In arid Western states, the climate is growing warmer and drier, leading to increased demand for water resources from humans and ecosystems. Now, the atmosphere across much of the U.S. is also demanding a greater share of water than it used to, according to a new study by a team from DRI, University of California, Merced, and Scripps Institution of Oceanography at UC San Diego.
The study was published in the Journal of Hydrometeorology and assessed trends in evaporative demand across the U.S. during a 40-year period from 1980-2020 using five datasets. Evaporative demand, sometimes described as “atmospheric thirst,” is a measure of the potential loss of water from the earth’s surface to the atmosphere based on variables including temperature, humidity, wind speed, and solar radiation.
The team’s findings showed substantial increases in atmospheric thirst across much of the Western U.S. during the past 40 years, with the largest and most robust increases in an area centered around the Rio Grande and Lower Colorado rivers. These regions have experienced changes on the order of two-to-three standard deviations from what was seen during the baseline period of 1980-2000.
Read more at: Desert Research Institute
A dry Nevada landscape. New research led by DRI scientists shows that atmospheric thirst is a persistent force in pushing Western landscapes and water supplies toward drought. (Photo Credit: Riccardo Panella, DRI.)