LAUSR

Significance Flash drought has become increasingly common and threatens global food security. To help proactively manage and prevent the devastating effects of flash drought, we propose a flash drought early warning approach based on unusually slow increases or unusually fast decreases of a spaceborne proxy for plant photosynthesis, the solar-induced chlorophyll fluorescence (SIF). Relative to the operational US Drought Monitor, the SIF-based approach provides a lead time of 2 wk to 2 mo for flash drought onset and several weeks for drought recovery. It shows great potential to support the development of a global, agriculturally relevant early warning system that will help protect human food security, especially for regions where other drought indices are limited by sparse hydrometeorological data.