Ozone Hole Bigger Again
Written by Nancy Atkinson
Ozone hole during 7 October 2008 as measured by the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) atmospheric sensor onboard ESA’s Envisat. Credits: KNMI/ESA
Is the ozone hole was recovering? Maybe not. The protective atmospheric layer of ozone around our planet has been thinning over Antarctica for many years. New satellite data indicates the 2008 ozone hole is larger both in size and ozone loss than 2007 but is not as large as the record year of 2006. This year the area of the thinned ozone layer over the South Pole reached about 27 million square kilometers, compared to 25 million square kilometers in 2007 and a record ozone hole extension of 29 million square kilometers in 2006, which is about the size of the North American continent. Ozone is a protective atmospheric layer found about 25 kilometers in altitude that acts as a sunlight filter, shielding life on Earth from harmful ultraviolet rays. A thinner ozone layer can increase the risk of skin cancer and cataracts and harm marine life. What causes the ozone layer to change from year to year, and if CFC's have been banned, why isn't the ozone recovering?
The depletion of ozone is caused by extreme cold temperatures at high altitude and the presence of ozone-destructing gases in the atmosphere such as chlorine and bromine. Most of these gases originate from man-made products like chlorofluorocarbons (CFCs), which were phased out under the 1987 Montreal Protocol. But they continue to linger in the atmosphere.
Depending on the weather conditions, the size the Antarctic ozone hole varies every year. As the polar spring arrives in September or October, the combination of returning sunlight and the presence of so-called stratospheric clouds (PSCs) over the Antarctic leads to a release of highly ozone-reactive chlorine radicals present in the atmosphere that break ozone down into individual oxygen molecules. A single molecule of chlorine has the potential to break down thousands of molecules of ozone.
Chlorine activation and ozone hole extension early September 2007 and 2008. Credits: DLR
Colder temperatures in the stratosphere over Antarctica, combined with a high formation rate of PSCs caused more lingering chlorine radicals to be released, making the current hole one of the largest. 2006 saw the largest hole. A unit of measurement called a Dobson Unit describes the thickness of the ozone layer, and this year (2008) about 120 Dobson Units were observed compared to around 100 Dobson Units in 2006.
The analysis is based upon the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) atmospheric sensor onboard ESA’s Envisat, the Global Ozone Monitoring Experiment (GOME) aboard ESA’s ERS-2 and its follow-on instrument GOME-2 aboard EUMETSAT’s MetOp.
Source: ESA
Filed under: Earth, Earth Observation
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October 7th, 2008 at 9:41 am
"The depletion of ozone is caused by extreme cold temperatures at high altitude and the presence of ozone-destructing gases in the atmosphere such as chlorine and bromine. Most of these gases originate from man-made products like chlorofluorocarbons (CFCs), which were phased out under the 1987 Montreal Protocol. But they continue to linger in the atmosphere."
What about the history of ozone fluctuations in the atmosphere PRIOR TO human-based contributions? What is the chemical interaction of chlorine and bromine in the atmosphere with OTHER gases? Even if "most" of these gases were human made, what about even small quantities of these gases in the atmosphere…wouldn't even a small amount contribute in some way?
The findings, in other words, raise more questions than answers. Once again we see a correlation between human activity and environmental alterations…but there is no clear evidence to suggest to what extent and how such activity interacts with naturally occurring phenomena.
October 7th, 2008 at 9:54 am
I noted in the figure that there is significantly more ozone or thicker layer of ozone that surrounds the hole over Antarctica giving the impression that the ozone has been displaced away from the pole. Does anyone know the reason why ozone would accumulate around the edge ozone hole and not circulate into the hole?
October 7th, 2008 at 10:18 am
"Is the ozone hole was recovering?"
Would you all like a proof-reader for the site? I need a job.
October 7th, 2008 at 11:07 am
Why does the ozone hole pick on Antarctica? How much hairspray do they use down there? The amount of the evil gases must be much larger in the Northern hemisphere than the Southern – so why isn't the "hole" above Europe or North America, or even the North pole? This is not an area that I understand yet, so any serious explanation is appreciated.
