Agence France-Presse: The UN’s incoming chief on climate change cautioned on Wednesday it could take until 2050 to build the machinery that will ultimately tame greenhouse gases. In an interview with newswire reporters on the sidelines of UN talks in Bonn, Christiana Figueres said she was approaching her new job with optimism tempered by hard-edged realism. “I continue to be confident that governments will meet this challenge, for the simple reason that humanity must meet the challenge. We just …