Re: Environmental Issues
Dave Koerner 818-354-8820 (davidk@nicmos.jpl.nasa.gov)
Fri, 7 Jun 1996 11:10:32 -0700 (PDT)Henry said,
> Temperature rise: There is evidence that the earth's climate has
> always varied, and there have been proposals that there are long
> cycles. (More than 25 years ago when I was an undergraduate, they had
> already lost their new look. Based on the those cycles we should have
> been in a warming trend during the last half of this century and into
> the next.) Are we in one of those cycles, are we accelerating the
> rate of the temperature increase because of our fossil fuel combustion
> practices, or are the dampening effects of the cycle only slightly or
> far behind the increased temperature rise rate??
I can't believe that anyone could predict a warming trend during any half
of any century, "based on those [or any other] cycles" The weather
doesn't work that way, although people used to think it did. Globally
averaged climate may be a little more predictable, but there are no
recognizable cycles that can be used successfully to make predictions.
On the other hand, you can predict for certain that increased CO2 WILL
contribute to temperature increase. It's an efficent infrared absorber and
unquestionably will lead to the retention of heat in the lower atmosphere.
That CO2 is increasing is also without question -- the increase is thoroughly
documented in atmospheric samples taken from Mauna Kea, for example.
One thing's for certain, the sun is getting hotter and the earth WILL
experience a runaway greenhouse effect in the next few million years (i.e.
oceans boil and earth go the way of Venus...), long before the Sun enters
into its red giant phase and nearly swallows up the earth. Why hasten this
demise with additional man-produced greenhouse gases???
> Lastly the
> concern over ozone, is the presumed increase in UV, and the resulting
> effects. Why isn't there a coordinated network to measure UV?
Are you questioning whether depleted ozone will lead to increased UV-B????
Simple molecular physics assures us that it does! From a satellite, it's much
easier to measure the global distribution of ozone. Direct measurement
of incident UV radiation would have to be from the ground, and it would
require a Herculean effort to track it on global scales. Hopefully, ozone will
start turning around as a result of regulations that have been in force for a
while now.
Best Regards,
Dave