Anthropogenic climate change has reduced drought recovery probabilities across the western US

Abstract

During drought, resource managers want to know when the drought will end to make informed management decisions. However, as anthropogenic climate change has intensified drought conditions, we hypothesize it has affected drought recovery. Here, we leverage monthly self-calibrating Palmer Drought Severity Index data across the western US derived from observations and climate models, and quantify the probability of drought recovery following severe drought. We find that the probability of drought recovery is ~25–50% lower in recent decades (2000–2021) than in the historical record (1901–1980), with at least one-third of the reduced recovery probability attributable to anthropogenic climate change. Climate model ensembles show reduced recovery probabilities in the contemporary era (2000–2040), primarily due to increased evaporative demand in non-winter months, resulting in an additional 1–4 months for droughts to recover compared with the historical record. These findings suggest climate change is slowing drought recovery, with ramifications for water management decisions and drought planning.