see more

Chinese President Xi Jinping (C) shakes hands with US President Barack Obama and UN Secretary General Ban Ki-moon during a joint ratification of the Paris climate change agreement at the West lake State Guest House in Hangzhou on September 3, 2016. The United States and China on September 3 formally joined the Paris climate deal, with US President Barack Obama hailing the accord as the "moment we finally decided to save our planet". World leaders are gathering in Hangzhou for the 11th G20 Leaders Summit from September 4 to 5. / AFP / POOL / HOW HWEE YOUNG (Photo credit should read HOW HWEE YOUNG/AFP/Getty Images)

Chinese President Xi Jinping (C) shakes hands with US President Barack Obama and UN Secretary General Ban Ki-moon during a joint ratification of the Paris climate change agreement at the West lake State Guest House in Hangzhou on September 3, 2016.
The United States and China on September 3 formally joined the Paris climate deal, with US President Barack Obama hailing the accord as the "moment we finally decided to save our planet". World leaders are gathering in Hangzhou for the 11th G20 Leaders Summit from September 4 to 5. / AFP / POOL / HOW HWEE YOUNG        (Photo credit should read HOW HWEE YOUNG/AFP/Getty Images)