Leonardo DiCaprio (front), actor and UN Messenger of Peace, speaks during the opening ceremony of the Climate Summit at the UN headquarters in New York, on Sept. 23, 2014. The one-day summit, convened by UN Secretary-General Ban Ki-moon, is expected to galvanize global action on climate change. (Xinhua/Niu Xiaolei)

Li Bingbing (front), actress and UN Environment Programme Goodwill Ambassador, speaks during the opening ceremony of the Climate Summit at the UN headquarters in New York, on Sept. 23, 2014. The one-day summit, convened by UN Secretary-General Ban Ki-moon, is expected to galvanize global action on climate change. (Xinhua/Niu Xiaolei)

Li Bingbing, actress and UN Environment Programme Goodwill Ambassador, speaks during the opening ceremony of the Climate Summit at the UN headquarters in New York, on Sept. 23, 2014. The one-day summit, convened by UN Secretary-General Ban Ki-moon, is expected to galvanize global action on climate change. (Xinhua/Niu Xiaolei)

Leonardo DiCaprio, actor and UN Messenger of Peace, speaks during the opening ceremony of the Climate Summit at the UN headquarters in New York, on Sept. 23, 2014. The one-day summit, convened by UN Secretary-General Ban Ki-moon, is expected to galvanize global action on climate change. (Xinhua/Niu Xiaolei)

Leonardo DiCaprio, actor and UN Messenger of Peace, speaks during the opening ceremony of the Climate Summit at the UN headquarters in New York, on Sept. 23, 2014. The one-day summit, convened by UN Secretary-General Ban Ki-moon, is expected to galvanize global action on climate change. (Xinhua/Niu Xiaolei)

Li Bingbing, actress and UN Environment Programme Goodwill Ambassador, speaks during the opening ceremony of the Climate Summit at the UN headquarters in New York, on Sept. 23, 2014. The one-day summit, convened by UN Secretary-General Ban Ki-moon, is expected to galvanize global action on climate change. (Xinhua/Niu Xiaolei)