Even if there comes a day when the world completely stops emitting greenhouse gases into the atmosphere, coastal regions and island nations will continue to experience rising sea levels for centuries afterward, according to a new study by researchers at MIT and Simon Fraser University.In a paper published this week in the Proceedings of the National Academy of Sciences, the researchers report that warming from short-lived compounds — greenhouse gases such as methane, chlorofluorocarbons, or hydrofluorocarbons, that linger in the atmosphere for just a year to a few decades — can cause sea levels to rise for hundreds of years after the pollutants have been cleared from the atmosphere.