Don't forget the sunscreen...

I'm off on my holidays on Friday, hooray! Alongside my thermals, woolly hat and 5 season sleeping bag, I'll be packing my sunnies and plenty of factor 50. Sounds like a strange combination? Not in during the Antarctic ozone hole season...

Before I give anything away, why not test your ozone hole knowledge -

True or False:

1. The ozone hole is open all year round

2. Ozone absorbs harmful UV radiation from the sun

3. The ozone hole is the same everywhere on earth

4. The ozone hole was discovered here at Halley

5. One of the discoverers earned a Blue Peter badge for his efforts

6. The ozone hole is caused by global warming

7. The ozone hole will probably get better

8. The ozone hole affects everyone

9. Penguins get sucked into space through the ozone hole

10. It is possible to get sun burnt up your nose

So how did you do?

Answers:

1. False. It opens up every southern spring, towards the end August after the sun has returned to the high latitudes. It peaks in October then fades away during late November or early December. There is good reason for this timing. Ozone destruction requires 3 things:

REALLY COLD + CHLORINE (from CFCs) + SUN = DEATH TO OZONE

It has to be really cold because the chemical reactions that destroy ozone take place on ice clouds high up in the atmosphere that only form in temperatures below - 75 deg C. The ozone destroying reactions involve chlorine and also require sunlight to start them off. So ozone destruction starts as soon as the sun returns to the Antarctic in August (at Halley) and carries on until sometime in October it gets too warm for the ice clouds to form. The hole doesn't disappear immediately but instead hangs around until ozone from other regions of the world start to fill in the gap at the start of the southern summer.

2. True. The ozone layer protects us from some of the sun's most harmful radiation by absorbing it before it reaches us. The ozone hole is a bit of a problem for those of us underneath it allows more than double the normal amount of UV radiation to reach us. UV radiation is pretty nasty stuff, causing sunburn, eye damage and skin cancer. That's why I have to smother myself in sunscreen till I look like a yeti when I'm out and about.

3.False. Here's a satellite picture of the ozone hole a week ago, approaching its peak (the blacks, purples and darker blues show areas of serious ozone depletion). It stretches over most of Antarctica and sometimes as far as the tip of South America. Antarctica is ideal territory for ozone holes as it's cold and isolated. During winter and spring winds high up in the atmosphere circle around Antarctica cutting it off from the rest of the world and stopping any high ozone air from filling the hole. There is a much weaker and less well defined hole over the Arctic during their spring, but the Arctic is neither as cold nor as isolated so mostly it's a southern hemisphere thing.
4. True indeed, back in 1985.

5. True! Jon Shanklin, still in charge of ozone measurements at Halley and hence my boss is the proud owner of a well deserved Blue Peter Badge.

6. False. The cause of the ozone hole is completely separate from climate change or global warming. CFCs that used to be in refrigerators and aerosols are thought to be the biggest culprits.

7. True. But it's gonna take a while. Latest predictions are that it won't have recovered fully until at least 2070. Even though the release of CFCs has slowed down dramatically following the Montreal Protocol, they hang around in the atmosphere for a long time. CFCs are not very reactive (ironically, that's why no one thought they could do any harm at first) which means they're tough to get rid of, so we just have to be patient.

8. True. Each year in December, ozone from the rest of the world starts to fill the hole. At the minute, ozone is being destroyed much faster than new ozone is being made, so the amount of ozone everywhere on the planet is down by at least 10-15%. Doesn't sound like that much but it means a big increase in the risk of skin cancer pretty much everywhere. The ozone layer also plays an important role in global climate and the full implications of the hole are not yet fully understood.

9. ? A proper scientist would probably say something like "contrary to popular belief, penguins are not sucked out into space through the ozone hole," but how do they know? Science has taught me that when penguins are sucked into space they explode (because of the vacuum). So who's to say that all this dark matter cosmologists have been looking for is not made up of fragments of exploded penguin. Sounds at least as feasible as the average scientific theory to me

10. True. Here in Antarctica (or anywhere else where it's snowy) the sun is reflected back up at you from the snow surface. That means you get almost twice as much sun as normal = sunburn in some very strange places like up your nose and the roof of your mouth (especially if you visit the penguins and you can't stop mouthing the words 'they're so cute').

Scores:
8-10 You may even be in with a chance of qualifying for your very own blue peter badge one day.
4-7 Nice try but no cigar
0-3 You are in danger of being sucked out of the ozone hole along with the penguins.

One more thing... I've started writing for a blog on the website of a brand new American TV show called 'WIRED Science'.
I'll be writing lots more about Antarctic science so it's well worth a look.