Scientists find what links floods and droughts across the planet

A University of Texas study reports that ENSO (El Niño–La Niña) has been the main driver of extreme changes in total water storage worldwide over the past 20 years, often synchronizing wet and dry conditions across distant regions. Researchers used gravity data from NASA's GRACE and GRACE-FO satellites and probabilistic models to reconstruct gaps in the 2002–2024 record.

Scientists at the University of Texas at Austin examined how droughts and floods develop and spread globally and reported that ENSO (El Niño–La Niña) has played a leading role in driving extreme changes in total water storage over the past two decades. The team used gravity measurements from NASA's GRACE and GRACE Follow‑On satellites to estimate total water storage and applied probabilistic models to fill an 11‑month gap in the satellite record. By classifying wet extremes above the 90th percentile and dry extremes below the 10th percentile, the researchers mapped how extremes line up across continents. The study covers the 2002–2024 period and was published in AGU Advances, with funding from the UT Jackson School of Geosciences. Key findings: - ENSO has been identified as the leading driver of extreme changes in total water storage worldwide during the study period. - ENSO-related patterns tend to synchronize wet or dry extremes so that distant regions can experience unusually wet or dry conditions at the same time. - The analysis relied on GRACE and GRACE‑FO gravity data, percentile-based definitions of extremes, and probabilistic reconstruction to address gaps in the satellite record. - The authors note a shift around 2011–2012 from more widespread wet conditions before 2011 to a greater prevalence of dry extremes afterward, linked to a persistent Pacific pattern. Summary: Synchronized extremes linked to ENSO can affect water availability, food production and trade by creating simultaneous wet or dry conditions across multiple regions. Undetermined at this time.