A comprehensive review of recent progress on the drought-flood abrupt alternation

Drought-flood abrupt alternation (DFAA) events, characterized by rapid shifts between drought and flood conditions, are receiving increased attention due to their exacerbated impacts on human societies and ecosystems. This review systematically summarizes recent advances in the definitions, identifications, characterizations, attributions, effects, and future projections of DFAA events, along with current challenges and future research perspectives. Despite a significant increase in flood-related disasters since 2000, compounded by a notable rise in drought frequency, a unified definition of DFAA remains elusive. We explore meteorological, hydrological, and agricultural DFAA indices, highlighting limitations of threshold-based methods and indicator approaches. The synergistic interaction between anthropogenic climate change, driving a ∼7 % increase in atmospheric water vapor per degree Celsius, and natural climate variability exacerbates DFAA events. Climate projections indicate a potential increase in DFAA frequency, with global warming projected to raise the risk of DFAA, disproportionately affecting poorer populations. The review underscores the detrimental impacts of DFAA on crop yields and ecosystems, increasing soil erosion and wildfire risks. Future research should focus on standardized methodologies, integrated datasets, uncertainty analyses, and non-stationary fitting to improve the impact assessment and risk management of DFAA.