CLIMATE CHANGE THREATENS THE WATER SUPPLY OS WESTERN NORTH AMERICA

19/05/2005 - Climate change is causing temperatures in western North America to rise. The region will experience less mountain snow and the timing of snowmelt will become unpredictable. The spring snowmelt, which supplies the region’s rivers, will also come earlier in the year.

A recent study examining a network of 302 western North America gauges from 1948 to 2002 found evidence that the snow is already melting earlier. The results of this study suggest that widespread trends of earlier onsets of springtime snowmelt and streamflow have taken place across most of western North America, affecting an area that is much larger than previously recognized. According to this study, snowmelt is occurring earlier in the year by 1–4 weeks.

A reduction in the amount and timing of snowmelt will have negative impacts on the many cities that rely heavily on mountain snow as a natural water reservoir and on hydroelectric energy utilities. Increased unpredictability and earlier timing will complicate water management, lead to increased flood risk, and intensify the summer drought with important impacts on agriculture, ecosystems, and wildfire risks.