From the European Space Agency. By merging more than a decade of atmospheric data from European satellites, scientists have compiled a homogeneous long-term ozone record that allows them to monitor total ozone trends on a global scale – and the findings look promising.
Scientists merged monthly total ozone data derived from the vertically downward-looking measurements of the GOME instrument on ESA’s ERS-2 satellite, SCIAMACHY on ESA’s Envisat and GOME-2 on the European Meteorological Satellite Organization’s MetOp-A.
“We found a global slightly positive trend of ozone increase of almost 1% per decade in the total ozone from the last 14 years: a result that was confirmed by comparisons with ground-based measurements,” said Diego G. Loyola R. who worked on the project with colleagues from the German Aerospace Center (DLR).
Ozone is a protective layer found about 25 km above us mostly in the stratospheric layer of the atmosphere that acts as a sunlight filter shielding life on Earth from harmful ultraviolet rays. The thinning of this layer increases the risk of skin cancer, cataracts and harm to marine life.
The ozone layer is not distributed evenly, with more changes occurring in the upper stratosphere. By collecting data while looking sideways (limb viewing) rather than vertically downwards, instruments are able to provide highly accurate measurements of the stratosphere.
A team of scientists around Ashley Jones and Jo Urban from Sweden’s Chalmers University of Technology combined the limb measurements of US instruments SBUV, SAGE I+II and HALOE with data from OSIRIS, SMR and SCIAMACHY on the European satellites Odin and Envisat to analyse the long-term evolution of stratospheric ozone from 1979 to the present. These data show a decrease in ozone from 1979 until 1997, and a small increase since then.
“Our analysis shows that upper stratospheric ozone declines at northern and southern mid-latitudes at roughly 7% per decade during 1979–97, consistent with earlier studies based on data from satellites and ground networks. A clear statistically significant change of trend can be seen around 1997. The small increase (of 0.8–1.4% per decade) observed thereafter, from 1997 to 2008, is however not yet statistically different from a zero trend. We hope to see a significant recovery of (upper stratospheric) ozone in the next years using longer, extended satellite time-series,” Urban said.
The thinning of the ozone layer is caused by chemicals such as human-produced bromine and chlorine gases that have long lifetimes in the atmosphere. The Montreal Protocol (1987) was introduced to regulate and phase out the production of these substances. Its effect can clearly be seen in the satellite observations of ozone and these chemicals.
Using SCIAMACHY data in limb-viewing observation mode from 2002 to 2008, François Hendrick from the Belgian Institute for Space Aeronomy (BIRA/IASB) and his colleagues from the University of Bremen performed a trend analysis of bromine monoxide (BrO) in the stratosphere. BrO is a highly efficient catalyst in ozone destruction. The results show a negative trend in BrO abundance in the stratosphere during this period, marking the first time a decline in stratospheric bromine has been reported from a spaceborne observation.
“The good agreement with ground-based observations at high and mid-latitudes show that SCIAMACHY limb data can be used for stratospheric BrO trend monitoring. These findings provide strong evidences that the Montreal Protocol restrictions on brominated substances have now reached the stratosphere,” Hendrick said.
Having access to these atmospheric satellite data over long periods is important for scientists to identify and analyse long-term trends and changes. In addition to monitoring ozone trends, scientists will continue to monitor ozone-depleting substances that were phased out under the Montreal Protocol but continue to linger in the atmosphere.
All of these results were presented at ESA’s five-day ‘Atmospheric Science Conference’ held in Barcelona, Spain, 7–11 September. The objective of the conference was to provide scientists and researchers with the opportunity to present up-to-date results from their atmospheric research and application projects using space-based atmospheric sensors.
The conference, with some 200 participants, included presentations that detail the current use of satellite instruments for remote sensing of trace gases in the stratosphere and troposphere, clouds and aerosols, pollution and greenhouse gas monitoring.
Oh, and Clark, what does “ten times lower” mean? Does that mean it’s 1/10th?
