Agence France-Presse: The last edge of the Greenland ice sheet that had resisted global warming has now become unstable, adding billions of tonnes of meltwater to rising seas, scientists say. In a study published in the journal Nature Climate Change, they say a surge in temperature from 2003 has eased the brakes on a long "river" of ice that flows to the coast in northeastern Greenland. Known as an ice stream, the "river" takes ice from a vast basin and slowly shifts it to the sea - in the same way the Amazon River...