Cooperative Institute for Research in Environmental Sciences
Friday, November 8, 2024

Heat, not lack of precipitation, is driving western US droughts

Evaporative demand plays bigger role than reduced precipitation in doughts since 2000

Bridge over a dried-up lake in the mountains
A bridge in Oroville, California over a dried-up lake
- Andrew Innerarity/California Department of Water Resources

Higher temperatures caused by anthropogenic climate change made an ordinary drought into an exceptional drought that parched the American West from 2020-2022, according to a new study by UCLA, NOAA, and CIRES scientists.  

The scientists found that evaporative demand, or the thirst of the atmosphere, has played a bigger role than reduced precipitation in droughts since 2000. During the 2020-2022 drought, evaporation accounted for 61% of the drought’s severity, while reduced precipitation accounted for only 39%.

“Research has already shown that warmer temperatures contribute to drought, but this is, to our knowledge, the first study that actually shows that moisture loss due to demand is greater than the moisture loss due to lack of rainfall,” said Rong Fu, a UCLA professor of atmospheric and oceanic sciences and the corresponding author of the study, which was published in the journal Science Advances.

Read the full story from NOAA Research.

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