October 7th, 2008 at 12:00 pm
Well, in a nutshell: because atmospheric circulation is global. Since atmospheric circulation is global, gases produced and released mostly in the northern hemisphere are transported rather quickly to the southern hemisphere (and everywhere, really, which is why it is of everybody's concern the activity of major polluting states, currently China in 1st place and the US in 2nd). As explained in the article, the ozone isn't depleted solely due to the presence of those gases: it also needs cold temperatures. And Antarctida is the coldest place on Earth, therefore that's where the epicentre of ozone depletion lies.
October 7th, 2008 at 7:28 pm
The idea that the hole in the ozone layer is man-made is a myth. One must ask themselves this question: Why is the hole in the southern hemisphere when most of the poluting countries of the world (US/Europe/Russia/China) are in the Northern hemisphere? A very important question to ask. As a meteorologist, I can tell you that because of the way air flows on our planet that air in the northern hemisphere generally stays there and the same for the south.
To understand why the hole is there you need to understand how ozone is created. Ozone is formed naturally in the upper stratosphere by short wavelength ultraviolet radiation. Wavelengths less than ~240 nanometers are absorbed by oxygen molecules (O2), which dissociate to give O atoms. The O atoms combine with other oxygen molecules to make ozone. The bottom line is that you need sunlight to create ozone. Mild levels of ozone are found at the earths surface in city streets all across the world especially toward the end of the day. About an hour after the sun sets the ozone at the surface is gone.
Alright, now that you got that you need to ask yourself what the two poles don't have 6 months out of the year since the earth is tilted 23 1/2 degrees. Answer: Sunlight.
The reason why a hole develops over the south pole is because there is no sunlight there during its winter. During the summer time the hole gets much smaller.
So why isn't there a hole in the northern hemisphere if it gets dark there too? Good question. The main reason is because of the northern jet stream. The northern jet stream moves in a more North to South flow which is caused by all of the land masses the northern hemisphere has. Our jet stream dips deep down toward the equator at some points where there is a lot of ozone (because there is a lot of sunlight). It then transports that ozone into the north preventing it from developing a hole.
The southern jet stream moves in a basic East to West direction since there is little land masses in the south to affect it. Because of this, the southern pole does not get the boost of ozone from the equator like the north does.
I hope that this explanation helps some of you out there. We did not see a hole in the ozone develop. We "discovered" that a hole was there. I can assure you that man did not create it. Saying man is responsible for this hole would be like the first explorers to discover the Grand Canyon coming to the conclusion that it must have been something man did. The only other reason I can think of for this myth being perpetuated is that politicians like to use it to incite the public. Please feel free to look up these scientific claims for yourself.
October 7th, 2008 at 9:22 pm
John, your statement validates a suspicion I have harbored for some time now. I am compelled to think the issue of Global Warming falls into this category as well. If we were entering an Ice Age I am sure people would insist it was due to their actions. It's a testament to the power of human vanity.
October 7th, 2008 at 9:27 pm
Thank you John. Very educational, and better yet, makes sense.
October 7th, 2008 at 10:17 pm
May it is cause of destory of world rather than suspection about 21st december 2012?
October 7th, 2008 at 11:45 pm
"We did not see a hole in the ozone develop. We "discovered" that a hole was there."
This is incorrect; data on the ozone levels has been collected since 1979, before the formation of the hole in the ozone layer.
See: http://ozonewatch.gsfc.nasa.gov/index.html
The graph about halfway down the page on the right shows an annual record of the size of the ozone hole. The development of the ozone hole over the decade from 1980 to 1990 is clear.
Unless you have another explanation for the creation of the ozone hole during this time it seems that the conclusion can only be that the hole is a consequence of our actions.
October 8th, 2008 at 1:56 am
john C. roberts,
that is a first class explanation and i'm glad to have read and learned from it.
some may question that if man did not create the ozone hole, why the big fuss about banning CFCs? simple: they do "destroy" ozone in the stratosphere and each Cl atom has the potential to drift for some time, leaving a trail of destruction until it binds with something else. just how much of an effect they were/are having overall is open to debate, but why aggravate the situation further if it's not neccessary?
