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Projections of declining surface-water availability for the southwestern United States

Seager, Richard; Ting, Mingfang; Li, Cuihua; Naik, Naomi H.; Cook, Benjamin I.; Nakamura, Jennifer A.; Liu, Haibo

Global warming driven by rising greenhouse-gas concentrations is expected to cause wet regions of the tropics and mid to high latitudes to get wetter and subtropical dry regions to get drier and expand polewards. Over southwest North America, models project a steady drop in precipitation minus evapotranspiration, P−E, the net flux of water at the land surface, leading to, for example, a decline in Colorado River flow. This would cause widespread and important social and ecological consequences. Here, using new simulations from the Coupled Model Intercomparison Project Five, to be assessed in Intergovernmental Panel on Climate Change Assessment Report Five, we extend previous work by examining changes in P, E, runoff and soil moisture by season and for three different water resource regions. Focusing on the near future, 2021–2040, the new simulations project declines in surface-water availability across the southwest that translate into reduced soil moisture and runoff in California and Nevada, the Colorado River headwaters and Texas.

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Title
Nature Climate Change
DOI
https://doi.org/10.1038/nclimate1787

More About This Work

Academic Units
Lamont-Doherty Earth Observatory
Ocean and Climate Physics
Published Here
July 20, 2021