Associated Press: In a dramatic finish to a U.N. climate conference, world leaders adopted a breakthrough plan Saturday to broker a new pact by 2009 to battle global warming, after the United States backed down in a dispute with developing nations and Europe. The U.S. opposition had drawn loud boos and sharp floor rebukes – "If you are not willing to lead, then get out of the way!" one delegate demanded – before Undersecretary of State Paula Dobriansky reversed herself, allowing the adoption …