The world might be witnessing the bending of a key climate curve. Various projections have suggested that carbon emissions from China, the world's largest emitter, will probably peak soon — if they haven’t already — well ahead of Beijing’s pledge that they would peak before 2030.

“What happens with China’s emissions in the next year and next decade is absolutely decisive for the success of the global climate effort,” says Lauri Myllyvirta, an analyst who has tracked China’s emissions trends for more than a decade and is a fellow at the Asia Society Policy Institute, a think-tank based in Washington DC.

“Once China’s emissions peak, it’s likely that global emissions will also reach their peak,” says Dave Jones, an electricity analyst at Ember, a London-based think-tank.

But some researchers say that current peak predictions have big uncertainties owing to various factors, such as the future path of China’s economy. And although reaching the peak will be a major climate milestone, China's emissions must continue to fall to net zero, which could be challenging, say some researchers.

Early peak

China reports its greenhouse-gas emissions to the United Nations through a national communication on climate change every four years and a separate report every two years. But those statistics have a major lag, and China’s latest ones were for 2018.

Assessments by Myllyvirta suggest that China’s emissions have been declining since March. This points to a possible 2023 peak, he says, but only if China’s clean-energy production can stick to last year’s record-breaking growth rate in 2024 and its energy consumption drops to its pre-pandemic level. China installed a staggering 217 gigawatts of solar-power capacity in 2023 alone. The United States has installed 137 gigawatts in its entire history.

Myllyvirta calculates China’s monthly CO2 emissions by analysing energy, industrial and customs data from the Chinese government, industry bodies and commercial companies. Analysts can also estimate how much China’s emissions have changed every year by analysing data released by China annually, he said. He thinks the current downward trend is largely because of the growth of clean energy.

Peak still to come

Modelling by Ryna Cui, a researcher who specializes in coal transition at the University of Maryland in College Park, and her team predicts that emissions will peak before 2025. Cui’s team found that rapid deployment of green technologies and shrinking demand for emissions-intensive products, such as steel and cement, are pushing emissions down. But she cautions: “Emissions peaking can be a complex process, with possible small fluctuations, instead of one single point.”

Short-term fluctuations have happened before. China’s emissions declined between 2013 and 2016 after coal use dropped under a government campaign to tackle air pollution. But a rebound occurred after fossil-fuel consumption went up again.

Other analysts think that it will take another year or so to confidently assess whether China’s recent emissions decline is temporary or the beginning of a long-term trend. “There are very, very big uncertainties,” says Bill Hare, a climate scientist and chief executive of Climate Analytics, headquartered in Berlin. Normally, researchers would need five years of emissions data to make a call on a trend, he explains.

Life after peak

Peak emissions are just the beginning. China must also double down on its efforts to reduce emissions to net-zero to prevent global warming from getting worse, says Gunnar Luderer, an energy researcher at the Potsdam Institute for Climate Impact Research in Germany. China has pledged to reach this before 2060.

Hare and his colleagues are assessing China’s technology and policy trends to project its emissions trajectory. They forecast two scenarios, one showing emissions staying flat for a few years, whereas in the other, emissions begin to decline. The unknowns include whether China will put many of the coal-power plants it is currently building into operation and how fast it will deploy renewable-energy plants over the next few years.

China approved 83% less coal-power capacity in the first half of 2024 than in the year before, owing to massive renewable advancements, according to a report released in August by the Helsinki-based think-tank Centre for Research on Energy and Clean Air and Global Energy Monitor, a non-governmental organization based in Covina, California. This spells a possible end to China’s coal-power capacity expansion in the next few years, once the projects that are under construction and waiting to be built are complete, Cui says.

Although to slash emissions, China will have to wean itself off coal entirely, and Myllyvirta foresees “a lot of opposition from vested interests” in the coal industry, such as state-owned enterprises and local governments.

Time pressure

China will have a much shorter time frame to achieve net zero, compared with the European Union and the United States, whose emissions peaked around 1979 and 2005, respectively.

Nevertheless, Sun Yongping, a climate economist at Huazhong University of Science and Technology in Wuhan, China, is confident about China’s ability to reduce emissions after they peak. “Decarbonization requires two things: technologies and manufacturing capacity to bring these technologies into reality. China has both,” Sun says.

For others, China’s peaking will have a more profound significance. “The current global emission growth is largely driven by developing countries’ economic expansion,” says Mi Zhifu, a researcher in climate change economics at the University College London. “China’s experience in decarbonization could offer valuable lessons for other developing nations striving to decouple economic growth from their emissions.”