A new modeling based paper in Atmospheric Chemistry and Physics takes on that question directly.
Of course the result is another “saved the world” moment according to some:
[ Source: http://twitter.com/AndrewDessler/status/442342191067693056 ]
I certainly don’t have a problem with reducing CFC’s, but Andrew Dessler’s comment speaks to the hero syndrome some of these scientists seem to have, which sometimes results in the “noble cause corruption of science” where the end justifies the means. Here is the paper abstract, link to full text follows.
Abstract.
Ozone depletion by chlorofluorocarbons (CFCs) was first proposed by Molina and Rowland in their 1974 Nature paper. Since that time, the scientific connection between ozone losses and CFCs and other ozone depleting substances (ODSs) has been firmly established with laboratory measurements, atmospheric observations, and modeling studies. This science research led to the implementation of international agreements that largely stopped the production of ODSs. In this study we use a fully-coupled radiationchemical-dynamical model to simulate a future world where ODSs were never regulated and ODS production grew at an annual rate of 3%. In this “world avoided” simulation, 17% of the globally-averaged column ozone is destroyed by 2020, and 67% is destroyed by 2065 in comparison to 1980.
Large ozone depletions in the polar region become yearround rather than just seasonal as is currently observed in the Antarctic ozone hole. Very large temperature decreases are
observed in response to circulation changes and decreased shortwave radiation absorption by ozone. Ozone levels in the tropical lower stratosphere remain constant until about
2053 and then collapse to near zero by 2058 as a result of heterogeneous chemical processes (as currently observed in the Antarctic ozone hole). The tropical cooling that triggers the ozone collapse is caused by an increase of the tropical upwelling. In response to ozone changes, ultraviolet radiation increases, more than doubling the erythemal radiation in the northern summer midlatitudes by 2060.
Full paper: http://t.co/8LRrUDb3Yf
for which he won a Nobel prize…
“Air-conditioning sales are growing 20 percent a year in China and India, as middle classes grow, units become more affordable and temperatures rise with climate change.”
“The oldest CFC coolants, which are highly damaging to the ozone layer, have been largely eliminated from use; and the newest ones, used widely in industrialized nations, have little or no effect on it.
But these gases have an impact the ozone treaty largely ignores. Pound for pound, they contribute to global warming thousands of times more than does carbon dioxide, the standard greenhouse gas.”
http://www.nytimes.com/2012/06/21/world/asia/global-demand-for-air-conditioning-forces-tough-environmental-choices.html?pagewanted=all&_r=0
Not to be overly condescending, but the CFC issue was child’s play compared to the CO2 issue,
yet after all these years still requires a leap of faith and speculative models to convince the scientific community. Of course, the biggest piece of nonsense here is the implied connection between the two issues. Validating a climate model will not be accomplished by referencing irrelevant previous issues concerning CFCs and their behavior. That’s elementary school logic. So far, climate models have had a long period of time to convince and have done precisely the opposite – we pay less attention to them now than we did before, and all because of their total inability to explain and predict.
What would have happened to the ozone layer if chlorofluorocarbons (CFCs) had not been regulated?
1. My air conditioners would have been cheaper and worked more efficiently.
2. The ‘inhaler’ that I use occasionally would cost less and deliver the medicine more effectively.
3. An enormous amount of misdirected capital and labor would have been better utilized.
4. Other than that, nothing else would have changed.
You guys laugh, but thousands of polar bears and penguins are thanking the Montreal Protocol for keeping them free of skin cancer.
Meanwhile, I notice that the antarctic ozone hole hasn’t changed much since the protocol was introduced, but then I haven’t updated this chart recently. The big increase in the hole seems to coincide with the big increase in our satellites’ ability to measure it.
http://www.rockyhigh66.org/stuff/ozone_hole_2010.png
If CFCs were damaging the ozone, and it’s been over 20 years since they were banned, shouldn’t the ozone layer have started “recovering” by now?
“CFCs are amazing molecules. They are emitted in an ozone rich environment, and despite being highly reactive, they eschew the “dirty” ozone from our tail pipes, defy gravity,”
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CFC’s are NOT highly reactive until a chlorine free radical is formed by UV-C in the stratosphere. The Cl neutral free radical then catalyzes the decomposition of the stratospheric ozone. Stratospheric ozone is the only atmospheric molecule that that absorbs the near UV-C wavelength. All wavelengths of UV-C are hazardous. Less energetic UV-B is required to form vitamin D. UV-B is only partially absorbed by ozone.
