The Christian Science Monitor Discoveries Blog has an interesting article on the global decline of river flows. “Too many ’straws’ sucking water out of the Colorado River” describes how by 2050, the Colorado River be unable to live up to its current allocation scheme 60-90 percent of the time; even absent climatic changes, scheduled deliveries would be unmet 40 percent of the time. This news is based on a recent study by scientists at the Scripps Institution of Oceanography and published in the April 20 edition of the journal Proceedings of the National Academy of Sciences.
According to a forthcoming study by the National Center for Atmospheric Research and the College of William and Mary, the Colorado is not alone in suffering such shortfalls. The study reveals that over the past 60 years, some 300 of the world’s largest rivers have experienced significant changes in flow rates. While some rivers have gained volume, the rivers with reduced flow rates outnumbered the ones with higher flow rates by 2.5 to 1. As for the culprit, the study suggests that large dams and diversion projects have certainly caused their share of water problems. However, they place greater burden on global climate change, which is altering precipitation patterns and increasing the rate of evaporation.
This study, which represents the most comprehensive data base yet assembled to track river flows (assessing the flows of 925 of the planet’s largest rivers), is scheduled for publication in the May 15 issue of the American Meteorological Society’s Journal of Climate. You can download the research paper here, or view a simplified description of the study’s findings here.