OSLO (Reuters) - Reports of a historic dip in China's carbon dioxide emissions in the past two years are premature because of uncertainty over data showing the pace of a decline in coal use by the world's biggest consumer, a study showed on Monday.
The International Energy Agency (IEA) has been among those saying that energy-related carbon dioxide emissions by China, the biggest emitter, fell in 2015 and 2014 in what it hailed as a shift to cleaner energy after years of fast growth.
"Headlines about falling emissions may be misinterpreting the numbers," the Center for International Climate and Environmental Research, Oslo, (CICERO) said in a statement of a report published in the journal Nature Climate Change.
China has promised to peak its carbon dioxide emissions by around 2030 as part of a 195-nation plan agreed in Paris in December to combat climate change, blamed for stoking more downpours, heatwaves and rising sea levels.
But CICERO pointed to uncertainties in China's coal data, and frequent revisions.
It said Beijing has reported that coal consumption, measured by weight, fell 3.7 percent last year as economic growth slowed. But China is also using higher quality coal, which releases more energy and carbon dioxide per ton when burnt.
By that yardstick, China's coal energy consumption fell by just 1.5 percent last year, it said.
Overall, CICERO estimated China's carbon dioxide emissions from energy use, including oil and gas, dipped by just 0.1 percent in 2015 after a gain of 0.5 percent in 2014.
"Given uncertainties in the statistics, it is not possible to conclude whether Chinese carbon dioxide emissions went up or down in 2015," said Glen Peters, an author at CICERO. China's climate envoy Xie Zhenhua said on March 7 that carbon emissions were still rising.
By contrast, the IEA reported a decrease of 1.5 percent in China's energy-related carbon emissions for 2015 on March 16, underpinning its wider conclusion that a rise of global emissions stalled for a second year even as the economy grew.
The IEA stuck by the conclusions.
Even taking CICERO's advice on coal data, "the finding of a decoupling at global level between emissions and economic growth would not change to any significant extent", IEA spokesman Greg Frost said.
Even so, the difference between CICERO's estimate of a 0.1 percent dip in Chinese emissions last year and the IEA's 1.5 percent fall amounts to 125 million tonnes of carbon dioxide, CICERO said, roughly the annual emissions of Belgium.
"China's emissions growth has clearly slowed a lot, regardless of whether it has actually reversed," lead author Jan Ivar Korsbakken said.
(Reporting by Alister Doyle; editing by Susan Thomas)