As a bulk gas, CFC’s would hug the ground, but once mixed with air, CFC’s could move anywhere the air moves in the atmosphere and would reach the stratosphere because it is so chemically unreactive.
I suspect that when and if we ever figure out the “wicked” climate problem and the somewhat less “wicked” CFC problem, the answers will be that both CO2 and CFC’s have theoretical but trivial effects on our respective climate and ozone layers.
Francis Massen says:
March 8, 2014 at 1:00 pm
Thanks Francis for the correction… Some time ago that we have had some mail exchanges…
Do you have some figures of the evolution of the UV influx over the years in Diekirch? And/or from other parts of the globe?
R. Shearer (1:17pm): “Apparently a few people think it would be impossible for kites to fly as they are heavier than air.”
Jaakko Kateenkorva (12:26pm): “Thank you Ferdinand {and Shearer, apparently} for raising one of the AGW proponents’ favorite arguments, Brownian motion, … So, how can we take for granted that a wide family of CFC molecules mix randomly, float into a separate atmospheric layer and stay there? In addition CCl3F boiling point is 23 °C and it would go through phase transition well before reaching the stratosphere.”
Dr. Tim Ball (in his above-linked article):
“
{this is how the pseudo science was done:}
Source: http://drtimball.com/2012/effect-of-environmentalists-crying-wolf-over-ozone-thinning-appear/#sthash.zYbqfG3S.dpuf
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Leave the kites to Ben Franklin. OR…. better yet….
“Let’s Go Fly a Kite!” — from Disney’s Mary Poppins (1964)
#(:))
“Life’s short. Don’t miss it.”
(Ferris Bueller)
Yet another model untested (untestable, in fact) against prediction.
I guess it’s only good fortune that the major manufacturer of CFCs (DuPont) enjoyed financial gain from supplying more expensive substitutes for the banned CFCs at the same time the original patents were expiring, Their world was certainly saved.
Why did they need to ban something when the hole was there in 1956 and probably always has been? What if they looked in 1900 or 1870? Would the ozone hole have been there?
Why didn’t Du Pont push for a ban then?
“You guys cried wolf about ozone depletion.” Whomever Dressler adresses here were apparently falsely crying about a hazard that didn’t exist, since that is what “cries wolf” means. What he meant to say is “you guys wouldn’t cry wolf.” Conclusion: Andrew’s verbal skills lag his analytical ones.
“Actually we saved your lives.” I do not recall that the entire world was in danger over ozone depletion, but only the surface of the south polar oceans. Nonetheless Andrew takes credit for something he had no part in as he was in undergraduate/graduate school during the relevant time period. Conclusion: A common characteristic among these climate scientists that they take credit for things they didn’t do. There must be a fancy name for this pathology.
Wait a minute, in 2011 the ozone hole was as big as ever.
Not again with this BS on patents!
DuPont did not have a patent for CFCs. Those had been discovered long before and had long been out of patent as chemicals.
They had a few expiring process patents, that allowed them to manufacture them slightly cheaper than their competitors.
Nor did DuPont have patents on their replacements, which had been discovered long before. CHF3 was first made in 1894!
The mixture which is the main replacement, R-410A, was invented and patented by Allied Signal (now Honeywell) in 1991. So apparently DuPont conspired to give Honeywell an advantage!
(DuPont has a lot of valuable trademarks in this field. They are actually more valuable than the patents, as they don’t expire. But then it still has all the previously very valuable Freon CFC trademarks, so if anything it has lost in the shift.)
A hole appears in the dynamic doughnut once every year, over and over again like a repeating cycle. When it appears in the Antarctic spring, the dough surrounding the hole grows thicker.
Now that’s very interesting, because the Hole-in-the-Sky Game is contingent on you being ignorant of that fact, paying no attention, turning a blind eye, or pretending it doesn’t happen when people bring it to your attention.
What you see on graphs—if you look at the whole picture instead of just the hole–is a displacement of dough, not a depletion.
The CFC hypothesis was a fiction built to mulct us for DuPont.
“Wait a minute, in 2011 the ozone hole was as big as ever.”
I think his argument is that if they hadn’t banned CFCs, the ozone hole would’ve devoured the world by now or something. Science!
Stephen Wilde says:
Not long ago it was found that ozone amounts above 45km increased between 2004 and 2007 at a time of inactive sun.
