A study published in Nature Climate Change states that one of the gases that endangers the ozone layer has been significantly reduced. The decrease of the hydrochlorofluorocarbons (HCFC) happens for the first time in history since its impact on the planet’s protective layer has been recorded. The researchers in charge consider it a victory. The reduction demonstrates the benefits of adopting international protocols to mitigate the effects of climate change.
According to information obtained by the Advanced Global Atmospheric Gas Experiment (AGAGE) and the National Oceanic and Atmospheric Administration (NOAA), the chlorine associated with HCFCs is beginning to disappear from the Earth. In 2021, it recorded a peak accumulation, from then on the proportion of the gas gradually reduced in the ozone layer.
At their worst, hydrochlorofluorocarbons reached a magnitude of 321.69 ± 0.7 ppt (parts per million). In 2022, the value dropped to 321.35 ± 0.29 ppt, and in 2023 it fell to 319.33 ± 0.33 ppt. In addition, the rate of radiative forcing (the difference between sunlight absorbed by the Earth and the energy radiated into space) also showed a downward trend. It started from 61.75 ± 0.056 mW m-2 until reaching 61.28 ± 0.069 mW m-2.
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“This has been a great global success. “We are seeing that things are going in the right direction,” Luke Western, a scientist at the British University of Bristol and lead author of the study, told the AFP agency. For him, the disappearance of gases that threaten the ozone layer is the work of the ‘Montreal Protocol’. The pact was signed almost as an emergency 3 decades agowhen the “hole” that had formed in the ozone layer in Antarctica was revealed.
The long fight against chlorofluorocarbons
Mario Molina and Sherry Rowland proposed in 1974 that the chemical compounds most used in industry at that time decomposed in the atmosphere while damaging the ozone. The so-called chlorofluorocarbons (CFCs) were fragmented in the stratosphere to form chlorine and bromine. These molecules reacted with the oxygen in the environment and weakened it. Without ozone particles, the planet had a weak protective layer against the Sun’s UVC radiation.
The ‘Montreal Protocol’, an international agreement that came into force in 1989, aimed to phase out ozone-depleting substances, including CFCs. The countries that signed the protocol committed to replacing CFCs with friendlier compounds in favor of recovering the planet’s shield.
Hydrochlorofluorocarbons (HCFCs) were the industry’s response to the ‘Montreal Protocol’. HCFCs perform the same refrigerant function in aerosols, but their life cycle is considerably shorter than that of CFCs. While CFCs can remain in the atmosphere for 100 years, hydrochlorofluorocarbons barely last 20 years. Its adoption in the economy was considered a more environmentally friendly alternative. However, HCFCs are not free from affecting the ozone layer. Chlorine derived from the compound continues to react with oxygen, so its levels in the atmosphere are constantly monitored.
In 2010, the use of CFCs in industry was banned. International organizations expect the same thing to happen with HCFCs by 2040. While this happens gradually, scientists analyze the levels of gases in the ozone layer. This latest research reveals that the long climate fight against chlorofluorocarbons is finally beginning to show results. Companies will have to replace HCFCs in aerosols with hydroflourocarbon compounds. These are a chlorine-free version and therefore do not pose a threat to the ozone layer.
