Has China’s Carbon Dioxide Output Been Overestimated?

Even though the country has been blamed as the world’s number one contributor of the world’s greenhouse gas emissions has China’s carbon dioxide emission’s been overestimated?

By: Ringo Bones 

As an incident that will undoubtedly be soon exploited by climate change skeptics, scientists may have been overestimating China’s emissions of carbon dioxide, the main greenhouse gas driving global warming, by more than 10 percent, because of inaccurate assumptions about the country’s coal-burning according to a study published in August 19, 2015. The study’s findings - as published in the journal Nature, does not mean that the total level of greenhouse gases in the atmosphere is any lower than scientists had thought. That accumulation is measured independently. Rather, the finding may affect discussions of how much responsibility China bears for global warming in comparison with other nations during the upcoming climate change conference in Paris later this year. 

“This doesn’t change the fact that China is still the largest emitter of carbon dioxide in the world”, said Dabo Guan, a professor of climate-change economics at the University of East Anglia in England who is one of the paper’s two dozen authors in a telephone interview from Beijing. The study looked in detail at the coal used as fuel in China and found that it is generally less rich in carbon and is burned less efficiently than scientists had assumed. That means that each ton of burned coal yields less carbon dioxide that had been previously thought as well as less energy and more ash. 

China does not publish official data on annual greenhouse gas emissions, so “international organizations have to make large assumptions” than are required for other major countries, said another author of the study – Glen Peters – a senior researcher at the Center For International Climate and Environmental Research – Oslo. These assumptions often rely  on coal carbon content and combustible data collected in the United States and Europe, said Zhu Liu, a postdoctoral research fellow at Harvard University and another of the paper’s authors. But China’s rapidly growing economy mainly uses cheaper, less pure coal from local mines, often burned in less efficient furnaces and boilers in comparison to typical ones in the West, Dr. Liu said.