Increasing risk of simultaneous occurrence of flash drought in major global croplands

Abstract

Simultaneous occurrence of flash drought in major croplands can pose challenges for global food security. However, drivers of flash drought co-occurrence in the observed and future climate remain unrecognized. Using observations and climate model simulations, we examine the simultaneous occurrence of flash droughts in 16 major global croplands that grow wheat, rice, and maize. We show that significant warming combined with decreasing precipitation led to an increased frequency of flash droughts in several major croplands during the observed climate (1981-2020). The simultaneous occurrence of flash drought in many croplands in the same year has significantly (p-value = 0.007) increased during 1981-2020 and is likely to continue. Nine out of 16 major global croplands are projected to witness an increased frequency of flash droughts under the warming climate. The observed and projected rise in flash droughts in global croplands is mainly driven by vapor pressure deficit. The positive phase of El Nino Southern Oscillation influences flash drought co-occurrence in 10 out of 16 major cropland regions and remains a dominating factor of flash droughts co-occurrence in the future. Enhanced climate warming and increased frequency of El Nino events can further enhance the occurrence of simultaneous flash droughts in several major croplands, with substantial implications for food production.