The twenty-first century Colorado River hot drought and implications for the future

Bradley Udall, Jonathan Overpeck

Research output: Contribution to journalArticle

79 Citations (Scopus)

Abstract

Between 2000 and 2014, annual Colorado River flows averaged 19% below the 1906–1999 average, the worst 15-year drought on record. At least one-sixth to one-half (average at one-third) of this loss is due to unprecedented temperatures (0.9°C above the 1906–1999 average), confirming model-based analysis that continued warming will likely further reduce flows. Whereas it is virtually certain that warming will continue with additional emissions of greenhouse gases to the atmosphere, there has been no observed trend toward greater precipitation in the Colorado Basin, nor are climate models in agreement that there should be a trend. Moreover, there is a significant risk of decadal and multidecadal drought in the coming century, indicating that any increase in mean precipitation will likely be offset during periods of prolonged drought. Recently published estimates of Colorado River flow sensitivity to temperature combined with a large number of recent climate model-based temperature projections indicate that continued business-as-usual warming will drive temperature-induced declines in river flow, conservatively −20% by midcentury and −35% by end-century, with support for losses exceeding −30% at midcentury and −55% at end-century. Precipitation increases may moderate these declines somewhat, but to date no such increases are evident and there is no model agreement on future precipitation changes. These results, combined with the increasing likelihood of prolonged drought in the river basin, suggest that future climate change impacts on the Colorado River flows will be much more serious than currently assumed, especially if substantial reductions in greenhouse gas emissions do not occur.

Original languageEnglish (US)
Pages (from-to)2404-2418
Number of pages15
JournalWater Resources Research
Volume53
Issue number3
DOIs
StatePublished - Mar 1 2017

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twenty first century
river flow
drought
warming
river
climate modeling
greenhouse gas
temperature
river basin
climate change
atmosphere
basin
loss
trend

Keywords

  • climate change
  • Colorado River Basin
  • Colorado River Compact
  • megadrought

ASJC Scopus subject areas

  • Water Science and Technology

Cite this

The twenty-first century Colorado River hot drought and implications for the future. / Udall, Bradley; Overpeck, Jonathan.

In: Water Resources Research, Vol. 53, No. 3, 01.03.2017, p. 2404-2418.

Research output: Contribution to journalArticle

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