Among the more than 310,000 demonstrators marching through Manhattan in last week’s People’s Climate March were contingents of physicians. Now The Journal of the American Medical Association, the voice of the nation’s powerful medical establishment, has issued a call to arms to doctors, urging those in health-related fields to throw their weight behind climate change prevention efforts.

As heads of state from David Cameron to Barack Obama meet in New York for a UN climate summit hosted by Ban Ki-moon, expectations are high for bold commitments on cutting greenhouse gas emissions. Use this interactive, in-depth map to find out who the big polluters are internationally, how China’s emissions have grown stratospherically and see who is most vulnerable to global warming’s impacts. Turn your sound up to hear the introduction to the map