Experts and activists have welcomed Xi Jinping’s announcement China is to end involvement in coal-fired power stations overseas but called for more detail and clarity on how it will be translated into reality. The declaration, which came in a pre-recorded address to the UN general assembly, followed the US president, Joe Biden, saying it would double climate funding for developing nations. “China will step up support for other developing countries in developing green and low-carbon energy, and will not build new coal-fired power projects abroad,” Xi told the world body. Global Energy Monitor (GEM), a US thinktank, told Reuters it could affect 44 coal plants earmarked for Chinese state financing. Both announcements were welcomed by the UN secretary general, António Guterres, but he said the world still had “a long way to go” to make Cop26 climate summit in Glasgow a success. He urged countries to “go the extra mile” and bring their “highest level of ambition” to Glasgow, to keep the 1.5C goal – the lowest threshold in the 2015 Paris agreement – within reach. Swiftly ending coal use is seen as crucial to cap global heating at below 2C, and ideally 1.5C, to avoid rapidly worsening climate threats. China has been under heavy diplomatic pressure in recent months to put an end to its coal financing overseas and its move follows similar announcements by South Korea and Japan earlier this year. Together, the three countries were responsible for more than 95% of all foreign financing for coal firepower plants, with China making up the bulk, according to Georgetown University. “Many questions can be asked about the announcement, including whether it will be implemented immediately, does it include only financing or also construction, does it apply to state actors only, will it lead to a similar moratorium on fossil fuels?” said Li Shuo, a senior adviser at Greenpeace east Asia. “The answer to them is simply ‘we don’t know’. Seeking clarification should be a priority for the next few weeks.” Scott Moore, the director of China Programs and Strategic Initiatives at the University of Pennsylvania, also called for more detail. “While [Xi’s announcement] was hugely important, we need more clarity as to how this applies to all forms of financing as well as construction; and certainly one hopes this is a first step toward phasing out financing for all fossil fuel infrastructure abroad,” he said. Coal remains a mainstay for power generation in Asia, which accounts for 75% of global coal demand, according to the International Energy Agency. China, the world’s largest greenhouse gas emitter, is still heavily reliant on coal for its domestic energy needs. Despite pledges to peak coal consumption before 2030, China brought 38.4 gigawatts of new coal-fired power into operation domestically last year – more than three times what was brought on line globally. Beijing has pledged to cut China’s coal consumption after 2026. Xi repeated pledges at the UN that China would achieve a peak in carbon dioxide emissions before 2030 and carbon neutrality before 2060. “This [is a] major step, in spite of worsening tensions between the US and China, suggesting that a more competitive stance hasn’t impeded China’s ability to make more ambitious climate commitments,” said Moore of the overseas financing announcement. The US climate envoy, John Kerry, on Wednesday said he plans to visit China in the coming weeks, saying Xi’s coal announcement showed China was “really being serious” about tackling climate change and making China “a positive player”. “I’m going to be going back to China somewhere in the next weeks,” he told MSNBC, adding he was confident Biden and Xi would also meet at some point but he did not know when. Thom Woodroofe, a former climate diplomat and a fellow at the Asia Society Policy Institute, described Xi’s pledge as drawing a “big line in the sand”. “It is further evidence China knows the future is paved by renewables. The key question now is when they will draw a similar line in the sand at home,” he said. “It was also in many ways an easy decision for China to take ahead of Cop26 – far easier than peaking emissions by 2025, which many had hoped [Xi would do]. “The key thing to watch now is not just what China does at home, but also how much weight this announcement will hold. Will Beijing be able to rein in finance provided by all Chinese banks? What about the huge Chinese labour force involved in the construction of these coal plants?” Meeting its goal of net zero emissions at home by 2060 would also require significant action, with China needing to shut down nearly 600 of its coal-fired power plants in the next decade and replacing them with renewable electricity generation, according to a report by analysis company TransitionZero in April this year. Unless China reduces its own emissions sharply in the next 10 years, the world stands little chance of limiting global heating to 1.5C.