----- Original Message -----
From: "James Mahaffy" <mahaffy@mtcnet.net>
To: <asa@calvin.edu>
Sent: Tuesday, March 28, 2000 12:37 PM
Subject: Re: Another apologetical mess up--CO2 in atmosphere
> Folks,
>
> Just a few things on Glenn's post on CO2. Glenn's posting the data on
> carbon dioxide in the atmosphere could give the impression to the reader
> that we can directly measure the amount of carbon dioxide that was
> present at various times. Glenn did not imply we could, but citing the
> figures without indicating the method used to come up with them may give
> the reader the wrong impression. I have not read the article but am
> assuming it is the ratio of some isotopes (perhaps C) in rocks
> (?limestones). The indirect method may be a valid way of approximating
> Carbon dioxide [and it may be the only way we can do it] but I would
> like to know how it was calculated and what assumptions were made to
> come up with the calculation. Even the amount of error that results in
> direct measurements should be standard in citing data and I assume the
> error is potentially larger in indirect measurements like these. I know
> in the past assumptions about early atmosphere have changed quite a bit.
> That is not to say these figures may not be right but just to cite them
> gives them more strength than I would feel confident without
> understanding what they are based on.
>
> I would also caution that climatic modeling applied to the past should
> be taken with a lot of tentativeness. It is still interesting and may be
> right. I for instance was fascinated by modeling Crawley has done
> suggesting that coal formation occurred in a temperate everwet and not
> tropical environment. On the other hand my advisor (who is one of the
> leading paleobotanist studying Carboniferous coal - does not believe it
> - the modeling goes against the traditional assumption of tropical
> nature of those swamps) The reference is - Crowley, T.J., 1994 Pangean
> climates. In: Klein, G. D., (Editor), Pangea: Paleoclimate, Tectonics,
> and Sedimentation During Accretion, Zenith, and Breakup of a
> Supercontinent. Geol. Soc. Amer. Spec. Pap., 288:57-73. I have no idea
> if Crowley's modeling really fits with Raymo [since I have not read
> Raymo] who Glenn cites, but my initial feeling is it sounds different
> from Crowley who I do know, so the reader should be aware that some of
> the explanations are more tentative.
>
> All this is not to say that Glenn's criticism of Ross may not be
> correct, I am only concerned with not giving the wrong impression to the
> reader in what is know for sure about fossil carbon dioxide and
> paleozoic or earlier climates and what caused those changes. Sometimes
> we are more at the level of guesses than certainty.
>
A correction, it is Berner's model, not Raymo's.
Of course I don't want to give the wrong impression. James is correct that
we can't directly measure CO2 directly. But there are lots of proxies that
can be used and lots of boundary conditions. Before I get to that a couple
of comments. First, I don't think Berner's model says anything about the
environment of coal deposition. Whether coal is temperate or tropical is
irrelevant to the question of how much CO2 was removed from the atmosphere
during the Carboniferous. We have some pretty good estimates of the quantity
of CO2 required to produce such biomasses as we see in Carboniferous coals.
That data acts as a boundary condition for Berner's calculations.
The second comment is that I have been interested in atmospheric modeling
ever since the late 70s when I carried on a 2 year letter exchange with Jody
Dillow about his Th.D dissertation/turned into the book The Waters Above. I
said he had an error in his dissertation and my very first published article
(CRSQ Dec. 1979, Can the Canopy hold Water?) was a correction of Jody's
work. Eventually Jody was forced to acknowledge that I was correct and every
subsequent Creationist worker in that area has had to acknowledge the basic
correctness of my conclusions (see references below [1])
Third, one thing that even those who disagree with me on issues usually
acknowledge--I do a pretty thorough job of researching an issue about which
I write (personal note to James--remember our discussion of the emissary
veins and the reversal of blood flow?). I was aware of the conflict between
what Rana was saying and the CO2 data. My question is why didn't Rana? Why
do Christian apologetical ministries do such a sloppy job of research?
Surely this isn't doing our best for the Lord is it?
Now, back to Berner's model. James is correct that certain isotopes are used
as proxies as are the knowledge of how much carbonate was deposited in each
period. This data plus the observed rates of certain processes, like
photosynthesis, erosion (measured by Sr-87/Sr-86), spreading rates
throughout the Phanerozoic (CO2 comes out at the ridges), the volcanism rate
(samething--they produce CO2). In short the calculations are complex but
they are based upon observed processes and observed boundary conditions in
the geologic record (measured amounts of coal, carbonate, volcanic deposits
etc).
Now, for input of CO2 to the atmosphere one can almost ignore all sources
except volcanism and drift. As long ago as 1974, Budyko said:
"We have plotted the diagram characterizing the change in volcanic activity
during the Phanerozoic eon.