This page may be of interest to some
http://ozonewatch.gsfc.nasa.gov/meteorology/ozone_2009.html
We were told that these CFC’s were so long-lasting that they’d be destroying ozone at an exponential rate for eons into the future. This of course was an indisputable fact…. Then again it’s only 10 years so it’s surely just noise in an ever-rising trend.
I actually first read about aerosols and ozone as a kid reading Marvel comics. They had a storyline about the skin cancer getting so bad in the future that the people were forced to become cyborgs to replace missing body parts.
Wait a minute; a rise from 1979 to 1997 then a plateau. Is that a spurious correlation I see before me?
“After a crash, nobody wants to be surrounded by a cloud of explosive gas.”
You don’t think theres a market for hydrogen cars then?
I believe the ‘ten times lower’ reference relates to this topic. Actual kinetic data (as opposed to estimates used in the 1980s) showed that a key reaction rate was almost an order of magnitude slower than had been estimated. This led to the quote – “This must have far-reaching consequences,” Rex says. “If the measurements are correct we can basically no longer say we understand how ozone holes come into being.” excerpts from the article follow:
———————————
Chemists poke holes in ozone theory
News@Nature, 26 September 2007
http://www.nature.com/news/2007/070924/full/449382a.html
As the world marks 20 years since the introduction of the Montreal Protocol to protect the ozone layer, Nature has learned of experimental data that threaten to shatter established theories of ozone chemistry. If the data are right, scientists will have to rethink their understanding of how ozone holes are formed and how that relates to climate change.
Markus Rex, an atmosphere scientist at the Alfred Wegener Institute of Polar and Marine Research in Potsdam, Germany, did a double-take when he saw new data for the break-down rate of a crucial molecule, dichlorine peroxide (Cl2O2). The rate of photolysis (light-activated splitting) of this molecule reported by chemists at NASA’s Jet Propulsion Laboratory in Pasadena, California1, was extremely low in the wavelengths available in the stratosphere – almost an order of magnitude lower than the currently accepted rate. “This must have far-reaching consequences,” Rex says. “If the measurements are correct we can basically no longer say we understand how ozone holes come into being.” What effect the results have on projections of the speed or extent of ozone depletion remains unclear.
The rapid photolysis of Cl2O2 is a key reaction in the chemical model of ozone destruction developed 20 years ago2 (see graphic). If the rate is substantially lower than previously thought, then it would not be possible to create enough aggressive chlorine radicals to explain the observed ozone losses at high latitudes, says Rex. The extent of the discrepancy became apparent only when he incorporated the new photolysis rate into a chemical model of ozone depletion. The result was a shock: at least 60% of ozone destruction at the poles seems to be due to an unknown mechanism, Rex told a meeting of stratosphere researchers in Bremen, Germany, last week.
E.M.Smith (01:17:54) :
‘So do we REALLY know that it isn’t just UV variations and variation in the solar wind / energetic particle impact? If not, then just exactly WHY is the N. Pole so high in ozone? Looks like a Birkeland Current signature to me.
If we get a flip of what pole the solar current lands upon, I’d bet we also get a flip of which pole has an ozone hole. Wonder if there is any way to dig that out of ocean sediments along with the magnetic polarity of the planet…’
Now there’s a possible grant-worthy research project surely. Is there a suitable proxy? Would subaerial lavas be better than seabed lavas? Can anyone develop this?
The excerpts I quoted on ozone kinetics are from this link for those who may want to read more.
http://groups.google.com/group/alt.politics/browse_thread/thread/d68c75cd9a454d73/37d6d42ca985cedd?lnk=raot
The link in my earlier post goes to a Nature premium content abstract.
———————-
This related opinion posting also covers the ozone kinetics topic
Ozone chemistry confounds everyone
New research throws our understanding of the chemistry driving ozone depletion into doubt.
