Climate change means water shortfall for the Colorado River
April 23rd, 2009 by Jim JustThe Colorado River system supplies water to tens of millions of people and millions of acres of farmland. But a new study by a pair of climate researchers at Scripps Institution of Oceanography, UC San Diego finds:
If human-caused climate change continues to make the region drier, scheduled deliveries will be missed 60-90 percent of the time by the middle of this century.
Even under conservative climate change scenarios, Scripps climate researcher David Pierce found that reductions in the runoff that feeds the Colorado River mean that it could short the Southwest of a half-billion cubic meters (400,000 acre feet) of water per year 40 percent of the time by 2025.
The paper, “Sustainable water deliveries from the Colorado River in a changing climate,” appears in the April 20 edition of the journal Proceedings of the National Academy of Sciences.
Lakes Mead and Powell were built during and calibrated to the 20th century, which was one of the wettest in the last 1,200 years. Tree ring records show that typical Colorado River flows are substantially lower, yet 20th Century values are used in most long-term planning of the River.
The Colorado River situation is not unique. The Columbia River, China’s Yellow River, India’s Ganges, and the Niger in Africa all have seen long-term declines in flow, according to a new analysis by scientists at the National Center for Atmospheric Research, in Boulder, Colo., and the College of William and Mary in Virginia.