The two papers are part of RFF's series of policy briefings on key issue in the debate over climate change. In his issue brief, Water Resources and Climate Change , RFF Senior Fellow Kenneth Frederick outlines the possible impacts of climate change on water supplies, including its implications for regional uncertainties, sea levels, and carbon dioxide effects. He starts by reviewing the most recent scientific assessment by the Intergovernmental Panel on Climate Change, which suggests that global warming will have a wide range of effects on water resources. Frederick also discusses the possible impacts of climate change on the various demands for water. Demands are outpacing supplies, water costs are rising sharply, and current uses are depleting or contaminating some valued resources.
Climate change has the potential to either aggravate or alleviate an area's water situation.
He notes that one of the more likely impacts, however, is in areas such as the western United States where precipitation is largely in the form of winter snowfall and streamflow largely comes from spring and summer snowmelt. Gradual warming in areas like this would likely result in a distinct shift in the relative amounts of snow and rain and in the timing of snowmelt and runoff. The resulting changes in runoff patterns could greatly increase the likelihood of flooding and reduce the availability of water during the spring and summer periods of peak demand for irrigation water. During most of this century, dams, reservoirs, pumps, canals and levees provided the primary means of adapting to climate and hydrological variables and meeting the growing demands for water. While the focus has been on supply-side solutions, institutions that can establish opportunities as well as incentives to use, abuse, conserve, or protect water resources were slow to adapt to the challenges of growing scarcity, rising instream values, and the vulnerability and variability of supplies.