President Xi Jinping of China will make a landmark commitment on Friday to start a national program in 2017 that will limit and put a price on greenhouse gas emissions, Obama administration officials said Thursday. The move to create a so-called cap-and-trade system would be a substantial step by the world’s largest polluter to reduce emissions from major industries, including steel, cement, paper and electric power. The announcement, to come during a White House summit meeting with President Obama , is part of an ambitious effort by China and the United States to use their leverage internationally to tackle climate change and to pressure other nations to do the same. Joining forces on the issue even as they […]