The earlier observed decrease in ozone occurred during a period of active sun through solar cycles 21 to 23.
It is exactly that. Solar activity is increasing, decreases ozone and temperature in the stratosphere.
http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_ANOM_JFM_NH_2014.gif
Rich Carman says:
March 8, 2014 at 2:24 pm
CFC’s are NOT highly reactive until a chlorine free radical is formed by UV-C in the stratosphere.
Seconded!
There are some misconceptions by some here about the possibilities of mixing heavier and lighter molecules in the atmosphere:
– If there is a huge release of any gas or vapour that is heavier than air, it will spread over the ground and can do a lot of damage. But with sufficient wind and turbulence, it will mix up in the rest of the atmosphere and ultimately spread from pole to pole and from ground level to the stratosphere.
– Once mixed it wil stay mixed, except if absorbed (CO2 by plants and oceans), destroyed (most organics) or raining out (SOx, NOx). It may take a year or two to get from one pole to the other (the intertropical convergence zone allows only some 10% air exchange between NH and SH) and from the ground to the stratosphere (as the exchanges are limited).
– In stagnant air like is the case in compacting snow (firn) once a certain layer thickness is reached, some separation of the different molecules and isotopes does occur. For the Law Dome firn measurements, the measured enriching of CO2 at the bottom was about 1% over 40 years, for which was corrected for in the ice core CO2 measurements.
– That doesn’t play much role in the atmosphere where there is a lot of wind/turbulence and where even sand particles, weighing a thousand time more that air, are carried over thousands of kilometers…
Kevin Kilty says:
March 8, 2014 at 2:44 pm
Conclusion: Andrew’s verbal skills lag his analytical ones.
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more likely his analytical skills match his verbal skills.
Apparently you do not know about sulfur hexafluoride. Let Rosie and Anna explain it to you:
BTW, sulfur hexafluoride has a molecular weight of 146 g/mol. Many CFCs weight more than that.
That does not mean that some molecules can reach the stratosphere, though. The problem is that they will concentrate in warmer areas because vapor pressure depends on temperature. ( http://en.wikipedia.org/wiki/Vapor_pressure ) CFCs are more concentrated at the equator than at the poles. If CFCs were the cause of ozone deplection, it should be more noticeable at the equator that at the poles, because CFCs are more concentrated at the equator and also because chemical reactions go faster as temperature increases.
Also, solar radiation and therefore halogen radical formation is higher at the equator. So, ozone destruction should be higher at the equator. But it is not, the “holes” appear at the poles. The correlation CFC concentration – ozone destruction is negative, The more CFC there is in the stratosphere, the more ozone is in the stratosphere. CFC cannot be the cause of ozone destruction.
In fact ozone does not need anything to decompose, it decomposes by itself.
Janice Moore says:
March 8, 2014 at 2:31 pm
From Dr. Ball:
CFCs are four times denser than air, so there was a transport question – how did they get to 15 km above the surface? The answer is they didn’t. ***
From:
http://uars.gsfc.nasa.gov/uars-science/CFC.html
CLAES made the first global measurements of CFC’s (chlorofluorocarbons) in the stratosphere. CFC’s enter the stratosphere through upwelling in the tropics. The CFC’s decrease with height as they are broken down by UV radiation. CFC’s are the major source of stratospheric chlorine. Red indicates large amounts of CFC-12.
In the tropics, CFC-12 is rather evenly distributed (0.3-0.5 ppbv) between ground level and 30 km altitude, decreasing in height and concentration with latirude.
Ozone is not stable. It naturally breaks down into O2, which is then combined with other O2 in the presence of UV to make O3.
Breaking down O3 into O2 with CFC’s would simply make more O2 to be combined into O3 with UV and thus add protection.
Worse case if you make the O2 unavailable with chemical absorption it will simple be absorbed by lower level O2.
O3 is the result of protection, not the source.
Will Pratt at 1:44 pm & Keitho at 11:41 am: Agreed. With most of the world’s industry in the northern hemisphere, logic would dictate that the hole at the north pole would be at least as big as the hole over the south pole.
I just found a graph depicting concentration of CFC-12 (molecular weight 120 g/mol) versus lat.itude: (It is from nasa)
http://svs.gsfc.nasa.gov/vis/a000000/a000800/a000829/a000829.mp4
As you can see, CFCs are more concentrated at the equator, and therefore if they were destroying ozone, they should be destroying more ozone at the equator.