despite overwhelming scientific evidence that the world<u+2019>s climate is changing, the president-elect of the united states, donald j. trump , has long been on the side of the deniers. in 2012, he posted on twitter a couple of messages that asserted that climate change was a hoax that china had devised to secure an unfair trade advantage, presumably because the obama administration was seeking to curb coal consumption in the united states. <u+201c>the concept of global warming was created by and for the chinese in order to make u.s. manufacturing non-competitive,<u+201d> mr. trump wrote. that message has been reshared more than 104,000 times and <u+201c>liked<u+201d> nearly 66,000 times. on wednesday, a deputy foreign minister of china, liu zhenmin, told reporters at a climate conference in marrakesh, morocco, that starting from the 1980s, the administrations of mr. trump<u+2019>s republican predecessors <u+2014> presidents ronald reagan and george bush <u+2014> supported climate change negotiations under a united nations panel. that was apparently an important moment in china<u+2019>s realization of the onset of climate change. mr. liu said that president xi jinping brought up the issue in his call with mr. trump on monday, saying that china would continue its struggle to curb climate change <u+201c>whatever the circumstances,<u+201d> according to bloomberg news . china<u+2019>s lecturing the united states on the need to fight climate change is a reversal from the usual roles and a sign that, with the united states governed by mr. trump, china may have to take the leadership position in the global campaign. under president obama, the united states government persuaded china to announce important pledges in the fight against climate change. in 2014, mr. xi stood next to mr. obama in beijing and said that china would ensure that its greenhouse gas emissions peaked by 2030 and that 20 percent of its energy would come from non-fossil fuel sources by that year. mr. obama pledged to greatly reduce coal use by 2025. diplomats and climate negotiators have been meeting in marrakesh this week to discuss steps needed to carry out the paris climate agreement, which was negotiated last year and which china and the united states signed this year. there has been much anxiety over whether mr. trump might try to withdraw the united states from the pact after he takes office. but the agreement now has enough countries as signatories to make it legally binding, and mr. trump may have a hard time extricating the united states from the deal. in addition, other countries have said they intend to go ahead with the plan on their own. <u+201c>it is a new world order,<u+201d> erik solheim, the executive director of the united nations environment program, said in marrakesh. <u+201c>leadership on climate change policy has now gone to the developing countries, china among them.<u+201d> however, having the united states on board would be hugely helpful in trying to meet the ambitious goal of keeping the future increase in global temperatures below 3.6 degrees fahrenheit . the united states is the second-leading emitter of greenhouse gases, after china. researchers say greenhouse gas emissions have leveled off for at least three years now, mostly because of a drop in coal consumption in china. a major reason is the slowing chinese economy. but it is still unclear whether china<u+2019>s emissions have hit a peak , well before the 2030 deadline. china is already grappling with the direct consequences of climate change, like melting glaciers in western mountain ranges and expanding deserts . follow edward wong on twitter @comradewong . get news and analysis from asia and around the world delivered to your inbox every day with the today<u+2019>s headlines: asian morning newsletter. sign up here . a version of this article appears in print on november 19, 2016, on page a16 of the new york edition with the headline: in sign of shifting roles, china gives u.s. a lecture on climate change. order reprints | today's paper | subscribe
trump has called climate change a chinese hoax. beijing says it is anything but.
edward wong