The Montreal Protocol, which was signed by 197 countries, including Canada, the US and China, in September 1987, is an international treaty intended to protect the ozone layer by banning CFCs, chemicals used in the manufacture of aerosol sprays, propellants, refrigerants and solvents that are known to contribute to ozone depletion in the upper atmosphere.
Last year, scientists with the National Oceanic and Atmospheric Administration (NOAA) found that global emissions of Trichlorofluoromethane (CFC-11) have increased by 25 percent since 2012 based on emissions levels observed at measurement sites.
"I've been making these measurements for more than 30 years, and this is the most surprising thing I've seen," NOAA scientist Stephen Montzka said at the time. "I was astounded by it really."
A new study published on May 22 in the journal Nature found that between 40% and 60% of total global CFC-11 emissions since 2012 were produced by eastern China and that CFC-11 emissions in eastern mainland China had increased by 7,000 tonnes per year since then. The study, conducted by scientists from University of Bristol, Kyungpook National University and the Massachusetts Institute of Technology, examined weather and wind patterns to identify the origin of the gas emissions.
"Using high-frequency atmospheric observations from Gosan, South Korea, and Hateruma, Japan, together with global monitoring data and atmospheric chemical transport model simulations, we investigate regional CFC-11 emissions from eastern Asia. We show that emissions from eastern mainland China are 7.0 ± 3.0 (±1 standard deviation) gigagrams per year higher in 2014 — 2017 than in 2008 — 2012, and that the increase in emissions arises primarily around the northeastern provinces of Shandong and Hebei," the report's abstract states.
However, the report was unable to determine where the rest of the CFC emissions were coming from, due to the "sparsity of long-term measurements of sufficient frequency near potentially emissive regions."
According to lead author of the study, Matthew Rigby, the findings were not "entirely a surprise," the National Post reported.
Following the release of the NOAA report last year, the New York Times and the Environmental Investigation Agency, an international non-governmental organization that investigates environmental abuse and crime, published stories claiming that the illegal use of CFC-11 in China mostly occurs in its foam blowing sector. CFCs are used as foam blowing agents to create cellular structures from liquid plastic resin.
In response to the recently released study, the EIA issued a statement that the "new paper scientifically confirms that large scale CFC-11 emissions came from eastern China, as identified by our investigations and reports." However, the statement also notes that the inability of scientists to determine the origin of the remaining emissions highlights the need for better "monitoring capacity" in parts of the world such as South America, western China and India.
Indeed, the study may not even paint a complete picture of China's emissions.
"There are still multiple unresolved issues, including how much illegal CFC-11 remains in hidden stockpiles or may have been already exported in foam products or polyol blends. However the most critical action for China now is to locate and permanently shut down all CFC-11 production. This will require a significant and sustained intelligence-led enforcement effort from China," Clare Perry, EIA UK's Climate Campaign leader, said in a Thursday press release.