nature.com
Global drought shows no detectable recent acceleration under climate warming
Drought is a major constraint on freshwater availability, ecosystem functioning, and food security1,2,3,4, and its evolution under global warming remains a central concern in climate impact assessments5,6,7. Numerous studies have reported increasing drought severity and expanding drought-affected areas over recent decades8,9,10,11,12, drawing on converging evidence from multivariate atmospheric drought indices, which combine precipitation with atmospheric evaporative demand (potential evapotranspiration (PET), calculated from near-surface atmospheric variables) to infer surface drought conditions5,11,13, together with independent, hydrological evidence such as observation-calibrated soil moisture reconstructions14, remotely sensed terrestrial water storage15, and observed streamflow declines16. However, substantial quantitative uncertainties remain specifically in the magnitude of drought trends inferred from PET-based drought indices, as such inferences depend critically on how atmospheric evaporative demand is estimated17,18,19,20. Given that PET-based indices remain among the most widely used tools for characterizing large-scale, long-term drought variability owing to their global data coverage and standardized formulation, these uncertainties arguably affect our ability to anticipate future hydroclimatic impacts and complicate downstream adaptation decision-making. Beyond the qualitative consensus of drought intensification, whether hydroclimatic extremes are accelerating (i.e., intensifying at an increasing rate) has recently emerged as a pertinent scientific question, motivated by two related lines of evidence: recent reports that global surface warming...
