Ozone hole news

[Brian Ellis]

Gurm

I did say 5 cans, not one. This calculation is based on 1 kg of CFC-11 or 12 (they have equal ODPs). For the sake of ease of calculation, let's say the football field is 0.75 ha (near enough). That means 133/km2. The surface area of the earth is 509,600,000 km2. Are you going to tell me that 340 billion aerosol cans were made before 1978? If there were, each can holding an average of 200 g of CFC, then I don't know where the CFC was coming from because there wasn't that amount ever made, or anything like it!!!

Of course, this was a shock illustration and it wouldn't work like this, as if all the CFC were released at once. In reality, as ozone was formed and depleted in a constant process.

I'll give you another shock illustration. Imagine an enormous tube, let's say 1 m diameter, 50 km long, pointing straight up into the stratosphere, through the ozone layer. You remove all the gases out of that tube except the ozone. Of course, gravity will pull the ozone down to the bottom of the tube. How thick will that layer of ozone be, without any depletion, at ordinary atmospheric pressure?






1 km? No, that's far too much.







100 m? Try again






OK, 10 m, then?







What, 1 m? Can't be less than that, can it?






It is? Really? Then 10 cm?







No, not 10 cm? Well, 1 cm? Now you're getting warm.







An average of 4 mm (400 Dobson Units) is the answer. That's the thickness of the ozone layer that protects us from the intense UV radiation. Now you see why it is so fragile.

[Gurm]

Yep. But now since we're not using any more CFC's, then it stands to reason (purely from common sense) that since the hole is STILL getting bigger, then the damage must build up faster and last longer than it gets undone or the ozone is replenished. True?

Ok. So for every 5 cans of ANY sort of aerosol that used a CFC, we've lost a football field - and despite your protestations that it wouldn't happen as if it were all at once, it would appear from your own data that it's WORSE than that - that it accumulates and keeps causing damage despite the cessation of the glade-spraying, as it were!

Therefore, let's say that there were 500 million cans of aerosol sold in the 70's. I think that's an UNDERestimation. There are several thousand that were used by my grandmother alone from 1976-1978, and that was in her UPSTAIRS bathroom. I shudder to think of how many were used in the GUEST bathroom downstairs.

Now, that's 100 million football pitches. That's quite a bit of space, isn't it? That would all by itself amount to a pretty sizable hole - probably bigger than the one that's there.

But since these CFC's are MAGICAL, and are STILL destroying the ozone layer at an alarming rate...

Do you see where I'm going with this?

I'm not arguing with your theory, I'm arguing with the results of your calculations.

It's like the people that say that every time someone masturbates, God kills a kitten. There aren't enough kittens on earth to account for one day of masturbation in San Francisco alone, so the numbers don't add up.

Or the people that say that we evolved slowly, gradually, from one generation to the next... and then ignore that there hasn't been enough time since the beginning of the universe for that many generations, nevermind the relatively short span of multicellular life on Earth.

I'm not saying your work isn't valid. Heck, it's more valid than the idiots who churned out that "dumb people don't know they're dumb" report a couple threads up.

I'm just saying that you have, sadly, fallen prey to the propaganda of your own field.

And I've talked to better experts than you who have EQUALLY compelling data on the other side of the coin. So there's really no need for ME to publish a paper, plenty have already been published. They're just not POPULAR. It's not politically popular in the non-USA portion of the world to say 'yeah we aren't REALLY destroying the planet as much as the environMENTALists say we are and here's proof'. It just doesn't wash.

I blame the Catholics actually. It's all that repressed guilt looking for an outlet.

It's the difference between Christians and Jews. Jews believe that sinning makes you a sinner - that nobody is BORN evil. Christians believe that being a sinner makes you sin - that nobody is BORN good. Then they spend their whole life feeling GUILTY about it, and looking for someone to BLAME.

This is where Political Correctness, environMENTALism, and fymynysym all come from.

- Gurm

[cjolley]

GURM:
You started to show some calculations and then you quit.
What happened?
Inquiring minds want to know.

[Gurm]

I gave up because my RBN's can't compete with Brian's RBN's. Because he's an "expert".

(Here's a hint - I know guys that have been painting houses for 50 years... who do it wrong. It happens all the time.)

- Gurm

[Brian Ellis]

OK, Gurm, I'll try and keep it simple.

Ozone is formed in the stratosphere by the action of UV from sunlight on oxygen molecules. The simplified reaction is
3O2 > 2O3

At the same time, ozone, which is a highly reactive gas, is decomposed by contact with other gases. For example, if a nitric oxide (NO) molecule meets an ozone molecule, it reacts and forms a nitrogen dioxide molecule, releasing the oxygen:
NO + O3 > NO2 + O2

This is a carefully balanced equilibrium situation.

