Research Highlights
Nature Reports Climate Change
Published online: 30 April 2009 | doi:10.1038/climate.2009.39
High and dry
Alicia Newton
Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0812762106 (2009)
US BUREAU OF RECLAMATION
Millions of residents in Mexico and the southwestern United States who rely on the Colorado River for their water supplies may be left high and dry by the middle of the century. If temperatures continue to rise in the region, as anticipated, less runoff will mean that by 2050 the river will be unable to deliver the required water almost 60 to 90 per cent of the time.
Tim Barnett and David Pierce of the Scripps Institution of Oceanography in San Diego, California, assessed the ability of the Colorado River to meet the demand from scheduled future water deliveries under different climate change scenarios. The authors found that under a conservative scenario of 10 per cent less runoff, expected water deliveries will fall short by 2040, and that with 20 per cent less runoff, water supplies will be inadequate to meet demand by 2025.
By mid-century, shortfalls are anticipated to exceed 1 billion cubic metres of water each year, equivalent to the water usage of 1.6 million households. Given the expected influx of 20–30 million people to the region by 2050, the authors conclude that drastic changes in water use will be necessary to prevent regular shortages.
