How big is the hole in the ozone layer, if there really is one?
Should we be worried?
It depends on which hole (there’s more than one) and what time of year (they fluctuate in size). Generally, if you’re talking about “the” hole in the ozone layer you’re talking about the one over Antarctica, which at its largest swallows up the entire continent and then some, making an approach towards southern Australia and the like. I think there’s also a hole over the north pole, but it’s not as big. Why, I don’t understand… considering that the vast majority of the industrial pollution of the last couple centuries has occurred in the northern hemisphere, specifically the United States and Europe, shouldn’t the bigger hole be the one over the Arctic?
Moreover, it’s not really a true “hole.” The ozone layer doesn’t simply disappear in those areas, it’s just very thin. Again, I don’t know why it happens the way it does.
The chemical process by which chlorine breaks down ozone occurs much faster on surfaces than in free air. Specifically, it usually occurs on the surface of ice grains in a certain type of cloud. Because of the lower temperatures at the South Pole and a variety of other factors, these clouds are a lot more common in the Antarctic than the Arctic. What this means, among other things, is that global warming from the ozone hole is very self-limiting: If the temperatures rise too much, these clouds won’t form anymore, no more ozone will be destroyed, and the holes will start to shrink again.
Like MicroFurry said, the one over the south pole is larger than Antarctica. And its more of a thinning of the ozone layer than a complete hole, but the effects are still to let more harmful UV light through. So in that sense, yes, increased amounts of harmful UV light reaching the ground should be a big concern. As Chronos said, cold temperature does play a role in it, but I’m not sure to what extent. I’d note though that the ozone layer damage does not cause global warming (well, except that CFCs are a minor greenhouse gas). These two issues may interact (unknown to what extent), but they have separate causes and effects.