Reuters: The top U.S. climate envoy on Thursday urged other countries to set carbon emission targets to fight global warming by the end of this month as a crucial step toward a global legally-binding agreement. Todd Stern said the Copenhagen Accord hammered out last month provided the best path toward a concrete, binding climate agreement, but first countries needed to pledge targets and put them in the document. “We have an accord that is lumbering down the runway and we need for it to …