An iceberg floats in a bay off Ammassalik Island, Greenland July 17, 2007. U.N. Secretary-General Ban Ki-moon told an unprecedented summit on climate change Monday Sept. 24, 2007 that "the time for doubt has passed" and a breakthrough is needed in global talks to sharply reduce emissions of global-warming gases. Arctic sea ice melted to its lowest level ever this year, shattering a record set in 2005 and continuing a trend spurred by global warming