Antarctic Ozone Hole Leveling Off

twistedfuck writes: "An Irish Time article reports that the size of the hole in the antartican ozone layer is levelling off and should begin reducing in size. It seems like it should be welcome news but it is tempered by the fact that more UV radiation will reach the southern hemisphere this year because the hole will persist longer. Unfortunately I can not find any details regarding the NOAA report on their website." Update: 11/06 17:31 GMT by H :Thanks to Isaac Lewis, NOAA Sysadmin and Slashdot reader, for pointing out more information, as well as pointing out the ozonelayer site.

Comments

Press Release

[ukryule]

is at http://www.publicaffairs.noaa.gov/releases2001/oct 01/noaa01104.html.

To summarise the findings, it seems the density of Chlorine from CFCs has peaked, and it is expected the Ozone hole will gradually (i.e. over the next 50 years!) disappear.

It now seems to be an interesting case of us screwing up our environment, working out what we'd done, and fixing it. However, you could consider that we just 'got lucky':

• The fact that it was concentrated in one spot meant that the problem was identified before we'd managed to strip the whole atmosphere of ozone.
• It was concentrated over the least populated part of the globe. Compare the increase in awareness/incidence of skin cancer in Australia/New Zealand with what might have happened if it was concentrated around the equator.
• The solution (banning CFCs) had relatively little economic impact making it easily implementable. It was also a universally accepted solution.

Compare this with the current situation re global warming, and this looks less like a successful victory and more like a warning shot across the bows ...

Re:Press Release

[frankie]

I read a nice article (not sure if was on slashdot)

Danger! Danger, Will Robinson! Moderators, please do not Not NOT mark a comment "Informative" if it makes a scientific claim without providing any hard links to back it up.

A quick google search, for example, led me to several potentially informative web sites, such as:

• European Chlorine industry association
• American Chlorine industry association
• an anti-Chlorine lobbying group
• Women's Environmental Network

etc, etc, etc. Don't just spout off random crap that you think you heard once.

Google means never having to say "I don't remember".

Re:Problem with Environmental Theories

[CaptainCarrot]

As a side note-it is my understanding that CO2 levels during the time of the dinosaurs were much higher than they are today. The Earth can handle huge changes with relatively little environmental impact.

Actually, the environment at the time of the dinosaurs was hugely different. Earth had no polar ice caps, and the continents were arranged differently. In the dinosarus' heyday around the middle of the Jurassic, the Atlantic Ocean didn't exist. The bulk of the land was grouped into an enormous crescent surrounding what is now the Indian Ocean. The coasts were warm and humid; the continental interior was desert. It was a world utterly unlike that we live in today, and we probably could not have flourished in it.

Re:Problem with Environmental Theories

[Jormundgard]

Environmental science is over 100 years old, but it didn't start to thrive until after WWII.

The ozone hole and CFC sitatuion is one of the most well understood things in science however. It's due to the following:

• Companies used to produce CFCs - a combination of Chlorine, Fluorine, and stuff that is extremely resilient. Most importantly, it's resilient to radiation, so it can survive long distances. Note that some people try to compare this to the chlorine dumped by Mt. St. Helens - but free chlorine is easily busted apart by radiation, while CFCs can survive the trip ahead of it.
• The Equatorial Winds are a series of currents that blow from the equator to the poles (with a slight lean towards the north(?) ) - these blow chemicals form the equator (where humans mainly live) to the poles. Chlorine molecules are destroyed in the upper atmosphere by radiation, but CFC's survive the trip.
• Finally, at the poles, the CFCs (which take a while to decay) break up in appreciable amounts at the poles, where the free chlorine reacts with the ozone, and breaking it apart. The fact that there are free fluorine atoms in the poles, which is only possible by man-made actions, is the smoking gun.
• 
  Based on the equatorial cycle, one would expect to be free of CFC effects after about 100 years - I guess it's been about 25? So I guess this is about when one would start to notice the effects.
  
  Although there are the occasional puppets who still denounce ozone problems, the industries and governments were immediately convinced by the evidence, which is why humans have probably fought off this problem.
  
  Finally, the CO2 issue is a global warming thing, which isn't really related to the ozone hole problem. That's a polar icecap melting problem, and the data is still not totally convincing---the problem is that some predictions say that it's too late to prevent a 1m rise in sea level.