When dealing with multiple greenhouse gases, we need some way to establish equivalence among gases. The Intergovernmental Panel on Climate Change (IPCC) has suggested the use of global warming potentials (GWPs) for making such trade-offs. We begin by examining the implications of such an...

A particular ceiling on atmospheric CO2 concentrations can be maintained through a variety of emission pathways. Over the past decade, there has been considerable debate over the characteristics of a least-cost pathway. Some have suggested that a gradual departure from the emissions baseline...