Chemical industry’s nitrous oxides rising in China
Li L, J Xu, J Hu, J Han. 2014. Reducing nitrous oxide emissions to mitigate climate change and protect the ozone layer. Environmental Science and Technology. http://dx.doi.org/10.1021/es404728s
China’s emissions of nitrous oxide – a potent greenhouse gas and ozone-depleting chemical – will more than triple by 2020 if China’s chemical industry does nothing to control them, according to a new study.
Under current scenarios, China’s nitrous oxide emissions will reach five times that of the United States, which is the second biggest emitter.
Nitrous oxide is a byproduct of the production of nitric acid, used to make fertilizers, and adipic acid, used to make nylon. China is one of the biggest producers of those two chemicals.
In a new study, researchers from Peking University determined that between 1990 and 2012, China’s nitrous oxide emissions from production of industrial chemicals rose 37-fold, from 5.07 gigagrams per year to 174 gigagrams per year. Industrial emissions could rise to 561 gigagrams per year by 2020 under current policies, the researchers wrote in the journal Environmental Science & Technology.
Industrial emissions account for only 10 percent of China’s total nitrous oxides. Agriculture contributes 80 percent, while power plants contribute about 9 percent.
However, the researchers say that requiring cleaner technologies in the chemicals industry could go a long way in cutting global emissions.
If control measures for nitrous oxides are implemented in China’s industrial sector alone, the climate benefit would be comparable to eliminating all greenhouse gas emissions from Australia in 2011, the researchers wrote. In addition, the ozone protection benefit would be greater than reducing all halocarbon ozone-depleting chemicals from China in 2011.
One limitation is that current technologies to capture and break down nitrous oxide require electricity. Burning coal or other fossil fuels to generate electricity may erase some of the benefits of reducing nitrous oxide.
While tackling industrial emissions may be “the most cost-effective control option” in the short term, “attention is also needed to reduce nitrous oxide emissions in the agricultural sector where they are very significant,” the researchers wrote.
Nitrous oxide is thought to be the third largest greenhouse gas contributor and the largest source of chemicals that deplete the ozone layer, which shields plants, animals and people from the sun’s UV rays.