Re: [Phys-l] Prof. Hal Lewis resigns from APS

[Kyle Forinash <kforinas@ius.edu>]

 Rick;

As I understand it (but I am not an expert) the CO2 and methane act as 
feedbacks, much like ice cover. Shifting orbital parameters change the 
timing and angle of maximum sunlight at various locations which cause 
local warming. This causes the oceans to emit CO2 and tundra to emit 
methane. This increases warming due to atmospheric IR trapping and 
causes more warming. etc. It can act in reverse as well (cooling causes 
oceans to take up more CO2, sequesters methane, reducing greenhouse 
gases, etc.). As I understand it, the very small orbital changes occur 
too slowly (cycles of 96,000, 43,000 and 20,000 yrs) to account for the 
abrupt switch from ice age into interglacial (some papers seem to think 
this can occur in around 100 yrs). Only by including various feedbacks 
is there enough forcing to account for the 10C or so change between ice 
age and interglacial. Part of the connection between quantity of CO2 and 
amount of forcing due to CO2 is based on the amount of change in surface 
temperature during these switches. The orbital changes do not change the 
total annual average insolation so there has to be something else going 
on (i.e. feedback).

Also, if I am not mistaken, the Paleocene-Eocene thermal maximum 
occurred after the injection of carbon. But don't quote me on that.

kyle

Message: 4 Date: Tue, 12 Oct 2010 20:02:00 -0400 (EDT) From: Richard 
Tarara <rtarara@saintmarys.edu> Subject: Re: [Phys-l] Prof. Hal Lewis 
resigns from APS To: Forum for Physics Educators 
<phys-l@carnot.physics.buffalo.edu> Message-ID: 
<87748974.700261.1286928120055.JavaMail.root@zimbra.saintmarys.edu> 
Content-Type: text/plain; charset=utf-8 But the data--and the big 
misrepresentation in Gore's 'Truth'--seems to say the reverse. Gore's 
big chart clearly shows that the temperature rises preceed the rises in 
CO2, not the other way around. Hard to make the argument that increased 
CO2 causes warming from the historical data! Rick ----- Original Message 
-----

> >  Rick
> >  
> >  Hanson makes the argument in his "Grandchildren" book that we aren't
> >  relying on computer models when we say we know CO2 will raise the
> >  temperature. He says (I have not found the scientific paper) there
> >  were
> >  natural experiments in the geological past that show warming driven by
> >  CO2. One example he talks about (besides the feedbacks that pushed
> >  climate out of ice ages) was the Paleocene-Eocene thermal maximum.
> >  Hanson seems to think that a large injection of carbon into the
> >  atmosphere (the cause of which is poorly understood) resulted in a
> >  sharp
> >  6C global temperature increase.
> >  
> >  kyle

--
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 'Before you open your mouth, just remember,
  the empty wagon rattles the loudest.'
         -- my dad

  kyle forinash   812-941-2039
  kforinas@ius.edu
  http://Physics.ius.edu/
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