Ozone hole: how do CFCs get up there?

[chorpler]

So, the same guy I’ve posted about in these threads has now claimed that the theory of ozone depletion by CFCs has been “thoroughly debunked” and is now regarded by most scientists as “junk science.”

He says this is largely because there’s no way that CFCs can get up to the stratosphere where the ozone layer is, and hey, they’re 60 times heavier than carbon dioxide and there’s no significant amount of carbon dioxide up there, so clearly there’s no way the much heavier CFCs could get up there either. He says that all ozone holes are right near volcanoes, and it’s the chlorine from powerful volcanic eruptions (which punch right up into the stratosphere directly) that deplete ozone, not chlorine from CFCs.

My questions:

A) Is his characterization of the ozone-depletion-by-CFCs situation accurate? I have my doubts.

B) CFCs do get up there, right? Do we know how?

C) Even if we don’t know how they get up there, haven’t we actually observed CFCs up there many times, via balloons, aircraft, satellite observations, etc.? Regardless of how they got there, haven’t we actually seen them there many times?

D) I thought volcanoes emitted chlorine mostly in the form of HCl, which, being water soluble, quickly gets washed out of the atmosphere by rain, giving it almost no chance to attack ozone molecules; CFCs, though, are water insoluble and don’t get washed out by rain. One of the articles I cite below says that humans are responsible for 80-85% of the chlorine in the stratosphere, while volcanoes are directly responsible for only about 3%. It says they do indirectly harm ozone, though, by providing abundant particles that give chlorine from human sources a better chance to do its ozone slaying work.

Um … I think those are all of my questions. Two of the articles I found while looking this stuff up are below. Please, if I’ve gotten anything wrong, correct me. Thanks for any help!

http://www.epa.gov/ozone/science/volcano.html

http://volcano.und.edu/vwdocs/Gases/ozone.html

[Alive_At_Both_Ends]

@chorpler

there’s no way that CFCs can get up to the stratosphere where the ozone layer is

CFC’s diffuse up there, the same way any gas gets anywhere.

hey, they’re 60 times heavier than carbon dioxide and there’s no significant amount of carbon dioxide up there, so clearly there’s no way the much heavier CFCs could get up there either.

Gas expands to fill the whole space available for it, regardless of how heavy it is. Heavy gases don’t just hang around near the ground. If they did, the oxygen, nitrogen, argon etc. in the air would form separate layers since they all weigh different amounts.

As far as I’m aware, there’s as much CO[sub]2[/sub] in the stratosphere as there is at lower levels. Of course, it’s not much in absolute terms (only 0.035%), but that’s enough.

[Nava]

There is layering (different layers of the atmosphere have different compositions) but yeah, a gas will try to occupy all available space and CFCs/CFCHs reach the ozonosphere just by floating up.

CFCs and CFCHs are simply molecules containing “only C, F and Cl” or “only C, F, Cl and H”. Some of them are TINY molecules (ex, CCl4 or CCl3H, chloroform). The guy referenced by the OP wouldn’t recognize either Chemistry or Gas Physics if either of them wacked him with a baseball bat.

[Smeghead]

Lotta volcanoes in the Antarctic, are there?

[Squink]

@chorpler

CFCs … they’re 60 times heavier than carbon dioxide

CO[sub]2[/sub] masses 44. Sixty times that is 2,640.
CFC11 (CCl[sub]3[/sub]F) masses 137.5, CCl[sub]2[/sub]F[sub]2[/sub] masses 121.

The claim that CFC’s are 60 times heavier than CO[sub]2[/sub] is massively wrong.

[chorpler]

@Smeghead

Lotta volcanoes in the Antarctic, are there?

He specifically says:

@some guy

I might also add that the site that measures the OZONE HOLE is about 80 miles down wind from Antarctica’s only active volcano, AND that no viable transfer method to move CFCs from the surface of the Earth to the levels where the Ozone destruction takes place. There also seems to be a link between Ozone hole size and the activity of that volcano… Just as there seems to be one between active volcanos in the Arctic area and the small Ozone hole there. That brings up another question.

