Re: Global warming problems in homeschool text

From: Glenn Morton <>
Date: Thu Aug 18 2005 - 18:15:34 EDT

The point is that we are more worried than we should be. Do I believe that anthropogenic causes are at work? Yes, but I kind of say so what. In the year 1000 AD there were 3500 wheat farms in Greenland and numerous vineyards in England. Only in the last few years have vineyards moved back into the UK but you still can't grow wheat in Greenland.
My strong suspicion is that once the Arctic ocean opens up and the ice cap melts, there will be huge snowfalls each winter in Northern Canada (think of the lake effect south of the Great Lakes each winter prior to their freezing) causing the albedo of the planet to rise and thus the temperature to cool.

George Murphy <> wrote:
Not quite sure of your point. The fact that there were high CO2 levels in the distant past without fossil fuels certainly doesn't mean that anthropogenic effects can't contribute to high levels today.
----- Original Message -----
From: Glenn Morton
To: George Murphy ; Sarah Berel-Harrop
Sent: Thursday, August 18, 2005 10:09 AM
Subject: Re: Global warming problems in homeschool text

George Murphy <> wrote:

There is 1 rather glaring reason for resistance to global warming &
especially the idea that a major cause of it is use of fossil fuels & other
human actions: Acceptance of these claims would require some costly actions
to deal with the problem. I'm not suggesting that all resistance is driven,
consciously or subconsciously, by economic interests but they certainly are
a part of the mix.

GRM: There is another. IN the Cretaceous the level of CO2 in the atmosphere was about 5 times that of today. Life survived it. And It was warmer in the year 800 than it is today. Both of those periods in history lacked cars (to the best of my understanding. At least I don't think dinosaurs were driving hummers)

Here is some backup data:

  "Several authors have presented evidence that CO2
and O2 concentrations were elevated throughout the
Mesozoic. Cerling's (1991) analysis of root paleosols
found CO2 concentrations from two to ten times that of
present atmospheric levels (PAL) in the Mesozoic. Carbon
dioxide concentrations in the low end of this range are
known to differentially promote plant growth in modern
plants, but concentration effects in the upper range in
modern plants or effects of elevated CO2 on plants of
Mesozoic origin are not complete at this time." Richard
A. Hengst et al, "Biological Consequences of Mesozoic
Atmospheres: Respiratory Adaptations and Functional Range
of Apatosaurus," in Norman Macleod and Gerta Keller,
"Cretaceous-Tertiary Mass Extinctions: Biotic and
Environmental Changes (New York: W. W. Norton & Co.,
1996), p. 328

When I was born the CO2 content was about 300 on the scale below:

 "Early in late Miocene.—The first evidence of C4 biomass
being a significant part of local ecosystems in the Old World
is about 7 to 8 my. Carbonates from preserved paleosols in
Africa, Asia, and Europe older than 8 my have del 13 C values
from about –10 to –12 permil. Figure 7 and table 2 show that
there are compatible with a maximum P(CO2) level of about 700
ppmV." Thure E. Cerling, "Carbon Dioxide in the Atmosphere:
Evidence from Cenozoic and Mesozoic Paleosols," American
Journal of Science, 291(1991):377-400, p. 394
Miocene Pakistan <700
Miocene E. Africa <400
Eocene Wyoming <600
L. Cretaceous Texas 2500-3300
               Spain 1600-2600
U. Triassic/
l. Jurassic New Haven 2000-3000
            New Haven 2500-4200
            Fundy Rift 3000-6000
Thure E. Cerling, "Carbon Dioxide in the Atmosphere: Evidence
from Cenozoic and Mesozoic Paleosols," American Journal of
Science, 291(1991):377-400, p. 394



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