Efforts to reduce greenhouse gas emissions are falling far short of what a consensus of scientists argues is necessary to avoid potentially catastrophic increases in the mean global temperature. Increasingly, attention is devoted to understanding the vulnerability and adaptability of social and ecological systems to climate change in particular areas of the world. In the Western United States and other semi-arid regions of the world, possibly the most immediate, direct impacts of climate change involve the availability of water resources. Scientific evidence suggests that the West is likely to become hotter and drier and will experience greater variability in precipitation. These changes will affect tens of millions of residents in Western states, and nearly every sector of the economy, especially agriculture. The logic of common-pool resource theory is applied in this Theory to Practice essay to assess the vulnerability and adaptability to climate change of interstate river compacts and to offer recommendations for coping with climate change. Future areas of research on this critical topic are also outlined.

Expert e-commentaries by Richard Kashmanian and Roger Gorke of the U.S. Environmental Protection Agency, and by Elisabeth Graffy of the U.S. Geological Survey, can be found on the PAR website (go to, click on the link to PAR, and then on the Theory to Practice link).