But I already addressed that above (I think).

[wevets]

Perhaps a good place to start would be this article:

http://cat.inist.fr/?aModele=afficheN&cpsidt=3438109

Its Absract:

For almost half a century it was widely believed that the photochemistry of the stratosphere and hence ozone distribution were well understoood. As observarions revealed a gap between observed and predicted values it was recognized that a number of substances acted as catalysts thereby increasing the destruction of ozone and that humanity could augment those catalysts and affect the ozone layer. Initial concern focused on nitrogen oxides from the exhausts of supersonic transport, but attention switched in the mid-1970s to chlorofluorocarbons (CFCs). Although the theory of anthropogenic ozone depletion by CFCs found widespread scientific support the perceived threat was minimized in particular by successive model predictions downgrading the amount of depletion. The appearance of the ozone hole over Antarctica in the mid-1980s reopened the debate as to whether such depletion was anthropogenic or natural in origin. It also highlighted the model’s inadequate treatment of the processes occurring in the stratosphere and the importance of dynamics and radiative transfer in stratospheric ozone destruction. Scientific consensus again favours the anthropogenic depletion of the ozone layer. In conclusion it is considered that the degree of consensus outweighs the image of scientific uncertainty that is often portrayed in relation to the issue of stratospheric ozone depletion.

It sounds like he’s still living in the 1970s era of ozone science.

[chorpler]

Thanks for the articles and whatnot, folks. Just like I thought; he’s pretty out of it.

@wevets

It sounds like he’s still living in the 1970s era of ozone science.

Well, this is a guy who started the discussion by saying this:

@guy

My impression is that the theoretical causal connection between the
supposed depletion of the ozone layer and CFCs has been thoroughly and
completely debunked. Just another case of the sort of “junk science” that
is rife in the greenies’ climatology.

[wevets]

Ah, I see. A paragon of evenhandedness without any political axe to grind. Undoubtedly your discussion with him shall be quite enlightening.

[chorpler]

@wevets

Ah, I see. A paragon of evenhandedness without any political axe to grind. Undoubtedly your discussion with him shall be quite enlightening.

That’s what I thought. But now he has actually admitted that he was wrong, or at least the he “overstated it” and “the link is proven, although some of the alarmism DOES use junk science.”

Thanks for all the information. Part I of The Ozone Depletion FAQ addresses the question of how CFCs get up to the stratosphere in great detail in subject 1.3, pointing out that the mixing mechanisms like convection, turbulent mixing, and eddy diffusion are sufficient to keep the troposphere and stratosphere well mixed, and it’s not until much higher that the atmosphere becomes thin enough that gravity takes over and molecules segregate by weight.

[wevets]

@chorpler

That’s what I thought. But now he has actually admitted that he was wrong, or at least the he “overstated it” and “the link is proven, although some of the alarmism DOES use junk science.”

Well, I’m pleasantly surprised. There are far too many whose views are resistant to change, and it is enlightening to find someone who can change their views in the midst of a dispute. I thought his use of the term “greenies” did not bode well, but I’m happy to have been wrong about that.

[chorpler]

@wevets

Well, I’m pleasantly surprised. There are far too many whose views are resistant to change, and it is enlightening to find someone who can change their views in the midst of a dispute. I thought his use of the term “greenies” did not bode well, but I’m happy to have been wrong about that.

I’m pleasantly surprised too. His use of the term “junk science,” favorite term of the infamous against-every-bit-of-science-that-doesn’t-back-him-up Steven Milloy, led me to believe it didn’t bode well either. And there are still several other people who have fulfilled my expectations. (“Oh yeah? Then why is it only in the Antarctic and not in the Arctic? We produce most of the CFCs in the Northern Hemisphere!”) I swear, anybody could answer these questions by reading the Ozone Depletion FAQ, but they prefer not to actually fight any ignorance. At least in one case the fight against ignorance hasn’t been totally in vain…