U.N. Secretary-General says time is running out for world leaders to lead . Report is `` another canary in the coal mine , '' U.S. Secretary of State John Kerry says . The report comes as a new round of talks between Iran and six major powers over its nuclear program are set to begin Monday at Geneva. IPCC says it is more certain than ever that humans are causing temperature rises .
U.N. Secretary-General says time is running out for world leaders to lead . Report is `` another canary in the coal mine , '' U.S. Secretary of State John Kerry says . U.N. calls for the elimination of greenhouse gas emissions by 2100 . IPCC says it is more certain than ever that humans are causing temperature rises .