Agence France-Presse: Climate change is speeding up the melting of the great sheet of ice covering Greenland, a frozen mass the size of Alaska that holds an estimated 10 percent of the worlds ice--and scientists are sure of it.
If the entire ice sheet melted, it would raise the level of the sea by more than 20 feet worldwide.
But within that certainty, there are still many open and important questions. How much faster is the ice sheet melting? Is that melt affecting the ice sheet in other ways? What does it mean...