REUTERS IN BEIJING
PUBLISHED : Thursday, 20 August, 2015, 11:54am
UPDATED : Thursday, 20 August, 2015, 12:13pm
Chinese carbon emissions last year are estimated to have been about 9 to 10 billion tonnes. Photo: AFP
International organisations could be overestimating carbon emissions from China – the world’s biggest producer of climate-warming greenhouse gas – by as much as 14 per cent because of problems in the way they calculate their data, says a new study published by the journal Nature.
Talks on a new global climate accord are set to take place in Paris in December, and China has promised to bring its emissions to a peak by “around 2030”.
However, it remains unclear how much carbon dioxide China is actually producing and how much it will produce in 15 years.
While there is no official figure for Chinese carbon emissions last year, estimates stand at about 9 to 10 billion tonnes, while forecasts for 2030 range anywhere between 11 billion and 20 billion tonnes.
“Without an accurate baseline, any target will become a number-crunching game,” said Dabo Guan, chair of climate change economics at the University of East Anglia, and one of the authors of the Nature study published on Wednesday.
The paper said organisations such as the European Union’s Emissions Database for Global Atmospheric Research (EDGAR) had overestimated China’s emissions by as much as 14 per cent by using default conversion rates that should not apply in China.
“The main difference in our paper is for the first time we have taken fuel quality into consideration, which is missing from other estimates,” Guan said.
The authors used updated energy consumption data and said the difference was caused mainly by the coal industry.
Researchers calculated their figures by analysing coal supply data from 4,200 domestic coal mines.
Taking into account China’s lower quality coal, the study calculated China’s 2013 carbon emissions at 9.13 billion tonnes, below the EDGAR figure and 5.6 per cent lower than an estimate in oil company BP’s statistical yearbook.
The Intergovernmental Panel on Climate Change (IPCC). recommends a default “emission factor” of 0.713 tonnes of carbon for every tonne of coal produced, but the Nature authors, looking closely at about 600 samples from domestic mines, said the figure in China should be closer to 0.518 tonnes.
The study also estimated China produced 2.9 gigatonnes less carbon dioxide than previous estimates from 2000 to 2013, although Chinese government researchers said it might have overestimated lower-grade coal consumption over the period.
“More cheaper, poor quality coal was supplied in 2013 as the industry was hit by lower demand in China,” said Jiang Kejun of the Energy Research Institute, a government think tank.
“It is not accurate to use emission factors for a single year to calculate China’s emissions.”
The last time Beijing gave an official number was for 2005, when emissions stood at “approximately” 7.47 billion tonnes. It is due to submit an updated number for 2010 next year.
However, Guan cautioned that the analysis “does not prove that the IPCC is wrong”, while the report states that “estimates of Chinese emissions remain subject to large uncertainty”.
While the study might ease some of the pressure on China, it still had a lot to do to rein in its spiralling greenhouse gas emissions, said Guan
“Our estimates, which use a lower emission factor, don’t change the fact that China is still the largest emitter in the world,” he said.
“This will give some carbon space for the less-developed regions in China, but it is not a game-changer. It won’t disrupt China’s mitigation efforts.”
Additional reporting The Guardian
http://m.scmp.com/news/china/policies-politics/article/1851038/data-error-means-chinas-carbon-dioxide-emissions-count
