Recalculating the Costs of Global Climate Change

The Stern Review on the Economics of Climate Change was released Oct. 30 and became front-page news because of its striking conclusion that we should immediately invest 1 percent of world economic activity (referred to as global gross domestic product in the report) to reduce the impact of global warming. The British report warned that failing to do so could risk future economic damages equivalent to a reduction of up to 20 percent in global G.D.P.