By Chris Lee | Last updated October 1, 2007 8:59 AM CT
http://arstechnica.com/science/news/2007/10/ozone-chemistry-confounds-everyone.ars
JamesG, people drive Priuses (Prii?), so there’s a market for pretty much any useless vehicle technology if it’s sold as “saving the planet”…
(Yes, that was intended as humor)
Dave in Delaware 9 30 54
This refers to my post much earlier in this thread whereby ozone hole depletion is being linked to cosmic rays by Dr Qing Bin lu
http://www.science.uwaterloo.ca/~qblu/Lu-2009PRL.pdf
tonyb
Well when I look at that ozone graphs, I see a very prominent annual cyclic variation in ozone; something which has been well known by proxy for eons; due to studies of the effective color temperature of ground based solar radiation measurements. These annual variations as well as other more random changes in the color temperature are attributed to changes in the UV and short wavelength (below the peak) solar spectrum that makes iut through the atmosphere.
These studies point to the existence of ozone holes long before there were freons to blame for what seems to be a perfectly natural variability.
Ozone is also an important GHG specially in the tropics, so it is not something we want to be messing around with in the belief that we can engineer a better climate.
The move away from freon made cooling more expensive and less efficient. That means it took more energy to produce the same amount of cooling. More energy means more CO2 emitted from the burning of fossil fuels. So, yes, the elimination of freon led to more man-made global warming! Obviously, the real threat to the planet is modern environmentalism:-)
E.M.Smith (01:17:54) :
“…And I’m now feeling skeptical about the “chemicals cause ozone depletion” thesis too. The seasonal variations are so large that seems to dominate. Solar variation in UV production (that makes O3) also varies rather much. So do we REALLY know that it isn’t just UV variations and variation in the solar wind / energetic particle impact? If not, then just exactly WHY is the N. Pole so high in ozone? Looks like a Birkeland Current signature to me…
Reply: I think you are onto something here. This could be part of the mechanism by which the solar cycle effect earth’s climate. If the current quiet sun continues, we should be able to observe if this hypothesis could be true.
For the record, the story line above says that the ozone layer forms about 25 km high above the earth’s surface. That puts it at about 40,000 ft altitude.
so why would it matter temperature wise whether you are over Antarctica of over the equator; at 40,000 feet it doesn’t matter much.
The story also says that chlorine and Bromine appear in the atmosphere from salt spray.
I suspect that the ocean is the largest source of bromine worldwide; haven’t ever heard of anybody minig bromine on land.
At least in California, farmers aren’t aloud to use ethyl bromide any more to stop their crops from rotting.
So it seems to me that chemical destruction of ozone is probably quite natural and beyond our control.
Ozone is far less stable than oxygen, and in order to get ozone you first have to decompose O2 molecules, and that takes out the short wave UV.
Life on earth evidently evolved before there was either oxygen or ozone to protect us from UV; so I doubt that life will cease to exist, with ozone holes that are just part of the natural environment and beyond our control.
In any case ozone is a GHG so we don’t want too much of it anyway.
The Montreal Protocol substituted ozone depleting gases with known powerful synthetic greenhouse gases.
Synthetic Greenhouse Gases (SGGs) were largely introduced as replacements for some ozone-depleting substances. Three of the six Kyoto Protocol gases – hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6) – are SGGs. While these gases do not present a direct risk to the ozone layer, they often have very high Global Warming Potentials (GWPs) and will contribute significantly to the enhanced greenhouse effect if emitted to the atmosphere.
http://www.environment.gov.au/atmosphere/ozone/index.html
The Montreal Protocol is causing global warming.
Even I was shocked to discover this.
Dave in Delaware (10:07:20) :
Those questions are now claimed to have “been resolved.”
http://www.nature.com/news/2009/070509/full/news.2009.456.html
Without calling into question the chemistry of ozone depletion, which I generally think is sound, I still continue to be puzzled over actual atmospheric ozone levels. In an earlier discussion on ozone depletion on WUWT, phil.dot linked to this useful site and referred to Figures 8&9
http://omsriram.com/GlobalWarming.htm
Those cfc levels certainly are consistent with ozone recovery starting in “about 1997”. But my poor ole eyes look at the six instrument anomaly figure in Anthony’s post and I swear the recovery seems to be starting in the early 90s. As someone alluded to above, Pinatubo did distort ozone measurements then (which led to a lot of hyped-up “OMB, it’s worse than we thought” reporting back then), but it still looks curious to me.
