Re: Global warming problems in homeschool text

From: Joel Moore <>
Date: Fri Aug 19 2005 - 09:20:24 EDT

The theory behind global warming is actually pretty simple and goes
back to Arrhenius in the 1890s. CO2 traps more heat than most gases
and without the presence of CO2 in the atmosphere the earth would be a
lot cooler than the present. In essence, since that time people have
been trying to figure out how much things will change and warm up (or
perhaps cool in some regions, like northern Europe) as humans add CO2
to the atmosphere.

A couple of quick points Glenn.

Geologic time.... I'm pretty sure the Cerling paper on the Miocene is
out of date and new evidence shows lower CO2 in the Miocene than was
previously thought. Pagani et al. 1999 or 2000 is one of the relevant

  Also, overall atmospheric CO2 levels have been declining for
millions to hundreds of millions of years but the strength of the sun
has been increasing. CO2 (and methane and other greenhouse gases)
concentrations billions of years ago needed to be much higher because
the strength of the sun was significantly less than the present.

More modern... No strong evidence exists for the global average
temperature being higher in 800 AD than the present. The temperature
in the northern hemisphere may have been close to as warm for a few
years, but it is not likely that any 3-decade period in the last 1000
or more years has been as warm as the last 3 decades. Also, higher
temperatures in one area or region do not mean that the global average
temperature was higher (or even the average temperature of the
northern hemisphere was higher).

On 8/18/05, Glenn Morton <> wrote:
> 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.
> Shalom
> George
> ----- Original Message -----
> From: Glenn Morton
> To: George Murphy ; Sarah Berel-Harrop
> Cc:
> 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
> P(CO2)
> 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
> **
> glenn
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> glenn
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Received on Fri Aug 19 09:21:26 2005

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