| Modellers have examined a wide array of ideal-world scenarios for regulation of greenhouse gases. In this ideal world, all countries limit emissions from all economic sectors; regulations are implemented by intelligent, well-informed forward-looking agents; all abatement options, such as new energy technologies and forestry offsets, are available; trade in goods, services and emission credits is free and unfettered. Here we systematically explore more plausible second-best worlds. While analysts have given inordinate attention to which countries participate in regulation—what we call “variable geometry”—which has a strikingly small impact on total world cost of carbon regulations if international trade in emission credits allows economies to... |
