[From Bill Powers (951014.0830 MDT)]
Bill Leach (951013.1937 EDT) --
Well, you're obviously more up-to-date on global warming research than I
am! However --
The only problem (which seems to be universally ignored by the
"media" global warming "experts" is that if there is any causality
then global average temperature change is causing CO2 concentration
changes. The other way around is just plain impossible if the
basic concept of causality not acting backward through time holds.
All that is required for a gas to be a "greenhouse gas" is that it be
transparent to most of the solar radiation but absorbent of long-wave
infra-red radiation, which is how the earth gets rid of its heat to
space. Window glass has this property, which is why it is used for
greenhouses. CO2 has this property, as do a number of other gases like
methane. It may be true that increasing temperature increases CO2, but
this does not mean that an increase of CO2 can't cause an increase in
temperature. I don't think there's much question that simply as a
physical phenomenon, an increase of any greenhouse gases will result in
blocking some of the re-radiation of the earth's heat into space, and
will therefore increase the mean temperature. This isn't anything new;
some double-glazed windows are (or used to be?) filled with CO2 for just
this reason.
If you wish, I will try to locate the numbers and information
sources for this but the assertion that mankinds' burning of fossil
fuels being a significant contributor to global average CO2
concentration looks pretty absurd. Just from memory which I admit
is not always too good but I seem to remember four orders of
magnitude difference between the activities of man and the known
"natural" sources of CO2 such as ocean off gassing.
I don't know the numbers. One also has to take into account sinks, which
is what a lot of current research on the oceans is aimed at. But what is
the size of the energy budget? It might be that raising the CO2 level by
one part in 10^4 would be enough to raise the global temperature by a
degree or two, through unbalancing a very large rate of energy input and
loss a slight amount.
Your assertion concerning "greenhouse gases" is just plain not
proven true
I agree, it hasn't been proven true. What's your cutoff for the
probability of truth at which you would start hedging your bet?
Your dire consequences assertion is yet another case of "terrify
the public enough and funding will be provided". There really are
scientists studying the potential effects of a potential increase
in global average temperature (but like PCTers, you never hear from
them). The consensus of those that I have either read or talked
with is that overall, an increase in global average temperature
would increase the productive capacity of the earth's ecosystem
dramatically but there would be some species of plants and animals
that would probably not survive.
I'm not predicting any dire consequences. I'm only predicting that they
would be dire IF there were significant warming. The work is still in
progress, isn't it? Yes, the productive capacity of the ecosystem (that
is, a somewhat different ecosystem) might greatly increase. Is that
good? Who knows?
The ocean level is a hotly debated issue. In the first place,
melting of the antartic ice cap is not likely since summer
temperatures are not increasing. Some scientists maintain that a
global average temperature increase will decrease the amount of H2O
in the atmosphere, reduce the amount of rain, ice and snow held on
land and thus raise the ocean levels. Other scientists assert
exactly the opposite, that is global average H2O concentration will
increase as will H2O on land and therefore ocean levels with
decrease. I believe that as it stands, the latter group has the
benefit of history on their side.
One thing's for sure; there would be more water vapor in the air (which
you said above was the main greenhouse gas, so we'd have positive
feedback). But we don't know now whether this would lead to an increase
in ocean levels, or an ice age (due to increased transport of water to
polar regions). However, that's just the local energy distribution: when
you're talking global averages, all that counts is the balance of heat
energy in versus re-radiated energy out. Maybe there are some negative
feedback effects, as from cloud cover, that would counteract the warming
effects (although cloud cover hasn't done much to cool Venus).
Maybe.
From your rather het-up reaction to my post (been breathing too much
CO2, Bill?), I can see that I dealt with the issue too casually. I'm not
really prepared to deal with it any other way, since as far as I can
tell everyone on the strongly opposing sides is selecting data from the
noise that prove their points. If you have already decided there's
nothing to any of these controversies, you'll pick data from the middle;
if you're on one side or the other you'll choose the appropriate
extremes of data. There's data there to prove whatever you like. Heck,
you can even pick scientific principles to suit your conclusion, like
saying there's no causal effect of CO2 concentration on temperature.
I think I'll just conclude that it was a mistake to bring up the
subject!
P.S. Regarding the later posts, I find that it's very uncomfortable for
me to hear you supporting my own suspicions about self-interest,
governmental and scientific incompetence, semi-conspiracy theories, and
so on -- but amplified by about 10. I find that I'm not nearly as
suspicious as I thought I was.
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Best,
Bill P.