By 2050, the average moisture conditions in the southwestern United States will rival the worst conditions observed in the 1953–1956 and 2000–2003 droughts. These changes will be a consequence of increased temperatures and will occur even if precipitation levels remain fairly constant. As a result, all predicted scenarios of Colorado River flow at Lees Ferry, Ariz, indicate that within 20 years, discharge there will be insufficient to meet current consumptive water resource demands.
This sobering analysis was presented by Martin Hoerling and Jon Eischeid of the U.S. National Oceanic and Atmospheric Administration at the meeting Managing Drought and Water Scarcity in Vulnerable Environments—Creating a Roadmap for Change in the United States, presented by the Geological Society of America (GSA) in partnership with 20 other scientific organizations. Participants, including physical scientists, life scientists, social scientists, policy makers, Native Americans, water managers, and water users, represented a broad and diverse range of interests. Some preliminary findings are as follows.