October 8th, 2008 at 7:13 am
As Zidtt wrote, the claim that the hole "was simply there" is just plain false. Actual data shows the hole was not there before widespread use of CFCs, and even if ozone levels varied down there over the south pole, there are no signs that a hole proper ever existed prior to anthropogenic factors stepped in.
The implication that the hemispheres are sort of closed boxes is also not true. Most of air circulation stays within one hemisphere, that's correct – I guess we've all seen schematics of the 6 "cells" before -, but exchanges do take place over the tropics, and since CFCs tend to linger for many years in the stratosphere, they get disseminated all over the globe after a while.
In this, as in most other contemporary environmental fenomena, there's a mix of anthropogenic and natural influences in play, some well understood, some not so much. We can go on arguing untill doomsday about which predominates, which has the strongest influence on changes that are happening, etc. But no intellectually honest debater can deny that human influence exists, that at least part of the changes is due to our actions and the untreated emissions of our industries. How strong that influence is is debatable; its existence is not.
And the problem gets more serious if we consider that if we just debate these issues until doomsday and do nothing, we'll be making sure that day gets closer, closer and closer. In this, climate change deniers are just as irresponsible as the scumbag CEOs that did their best to dip the planet in a global recession while filling their own pockets with billions.
October 8th, 2008 at 9:02 am
The anually ozone depletion zone did dip, and even disappears for a few years, shortly after fluorocarbons were banned. Likewise, the fluorocarbon content measured in the upper atmosphere also dipped.
As mentioned by others, chlorine is a big contributor. Not mentioned is a potential effect of global warming: trapping energy in the lower atmosphere has the potential for cooling the upper atmosphere. More cold air, greater ozone depletion.
Also not mentioned is the correlation between the ozone hole size and skin cancer rates in Australia; although, due to the widespread use of sunscreens, it is likely this effect has been mitigated.
October 8th, 2008 at 12:42 pm
I also agree that both the "human caused ozone hole" and "human caused global warming" are insignificant. What's with the bromine? There's no bromine in CFC's. It seems we grasp at any explanation for human causation no matter how unlikely. The stagnent atmospheric conditions over Antarctica is one cause even though it suggests that pollutants from the North aren't having any real effect. Global warming, on the other hand, has been going on for the last 12000 years. Has anybody noticed that the Canadian ice cap is gone?
October 8th, 2008 at 12:56 pm
Nancy! How did you miss mentioning that the Polar Vortex in Antarctica routinely varies in intensity? Specifically that it is substantially larger every other year and the ozone hole follows the same trend. I thought this was common knowledge; enough so that with all the above comments that someone else would have brought it up. Frankly, I'm surprised it wasn't in your article.
Incidentally, I did find a paper from the 1950's (1954 I think) where the ozone hole was observed. The data made no sense to the researchers at the time to the point where they questioned the validity of the data. I would have to dig to find my old references to it. Subsequent data suggests that human activities have impacted the ozone hole, but it likely was there to some degree or another all along and will likely not go away completely. And will continue to alternate in strength every other year. if 2006 was still the record, I submit that we are still seeing a downward trend.
D-L
October 8th, 2008 at 2:26 pm
neoguru, that missing Canadian ice cap is a common anegdote, but it's pretty much irrelevant. Why?
Because the problem is not that the climate changes. The climate has changed numerous times throughout Earth's history, for all sorts of reasons, and will continue changing. No, that's not the problem. The problem is twofold:
1. How fast it is changing now, which is not unprecendented only because there were sudden global climate changes caused by major catastrophes, such as the eruption of supervolcanos or asteroid impacts.
2. The fact that our whole civilization is much more dependent than people usually think on climateric stability in the levels we've known for the last 2-3 centuries. A disruption of climateric patterns will have immediate and strong impacts on things as vital as food production, and the economic cost of infrastructure loss in case of a significant rise in global sea levels is just immense. If you think the economy is bad now, just wait until the whole impact of climatic change hits us.
