In this age of terrifying news regarding humanity’s future on this planet and our stress over the pandemic, some good tidings are always welcome. An international team of researchers has found that ozone-depleting CFC chemicals are back on the decline, five years after a major spike, as per two papers published in the journal Nature. “We should see recovery of the ozone layer back to levels that we saw in 1980” later this century, said Luke Western, lead author of one of two papers.
Researchers had discovered that from 2014 to 2016 concentrations of some CFCs were increasing again. They had jumped by over 14,000 tons per year to about 65,000 tons per year. This was a 25% jump above average emissions from 2002 to 2012 and 60% of this was from unregulated industry in China, where it is used as foam insulation in refrigerators, air-conditioners and buildings.
However, the two new papers indicate that the trend has been reversed. The first paper shows that emissions of CFC-11 for 2018 – 2019 fell by 26% globally (about 20,000 tons a year to 57,000 tons). According to the second paper, in 2019, CFC-11 emissions in eastern China fell by 11,000 tons per years compared with the period 2014 – 2017. This is a decline of 33% and similar to the pre-2013 levels of 5,500 tons per year. In 2019, modelling by the UN’s Environmental Agency (UNEP) also indicated that the Ozone layer is on track to returning to 1980s values by 2060.
All of this great news is due to the power of cooperation and coordination, which is what a treaty known as the Montreal Protocol resulted in.
Let’s talk about the ozone layer first. It is that region of the Earth’s stratosphere that absorbs most of the Sun’s ultraviolet radiation and contains high concentrations of Ozone (O3). This layer is found in the lower part of the stratosphere at around 15 to 35 km above the Earth. Keep in mind though that the thickness varies seasonally and geographically.
It was discovered in 1913, by Charles Fabry and Henri Buisson. Then G.M.B Dobson studied its properties in detail and even developed a spectrophotometer called the Dobsonmeter to measure it, modern versions of which we still use to this day. We have discovered that the ozone layer absorbs up to 99 % of the Sun’s medium frequency ultraviolet light, which otherwise would be damaging to life on Earth.
Enter the hydrocarbons, called the chlorofluorocarbons (CFCs). Some varieties had been used in fire extinguishers since the late 19th century and some were used for fire suppression in military aircraft, as early as the 1920s. From 1928 onward, some CFCs started being used as refrigerants, and by the 1960s, were standard in fire extinguishers in labs, museums and art galleries because they would not cause water damage. Meanwhile, bromofluoroalkanes were being used to extinguish fires in warships. Consumption of CFCs increased drastically when they were included in aerosol sprays.
Research in 1976 revealed that the Ozone layer was being depleted by CFCs and there was concern that this would threaten life on Earth, including increasing the risk of skin cancers. Both chlorine and bromine react with the oxygen (O3) in the ozone layer and break it down, rendering it useless as a protective layer against UV radiation.
By 1985, it was clear that there was a hole in the ozone layer and approximately 10% had been eroded. In 1978, some countries, such as the US, Canada and Norway, had instituted bans on the use of CFCs in aerosol sprays but they continued to be used as refrigerants and in industrial cleaning.
Finally, in 1987 one of the most successful multilateral environmental efforts were undertaken and the Montreal Protocol was signed, with the objective to completely phase out CFCs. On September 16, 1987, 196 states and the European Union (a total of 197 parties) got together to sign the Montreal Protocol. This was such a huge success that 99% of CFCs were removed from the products in which they were used. Ozone Day has been held on September 16 since then, to commemorate this occasion.
The Montreal Protocol is clearly a great example of how human beings are capable of tackling global challenges through cooperation and solidarity. Nations have continuously worked for over 30 years to slash the use of ozone depleting chemicals and the result is now obvious: the ozone layer is healing.
The Kigali Amendment to the protocol came into force in 2019 and it aims to strengthen enforcement, and continue to protect the ozone layer, while also phasing out hydrofluorocarbons (HFCs) that replaced CFCs because of their potential for greenhouse gas emissions.