Over the past two decades, the influence of ENSO (El Niño-Southern Oscillation) has become a key factor in the emergence of extreme changes in water supplies on a global scale. These climatic phenomena contribute to the simultaneous occurrence of abnormally wet or dry conditions across various continents.
Bridget Scanlon, a co-author of the study, explained: “At a global level, we can identify which regions are simultaneously experiencing excess moisture or, conversely, a deficit. This, in turn, affects water availability, agricultural production, and international food trade—all of which have global significance.”
For their analysis, the researchers used data from NASA's GRACE and GRACE-FO satellites, which track gravitational anomalies resulting from changes in water mass. This approach allows for information on water supplies, including rivers, lakes, soil moisture, and groundwater.
The study identified specific examples of synchronization of water extremes. For instance, in the mid-2000s, El Niño coincided with a severe drought in Southern Africa, and in 2015-2016, it coincided with drought in the Amazon. At the same time, La Niña in 2010-2011 exacerbated wet conditions in Australia, southeastern Brazil, and Southern Africa.
Additionally, the study showed a global trend: until 2011, the planet more frequently experienced abnormally wet conditions, while after 2012, there has been a predominance of dry phenomena.
Jay T. Rieger, who was not involved in the study, noted that satellite data helps identify patterns of how climate cycles impact water crises.
“These observations truly capture the rhythms of major climate cycles, such as El Niño and La Niña, and their impact on the floods and droughts faced by humanity. These are not just isolated events in the Pacific Ocean, but processes that ultimately affect all of us on land,” he added.
Bridget Scanlon also emphasized that the study's findings highlight the need to revise approaches to water resource management: instead of focusing solely on water scarcity, it is important to consider fluctuations between excess and deficit.