We can cope with slow climatic change, with the comings and goings of glaciers throughout the millenia. We cannot cope with sudden, fast and uncontrollable climatic change. If the worst case scenarios do unfold, that means the end of civilization as we know it.
October 8th, 2008 at 3:49 pm
Jorge, You are wrong here too. The amount of change in the worse case IPCC scenario (one which has been debunked by statisticians calling the Mann "hockey stick" chart a fraudulent artefact of intentionally biased software) remains in the order of the change since the peak of the Little Ice Age in the 17th century. The changes weve seen have a lot more to do with variations in sunspot and solar electromagnetic activity (a tight solar EM field means a compact and hotter sun, while a loose weak one means an expanded cooler sun with few sunspots). Ask the solar astronomers what they are predicting for Solar Cycle 25: an extended solar minimum that will cool the planet by 1.5-2.0 C by 2022. Ask them about the current cooling trend of the past two years, a function of an extended solar minimum and a significant cooling in the north atlantic occillation.
Global warming is being observed on every planet in the solar system, not just Earth. You cant blame that on mankind. Likewise, the elephant in the room with the ozone hole is COOLING. Why is antarctica COLDER if we are in global warming? Antarctic ice is building up much more massively in the center, much more than is calving off at the ice shelves. Likewise in Greenland.
October 8th, 2008 at 4:50 pm
Ouch. So many disinformation in such a short text!
First of all, the Little Ice Age (LIA for short) isn't even for sure a global phenomenon. There are some doubts that it extended further from the Northern Hemisphere.
But let's assume it was a global phenomenon. The LIA followed a medieval warm period, with a slow decline in temperatures that went on for 500 years. In those 500 years, temperatures dropped less than 1 ºC. That's 0.002 ºC per year, in average.
Now fast-forward to 1950. From 1950 to 2007, temperatures raised 0.6 ºC. That's a 0.01 ºC raise per year, in average, i.e., a change that is 5 times faster than during the cooling that let to the LIA.
In 1950, BTW, global temperatures were about 0.4 ºC higher than during the peak of the LIA. Not even half a degree. This is what I call a slow climate change.
Now shift focus to the IPCC. The IPCC's worst case scenario, far from "remaining in the order of the change since the peak of the Little Ice Age in the 17th century", as you very wrongly claim, talks about a raise in global temperatures of 6.4 ºC during the XXIst century. That means an average annual raise of 0.064 ºC, which is 32 times faster than the drop that lead to the LIA. Let me stress out this number you claim to be "in the order of the change since the LIA": Thirty two times faster. That's just about the degrees of separation there are between what you say and the truth.
Unfortunately something just came up and I've got to run, so I don't have time to tackle that ghostly other planets' connection with global warming and what solar scientists say about this issue. I'll just leave you with that Phil Plait wrote about the first topic, at http://blogs.discovermagazine.com/badastronomy/2007/04/29/is-global-warming-solar-induced/ and what Ian O'Neil (who, unlike you and I, is an actual solar scientist) wrote about the second topic right here in UT: http://www.universetoday.com/2008/04/03/there-is-no-sun-link-with-global-warming/ . Enjoy your read. And while you're at it, I'd advise you to stop getting all your disinformation from propaganda sites connected with the oil industry.
October 9th, 2008 at 4:28 am
What the heck happened to the comment I left here yesternight debunking the load of misinformation this comment above is?!
October 9th, 2008 at 7:18 am
Hm… and now I see it.
OK, I have a few questions to the bloggers.
When I posted the comment, it showed normally on my screen, without a hint that it went into moderation. Now, however, it appears with the following note: "Your comment is awaiting moderation." I'm the only one who sees it, I guess, and the first question is: are the UT editors also able to see it, or was it stashed away by some automatic "spam" filter you've installed recently? I'd like to know if that's the case, to know if I should repost or not.
The comment includes a lot of text and two links. It's the first time I've had problems with links, and I must say that not being able to post links is a big problem here, because discussions often get to a level where it's very useful to be able to show references or point people to other sources of relevant information. Still, and here's the second question, it would be useful to know what can be done and what can't be done. Maybe there are possible workarounds. Can you give us that information?
