Re: AAPG on Global Climate Change

In article <12tmc5houm0e8ea@xxxxxxxxxxxxxxxxxx>,
Jo Schaper <jospamnotschaper34@5socket78dot9net> wrote:
Daryl Krupa wrote:
On Feb 19, 9:32?am, J. Taylor <nchiw...@xxxxxxxxxxxxxxxxxxxx> wrote:
Very good Daryl, it is so hard to detect those subtle ad hominem.

I do not know to what you refer.

It is completely irrelevant it was a personal website or the
occupation of owner of it.

No, it is not irrelevant.
The source is unscientific, and unreliable, and inaccurate.
That's why we should only consider peer-reviewed research as an
information source: it reduces the chance that our opinions will be
swayed by clumsy propaganda.

Well, I'm slightly disturbed by this assessment, Daryl. All personal
websites don't fit into this category; for one, I've bent over backwards
to make sure info on my website on Missouri springs, caves, karst and
geology is as accurate as humanly possible. I quite understand relying
on peer-reviewed articles for science citations; also, doing a reality
check on stuff one finds on the web--everything, including Wikipedia,
academic sites and even information posted in online papers published
Science or Nature. But not all of us out there are trying to bluff or
baffle the public.

Certainly there are plenty of good personal sites. Some of
those personal sites are by folks who also write in the peer-reviewed
literature (realclimate, pharyngula, badastronomy, ... plus my own).
But as a statement of odds, you're more likely to find informed
content in the peer-reviewed literature than on a personal web page.

Interestingly, when (through the generosity of a
staff friend--not even an academic) this same web stuff was on an edu
address I got many more citation-- the information has not changed, just
the location. Granted one expects to find diamonds in a diamond mine not
a dunghill, but I'm not sure the web address of information means that
much anymore. Caveat emptor, regardless of the online source.

Indeed. But then again, there's the stability/findability issue.
A personal page at [insertyournamehere].com hasn't been on the
web long compared to the .edu site's, so it hasn't had time to
accumulate the links from outside that would raise its profile
on search engines.

[snip]

Well, if one is considering ALL factors which contribute to the
greenhouse effect (warming of the earth beyond a dry atmosphere)
water vapor is indeed a major player. The 95% seems overblown, but
taking a look at the explanation on
http://www.realclimate.org/index.php?p=142 (check these fellows bios, to
ensure they at least theoretically have proper academic credentials)
it still ranks quite high (they cite water vapor alone accounts for
between 36% and 66% of the greenhouse effect, and together with clouds
makes up between 66% and 85%.)

The origin of that 95% number is something that William Connolley
(one of the realclimate folks) and I have been trying to track down.
Note that the 95% attribution by Heib (and the many copying him)
is for water vapor, not water + clouds. As best William and I have
found, the 95% was indeed plucked out of thin air. Not by Heib, but in a
different report that he copies from. That report presents a citation
to the Ramanathan source cited in
http://www.radix.net/%7Ebobg/climate/halpern.trap.html
(The Rev. Geophysics and Space Physics paper). And copies much of
the same table (with citation). The text, however, inserts a totally
uncited assertion of water vapor being 95% of the greenhouse effect.
It is this that Heib (et al.) quote, not the scientific citation
and result on the same page.

How that uncited assertion was put into the (US Govt, early in the
current Bush administration) report is still unanswered.

Water vapor is usually neglected, because for the most part, we are not
contributing massive amounts of water vapor to the atmosphere--not in
the same way we are contributing CO2, and introducing entirely new
manufactured gases. Like solar insolation--there isn't much we can do
about water vapor in the atmosphere. We can do something about the minor
greenhouse gases.

Actually, no, go back to realclimate for the discussion of why
water vapor is ignored. In brief, it is because water vapor is a
responder, not a source. That is, if it's warm, atmospheric water
vapor increases, which gives further warming (and amplifier of
warming, but not a runaway under earthly conditions). But without
the dry (noncondensing) greenhouse gases, the atmospheric water vapor
drops near zero rapidly, and hence provides essentially no greenhouse
warming. With more dry greenhouse gases, we also expect more
water vapor (and its amplification of the dry greenhouse gase warming).

