The effects of decisions made today about many environmental policies - including climate change and nuclear waste - will be felt across hundreds, if not thousands, of years. In the case of issues with such long-term ramifications, analysts often employ discount rates to compare present and future costs and benefits.

In this book, Paul Portney and John Weyant have assembled some of the world's foremost economists to reconsider the purpose, ethical implications, and application of discounting in light of recent research and current policy concerns.