The problem starts when a chlorine or bromine atom, knocked off a CFC or halon molecule, also by sunlight, enters into this region. A very complex series of reactions takes place but can be summed up as:
Cl + O3 > ClO + O2
ClO + O3 > Cl + 2O2
This means that two ozone molecules have been buggered up and the causal chlorine atom is free to repeat the process. This causes a chain reaction and it has been calculated that ~250,000 ozone molecules are destroyed by a single chlorine atom, on an average, before the chlorine is captured by a different reaction. Bromine is about 50 times worse. This obviously upsets the natural equilibrium.

OK, CFCs usually have what is called an atmospheric residence time of ~100 years. That means the 1/e (~0.37) of the substance remains after that time, the remaining 0.63 having been destroyed in the stratosphere. So if you release 1 kg today, it will take ~6-10 years before reaching the stratosphere and starting the problem, which will build up gradually. After 100 years, 370 g will still be up there and after 200 years about 135 g and so on. Fortunately, there are other substance with residence times much shorter, such as methyl bromide (pesticide), methyl chloroform (solvent) and carbon tetrachloride (feedstock chemical), all of which are partially destroyed in the lower atmosphere, so that their reduction in use has a much faster recovery in the stratosphere, which has enabled us to slow down the increase of ozone depletion already.

Anyway, CFCs were first used for refrigeration, on a large scale, in the 1930s, so some of the gas from those old fridges is still causing depletion and will continue to do so for years to come. The best predictions are that the peak depletion will occur about 2045 ± 10 years and then it will slowly start to decline. By 2100, with any luck, we should be back to about 1970 levels and by 2200 to about 1955 levels. It may take 500 years to be at substantially pre-CFC levels. These predictions assume that the Montreal Protocol is followed to the letter and that no new ozone-depleting substances are emitted, which may be a little utopian.

I hope that this explains why my football pitches did not appear all at once and why we still need to be vigilant.

Atmospheric sciences is a vastly complex subject that are still in their infancy. The ozone issue has been the impetus for a vastly increased knowledge in the processes and climate change a further kick forward. We know at least 100 times more on these subjects than we did in 1980. I am not an expert in these subjects, but I have picked up a lot of knowledge and understanding through my work for the Swiss Government and the UN on the industrial use of ozone-depleting substances and, in particular, solvents, which is my area of expertise. I agree that this does not make me infallible even in the latter field, but I do my best. As an engineer and a scientist, I hope I have enough discernment to sort out the sheep from the goats. So, yes, I can get it wrong, but I am very sincere in this respect.

And, just to put the record straight. I am not a tree-hugger nor a politico-ecologist (type Greenpeace, FoE etc.). I neither support nor am a member of any such organisation. And I have vociferously opposed many supposedly environmentally-friendly proposals, such as the EU WEEE and RoHS directives and the new proposal for the registration of chemicals in the REACH debate.

[Gurm]

Brian,

I know. And YOU should know by now that I'm giving you a hard time, that I got it the first time, and that I'm well aware of the facts and how ozone works.

But it IS fun arguing with you.

- Gurm

[Marshmallowman]

It is a well known ands accepted scientific fact that Brian just pointed out. The chemicals are not used up and do remain to cause further damage..

And glib commments are not welcome when you live near the edge of the ozone hole...

In 1991 I had a freind complete his physics degree..his was of course do his thesis in UV level changes , both seasonal and over time.

They started showing UV levels on weather reports about that time as well( his results at first)

And over the years we have seen and felt the changes, 10 minuntes on cool day will get your suburnt down here...but if I go further north to where I grew up, I can sit for 30 minuteds on 40 Degree day and barely get red...heatstroke maybe but no sunburn... The changes in UV from top of OZ to the bottom are VERY obvious

Oh in perth the UV level is pretty much graded as extreme for 10 months of the year, and high for the other 2..

One of the to causes of death here is skin cancer, and it is on the increase inspite of all the advice we get to protect ourselves form the sun..

The given recomended sunblock is spf 30+ sunblock (15+ was considered overkill 10 years ago)
And thats not just 30+ by itself, it recomended you wear a long sleeve UV block shirt and hat.(thats beach clothing)

We have a good climate esp in summer, but we can only enjoy it at our own risk.... Stuff you probably take for granted in the northern hemisphere.

The OZone hole SUX, and it is a FACT

[Brian Ellis]

And the increase in melanomas is greatest on the right ear lobe in Ozland. The cause has been determined : long distance drivers drive with their windows open and, out of sheer boredom, lounge against the cab door, so that their ear gets a dose of sunlight.

[McRhea]

Originally posted by Brian Ellis
And the increase in melanomas is greatest on the right ear lobe in Ozland. The cause has been determined : long distance drivers drive with their windows open and, out of sheer boredom, lounge against the cab door, so that their ear gets a dose of sunlight.

Heh, that sucks.... I guess the answer is to get an F1 McLaren so you can sit right in the middle of the car and not get cancer.

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