Chinese President Xi Jinping will announce at a White House summit meeting on Friday a commitment to start a national cap-and-trade system in 2017 that will limit and put a price on greenhouse gas emissions, The New York Times reported, citing Obama administration officials. The agreement, which American officials said had been in the works since April, would be China’s first commitment to a specific plan to limit emissions. Xi will pledge to put in place a “green dispatch” program intended to create a price incentive for generating power from low-carbon sources, officials said, and agree to help provide financing to poorer countries to pay for projects that reduce harmful emissions.