Reuters: Diplomats from the world’s biggest greenhouse gas polluters including the United States, China and India are set to take part in a forum on Monday at the U.S. State Department aimed at getting a U.N. agreement to curb global warming. The two-day meeting of so-called major economies is meant to jump-start climate talks in advance of a December deadline, when the international community meets in Copenhagen to find a follow-up agreement to the Kyoto Protocol, which limits climate-warming …