Climate Warming Favors the Early Emergence of Rapid Flash Drought

Global warming is expected to increase the likelihood of the rapid onset of drought development. Yet the timescale and region of the emergence and disappearance of the anthropogenic flash drought remain poorly constrained. Here, we assess the time of emergence and disappearance of soil-moisture-based flash drought across five onset timescales using a large ensemble of climate simulations. Anthropogenic influence is quantified through the Signal-to-Noise Ratio, defined as the forced response relative to internal climate variability. Rapid-onset FDs of 1 and 2 pentads onset timescale emerge earliest, in the mid-20th century, and expand over increasing land areas by the late century under SSP3-7.0. In contrast, moderate- to slow-onset FD, 3 to 5 pentads onset timescale emerge later in more spatially confined regions and disappear by 2100. The Time of disappearance patterns show broader regional variability, especially for slow-onset flash drought. Globally, median ToE occurs in the 2020s for rapid-onset flash drought and in later decades for longer-onset events, while disappearance occurs between the 2000s and 2050s, depending on onset timescales. Both emergence and disappearance exhibit strong regional variability and occur earlier under higher forcing. Mechanistically, Flash drought onset is governed by region-specific land–atmosphere processes, driven either by short-term precipitation deficits or rapid increases in evaporative demand. These results indicate an increasing tendency toward rapid, climate-driven flash drought emergence, emphasizing the need for region-specific early-warning strategies.