Extensive increases in precipitation should have moistened the land surface, yet persistent soil drying has contradicted this expectation over recent decades. Here, we reveal that this hydrological paradox—more rainfall but drier soils—has emerged over two-fifths of global land. In these regions, rising precipitation is accompanied by a shift from low and moderate to heavy precipitation, channeling more water into rainfall that is poorly retained by the soil and less able to sustain soil moisture. This drying effect of increasing unevenness is roughly eleven times stronger than the wetting effect of increased total precipitation, causing soils to dry despite a wetter climate. Our results reveal the critical role of precipitation intensity distribution, rather than total amount, in shaping this hydrological contradiction.