I understand perfectly the need to close the gates to spam, believe me I do, but you might consider installing a smarter filter, one with the possibility of whitelisting some domains, for instance. The two links I put in my comment would send people to Phil Plait's blog and to another post in Universe Today itself. Duh, right? Automatic spam filters tend to be this dumb, but the better ones can be tweaked in order to allow for some flexibility. We need the links.
October 9th, 2008 at 5:25 pm
OK, then. Here it goes again, without the start of the links, and otherwise unchanged. Again, I don't have time to touch it up, so even the typos remained exactly as they were:
Ouch. So many disinformation in such a short text!
First of all, the Little Ice Age (LIA for short) isn't even for sure a global phenomenon. There are some doubts that it extended further from the Northern Hemisphere.
But let's assume it was a global phenomenon. The LIA followed a medieval warm period, with a slow decline in temperatures that went on for 500 years. In those 500 years, temperatures dropped less than 1 ºC. That's 0.002 ºC per year, in average.
Now fast-forward to 1950. From 1950 to 2007, temperatures raised 0.6 ºC. That's a 0.01 ºC raise per year, in average, i.e., a change that is 5 times faster than during the cooling that let to the LIA.
In 1950, BTW, global temperatures were about 0.4 ºC higher than during the peak of the LIA. Not even half a degree. This is what I call a slow climate change.
Now shift focus to the IPCC. The IPCC's worst case scenario, far from "remaining in the order of the change since the peak of the Little Ice Age in the 17th century", as you very wrongly claim, talks about a raise in global temperatures of 6.4 ºC during the XXIst century. That means an average annual raise of 0.064 ºC, which is 32 times faster than the drop that lead to the LIA. Let me stress out this number you claim to be "in the order of the change since the LIA": Thirty two times faster. That's just about the degrees of separation there are between what you say and the truth.
Unfortunately something just came up and I've got to run, so I don't have time to tackle that ghostly other planets' connection with global warming and what solar scientists say about this issue. I'll just leave you with that Phil Plait wrote about the first topic, at blogs.discovermagazine.com/badastronomy/2007/04/29/is-global-warming-solar-induced/ and what Ian O'Neil (who, unlike you and I, is an actual solar scientist) wrote about the second topic right here in UT: http://www.universetoday.com/2008/04/03/there-is-no-sun-link-with-global-warming/ . Enjoy your read. And while you're at it, I'd advise you to stop getting all your disinformation from propaganda sites connected with the oil industry.
October 9th, 2008 at 10:30 pm
I just returned from visiting Yellowstone and was struck by the devastation of the 1988 fires, which were preceeded by acute drought and record setting dry lightening. I began to wonder what solar activity occured leading up the 1988 fire storms. Solar cycle 22 started just a couple of years before that summer of drought and dry lightening. Check this out. Relative to other cycles, that solar cycle had 1) a very fast rise time – 2.8 years, 2) a very short cycle length – 9.7 years, 3) a high minimum sun spot number – 12.3, and 4) a high maximum sun spot number – 158.5
more:
“Cycle 22 certainly provided us with many highlights. Early in the cycle the smoothed sunspot number (determined by the number of sunspots visible on the sun and used as the traditional measure of the cycle) climbed rapidly; in fact more rapidly than for any previously recorded cycle. This caused many to predict that it would eclipse Cycle 19 (peak sunspot number of 201) as the highest cycle on record. This was not to be as the sunspot number ceased climbing in early 1989 and reached a maximum in July of that year. Whilst not of record amplitude, Cycle 22 still rated as 4th of the recorded cycles and continued the run of recent large solar cycles (Cycles 18, 19 and 21 were all exceptional!). A very notable feature of Cycle 22 was that it had the shortest rise from minimum to maximum of any recorded cycle.”
Material Prepared by Richard Thompson. © Copyright IPS – Radio and Space Services.
December 7th, 2008 at 6:17 pm
coolll
April 15th, 2009 at 2:52 am
"Is the ozone hole was recovering?"
Huh? English?
The heading's right next to an ad on improving your brain.