Reuters: World leaders on Friday rallied to a diplomatic offensive to forge a U.N. climate deal in Copenhagen next month and U.N. Secretary-General Ban Ki-moon said an agreement was "within reach". Ban, and Danish Prime Minister Lars Lokke Rasmussen who will host the December 7-18 U.N. climate talks, hailed what they portrayed as a growing international momentum toward a pact to curb greenhouse gas emissions and limit global warming. "Our common goal is to achieve a firm foundation for …