Here’s another graph that show the Pinatubo effect more clearly.
http://www.iac.ethz.ch/en/research/chemie/tpeter/totozon.html
Again, recovery seems to be earlier than the late 90s. but then, how do you back out Pinatubo?
Why can’t scientists, and science journalists, just say “we don’t know”?
DocWat (01:41:02) :
Isn’t the life expectancy of an ozone molecule about 30 minutes?
No, more properly the lifetime of odd-Oxygen is months.
Isn’t ozone formed by sunlight striking oxygen?
No, but odd-Oxygen is.
Doesn’t oxygen actually absorb 97% of UV’s and ozone about 3%.
No.
Doesn’t the angle of incidence of sunlight to atmosphere have something to do with the concentration of ozone at the equator? Doesn’t the extreme cold at Antarctica stop the formation of ozone?
No.
If these things are true, then one’s altitude and latitude have a great deal more to do with UV exposure than atmospheric chemicals. And, incidentally, doesn’t the ozone hole actually cover the entire dark side of the earth?
No.
Doesn’t ozone have seasonal variations? (See Graph above.)
Got one right at last!
For the record, I oppose the introduction of chemicals into the atmosphere, lithosphere, and the hydrosphere. But as a former science teacher I feel some of this ozone hysteria is slightly over-done.
I favor getting the facts and thoughtfully considering them before running naked through the streets yelling something.
Perhaps you should start getting the facts then.
When the boogeyman was Nuclear Winter, we were assured that the Southern Hemisphere would be a better place to be because the majority of the bombs would be exploded in the N. Hemi. and the opposing windbelts at the equator would delay or stop the passage of the fallout and smoke. Then we were told that N. Hemi. CFCs went straight to the S. Pole to do in the precious ozone. Nat. Geographic, in an article on Antarctica, stated that Mount Erebus was discharging tons of Hydrogen Chloride right in the middle of the South Polar Gyre. I think that the Montreal Protocol was another swindle.
mr.artday (21:02:24)
http://www.mfe.govt.nz/publications/ser/ser1997/html/images/figure5.18.gif
http://www.mfe.govt.nz/publications/ser/ser1997/html/chapter5.8.html#figure5.18
After the Antarctic Ozone Hole was discovered, some scientists took the view that it might be a natural event caused by volcanic chlorine emissions from Mount Erebus rather than manufactured chlorinated chemicals. Eventually, however, Mount Erebus was exonerated (Zredna-Gostynska et al., 1993). Most of the chlorine Mount Erebus throws up takes the form of hydrogen chloride (HCl), which (like other chlorine from natural sources) readily dissolves in the water vapour of the lower atmosphere well before it can reach the stratosphere.
For Mount Erebus to affect the ozone layer, the volcano would have to inject a large proportion of its hydrogen chloride directly into the stratosphere, above a height of about 10 km. Mount Erebus has been active since it was first observed by James Ross in 1840, but appears never to have erupted with the force necessary to send chlorine directly into the stratosphere. The mountain itself is almost 4,000 m high (3,794 m), but the volcanic plume seldom rises above 5,000 m. The amount of gas Mount Erebus emits also bears no relation to the size of the ozone hole. In the summer of 1983, chlorine emissions from Mount Erebus were about 170 tonnes a day. In the following seven summers, when ozone depletion was even more severe, the chlorine emissions ranged from one-tenth to one-quarter of the 1983 figure (Zreda-Gostynska et al., 1993).
From Junk Science (perhaps it’s all in the title)
http://junkscience.com/Ozone/ozone_seasonal.html
Is “the hole” of any real significance to people or the planet? Not so far as anyone can tell.
