WASHINGTON -- U.S. government scientists Friday said the long-term outlook for global warming may be more dire than suggested by this week's United Nations' report, which they say doesn't fully address the impact of clouds and melting glaciers. Recent evidence of accelerated melting of glaciers in Greenland and the Antarctic ice cap came too late to be included in the report released Thursday by the U.N.-sponsored Intergovernmental Panel on Climate Change. Glaciers are among the largest sources of fresh water in the world and are contributing to rising ocean levels. Rising sea levels could expose population centers bordering the ocean...