Study: China's Carbon Emissions Lower Than Thought

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By Michael Standaert

Aug. 19 — China's carbon emissions since the turn of the century were significantly lower than estimated by international organizations, the journal Nature reported Aug. 19, basing its finding in large part on a closer scrutiny of the type of coal burned across China.

The report said carbon emissions from China—the world's largest carbon emitter—may have been overestimated by 2.9 billion metric tons during the 13-year span studied, between 2000 and 2013. Nature.com quantified that amount as “larger than the estimated amount of carbon that the world’s forests pulled out of the atmosphere from 1990 to 2007.”

The report estimated that China's carbon emissions for the year 2013 alone could be 14 percent lower than previously estimated.

“This doesn't change the fact that China is still the largest emitter [of carbon dioxide] in the world,” Guan Dabo, lead researcher from the University of East Anglia, told Bloomberg BNA Aug. 18. East Anglia cooperated on the project with 15 other institutions, including Harvard University, the Chinese Academy of Sciences and Tsinghua University in Beijing.

Coal Quality

Guan called an accurate snapshot of China's emissions “crucially important because these are fundamental to discussing any climate change policy” domestically and globally.

The researchers found that because of the quality of the coal used throughout China, the amount of greenhouse gases emitted may have been as much as 40 percent lower than that predicted by international bodies, including the Intergovernmental Panel on Climate Change.

China is the world's largest coal producer and its largest consumer, but has recently embarked on a concerted push to de-emphasize coal because of carbon emissions and air pollution.

“Coal types vary widely internationally, and China's coals tend to have more silicon and emit less carbon dioxide on average,” Zhu Liu, a researcher on the project from the Sustainability Science Program at the Kennedy School of Government at Harvard University, said at an Aug. 19 press briefing in Shanghai to launch the report.

In its article accompanying the study, Nature.com said: “Even when the lower estimate is taken into account, China’s carbon output for 2013 is still more than two-thirds higher than that of the United States, the second-largest emitter. But the study underscores long-standing uncertainties in the methods with which scientists calculate the emissions of individual nations and how much carbon cycles through the atmosphere and into oceans and ecosystems.”

China Reaction 

Wei Wei, director of the Shanghai Advanced Research Institute of the Chinese Academy of Sciences, said at a press briefing that China's National Development and Reform Commission may adopt the carbon dioxide calculation methods Nature scientists used to better formulate its national carbon dioxide emissions inventory.

In June, China submitted a pledge to the United Nations that it would cut carbon emissions per unit of gross domestic product by 60 percent to 65 percent by 2030 compared to 2005 levels, and to reach peak carbon emissions by “around 2030.”

That was China's commitment ahead of this winter's climate summit in Paris, where world leaders will try to reach a global agreement to fight and mitigate climate change.

 

Cement Production

Researchers also found that by reevaluating what at times can be conflicting estimates about energy and emissions data that provincial and national-level agencies in China have compiled, total energy consumption was 10 percent higher than previously thought for the 13-year period, but emissions from cement production were 45 percent less.

On data accuracy and quality of data being put out in China, Guan said there is starting to be a lot better information about point sources of emissions, but still “large uncertainty between point source [data] and provincial and national-level” data.

“China is putting a lot of effort into setting up monitoring systems, but this is just starting now,” Guan said.

According to the researchers, revised estimates of China's carbon dioxide output from coal-fired power and cement production for 2013 are between 10 percent and 14 percent lower than previous estimates given by the Carbon Dioxide Information Analysis Center in the U.S., the Emissions Database for Global Atmospheric Research in the European Union and the annual Global Carbon Project report. 

To contact the reporter on this story: Michael Standaert in Shenzhen, China, at correspondents@bna.com

To contact the editor responsible for this story: Greg Henderson at ghenderson@bna.com