The tragic irony of these island nations struggling against encroaching seas is that most of them don’t have much of a carbon footprint. Many residents live without cars or electricity and subsist on food they catch or grow themselves. In fact, countries at the greatest risk from rising seas, such as Kiribati, Nauru, the Marshall Islands and the Maldives, account for less than 0.1 percent of the total output of carbon dioxide emissions. (Combined, the U.S. and China account for nearly half.) Still, some of these nations are leading the world in reducing carbon emissions. Maldives President Mohamed Nasheed says his country will be carbon neutral by 2020, and he’s investing $1.1 billion in alternative energy. “Going green might cost a lot, but refusing to act now will cost us the Earth,” he said.