What happened with the Ozone Hole?

 The Ozone (O3) layer is a naturally produced coat in the stratosphere resulting from the division of oxygen molecules. The purpose of such blanket is to protect planet Earth through the absorption of damaging UV radiation (Royal Geographic Society). 

It was only in the 1980s that scientists started to measure a peculiar hole being created in the ozone concentration above the South pole (Royal Geographic Society).

The reason for this phenomenon is the insertion of chemicals such as chlorofluorocarbons (CFCs for short), halons, and carbon tetrachloride containing chlorine and bromine, which, due to their resistance, can live long in the atmosphere until reaching the stratosphere layer and damaging the ozone blanket (Solomon 1988). The reason why this hole generated above Antarctica specifically lies in the deep drop of temperatures during the winter and spring time which allows water vapour to condensate in stratospheric clouds (PSCs). Special reactions occurring within PSCs allows chlorine and bromine to react with ozone and break down its molecules.


Why is the ozone hole not a topic anymore in the public discourse?


After the implementation of the Montreal Protocol stating the harmful effects of such chemicals to the international community and general public, the world came together to develop substitute substances to polluting CFCs in order to tackle the climate crisis. Thereafter, the ozone hole stopped expansion, started to shrink and the topic faded away from public discussion. In 2020, the Copernicus, atmospheric monitoring services (CAMS announced the closure of the biggest ozone hole registered over the Arctic. Nonetheless, this does not mean that the whole ozone layer has been completely restored, thus we must keep the Montreal targets on track to make sure that the ozone hole is finally closed by 2065.

The COVID19 crisis supported as well the reduction in air pollution by diminishing for example in certain cities NO2 (chemical by product of fossil fuel burning) levels by 60%. Notwithstanding, "Scientist of Copernicus Atmosphere Monitoring Services (CAMS) reported that [the "closure" of the ozone hole] is because of strong and long-lived polar vertex and not related to change to air quality (Arora 20202).

References:


Solomon, S. (1988), The mystery of the Antarctic Ozone “Hole”, Rev. Geophys., 26(1), 131–148

1987 Montreal Protocol on Substances that Deplete the Ozone Layer

Discovering Antarctica, The Ozone Hole, Royal Geographic Society, Available at: https://discoveringantarctica.org.uk/oceans-atmosphere-landscape/atmosphere-weather-and-climate/the-ozone-hole/

Vox, (24 November 2021), Why you don’t hear about the ozone layer anymore, [video]. Youtube. Why you don’t hear about the ozone layer anymore

Treska Dhia Al-Deen Kamil, (2020), The positive impact of COVID-19 lockdown on air pollution and the ozone layer, Cihan University-Erbil

Arora S, Bhaukhandi KD, Mishra PK. (2020, Coronavirus lockdown helped the environment to bounce back, Sci Total Environ

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