Researchers have discovered a new hole in the ozone layer above the Arctic – but there is no need to panic.

The ozone layer protects life on the surface of our planet from ultraviolet (UV) radiation. It is therefore easy to panic when there are reports of yet more damage to this armour on which life on Earth depends. However, scientists who study the atmosphere have identified a rare gap in the ozone layer above the Arctic which is a harmless, and hugely interesting, environmental phenomenon.

The ozone layer is found approximately 15 to 35 kilometres above Earth, meaning it lies mostly within the lower stratosphere. The layer varies in thickness seasonally and geographically and is generally thinner near the equator and thicker near the poles. However, holes can form in the ozone layer. The main cause of ozone depletion is the presence of CFCs and HCFCs (found in old refrigerators and aerosol sprays) in the atmosphere — when UV light hits these chemicals, they release chlorine which reacts with ozone (O3), causing it to break down into regular oxygen, O2.

The effects of this chlorine-catalysed ozone depletion are enhanced by polar stratospheric clouds (PSCs) which form at the poles under the very coldest of temperatures. A period of three long, dark months with no sunlight cools the air, which is trapped and chilled by the polar vortex. These clouds provide a surface for the chemical reactions which cause ozone depletion in the spring when UV light returns.

This happens every year in the Antarctic as winter temperatures there are much colder than in the Arctic, which has a more variable winter climate. This year, however, the Arctic has braved a polar vortex — an onslaught on swirling cold air resulting in the rare Arctic ozone gap scientists can now see.

False-colour view of total ozone over the Arctic pole. Images: NASA Ozone Watch.

This particular ozone hole is not a cause for concern for human health because it is currently positioned in such a way that the sun will not directly hit largely populated areas. In the near future, scientists say there is a chance that the ozone hole could expand, meaning those populating some areas will need to apply sun cream. Temperatures are already starting to increase, and humanity’s commitment to reducing the amount of chlorine and other harmful chemicals in the atmosphere means it is unlikely this ozone gap will impact our everyday lives. This measure has also helped the more troublesome ozone hole in Antarctica which is now on its way to recovery due to a reduction in reactive chemicals.

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