By Clement Uwiringiyimana KIGALI (Reuters) - The world will not forgive leaders gathered in Rwanda this week if they fail to back a proposed agreement to cut greenhouse gases, a top U.N. official said on Thursday, calling the deal an easy one to achieve. Representatives from about 150 nations heard the appeal as they opened negotiations on a deal to phase down the use of factory-made hydrofluorocarbon (HFC) gases, which are used in refrigerators, air conditioners and aerosols. U.S. Secretary of State John Kerry was expected to join the conference later in the day.