Should we worry about it? Unless you’re a scientist earning a living from it, it’s probably not worth a second thought
http://www.mfe.govt.nz/publications/ser/ser1997/html/chapter5.8.html#figure5.18
UV-B related cancers are not confined to humans. Where pigs and goats, cattle and horses have inadequate access to shade they also fall victim to skin and eye cancers, and their exposure is less subject to seasonal fashions. It is not known whether their melanoma rates have increased in recent years. Plants are also affected by excessive UV-B light, and, because they rely on direct sunlight for energy, many species have developed protective mechanisms against high levels of UV-B. Despite this, experiments have shown that cotton, peas, beans, melons, and cabbage grow more slowly under intense UV-B, and pollen fails to germinate in some plants. Plant hormones and chlorophyll, the chemical mainly responsible for photosynthesis, can also be damaged. New Zealand scientists are currently studying ways of making crop plants more ultraviolet-resistant through selective breeding programmes and gene modification (Markham and Ryan, 1996
Aquatic ecosystems are also vulnerable. UV-B can penetrate clear water to a depth of many metres, posing a threat to single-celled algae which are known from laboratory studies to be sensitive to UV-B. These organisms are at the very base of the aquatic food chain, and are also major consumers of carbon dioxide and emitters of anti-greenhouse sulphate aerosols. A serious reduction in algal biomass could therefore reduce fish populations and enhance the build-up of greenhouse gases in the atmosphere.
A study of Antarctic algae which were shielded from UV-B radiation by ice found no change in species composition over two decades of ozone depletion (McMinn et al., 1996). However, a survey of algal blooms in open water found that biomass (total weight) fell by 6-10 percent in the waters where UV-B was most intense, beneath the springtime ‘ozone hole’ (Smith et al., 1992). This represents about 7 million tonnes of lost photosynthesis per year, or a 2 percent depletion of the Southern Ocean’s phytoplankton. The researchers noted that this reduction, though significant, was small compared to the seasonal advance and retreat of the ice pack which causes biomass reductions as high as 50 percent.
http://wapedia.mobi/en/File:Sources_of_stratospheric_chlorine.png
http://wapedia.mobi/en/Ozone_depletion?t=7.
Another objection occasionally voiced is that It is generally agreed that natural sources of tropospheric chlorine (volcanoes, ocean spray, etc.) are four to five orders of magnitude larger than man-made sources. While strictly true, tropospheric chlorine is irrelevant; it is stratospheric chlorine that affects ozone depletion. Chlorine from ocean spray is soluble and thus is washed out by rainfall before it reaches the stratosphere. CFCs, in contrast, are insoluble and long-lived, which allows them to reach the stratosphere. Even in the lower atmosphere there is more chlorine present in the form of CFCs and related haloalkanes than there is in HCl from salt spray, and in the stratosphere halocarbons dominate overwhelmingly. [51] Only one of these halocarbons, methyl chloride, has a predominantly natural source [52] , and it is responsible for about 20 percent of the chlorine in the stratosphere; the remaining 80% comes from manmade compounds.
CFCs are well mixed in the troposphere and the stratosphere. The reason the ozone hole occurs above Antarctica is not because there are more CFCs there but because the low temperatures allow polar stratospheric clouds to form. [55] There have been anomalous discoveries of significant, serious, localized “holes” above other parts of the globe. [56
As shown by the animation above there is a difference between the north pole and the south pole, the ozone hole.
I agree with the proposition that it is not of anthropogenic origin but caused by the sun itself, through the reduction of ozone by protons (hydrogen nucleus), producing water as the result.
bill (04:47:15) : “Another objection occasionally voiced…
Rather sobering, bill… I hope you or others follow up on this.
The geo and solar magnetic fields may turn out to be far more influential than realised on climatic oscillations and inverse relationships ( viz conflicting temperature trends, ozone and probably a lot more). NASA seem to keep discovering startling new information emerging from their various mission probes, for instance that highlighted last December on this site-
http://wattsupwiththat.com/2008/12/16/earths-magnetic-field-has-massive-breach-scientists-baffled/
Everythingok (05:46:34) : there is a difference between the north pole and the south pole, the ozone hole … but caused by the sun itself, through the reduction of ozone by protons (hydrogen nucleus)
I assume you must live in a desert to have buried you head so far in the sand!
I think it is obviosly LGM (little green men) with a large vacuum cleaner sucking the ozone away to repair their planet – prove it is not!