A photograph showing changes in the ozone hole in Antarctica. The left hemisphere shows the largest ozone hole since observation in September 2006, and the right hemisphere shows the smallest ozone hole since observation in October 2019. Photo source: United Nations and National Aeronautics and Space Administration (NASA)Freon gas (CFC), which was once used as a refrigerant for refrigerators and air conditioners, has been called a nontoxic ‘refrigerant of dreams’. However, things changed in the 1980s when it was discovered that it was destroying the ozone layer in the stratosphere, which absorbs the sun’s ultraviolet rays. Countries met in Montreal, Canada in 1987 to adopt the Montreal Protocol, an international climate agreement on the regulation of substances that deplete the ozone layer. The main content was to completely ban the use of Freon gas and to encourage the use of alternative substances. It has been completely banned in developed countries since 1996 and in developing countries since 2010.
As of July, the Protocol has been expanded to become the largest global agreement in history with 197 countries participating. Former UN Secretary-General Kofi Annan called the Montreal Protocol “the most successful single international agreement in history”. On the 18th (local time), the international scientific journal Nature highlighted the scientific achievements of the Protocol by introducing the results of an analysis by a research team at the University of Lancaster Environment Center in the UK, which found that the adoption of the Montreal Protocol prevented the temperature increase by up to one degree Celsius by 2100.
○ “It would have been a disaster without the protocol”
The ozone layer absorbs harmful ultraviolet rays from the sun when it comes into direct contact with the human body and prevents it from reaching the earth’s surface. Plants, like humans, suffer from damage to proteins and DNA of cells when exposed to harmful UV rays for a long time, stopping growth and losing their lives. Plants absorb carbon dioxide through photosynthesis and produce the energy needed for plant growth. The ozone layer must be maintained so that plants can thrive and absorb carbon dioxide from the atmosphere. Based on this, the Lancaster University research team developed a model that analyzes the increase or decrease of carbon dioxide in the atmosphere according to the degree of destruction of the ozone layer. This model calculated the surface influx of harmful UV rays according to the degree of ozone depletion. Then, we analyzed how much photosynthesis would be affected by using existing studies that analyzed damage to plants according to the amount of harmful UV rays. Based on this, the amount of carbon dioxide uptake by plants was calculated. The research team found that 325 billion to 690 billion tons of more carbon dioxide would have been emitted by 2099 if the protocol were not adopted. Considering that global carbon dioxide emissions were 34 billion tons last year, it is interpreted that about 10 to 20 years’ worth of additional emissions would have been generated. “This is equivalent to an amount that could further increase global temperature by about 0.5 to 1 degree Celsius,” the research team said. The United Nations recently made a similar analysis in a report introducing the scientific effects of the Montreal Protocol. “Without the protocol, the global temperature would have risen by more than 2 degrees Celsius on average by 2070 alone with ozone-depleting substances alone,” the UN said.
○ Development of alternative substances, urgent global response
These achievements are evaluated as a result of the creation of various research support funds to protect the ozone layer and develop alternatives to freon gas after the adoption of the protocol. About $3.9 billion (about KRW 4.6 trillion) has been raised since the first fund was established in 1991, and about 8,600 studies have been supported so far.
Countries are developing a strategy to reduce the use of ozone-depleting substances in stages while developing alternative substances, and to permanently ban existing ozone-depleting substances after successful development.
Freon gas was included in the list of banned substances first along with Halon gas, which is used as a powder medicament for fire extinguishers. Hydrochlorofluorocarbons (HCFCs), which are used as substitutes for Freon gas, are also classified as secondary regulated substances and will be eliminated by 2030. This is because HCFCs have low ozone depletion, but their adverse effect on global warming is 2000 times greater than that of carbon dioxide. This is why we are once again looking forward to the protocol following the ban on ozone-depleting substances.
Synergy effects are also expected with subsequent climate response agreements that emerged after the Montreal Protocol. International efforts are continuing, such as the 1997 Kyoto Protocol, which focuses on reducing greenhouse gas, and the 2015 Paris Agreement on Climate Change, which prevents the global temperature from rising by more than 1.5°C above the pre-industrial level.
However, strong global efforts are still urgently needed. According to the Intergovernmental Panel on Climate Change (IPCC) report released on the 12th of this month, the average global temperature between 2021 and 2040 is expected to rise by more than 1.5 degrees compared to pre-industrial levels if current greenhouse gas emissions are maintained.
In a briefing on the IPCC report of the Korea Meteorological Administration on the 9th, Lee Jun-yi, a research fellow at the Institute for Basic Science (IBS) Climate Physics Research Group, who participated as the overall lead author of this IPCC report, said, “If we do not respond quickly, global warming will become more serious. There is a possibility that it can be limited to 1.5 degrees or less.”
Ko Jae-won, staff reporter for Donga Science jawon1212@donga.com
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