"Figure 29 shows that the intensity of volcanic activity during
different epochs underwent manifold variations. The carbon dioxide
concentration changed in a more or less similar way, which is understandable
as the eruptions are one of the main sources of carbon dioxide in the
atmosphere. The diagram reveals a tendency toward a decrease of carbon
dioxide from the second half of the Mesozoic." [2]
A look at his CO2 curve from 20+ years earlier shows that it is quite
similar to Berner's and his used an entirely different methodology. He has a
bit lower level of CO2 in the lowest Paleozoic.
Now, we have a fair knowledge of the carbon cycle, the volcanism throughout
geologic time, the amount of carbonate, the amount of coal, the amount of
weathering through the Phanerozoic. Knowing all these things greatly
constrains the possible out puts of the model. While I obviously won't
stand by the values of the calculations to the 5th decimal place, I do think
they are close to correct. The vast quantities of carbonate in the lower
Paleozoic REQUIRE a huge quantity of CO2 in the atmosphere. And given the
dim sun 600 million years ago, if you didn't have more CO2 in the atmosphere
then, the earth would have frozen! I have done lots of global temperature
calculations and I will assure you if you dim the sun and remove the CO2,
the earth would be an iceball.
References
[1] I am particularly proud that the work I did in my first paper has stood
the test of time over and over again with acknowledgments from the canopy
advocates.
Dillow: "In an earlier publication a crude approximation for calculating the
canopy temperature was employed. It has since come to my attention that I
made a mathematical error which would yield canopy temperatures that were
several times larger than what had been previously reported.(36)" Joseph C.
Dillow, "The Vertical Temperature Structure of the Pre-Flood Vapor Canopy,"
Creation Research Society Quarterly, 20(1983):1:7-14, p. 13
His reference (36) says: reference 36 says:
"36 Reference 1, 1st edition, p. 227. A conversion from CGS to SI should
have given for the optical path of 12,190 kg m-2. I am indebted to Mr.
Glenn Morton, of Texas, for pointing this out to me, July, 1981." Joseph C.
Dillow, "The Vertical Temperature Structure of the Pre-Flood Vapor Canopy,"
Creation Research Society Quarterly, 20(1983):1:7-14, p. 14
Vardiman, ICR's meteorologist says in 1990:
"Morton(1979) was apparently the first to conclude that the canopy would
have made the earth's surface too hot for human habitation (Kofahl did not
calculate surface temperatures). Morton made a number of assumptions that
greatly simplified the problem, and his surface temperatures are much higher
than ours, but the general conclusion is the same: Life as we know it would
not have been possible under a canopy of 1013 mb (1 atm), nor even with a
canopy of only 50 mb. When other features such as clouds are added to the
model, this conclusion could be modified greatly, however. Preliminary
explorations with cloud layers at the top of the 50 mb canopy have shown
significant radiation effects which lower the surface temperature
drastically. Unfortunately, while the surface temperature decreases when
clouds are added, so does the temperature of the canopy, reducing its
stability." ~ David E. Rush and Larry Vardiman, "Pre-Flood Vapor Canopy
Radiative Temperature Profiles," in Robert E. Walsh, and Christopher L.
Brooks, Proceedings of the Second International Conference on Creationism,
(Pittsburgh: Creation Science Fellowship, 1990), p. 238
And in 1998 he said:
"Attempts have been made by Kofahl (1977), Morton(1979), Dillow (1982) and
Rush and Vardiman (1990) to model the amount of water which can be held in a
water vapor canopy surrounding the earth and associated temperature
profiles. It has become increasingly obvious through radiation modeling
that the strong greenhouse effect produced by water vapor severely limits
the amount of water that can be maintained in a canopy which is in contact
with the atmosphere. For example, Rush and Vardiman (1990) found that a
canopy containing enough water to create 50 millibars of pressure at its
base (the equivalent of about 0.5 meters of precipitable water) would
produce a surface temperature of over 400K. Even a water vapor canopy
containing only 0.1 meters of precipitable water would produce a surface
temperature of about 335K." Larry Vardiman and Karen Bousselot, "Sensitivity
Studies on Vapor Canopy Temperature Profiles," 4th ICC, 1998, p. 607
20 years later, I am still correct on that.
[2] M. I. Budyko, Climate Changes, (Washington: American Geophysical Union,
1977) p. 129. This book was first published by Gidrometeoizdat, Leningrad
Russia in 1974.
glenn
Foundation, Fall and Flood
Adam, Apes and Anthropology
http://www.flash.net/~mortongr/dmd.htm
Lots of information on creation/evolution
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