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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.
I was just looking into this not too long ago. Strangely enough, we met someone from Israel while we were travelling in New Zealand who said it had closed, which I was sure was wrong. Turns out it's still there.
And remember it's not really a hole, i.e. there is ozone present, it's just at significantly lower levels.
Here are a couple of sites I found useful :
www.epa.gov/ozone/science/hole/holehome.html
www.atm.ch.cam.ac.uk/tour/
When we were in New Zealand the sun feels different ! It feels very intense and somewhat uncomfortable, and it was only the first month of spring. You HAVE to use sunscreen.
Absolute statements are never true
Oh well. Luckily the world will end AFTER I'm dead.
Department of Homeland Security: Removing the rights real patriots fought and died for since 2001
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
Sunlight naturally converts some oxygen to ozone in the upper atmosphere. Problem is that when CFCs and other chemicals are present, they eat up ozone far faster than it is typically produced.
Ozone is harder to produce and easier to break down when it is cold, which is one reason ozone is at its lowest levels over the poles in winter (also when there is a deficit of sunlight). The poles are also especially vulnerable because global wind patterns circle around them rather then refreshing the air. Even the most stubborn air pollutants will break down or become absorbed by the environment if we stop pumping them out and give the Earth time to get back to normal.
No, but it is what the preponderance of the evidence suggests.
... Oh wait, that happens all the time?
a) Upon seeing problems, we've heavily cut back on all sorts of emissions under the belief that it will fix the problem.
b) Results of a) (above) will take sixty more years to manifest.
c) Problem is disappearing long before results of a) are known.
Therefore, perhaps a) was a faulty assumption that costs businesses billions annually, and the ozone hole is really just a cyclical thing?
That said, lower emissions are good, if only for two reasons - one, so that whilst canoeing the Indian Arm of the Fraser River, I don't know that Vancouver is (that way) due to the brown sky. Two, because they *do* seem to be responsible for all sorts of human respiratory problems. You know, if environmentalists weren't all a bunch of crackpots who use pseudoscience to justify whatever their jihad of the day is, I'd probably identify myself as one.
PS - The ICE at the NORTH POLE is MELTING!!! Oh NO!!!
If a tree falls on an anonymous coward yelling 'first post' in the forest, does anybody hear?
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.
Which volcano in the Phillipines poured out CFCs? I'd be very interested in hearing about a volcano that poured out chemicals that do not naturally occur! CFCs are manmade - they are no naturally occuring CFCs.
The hazards we now associate with CFCs were discovered in the 1960s when a British chemist (Lovelock) was interested in tracing the motions of air masses. He was using CFC's to do so, as they were ideal for tracing air motions, being chemically stable and not naturally-occurring (they are only man-made) so their presence in an air mass could not be confused with CFC's coming from natural sources.
Perhaps you are thinking of the theory that volcanic chlorine caused ozone depletion? There are a number of problems with this:
(1) There was significant O3 loss in the 1980's, but no major volcanic activity then.
(2) There has been major volcanic activity since O3 monitoring began in the 1950's, but it was not necessarily associated with declines in O3. That is, O3 losses and volcanic activity appear to be uncoupled in time (lack temporal consistency)
(3) Measures of hydrogen chloride in the stratosphere after the relatively recent eruptions of Mt. Pinatubo and El Chicon showed less than a 10% increase in stratospheric HCl following those eruptions, while stratospheric HCl has increased steadily across recent years. Furthermore, it is estimated that 1% of the Cl released by the eruption of Mt. Pinatubo Cl made it to the stratosphere, judged by the increase in HCl in the stratosphere following the eruption and the estimated release of Cl by the volcano.
(4) Stratospheric hydrogen fluoride has also increased steadily in parallel with HCl, as would be consistent with CFC sources.
(5) Much of the HCl produced by volcanoes (or Cl from sea salt) is injected into the troposphere and very little of that makes it to the stratosphere, as it is washed out first. Volcanic emissions include abundant water vapor, and HCl and NaCl are quite soluble in water, while CFC's are not.
(6) Most of the HCl that does make it to the stratosphere is rapidly washed out -- that is the major removal mechanism for Cl from the stratosphere.
(7) After volcanic eruptions, scientists find enriched sulfate in ice caps, suggesting that the eruptions inject sulfate into the stratosphere, where it gets widely distributed before being washed out. However, ice caps are not enriched with Cl following volcanic eruptions, suggesting that most Cl doesn't make it to the stratosphere where it could get dispersed as sulfate does.