> Look at it this way. The ozone we're worried about is heavier than
> air, yet it's higher in the atmosphere. If his argument held we would
> all be poisoned under a big sheet of ozone.
Doesn't necessarily follow ... the ozone is being created at the outer edges
of the stratosphere and decays as it drifts towards the surface. Ozone
molecules are very reactive, and will decay if they bump into almost
anything else, including another ozone molecule. (Ozone is really just an
excited form of oxygen.)
> > I friend of mine insists that CFCs are heavier than air, and thus
> > cannot
> > rise to the ozone layer. His contention is that the whole thing was
> > dreamed up for political purposes.
Having followed this topic with some interest (and being the son of a PhD
chemist), there remains a real doubt in my mind that use of CFCs has
anything to do with the "hole in the ozone". I don't think it was "dreamed
up for political purposes", there are some scientists that are convinced
this is a real problem. There are others that disagree, so it's hard to say
for sure who is right. Most likely, neither side is entirely right.
That said, there are certainly some people who expect to make a lot of money
off of the CFC "scare", and these people are not above manipulating the
government or the media to twist the "facts" in their favor. I believe this
is happening.
The earth has a great many huge feedback mechanisms, that we understand
poorly at best. Some of these mechanisms appear to oscillate, some with
periods of tens or even hundreds of thousands of years. We simply don't
have enough good observations to be sure we know anything about these
cycles. The very first time anyone thought to look at the ozone over
Antarctica (back around 1929), there was a hole there. Well, since ozone is
created by sunlight hitting oxygen in the stratosphere, and there is blessed
little sunlight over Antarctica in the (local) winter, it's not too
surprising that there isn't much ozone there, either. The data that the
winter hole has been getting larger for a few years now seems reasonably
persuasive, and we know that CFCs can accelerate the decomposition of ozone.
However, concluding that this means CFCs are "destroying" the ozone layer is
a lot like looking at the Mississippi River and saying it's because someone
left the water running !
One other thing ... there is a much larger difference between the density of
R12 and "air" than among any of the normal components of air. The oceans
get churned up a lot, just like the atmosphere does, but you find very
little sand on top of sea water ...
Randall
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