Environmental imperative has arrived once more at its inevitable intersection with economic realism. For the rest of the world, navigation through the impasse in Canada will be instructive.Canada’s federal government has set ambitious targets for lowering emissions of greenhouse gases (GHGs). In a policy statement called “Turning the Corner,” it pursues cuts during 2006-20 of 20% and through 2050 of 60-70%. The program requires emission reductions at the company level. Companies can lower emissions at their facilities, invest in emission-reducing technology, trade emission allowances, and use the Kyoto Treaty’s “clean development mechanism,” which credi...