Reuters: U.N. talks on a new climate treaty due to be agreed in December risk failure unless negotiations accelerate, a senior U.N. official said on Friday after a sluggish week-long session involving 180 countries. Many nations also bemoaned scant progress at the Aug 10-14 talks that failed to break deadlocks on issues such as sharing out curbs on greenhouse gases among rich and poor, and raising funds to help developing nations cope with global warming. "If we continue at this rate …