Why does it take my skin about 20 minutes to burn in New Zealand, when it takes longer than 2 hours in North America? (Sorry mum – I hope you’re not reading this).

Almost every Kiwi will be able to tell you that it’s because of the hole in the ozone layer. Is this true, and what does that even mean?

Ozone is a gas that forms a layer of our atmosphere. It’s made up of 3 oxygen atoms, but is held together in a way which makes it temperamental and easy to break down. – Especially when it reacts with chemicals called CFCs (chloroflurocarbons – which we used to produce in refrigeration, until they were banned).

Ozone – very fragile bonds

Air currents push CFCs into a polar vortex over Antarctica. (“Polar vortex” may sound like a door to another dimension, but it’s really just a big whirlwind. Sorry to disappoint). These CFCs break down lot of ozone over Antarctica, which (along with some other stuff which I won’t go into here) has lead to a “hole” which extends all the way to New Zealand. Fortunately for us, CFCs were banned a few years ago, and studies have found that the hole is starting to get smaller. To see a cool graphic of the ozone hole changing over time, click here.

The hole over Antarctica

But what does this have to do with sunburn?

Ozone acts as a shield between us and the sun, by filtering out a lot of the nasty UV rays which damage our skin. So in summer, when UV levels are at the highest, there is very little to protect us without ozone. As well as this, New Zealand levels of summer UV are about 40% higher than in the Northern Hemisphere, so we end up looking like this poor kid: (Dang)

Stupid as it sounds, people of the Northern Hemisphere are also protected by sulphur dioxide, which is basically pollution from burning fossil fuels. But here in New Zealand, we don’t have a lot of it, that’s one less line of defence than the other side of the world.

But there’s no need to keep your car running for hours to protect us from the sun – sulphur dioxide contributes to higher levels of lung cancer. So you’d only be saving yourself from one evil by exposing yourself to another.

Testament to the fact that our sun is harsh, New Zealanders and Australians have about four times as many cases of skin cancer than the UK, USA and Canada*. This map shows just how bad it is:

(The more red, the more cases of skin cancer (obviously). See here for actual numbers.)

So here is some (slightly hypocritical) advice: Cover up, and be careful out there!

All pictures: Wikimedia Commons

* According to this