More rapid intensification of flash droughts with shorter onset timescales

Abstract Flash droughts can cause more serious environmental and agricultural impacts than traditional droughts because of the sudden onset and rapid intensification. However, it remains unclear how rapidly flash droughts develop and intensify worldwide. Here, we present for the first time a comprehensive assessment of the onset development phase of flash droughts on a global scale. We find that humid and semi-humid regions are more vulnerable to flash droughts. And 56.8% of flash droughts are extremely fast-developing (timescale ≤ 15 days) and intensifying (intensification rate ≥ 12.5th percentile) droughts during 2000–2019. More importantly, the evolution of flash droughts is accelerating with a significantly shorter timescale and a faster intensification, implying that less time is left for early warning and impact preparation. Our findings suggest that urgent action is needed to upgrade existing drought monitoring systems for better capturing the more rapid onset and evolution of flash droughts.