Ozone layer: banned CFCs from China, say scientists

Copyright of the image
Getty Images

The researchers claim to have identified the main sources of a mysterious recent rise of a dangerous chemical destroying the ozone layer.

CFC-11 was mainly used for home insulation, but global production was to be phased out in 2010.

But scientists have seen a sharp slowdown in the rate of burnout over the past six years.

This new study indicates that this is mainly due to the new gas production in the northeastern provinces of China.

CFC-11 is also known as trichlorofluoromethane and is one of many chlorofluorocarbon (CFC) chemicals that were originally developed as refrigerants in the 1930s.

However, it took scientists several decades to discover that when CFCs decompose in the atmosphere, they release chlorine atoms capable of rapidly destroying the layer of ozone that protects us from ultraviolet rays. A gaping hole in the ozone layer over Antarctica was discovered in the mid 1980s.

The international community endorsed the Montreal Protocol in 1987, which banned most of the offending chemicals. Recent research suggests that the hole in the northern hemisphere could be fully repaired by 2030 and Antarctica by 2060.

When was the problem of CFCs discovered?

CFC-11 was the second most abundant CFC and initially found to be declining as expected.

However, in 2018, a team of researchers monitoring the atmosphere found that the rate of decline had slowed by about 50% after 2012.

This team explained that it was seeing new gas production from East Asia. The authors of this article argued that, if the sources of the new production were not closed, this could delay the recovery of the ozone layer for a decade.

What did the investigators find on the ground?

An additional detective work carried out in China by the Environmental Investigation Agency in 2018 seemed to indicate that the country was indeed the source. They found that the illegal chemical was used in most of the polyurethane insulation produced by the companies they had contacted.

A CFC-11 seller estimated that 70% of China's domestic sales used illegal gas. The reason was simple: the CFC-11 is of better quality and much cheaper than the alternatives.

So what does this latest study show?

This new document seems to confirm beyond a reasonable doubt that 40 to 60% of the increase in emissions comes from the northeastern provinces of China.

Using what is called "top down" measurements made by air monitoring stations in South Korea and Japan, researchers have been able to show that since 2012 the number of CFC-11 has increased compared to production sites located in East China.

Copyright of the image
Getty Images

They calculated that there was a 110% increase in emissions from these areas of China for the years 2014-2017 compared to the period 2008-2012.

"This new study is based on peaks in aerial data from China," said BBC Inside Science, the main author, Dr. Matt Rigby, a reader at the University of Bristol.

"By using computer simulations of the transport of these gases in the atmosphere, we can start to quantify the emissions of different regions." So we have achieved about 7,000 tons of additional emissions of CFC-11 from China compared to before.

"But from the data, we only see the ultimate releases to the atmosphere.We have no information on how the CFC-11 was used or where it was produced. quite possible that it was manufactured in another in another part of China or even in another country and were transported to the place where they make insulating foams, where part of it could have been emitted into the atmosphere. "

Where do the other programs come from?

The researcher is not sure. It is possible that the missing emissions come from other parts of China because the monitoring stations simply can not see them. They could also come from India, Africa or South America, again, with very little surveillance in these areas.

Does this have implications for climate change?

Yes, the authors say that these CFCs are also very potent greenhouse gases. One tonne of CFC-11 equates to about 5,000 tonnes of CO2.

"If we look at these additional emissions that we have identified from east China, that equates to about 35 million tonnes of CO2 emitted into the atmosphere each year, which equates to about 10% of emissions. from the UK, or about as much, London. "

Will China reduce production?

The Chinese say that they have already started to suppress production by the term "rogue manufacturers". Last November, several suspects were arrested in Henan Province, in possession of 30 tons of CFC-11.

Clare Perry of the Agency for Environmental Investigations (EIA) said the new findings reaffirmed the need to reduce production.

"I think with this study, there is no doubt that China is the source of these unexpected emissions, and we hope that China will spare no effort to discover the source of CFC-11 production.

"If the production of the chemical is not stopped, it will be almost impossible to stop the use and emissions of the foam companies."

The study was published in the journal Nature.

Follow Matt on Twitter.