From: tobis@meteor.wisc.edu (Michael Tobis)
Newsgroups: sci.environment
Subject: Re: Gallup Poll on Global Warming
Date: 7 Sep 92 17:31:02 GMT
Distribution: usa
Organization: University of Wisconsin, Meteorology and Space Science

In article <6181@taurus.cs.nps.navy.mil> rovero@oc.nps.navy.mil (Josh Rovero) writes:
>I'll believe the 4.3 W/m**2 figure cause I've done the calculation myself.
>It's a small part of the NET longwave flux (over 200 W/m**2).  That's
>when it has doubled; it hasn't happened yet.  

Fortunately, the direct effect is slower than linear, as a 5% change in
absolute temperature would be enormous, (6 K). The actual direct effect
works out to only 1.2 K as I recall, radiatively averaged. Most reasonable
guesses about the lapse rate (rate of increase of temperature with height)
indicate that the effect would be larger at the surface, about 2 K.

>Calculations of other
>feedback mechanisms are more speculative -- the contribution of water
>vapor dwarfs that of CO2.  

True enough. However, since saturation vapor pressure increases with
increasing temperature, this is almost certainly a positive (exacerbating)
feedback. The contribution of water vapor CHANGE is likely to add to the
effect by something like 50 % to 150 %. Recent experimental results
confirm this simple theoretical result. (Raman & Ramanathan, Nature v 342
p 358, e.g.)

>The immediate effects of things like volcanic
>eruptions and decreases in incoming shortwave radiation are observable now.

True, but unless you are expecting a systematic change in geologic activity,
perfectly irrelevant.

>I'll believe the American Meteorological Society Bulletin (within the last
>year) that discussed the length of record that would be required to 
>establish any change as being statistically significant.  It's on the
>order of 50 to 100 years with TODAYS's observing network, not the 
>historical record which is much sparser.  

Interesting. I'll try to look it up tomorrow when the library opens.
I am skeptical, though. In particular, surely statistical significance
depends on the magnitude of the increases. (If  temperature went up to that
of Venus next year, we wouldn't need a long record to confirm its significance.)
Theory predicts that the temperature rise is accelerating. (This accords
with observations btw.) If the acceleration continues, significance should
emerge soon. Evidence from meteorological observations, sea surface temperature
observations, and observations of glaciers are in accord that the world has
warmed in the last century. Did your Bulletin article account for this?

>Separating the human contributed
>warming from NATURAL variations is still a problem.  

True.

>Urban effects are
>clear, global effects are not.

Urban effects are measurable and a trend remains when they are discounted.

>As to any cultural bias (or subcultural bias), I don't think so.  I was
>a campaign worker for Eugene McCarthy and George McGovern, *before*
>I became a meteorologist and oceanographer.  The Navy came after that.

Well, two data points don't make a trend, I admit. Still, your willingness
to accept that the anthropogenic climate change question is purely political
and without significant scientific basis is frankly out of touch with the
research community. I observe that the only other informed person who
was similarly belligerent toward people who take the problem seriously
was also a meteorologist in the military.

Is my guess that your work is more operational than theoretical correct?
This is not a criticism. I just wonder how you got your frankly incorrect
model of the state of climate research.

This is not to say I'd bet my life that my theory is right and yours is
wrong. Just that I'm certain it's not a fringe opinion of new age crystal
rubbing fools without scientific merit or support, but rather the majority
opinion among climate researchers, that the problem is serious.

>My master's thesis involved sychronously coupled global atmospheric and
>oceanic forecast models (something that has yet to become operational) and
>systematic evaluation of differences between control (the way the op
>models work) and coupled models.  Used 48 CPU *hours* on a Cyber 205 back
>when it was a top-line supercomputer.  That's what gives me my extreme
>skepticism about climate modeling......... familiarity.

Agreed. But when various independent tools come up with similar results, and
no serious approach (well, except maybe Lindzen's) comes up with contrary
results, it is reasonable to start to take the thing seriously, despite
the weaknesses of the individual methods.

Just where do you think those 4 watts will go, anyway?

>I think climate change is worthy of study.  I have been a student of
>paleoclimatology for 20+ years.  Long enough to see some advocates
>switch from global cooling and "the next ice age" to global warming
>and unspecified future calamities.  

I admit that some people have a predeliction for predicting disaster,
while some have an opposite tendency to predict stability. I can answer
that I have seen some of the same people denying the significance of
the greenhouse problem who a few years ago denied the significance
of CFC ozone destruction. Neither observation has much bearing on the issue.

The only way to decide the question is to look at the evidence. Have you read
the IPCC report?

>Just call me a skeptic......

Skepticism is commendable. Misrepresenting the opinion of the research
community, whether intentionally or accidentally, is not.

mt
Newsgroups: sci.environment