Nature Water

Published date March 13, 2023

Changing intensity of hydroclimatic extreme events revealed by GRACE and GRACE-FO

Study key findings & significance

  • Intense drought and heavy rainfall events occurred more often in the last eight years — the hottest years on record — than in the previous decade
  • Warmer global temperatures are increasing the extent, duration, and severity of these extremes, and are having more of an effect than natural climate patterns
  • The study provides an emerging picture of distortions in the total amount of water both above ground and also in aquifers deep beneath the Earth’s surface, where most of the freshwater that humans depend upon comes from
  • The study uses direct NASA satellite observations, providing “indisputable” evidence that warmer global temperatures are increasing extreme droughts and floods

Author quotes

“As the world warms, we’re having more intense and more frequent wet and dry events around the world, which gives us a little insight into what’s going to happen in the future. This is an observation. It’s actual data.”

Matthew Rodell, study co-author and hydrologist at NASA


Distortion of the water cycle, particularly of its extremes (droughts and pluvials), will be among the most conspicuous consequences of climate change. Here we applied a novel approach with terrestrial water storage observations from the GRACE and GRACE-FO satellites to delineate and characterize 1,056 extreme events during 2002–2021. Dwarfing all other events was an ongoing pluvial that began in 2019 and engulfed central Africa. Total intensity of extreme events was strongly correlated with global mean temperature, more so than with the El Niño Southern Oscillation or other climate indicators, suggesting that continued warming of the planet will cause more frequent, more severe, longer and/or larger droughts and pluvials. In three regions, including a vast swath extending from southern Europe to south-western China, the ratio of wet to dry extreme events decreased substantially over the study period, while the opposite was true in two regions, including sub-Saharan Africa from 5° N to 20° N.