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Re: Ecological Economics and Entropy
dlj@inforamp.net (David Lloyd-Jones) wrote:
*On Tue, 26 Nov 1996 00:13:25 GMT, briand@net-link.net (Brian Carnell)
*wrote:
*>Siberia. I'm surprised you're not arguing Siberia is overpopulated.
*>Since the U.S. is overpopulated and Zaire is overpopulated, why stop
*>with Siberia?
*
*Brian,
*
*I would have thought that there is a good case to be made that Siberia
*is overpopulated. It's now twenty-four years since I've been there,
*but since that time Lake Baikal has been found to be severely polluted
*and shrunken in size. When I was there people already talked
*wistfully about how good the hunting had been in their fathers' time.
*
[snip]
Lake Baikal polluted, maybe, but shrunken in size??? No way!
Deep lakes drained by rivers (as opposed to evaporation) are very stable
in size (as long as the topography is stable) because the outflow rate
is extremely sensitive to the water level: Even if the environmental damage
reduces the inflow rate by half, the outflow rate would be likewise reduced
by half when the lake level drops by a fraction of the *outlet's*depth, typically
a few meters. If a lake is deep, that would mean a relatively small loss of the
lake's volume and hence similarly small loss of its area.
By comparison, shallow lakes drained by evaporation have equilibrium areas
proportional to the inflow rate. Cut the inflow in half, and lose half of the
lake's area:-(. Lake Aral is like a small see in area, but it's shallow, has
no outlet and is located in the middle of a desert, hence high evaporation.
When the Amu-Darja and Syr-Darja rivers had their waters diverted for cotton
agriculture, Aral "Sea" shrunk massively, resulting in the worst environmental
disaster on the planet:-(.
Lake Baikal is at the other extreme: It's the deepest lake on the planet
(Up to 2km depth in places and deeper than 1km *average*), it has a big outlet
-- Angara river -- and very low evaporation rate due to cold climate.
Short of digging a whole 'nother outlet -- which is next to impossible, since
Baikal is surrounded by mountains -- there is nothing people can do to shrink
Baikal's size.
So relax. Or better yet, check your facts before bringing up bogus environmental
disaters and focus your efforts on the real ones.
*****************************************************************************
Vadim S. Kaplunovsky, | vadim@physics.utexas.edu (NextMail OK)
Associate Professor of Physics, | #include <std_disclaimer.h>
University of Texas at Austin. | #excuse bad_typing.
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