[snip]

My guess where the 95% figure came from was it was not pulled entirely
out of a hat, but resulted when someone tried to compare the percentages
of H20 (g) to other known greenhouse gases on a ppm basis in a 'typical'
part' of the atmosphere. This difficulty with this is, of course, that
H20 is constantly variable-- with a little manipulation, you can come up
with any large number you like, because it is true that H20 is more
greatly abundant than even CO2 or other trace greenhouse gases. For
example:
take .0038 (CO2) and divide by .02 (midpoint of 0 to .04 often given for
% of atmosphere which is water vapor) This gives .19 or 2% CO2 vs 98%
water vapor. I could see how someone could get such a number, then use
Kentucky windage, and get from there to water vapor being 95% of all
greenhouse gases.

An interesting calculation, which I'll keep in mind next time that
William and I go looking for the source of the 95% figure.

It's also incorrect. Water vapor approaching 4% of the atmosphere
(40 g/kg mixing ratio) is suitable for near-saturation in extremely
warm air, say 35 C (I'm being fast and loose with water vapor saturation
curve; you can research the details if you're so inclined. The gist
of the argument is unchanged). For ballpark purposes, the atmosphere is near
saturation (70% relative humidity), so you're ok there. Where this
goes wrong is that the atmosphere isn't near 35 C for much of its
volume and the saturation pressure drops rapidly with temperature
(approximately halving for each 10 C cooling). Temperature drops
rapidly with elevation (ballpark 6.5 C per km). Upshot being that
that 2% is itself a very high number for water vapor (saturation at,
say, 25 C -- a temperature above global average surface temperature
of 15 C at any rate).

The outcome of the 70% RH over the globe, through the depth of the
atmosphere is a global average column of water vapor is equivalent
to 2 cm liquid H2O at the surface (it is the 2 cm which is a hard
figure, not the above saturation curve numbers). About 20 kg/m^2.
Surface pressure being 10^5 Pa gives an atmospheric mass of 10,000
kg/m^2 (roundly). So water is not 2%, but 0.2%. CO2, at 380 ppm,
is 0.038%. If we take these as the only gases of interest (by number
counts they're the most common greenhouse gases, but as they're both
saturated in their band centers, number counts aren't the best way
to look for their climate effects), then H2O is 84% by number.

[snip]

--
Robert Grumbine http://www.radix.net/~bobg/ Science faqs and amateur activities notes and links.
Sagredo (Galileo Galilei) "You present these recondite matters with too much
evidence and ease; this great facility makes them less appreciated than they
would be had they been presented in a more abstruse manner." Two New Sciences
.

Relevant Pages

  • Re: AAPG on Global Climate Change
    ... but resulted when someone tried to compare the percentages of H20 to other known greenhouse gases on a ppm basis in a 'typical' part' of the atmosphere. ... This difficulty with this is, of course, that H20 is constantly variable-- with a little manipulation, you can come up with any large number you like, because it is true that H20 is more greatly abundant than even CO2 or other trace greenhouse gases. ... I could see how someone could get such a number, then use Kentucky windage, and get from there to water vapor being 95% of all greenhouse gases. ... saturation, so you're ok there. ...
    (sci.geo.geology)
  • Re: AAPG on Global Climate Change
    ... I have no idea what Dr Gerhard's educational credentials are as climate scientist, but he does seem to have reasonable credentials as a geologist, including former KS state geo and former president of the AAPG. ... water vapor is indeed a major player. ... Like solar insolation--there isn't much we can do about water vapor in the atmosphere. ... My guess where the 95% figure came from was it was not pulled entirely out of a hat, but resulted when someone tried to compare the percentages of H20 to other known greenhouse gases on a ppm basis in a 'typical' part' of the atmosphere. ...
    (sci.geo.geology)
  • Re: Has "antenna" died?
    ... which the retention of heat in the atmosphere is not affect by the percentage of greenhouse gases and water vapor. ... Aren't you arguing both sides of the issue now, Cecil? ... Also augumenting/repressing is effects such as atmospheric dust and sulfur dioxide content, and yes, the amount of greenhouse gases in the atmosphere. ...
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  • Re: OT - *Some* Canadians get it . . . .
    ... the whole issue on water vapor is misleading at best. ... "Why Do Human-made Greenhouse Gases Matter When Water Vapor Is the ... the amounts of the various greenhouse gases in the Earth's atmosphere ... including the amount of water vapor in the atmosphere. ...
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  • Re: Has "antenna" died?
    ... the retention of heat in the atmosphere is not affect by the percentage ... of greenhouse gases and water vapor. ... Besides that.....earth has bigger catastrophic threats than CO2. ...
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