And cap-and-trade will be just one part of a wide-ranging agreement announced between the two countries, building on a breakthrough deal forged by President Obama and President Xi last November in Beijing, in which China promised to finally start to taper its coal use. In that deal, the US pledged to cut emissions by up to 28 percent by 2025, while China agreed that its emissions would peak around 2030 and promised to get one-fifth of its power from non-fossil-fuel energy sources by the same year.