U.S. President Barack Obama delivers remarks on the environment and climate change at the 20th Annual Lake Tahoe Summit at Harvey's in Stateline, Nevada, U.S. August 31, 2016. REUTERS/Jonathan Ernst

U.S. President Barack Obama delivers remarks on the environment and climate change at the 20th Annual Lake Tahoe Summit at Harvey’s in Stateline, Nevada, U.S. August 31, 2016. REUTERS/Jonathan Ernst

U.S. President Barack Obama delivers remarks on the environment and climate change at the 20th Annual Lake Tahoe Summit at Harvey's in Stateline, Nevada, U.S. August 31, 2016. REUTERS/Jonathan Ernst

September 2, 2016 5:05 PM (UTC+8)