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Re: fHuman vs. natural influences on the environment
In article <4ui4cq$k7n@igc.apc.org>, tomgray <tomgray@igc.apc.org> wrote
responding to charliew@hal-pc.org (charliew) statement:
>
> >Admittedly, there are events which have altered the
> >atmosphere's temperature. However, if the probability is
> >almost nil over one lifetime, I do not consider these events
> >to be particularly relevant.
My lifetime started in 1933 at roughly the same time as the first CFC.
When I was a child the first humans entered the stratosphere. During my
boyhood huge fleets of airplanes entered the upper atmosphere for the
first time: a place previously affected only by natural disturbances, like
gases and particles from violently erupting volcanoes, perhaps unusual
variations in solar energy output and perhaps comet and meteor showers
etc. The time span is anywhere from 3,500 to 1,000 million years.
So, in 50 years, waste gases and particles from human activity have
resulted in measurable change in the composition and structure of the
upper and lower atmosphere.
While the change in solar radiation on the surface of the earth has, so
far, not been catastrophic, from a homocentric point of of view, I am not
so sure that these change (see postings on Ultraviolet increases) should
not be considered catastrophic on a geological timescale.
I have spoken to a number of people in several countries in South America
who told me that their skin burns faster now than previously.
Dermatologists from two universities in Chile reported increased numbers
of serious sunburns among fair skinned people earlier in the Spring, and,
unusual numbers of darker skinned people suffering sun burned skin.(El
Mercurio, 4 November 1995)
This hardly seems unusual, if one keeps in mind the estimates of a 10%
increase in short wave ultraviolet radiation over the last ten years.(WMO,
and now GRL August 1, 1996) I started visiting Tierra del Fuego six years
ago and spent a month on the Straight of Magellan last year. The weather
is usually pretty bad (cold and cloudy), but I think it is fair to say,
the people who live there are not so philosophical.
A lot can happen in a lifetime.
Jim Scanlon
--
199 Canal St #8
San Rafael CA
94901
415-485-0540
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