... Last week, the British medical journal The Lancet released the product of a year-long partnership with the University College London that attempted to assess the impact of global warming on global health. "Climate change," they concluded, "is the biggest global health threat of the 21 century." But crucially, it's a terribly unequal threat. The graphic below -- click for full size -- presents two distorted maps. The first shows the world in terms of carbon emissions. America, for instance, is huge. So is China. And Europe. Africa is hardly visible. The second map shows the world in terms of increased mortality -- that is to say, deaths -- from climate change. Suddenly, America virtually disappears. So does Europe. Africa, however, is grotesquely distended. South Asia inflates.

"Loss of healthy life years as a result of global environmental change (including climate change) is predicted to be 500 times greater in poor African populations than in European populations," predicts the report. Which presents a particularly tricky political problem. The developed countries that benefit most from fossil fuels will suffer least. The countries with the maximum incentive to prevent climate change have no power to do it. At Notre Dame, Obama exhorted the graduates to recognize that "that our fates are tied up, as Dr. King said, in a 'single garment of destiny.'" But we are not bound equally. No wonder Obama is looking to create a new coalition.