United Nations Secretary-General Ban Ki-moon (L) speaks during a press conference in Marrakech, Morocco, on Nov. 15, 2016. The joint High-Level Segment of the 22nd Conference of the Parties to the United Nations Framework Convention on Climate Change (COP22) and the 12th Conference of the Parties to the Kyoto Protocol (CMP12) opens here Tuesday. (Xinhua/Zhao Dingzhe)