From: solomon@chaos.utexas.edu (Thomas Solomon)
Newsgroups: talk.politics.misc
Subject: Re: Ozone problem burns Politically Correct
Date: 9 Apr 92 13:40:49 GMT
Reply-To: solomon@chaos.utexas.edu (Thomas Solomon)
Organization: University of Texas at Austin, Center for Nonlinear Dynamics

In article <1992Apr5.153906.9233@anasaz> john@anasaz (John Moore) writes:
>
>I keep asking this question, and getting no answer: has anyone measured
>significant increases in UV-B in populated areas? Can you answer this?
>
>Malignant melanoma deaths are also greatly on the rise in the Southern
>US, but this has NOTHING to do with the ozone hole and everything to
>do with excess sunlight exposure. Furthermore, the ozone hole is a new
>phenomenon, and melanoma typically has a ten or twenty year latency.
>

In the Spring of 1988, the ozone hole over the Antartic broke up when
sunlight started hitting the pole and changing the nature of the
jet stream that encircles the region (as it does every spring).  In
1988, however, large pieces of the hole remained intact, even after
the hole had broken up.  One of these large pieces drifted right over
Australia.  This is documented.  I have seen videos of ozone concentration,
showing a very low concentration region drifting over Australia.  Here
is a clear-cut example of a situation where the existence of the ozone
hole has a negative impact on populated areas.  Now, whether the increases
in skin cancer noticed in the years after this event are due to the
increase in UV from this event can be debated, but I don't think that
risk can be debated, since a clear connection has been made between 
exposure to UV and risk of contracting skin cancer.

By the way, there are numerous reasons why the Antarctic region is more
susceptible to the formation of an ozone hole than the Arctic region.
The hole is maintained (in Antarctic winter) by the existence of a
Rossby wave (a jet stream wave) that completely encircles the Antarctic
during the winter.  This Rossby wave acts as a barrier to impurity
transport.  When the wave isn't there (in summer and autumn), ozone (and
CFCs) from middle latitudes can readily mix into the Antarctic region.
When the sun goes down in winter, though, the Rossby wave is established,
sealing off the region.  The CFCs then act on the ozone (this has also
been documented scientifically) with the assistance of ice particles,
lowering the ozone concentration.  The isolating properties of the
Rossby wave prevent ozone from middle latitudes from replenishing the
supply of ozone in the Antarctic region, producing a "hole".  The jet
streams that encircle the Arctic region are much more disorganized than
those in the southern hemisphere.  As a result, the Rossby waves keep
breaking up around the Arctic, even during the winter, so the arctic is
less likely to be isolated.  The absence of a well-defined hole does
not mean, however, that ozone depletion is not occuring in the Northern
hemisphere.  It just makes it harder to prove scientifically.  (Of course,
there appears to be credible evidence of significant ozone depletion
in the arctic region for this year.)

					Tom Solomon
					solomon@chaos.utexas.edu
Newsgroups: talk.politics.misc,soc.men,soc.women,alt.rush-limbaugh,alt.politics.correct