Focus on reducing short-lived atmospheric pollutants

U.S. researchers say concentrating on reducing emissions of certain atmospheric pollutants could slow down sea level rise in the century by 25 to 50 percent. While the greenhouse gas carbon dioxide would remain a long-term problem, reducing four specific pollutants that cycle comparatively quickly through the atmosphere could temporarily hold down the rate of sea level rise, they said. "To avoid potentially dangerous sea level rise, we could cut emissions of short-lived pollutants even if we cannot immediately cut carbon dioxide emissions," Aixue Hu of the National Center for Atmospheric Research in Boulder, Colo., said. "This new research shows that society can significantly reduce the threat to coastal cities if it moves quickly on a handful of pollutants." Rising sea levels with global warming are a concern for many of the world's major cities like New York, Miami, Mumbai, Tokyo and Amsterdam, Netherlands, that are in low-lying areas by the water, an NCAR release said Monday. The researchers focused on emissions of four heat-trapping pollutants: methane, tropospheric ozone, hydrofluorocarbons, and black carbon. Although short-lived in the atmosphere, they can influence climate more quickly than carbon dioxide, which persists in the atmosphere for centuries, they said. "It is still not too late, by stabilizing carbon dioxide concentrations in the atmosphere and reducing emissions of shorter-lived pollutants, to lower the rate of warming and reduce sea level rise," said Veerabhadran Ramanathan of the Scripps Institution of Oceanography at University of California, San Diego, who led the study. "The large role of the shorter-lived pollutants is encouraging since technologies are available to drastically cut their emissions."