Confirmed: Most of the gas emissions that destroy the ozone layer come from China

The gas, called CFC-11, was mainly used in the manufacture of home insulation foams, but it was agreed at the international level that production would cease gradually from 2010.

However, scientists have detected a strange phenomenon: the rate of reduction has become slower over the past six years.

A new study published in the journal Nature claims to have an explanation. Much of the emissions come from factories that continue to manufacture insulators containing harmful gas in the eastern provinces of China.

CFC-11, also known as trichlorofluoromethane, is a type of chlorofluorocarbon or CFC, a series of chemicals originally developed as refrigerants in the 1930s.

Scientists have spent decades discovering that when CFCs decompose in the atmosphere, they release chlorine atoms that quickly destroy the ozone layer that protects us from ultraviolet rays.

The large hole in the ozone layer over Antarctica was only discovered in the mid-1980s.

The international community approved the so-called Montreal Protocol in 1987, which bans the issuance of the most harmful CFCs.

Recent studies indicate that if the ban is respected, the ozone layer gap in the northern hemisphere could disappear by 2030 and that of Antarctica by 2060.

When was the problem of CFCs discovered?

CFC-11 was the second most abundant CFC and gas emissions began to decline after the Montreal Protocol, as planned.

However, in 2018, a team of researchers found that the rate of decline was reduced by 50% after 2012.

Measurements from monitoring stations in South Korea and Japan have been critical in detecting the mysterious sources of CFC-11.

The scientists hypothesized that the reduction in the rate of reduction was explained by the fact that gas was still produced in East Asia.

The authors of the new study point out that if factories using CFC-11 are not closed, this can delay the repair of the 10-year ozone layer.

What did the scientists find on the ground?

Additional studies carried out by the China Research Agency in 2018 indicated that this country was the source of the emissions.

The agency noted the illegal use of CFC-11 in the vast majority of polyurethane insulation factories under investigation.

A salesman told the agency that nearly 70% of Chinese home insulation was made with forbidden gas.

And the reason is simple: the CFC-11 is a product of better quality and much cheaper than other solutions.

What does this new study show?

The work confirms beyond a reasonable doubt that between 40 and 60% of the increase in CFC-11 emissions come from the eastern provinces of China.

Scientists have shown that since 2012, CFC-11 levels have increased due to production in Chinese factories in this part of the country.

Researchers calculated a 110% increase in gas production in this region between 2014 and 2017 compared to the 2008 to 2012 period.

"This new study is based on sudden increases in air measurements from China," said Matt Rigby, professor of atmospheric chemistry at the University of Bristol in England, at the BBC Inside Science program.

"By using computer simulations of the transport of these gases in the atmosphere, we have been able to calculate emissions from different regions, so we have estimated the additional emissions of 7,000 tonnes of CFC-11 in from China compared to levels before 2012 ".

"However, the data does indicate gas levels in the atmosphere, but not how that gas was used at the location where it was produced," Rigby said.

"It is possible that the gas was produced in another region of China or even in another country and was transported to the insulating foam manufacturing plants, it is in this last stage that a part CFC-11 is released into the atmosphere. "

Where does the rest of the emissions come from?

Scientists are not sure. The remaining 40% can come from other parts of China, which are not covered by monitoring stations.

They could also come from India, Africa or South America, but monitoring of CFC-11 emissions in these regions is very low, according to the study.

"Our study was limited to measurements of the network of available stations and only allowed us to quantify the emissions of eastern China, where 35% of the country's population lives, as well as the Korean peninsula and China. 39, western Japan. " explained to BBC World Luke Western, a researcher at the Department of Chemistry at the University of Bristol and another of the authors of the study.

Western pointed out that the surveillance network is also sensitive to parts of North America, southern Australia and Europe, but that none of these sites are n & # 39; 39, recorded increased emissions.

"This means that a good chunk of the recent increase in emissions has not been detected."

"Personally, I am not aware of any SWC-11 measure in Latin America, at least as part of the networks of NOAA (National Oceanic and Atmospheric Administration of the United States) or AGAGE (advanced global atmospheric gas experiment) used in the study, "said Western.

"If there are atmospheric measurements of CFC-11 in Latin America, we would very much like to know them to try to get another part into the puzzle of this gas."

Does the increase in CFC-11 affect climate change?

Yes, the study authors point out that these chlorofluorocarbons are also extremely potent greenhouse gases.

One tonne of CFC-11 equates to about 5,000 tonnes of CO2 or carbon dioxide.

"These additional emissions that we identify in eastern China equate to the emission of about 35 million tonnes of CO2 into the atmosphere per year, the equivalent of 10% of annual emissions in the UK, or total annual emissions from London, "said Rigby.

What measures will China take?

The Chinese authorities said that they had already begun to take steps to reduce the production of harmful gases by what they describe as "corrupt manufacturers."

Several suspects arrested in Henan province in November had 30 tons of CFC-11.

Clare Perry, of the Environmental Investigation Agency, the Environmental Investigations Agency, and the British NGO EIA, said the new study underscored the need to stop the production of this gas.

"I think that with this study, there is no doubt that China is the source of these unexpected emissions and we hope that the Chinese authorities will do all that is necessary to discover the sources of the production of CFCs. 11. "

"If the production of this chemical is not eliminated, it will be almost impossible to prevent its use by insulating foam manufacturers." (BBC)