The critique sought to portray China and its leader, Xi Jinping — who is notably absent from COP26 — as large-economy laggards in the race to limit rising temperatures. It was also aimed at shifting criticism away from America’s domestic struggles in pushing to reduce emissions. Briefing reporters on Air Force One, President Joe Biden’s national security adviser, Jake Sullivan, called the Chinese “significant outliers” among countries that have made commitments in an attempt to limit warming to 1.5 degrees. Sullivan said that China had “an obligation to step up to greater ambition as we go forward.” Asked about how the tense US-China relationship was affecting climate talks globally, Sullivan heaped blame on Beijing, calling the country’s climate steps “deeply asymmetrical.” “The United States, despite whatever difficulties we have with China, is stepping up,” Sullivan said. “We’re going to do 50% to 52% reduction by 2030. We’re coming forward with all of our commitments — we’re filling our end of the bargain at COP.” China is “a big country with a lot of resources and a lot of capabilities,” he added, “and they are perfectly well capable of living up to their responsibilities.” Diplomats from some of the world’s most vulnerable countries have avoided openly criticising China. When asked about the new target that Beijing announced last week, which is largely indistinguishable from its 2015 target of peaking emission before 2030, many diplomats said only that all Group of 20 nations must be more ambitious. “The world needs more,” Tina Stege, a climate ambassador for the Marshall Islands, said in a statement. “China can do more, and it should, as should all members of the G-20.” Alf Wills, a former chief negotiator for South Africa, said that developing nations were loath to publicly criticise China for several reasons. For one, Chinese diplomats can be instrumental in pushing wealthy nations to deliver funding for poor countries. For another, China now far outpaces the United States in delivering aid to the developing world. “To a large extent China represents, from an economic perspective, pretty much an economic superpower,” Wills said, “particularly among developing countries.” © 2021 The New York Times Company