Slashdot Mirror
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.
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':
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
Last summer I did some educational outreach for the lab I work for, at a day-camp for science kids, and the topic was ozone one day. If I remember correctly regulation can't possibly account for this, because the CFC's have a destructive lifetime in the atmosphere for something on the order of 100 years. ie. the little buggers break apart O-3 for a long time after we stop using them. Even if we stopped all CFC use today, we wouldn't see any atmospheric effect for many decades. Begging the question: why IS the hole reducing?
Getting diabetes AND salmonella would be a bad weekend.
Speaking as a New Zealander. The Sun and Heat here are probably unlike anything most people have felt. Burn time in the summer comes down as low as 10 minutes. You can't even get in your car and go for a drive without getting burnt. In mid summer you literally have to put on a top with long sleeves or your arms will physically hurt if you are out in the sun
Normal people worry me!
A good description of the process which results in the ozone hole can be found here.
Basically, the intense cold of an antarctic winter creates a vortex which isolates the air over the south pole, and allows build up of the CFCs. When the summer comes, the Chlorine from the CFCs acts as a catalyst to destroy the ozone.
It now seems to be well understood - but it's one of those things that nobody could have predicted before it happened.
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.
And the brethren went away edified.
The ozone hole and CFC sitatuion is one of the most well understood things in science however. It's due to the following:
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.
A few more web sites that I've come across, giving a saner perspective of Global Warming, etc.:
CITIZENS FOR A SOUND ECONOMY
http://www.cse.org/globwarm.htm
COOLER HEADS COALITION
http://www.globalwarming.org
THE ADVANCEMENT OF SOUND SCIENCE COALITION/THE JUNK SCIENCE HOME PAGE
http://www.junkscience.com
MOBIL
http://www.mobil.com
SCIENCE & ENVIRONMENTAL POLICY PROJECT
http://www.his.com/~sepp
MARSHALL INSTITUTE
www.marshall.org
The Cooler Heads site is the one with the more realistic views.
"Making linux GPL was the best thing I ever did" - Torvalds. I'd hate to see the worst thing...
Where is the evidence of the increase of human skin cancers due to "ozone hole" ?
Check cancer rates between Pennsylvania, USA and Sydney, Australia. I know this is far from a bulletproof arguement, for maybe Aussies are naturally more prone to skin cancer, or spend more time outdoors (which they do), or they use a sunblock which mutates them into sun cancer prone mutant freaks. But the (abeit weak) arguement some people say is that in the land down under there is mommothian awareness of skin cancer, everyone uses sun block, hats and that disgusting blue crap you put on your nose, there are advertisements all the time for sun awareness (remember that egg me no fry ad? Yes!), and here in the good old US of A we suffice with those annoying no-life weather channel dorks to tell us to put on a hat. I have lived in both countries for a decent (over 4 years) amount of time and the amount of people here in the US who care about skin cancer is miniscule compared to Aust. Yet (and the reason for that) rates are still higher down there. We are both about on the +/-40 degree latitude mark. This evidence is circumstantial at best but I'm sure someone else can post up a more scientific explanation for it (please?)
Just what I think, thats all
People (e.g. chemists) know that chlorine reacting with ozone will break ozone apart, and people know that CFCs can make it to the arctic, at which point they decompose (based on their decay rates). I hope that answers your question, but let me know if it doesn't (post or email).
CO2 is responsible for global warming, not ozone depletion.
CFCs (chlorofluorocarbons) and some other gases like halon(tm?) are responsible for the thinning ozone. Most of these gases have been banned under the Montreal protocol for some years now, but because they are largely inert they can rise far into the stratosphere (which takes them quite a few years) where they do their damage. What happens up there is that the suns intense UV rays break the CFC molecules up and the chlorine ends up binding with an oxygen atom from the ozone. The actual reaction is here
CO2, on the other hand, absorbs infrared radiation from the earth reradiated from sunlight and keeps the heat in the atmosphere. It basically acts like a big blanket. CO2 is what the Kyoto Protocol is trying to limit.
---
I didn't want to leave this space blank.
I work for the Climate Monitoring and Diagnostics Laboratory which is part of NOAA (National Oceanic and Atmospheric Administration). If anyone is interested, our lab launches balloons that help measure the level of ozone in the atmosphere at the South Pole.
More information can be found at the South Pole Ozone Page.
Eric
For ozone to be destroyed you need:
Although I am sure that other chemicals can break down ozone, CFCS are the most common and best at doing it because they are lighter than air and they normally DO NOT react with anything around us (at or near sea level). These two properties make them fly up high into the ozone layer. The non-reactant portion is what made these chemicals so great and so unthought of as causing problems. To destroy ozone molecules you have to have some very specific conditions:
Okay so now how do you get these conditions, and why is there no northern ozone hole? Well we have uv-light and aplenty so that's not a problem. The first issue is gathering a lot of CFCs (and ozone) into one place, this is taken care of by the Antarctic vortex. The vortex is there during certain months of the year and it builds up a lot CFCs and Ozone into a small space. In the northern polar regions it isn't so prominent because there are landmarks to break up these winds, however there are some weaker ones that are present in the north. Okay, we got ozone and CFC and light, now we need to get rid of the nitrogen. This is handled by formation of nitrogen clouds, which are clouds that are really cold and really high up that contain droplets of condensed nitrogen, and now the nitrogen is gone in the atmosphere and CFC havoc may occur. This doesn't happen in the north because the north pole is much warmer (or at least enough to prevent this). Now the scary thing is if we get a cold winter in the north then a big hole can form in the north, and if you look at a globe there are millions upons millions more people in the upper northen latitudes than there are in the southernmost latitudes. And if you use the following statistic, -1% ozone layer = +2% UV-light on the surface of the Earth = +4% skin cancer, which is sorta bad when applied to cities like London and Quebec and what not (yes these ozone holes can affect huge areas).
Now before someone tries to beat me down for using pseudo science, my mother is on the DIAL team which is a NASA group that measures the ozone hole using a LIDAR(Laser detection) system. These were the people who went to confirm the ozone hole when NASA originally thought the TOMS satellite was malfunctioning because it had almost no readings in the south pole for ozone. I may have bungled some of the facts so if I did please correct me. I think most of these chemical processes have been tested in a lab so they are empirical evidence.
As for the the stabilizing of the ozone I can only make a few conjectures: 1) the most likely IMHO, the temperature in the southern pole haven't been as cold lately, I know I have been going through some wacky yearly climate cahnges here, 2)the Earth is mucuh more resilient than we like to think, or 3) We're missing something that is there and it may not be only the CFCs or it could be a natural cyclical event, but I have trouble believing it is natural with all the scientific evidence I have seen. There are still too many CFCs in the ozone layer for it start repairing, and due to the resilience and the near-non-reactance of CFCs they will be around for another 60-100 years, before the ozone makes a come back and another 100 after that to repair itself.
----------
Just your ordinary BOFH
http://killertux.org
It is thought that the increase in fresh cold water could disrupt the "Atlantic Conveyor" effect that gives rise to the Gulf Stream. If this stopped, or diminshed significantly, many areas of Europe would have considerably colder climates (i.e. more like central Russia, but colder in the summer too).
Here's some statistics and information on the ozone hole from the Climate Prediction Center:
e /sbuv2to/ozone_hole.html
http://www.cpc.ncep.noaa.gov/products/stratospher
Bush Lies Watch