Just one month after leaving office, Michael Bloomberg (pictured) has been appointed a United Nations special envoy for cities and climate change. According to Reuters, U.N. Secretary General Ban Ki-moon said Bloomberg will help “raise political will and mobilize action among cities as part of his long-term strategy to advance efforts on climate change.” The former mayor is Johannesburg, South Africa this week for the fifth biennial C40 Cities Climate Leadership Group Mayors Summit. Bloomberg is the President of C40’s board, which is a “a network of the world’s megacities taking action to reduce greenhouse gas emissions.” This year’s conference is focused on creating liveable and sustainable cities. (Photo: Spencer T. Tucker )