I review the complex welfare economic issues that arise in environmental decision-making over very long periods, as in cases relating to climate change and biodiversity loss. I also consider the issues that arise in choosing a discount rate to apply to very long-run projects and indicate how...

The Conference of the Parties (COP) has proven a valuable outlet to advance the climate agenda. The combination of high media coverage, extremely high expectations set by influential environmentalists, and unanimity rules has, however, started to limit its effectiveness. Technical issues can...