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Re: population growth & physics ed





On Tue, 16 Jul 1996, James Mclean wrote:


What conclusion can be drawn from the relative increases in temperature and
CO2? One implication might be that, because the relative CO2 rise is much
larger, therefore the CO2 is not likely to be the cause of the temperature
rise.
But, of course, that logic is faulty. Even if the relationship were as
simple as T = T_0 + k *(CO2 conc), proper choices of T_0 and k could mean
that the temperature rise is *entirely* due to the CO2, regardless of what
the relative increases are.

The relative increases are an interesting fact, but in the absence of other
information, I don't see how that fact contributes to thinking critically
about global warming. I therefore wasn't clear why you felt it "should
always be pointed out".

--
--James McLean
jmclean@chem.ucsd.edu
post doc
UCSD

P.S. interesting that the CO2 concentration shown in the http site you
mention shows an annual cycle. Does anyone know why this is? Possibly
aphelion and perihelion?


I had a thought on this whole CO2 warming linkage a few months
ago (while teaching thermo of course). My idea was that warming may be
due to heat load on the atmosphere from simply driving cars, rather than
CO2 emissions. The central idea I had was that when one uses a gallon of
gas, then energy of combustion is entirely dumped into the atmosphere,
not just what comes out the tailpipe. Excess thermal energy is dumped to
the atmosphere by the radiator, and the kinetic energy of the car is
eventually dissipated also to the atmosphere through brake friction. In
other words, the entire energy of a gallon of gas ends up in the atmosphere.

I did a back of the envelope calculation after looking up the
total consumption of gasoline and using the heat of combustion. Then
using the approximate volume of the atmosphere I came up with .5 degree C
delta T per year. I felt this was significant, and though I haven't
checked it, I wouldn;t be surprised if the curve of gasoline consumption
and accompanying delta T has the same shape as the global warming curve.

I haven't pursued this more, and would like to know where the
flaws in my thinking are.


Mike Monce
Connecticut College