I wrote earlier about John Ray's profoundly ignorant arguments about ozone depletion. Now he's back, posting something even sillier:
Despite all the information you may have read, there is not one shred of supportable evidence that CFCs have found their way 40 miles up above the Earth. No one has ever found any up there because they are roughly five times heavier than air. They are like a brick in a swimming pool. It is not often that you will see a brick floating to the surface of your pool. CFCs are so dense that even as a gas you could fill a bucket with it and pour the contents of one bucket into another.
Not a shred of evidence except for thousands of measurements:
CFCs and other ozone depleting substances (ODS) are heavier than air. In a still room, they will pool on the floor. However, the atmosphere is anything but still. Numerous measurements have confirmed that these molecules are mixed nearly uniformly worldwide. In the same way that vinegar and oil normally separate when still, but mix when shaken, ozone depleting substances and air are thoroughly stirred together by winds in the troposphere.
Winds are also why the location of CFC and other ODS emissions is essentially irrelevant. CFCs released from a car in the U.S. are as likely to find their way to the stratosphere over India as are molecules released from much closer countries like China. Once they mix through the troposphere, CFC molecules eventually move into the stratosphere. Thousands of measurements over several decades have firmly proven the existence of these heavier-than-air molecules in the ozone layer.
I wonder whether he applies the same argument to other heavier-than-air objects that are occasionally seen in the sky.
This is another one of those provocations designed to capture the unwary. Forty (40) miles is 66 km. That is in the mesosphere. You would not find any CFCs there because they will have been photolyzed before they reach that height. An early experiment by Zander (see ozone FAQ at http://www.faqs.org/faqs/ozone-depletion/stratcl/ and search on "organic chlorine) showed that the CFCs were increasingly photolyzed as altitude in the stratosphere increased and the chlorine went into inorganic form. The amount of chlorine in the two forms remained constant, which is among the strongest evidence that the chlorine in the stratosphere comes from CFCs and methyl chloride. Only the latter has natural sources.
Quick primer on the structure of atmospheres. http://www.stormpages.com/swadhwa/complanet/cplecture12.htm All numbers subject to jiggle for latitude/season/planet/etc.
Thermosphere > 90 km Sometimes called the ignorosphere cause we don't know much about it.
Mesopause - 90 km
Mesosphere - 50 to 90 km
Stratopause - 50 km
Stratosphere -18 - 50 km
Tropopause -14-18 km
Troposphere < to the surface
Volcanic ash, soot, paper bags, never to be seen in the air. Will settle immediately. Heavier than air.
Umm, don't oxygen, nitrogen and CO2 also have different weights? However did they all get mixed together rather than forming a neat vertical column with the densest at the bottom?
It sounds like CK meant that statement ironically.
Anyway, it's a lucky thing that volcanic ash settles immediately. If it ever stayed up for a while, it might
have an effect on the weather.
Yes, another argument to dupe the rubes. Appeals to emotion are far better agitprop tools than appeals to Enlightenment principles, and appeals to emotion work well with certain crowds.D<p.
It's raining here in London at present ...
As a followup to Eli Rabett: the Zander experiment is actually fairly late (1992) - I used their data because it was the most recent and most comprehensive available when I was writing the first version of the FAQ. The basic trends in the data have been known since the late 1970's - in fact, the first measurements of CFCs in the stratosphere date to 1975, barely a year after Molina and Rowland proposed the CFC-ozone hypothesis. By 1985 it was generally accepted that manmade halocarbons were the primary source of stratospheric chlorine.
Reply to Ian Gould: it's a little more subtle than that. Oxygen, nitrogen, and CO2 are close enough in molecular weight that you would expect them to be thoroughly mixed at room temperature, even in a absolutely still atmosphere - you would see the relative proportions shift slowly in favor of the lighter components as you went to very high altitudes. Halocarbons, however, are so much heavier than O2 or N2 that in a perfectly still atmosphere you would expect them to be heavily concentrated in the first few kilometers with almost nothing in the stratosphere. Of course, the troposphere is nearly the opposite of "perfectly still", but one might expect that the stratosphere, which is much quieter, would show some segregation. Neertheless the data show - and have shown for 30+ years - that there is no such segregation. (You can actually push the discovery of the basic principle back another few decades - in the 1950's, measurements of air samples collected by rockets showed that the relative proportions of Ne, Ar and Kr in the mesosphere were essentially the same as at sea level. Rowland and Molina cited this work in their second paper on CFCs and ozone depletion, in 1975.)
Lessee...heptane and octane has a molecular weight of 86 and 100 respectively. Therefore John Ray should feel perfectly safe walking into a closed room where someone's spilled gasoline on the floor, with a lit match. 'Cos, like, heptane's almost three times heavier than air, man.
The ignorance of these twats of basic physical chemistry astounds.
"The factor is 1 in 100,000. So we get told of yet another scenario - that in some imagined chain reaction, chlorine would keep on getting released by the UV until all the ozone was destroyed. "
Argghhhh. This is old fucking science. I remember grinding the chain reaction as part of my ChemE degree exam over a decade ago. Doesn't this twat understand that the chlorine radicals act as a catalyst*?
* OK, they actually react with the ozone to form an intermediate in the degradation cycle, but the end result is an acceleration in the degradation rate.
"The factor is 1 in 100,000. So we get told of yet another scenario - that in some imagined chain reaction, chlorine would keep on getting released by the UV until all the ozone was destroyed. "
Argghhhh. This is old fucking science. I remember grinding the chain reaction as part of my ChemE degree exam over a decade ago. Doesn't this twat understand that the chlorine radicals act as a catalyst*?
* OK, they actually react with the ozone to form an intermediate in the degradation cycle, but the end result is an acceleration in the degradation rate.
Sort of amazing that anyone disputes the CFC stuff anymore.
Oh, I don't know. There are people who dispute evolution (quite vociferously).