Antarctica's Ozone Hole


· Antarctica,climate change,weather,leadership,ocean


Antarctic summers are bright and beautiful but you’d better not forget to wear your sunscreen and sunglasses. To the present day, the ozone hole above Antarctica, discovered in the 1980s, remains as large as the entire continent. While apparently no longer a news-worthy story, the environmental concerns associated with it remain significant and more timely than ever.

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Our planet Earth is constantly exposed to radiation coming from space and the Sun. Some of it is highly energetic ultraviolet (UV) radiation. When humans exposed to it, it causes skin burns (sun burns) and even cancer but also negative affects wildlife, plankton growth, and as such, the entire Antarctic food chain. Thankfully, our planet has a protection plan in place: an ozone shield. Each ozone molecule is made from three oxygen atoms. It has the amazing capability of absorbing the harmful UV space radiation before it can reach the surface, and us.

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A natural layer of ozone is present in the Earth’s atmosphere at about 10 km (6 miles) height which marks the bottom part of the stratosphere. This is just above the troposphere where airplanes fly. However, human activities, specifically the prolonged use of chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODS) have led to a reduction of ozone, particularly above Antarctica where these chemicals end up being channeled.

After these ODS chemicals get into the air, they break down in the stratosphere where they release previously bound chlorine and bromine atoms that then destroy ozone molecules. While international efforts, such as the Montreal Protocol adopted in 1987, have successfully phased out or regulated the production of many ODS, the persistence of these substances in the atmosphere has led to the continued occurrence of a seasonal ozone “hole”.

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Interestingly, this significantly thinned ozone layer had a maximum size of ~25 million square kilometers (the US land area covers 9 million square kilometers) during spring 2023. A (limited) recovery begins again with increasing daylight and warmer air temperatures since depletion levels are driven by low-temperature chemistry processes occurring on the stratosphere during the dark, cold Antarctic winters.

So — what could possibly go wrong?

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While a generally milder Antarctic climate would benefit the ozone layer recovery, global warming, caused by greenhouse gases (think CO2 and methane) that trap heat in the lower levels of the atmosphere, will not be the solution! That would have devastating consequences for our planet. Instead, these two issues need to be dealt with separately, and with expedience, to keep us and the Earth healthy and in equilibrium.

Presence of ODS chemicals in the stratosphere has decreased by 50% since the 1980s. That’s great progress but why aren’t we at 0% some 40 years later? Because ODS are still being used and they stay in the atmosphere for decades. Eventual recovery is estimated to take at least until 2070, but with no guarantees, affecting and endangering the Antarctic ecosystem until then, and probably longer through indirect ways. Sustained efforts and international cooperation are necessary to fully ban these substances now.

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It’s not too late. Yet. I don’t want Antarctica’s food chain cease to function due to UV radiation damage, or due to too warm waters and weather changes. Because once you’ve seen the icy continent with your own eyes, one thing is as crystal clear as the Antarctic water: Collectively, we need to preserve that Antarctic water, land, and air, at all costs. Anything else is simply not acceptable.