WASHINGTON — Massive crop devastation, melting glaciers, water shortages, millions of displaced people — all of these will drag the US military into conflict if global climate change goes unchecked, a Senate panel was warned today. The Senate Foreign Relations Committee hearing, convened by Senator John F. Kerry of Massachusetts, focused on what so far has received only modest attention in the climate change debate: the effect it is bound to have on national defense. ‘Addressing the consequences of changes in the Earth’s climate is not simply about saving polar bears or preserving the beauty of mountain glaciers,’ retired Navy Vice Adm. Lee F. Gunn, president of the American Security Project, told the panel. ‘Climate change is a threat to our national security.’ Gunn and other military specialists said that climate change could have broad effects on how the US military operates. It will likely expand the number of humanitarian missions the Pentagon will have to undertake, they said, and even change how it deploys its fighting forces. For example, they warned that rising sea levels could swamp critical US military bases in the Indian Ocean and even the headquarters of the Atlantic Fleet in Norfolk, […]