Everybody knows that climate change is one of the greatest threats facing the planet. The costs of failure to act are becoming unthinkable. Yet we know now that if developed countries agree to cut their collective emissions by 30% by 2020, annual economic growth would be trimmed by less than 0.2% and#8211; a small price to pay to avoid the potential long-term costs of climate change. Moreover, it is easy to appreciate the positive value of other benefits such as reduced air pollution, security of energy supply at predictable prices, and improved competitiveness through innovation....