One last chance to save the world - for months, that’s how the United Nations summit on climate change in Copenhagen, which starts in early December, was being hyped. Officials from 192 countries were finally going to make a deal to keep global temperatures below catastrophic levels. ...

Among the smartest and most promising - not to mention controversial - proposals is "climate debt," the idea that rich countries should pay reparations to poor countries for the climate crisis. In the world of climate-change activism, this marks a dramatic shift in both tone and content. American environmentalism tends to treat global warming as a force that transcends difference : We all share this fragile blue planet, so we all need to work together to save it. But the coalition of Latin American and African governments making the case for climate debt actually stresses difference, zeroing in on the cruel contrast between those who caused the climate crisis (the developed world) and those who are suffering its worst effects (the developing world). Justin Lin, chief economist at the World Bank, puts the equation bluntly : "About 75 to 80 percent" of the damages caused by global warming "will be suffered by developing countries, although they only contribute about one-third of greenhouse gases."

Climate debt is about who will pick up the bill. The grass-roots movement behind the proposal argues that all the costs associated with adapting to a more hostile ecology - everything from building stronger sea walls to switching to cleaner, more expensive technologies - are the responsibility of the countries that created the crisis. "What we need is not something we should be begging for but something that is owed to us, because we are dealing with a crisis not of our making," says Lidy Nacpil, one of the coordinators of Jubilee South, an international organization that has staged demonstrations to promote climate reparations. "Climate debt is not a matter of charity."

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