Flash droughts exacerbate global vegetation loss and delay recovery

The increasing incidence of flash droughts globally presents a great challenge to the agriculture sector, ecosystem resilience and water resource systems. Here we introduce a methodology that improves the accuracy of quantifying drought-induced global vegetation loss (using Normalized Difference Vegetation Index (NDVI)-derived metric). Our results reveal that NDVI loss during flash droughts (9.0%) is approximately 1.5 times higher than that during conventional droughts (5.3%), highlighting the increasing role of flash droughts as the key driver of drought-induced NDVI loss worldwide. Furthermore, we identify a significant upward trend (1.8% per decade) in global NDVI loss due to flash droughts, primarily driven by the increasing frequency of such events, which account for 81.2% of the overall trend. Although NDVI typically recovers within 36 pentads across more than 9256.3 × 10⁴ km² of the global land surface after flash droughts, there is a notable increase (0.4 pentads per year) in NDVI recovery time from 1982 to 2020, particularly in tropical rainforests and temperate forests. These findings highlight the alarming ecological consequences of increasingly frequent and intense flash droughts, with impacts expected to intensify in the future.