Ozone hole myths (was: Kyoto, Driving our car)

Hal Finney (hal@rain.org)
Wed, 10 Dec 1997 07:22:17 -0800

Warrl kyree Tale'sedrin, <warrl@blarg.net>, writes:
> Chloroflourocarbons.
> Those nice molecules that (as compared to most gas molecules in the
> air), weigh about as much as a small horse, and are extremely
> vulnerable to bioprocesses and sunlight.
> They are going to remain intact while they defy gravity to rise into
> the stratosphere and simultaneously cross not one, but two, breaks in
> atmospheric air current patterns. (The wind patterns of the earth
> are pretty neatly divided into three groups, and adjacent groups
> don't interact much. The groups can be described with a fair degree
> of accuracy as: the northern hemisphere, the southern hemisphere,
> and Antarctica. Almost all human industrial activity has occurred in
> the northern hemisphere.)

I'm surprised you would post this when I already provided information
which contradicts part of it (the segregation by latitude), along with
a pointer to a FAQ which contradicts the rest of it.


| 4.1) CFC's are 4-8 times heavier than air, so how can they
| reach the stratosphere?
| This is answered in Part I of this FAQ, section 1.3. Briefly,
| atmospheric gases do not segragate by weight in the troposphere
| and the stratosphere, because the mixing mechanisms (convection,
| "eddy diffusion") do not distinguish molecular masses.

| 1.3) How does the composition of the atmosphere change
| with altitude? (Or, how can CFC's get up to the
| stratosphere when they are heavier than air?)
| In the earth's troposphere and stratosphere, most _stable_ chemical
| species are "well-mixed" - their mixing ratios are independent of
| altitude. If a species' mixing ratio changes with altitude, some
| kind of physical or chemical transformation is taking place. That
| last statement may seem surprising - one might expect the heavier
| molecules to dominate at lower altitudes. The mixing ratio of
| Krypton (mass 84), then, would decrease with altitude, while that
| of Helium (mass 4) would increase. In reality, however, molecules
| do not segregate by weight in the troposphere or stratosphere.
| The relative proportions of Helium, Nitrogen, and Krypton are
| unchanged up to about 100 km.

To repeat what I posted yesterday about latitude differences:

| 4.2) CFCs are produced in the Northern Hemisphere, so how do they get down to
| the Antarctic?
| Vertical transport into and within the stratosphere is slow. It
| takes more than 5 years for a CFC molecule released at sea level to
| rise high enough in the stratosphere to be photolyzed. North-South
| transport, in both troposphere and stratosphere, is faster - there is
| a bottleneck in the tropics (it can take a year or two to get across
| the equator) but there is still plenty of time. CFC's are distributed
| almost uniformly as a function of latitude, with a gradient of ~10%
| from Northern to Southern Hemispheres.
| [Singh et al. 1979] [Elkins et al. 1993]

I'm curious. Do you really believe this stuff, or are you intentionally
posting falsehoods and misleading information for some reason?