Hi John Clark 

I suppose then that the cave men ended the last ice age and
began warming the earth again by driving big gas guzzlers.


Roger Clough, rclo...@verizon.net
9/17/2012 
Leibniz would say, "If there's no God, we'd have to invent him 
so that everything could function."
----- Receiving the following content ----- 
From: John Clark 
Receiver: everything-list 
Time: 2012-09-16, 12:43:12
Subject: Re: Before the automobile: Reconstructed global temperature over 
thepast 420,000 years


On Sun, Sep 16, 2012 at 1:44 AM, meekerdb <meeke...@verizon.net> wrote:



> In fact it [CO2] has been less than half the current level during the last 
> 600 thousand years

There have been at least 4 times in the last 600 thousand years when the CO2 
levels were nearly as high as they are now. And the link between CO2 and 
temperature is far from clear. During the late Ordovician period 450 million 
years ago there was a huge amount of CO2 in the atmosphere, about 4400 ppm 
verses 380 today, and yet the world was in the grip of a severe ice age. During 
the last 600 million years the atmosphere has almost always had far more CO2 
than now, abut 3000 ppm on average. The only exception was a period that lasted 
from 315 million years ago to 270 where there was about the same amount of CO2 
as we have now. The temperature was about the same then as it is now too, and 
during the late Ordovician that I mentioned before it was much colder, but 
other than a few very brief ice ages during the last few million years the 
temperature has always been warmer than now.



> But it is not just the level that is worrisome, it is the rapidity of 
> increase, which would appear as instantaneous on the paleoclimate studies.

If you adjust the scale of a graph you can always make a gentle rise look like 
a near vertical wall. 


?>> And I think people sometimes forget that CO2 is not the most important 
greenhouse gas, water vapor is
?
> But water vapor equilibrates with ocean temperature very quickly, whereas CO2 
> takes hundreds of years to come into equilibrium.? Water vapor is the most 
> important green house gas, but it acts as a positive feedback, amplifying 
> other warming (or cooling) effects.

?
If water always produced positive feedback then with all the water on this 
planet life would never have existed in the first place, but things are more 
complicated than that. Let me ask you something, if the world's temperature 
increases will that create more clouds or fewer clouds? It's a very simple 
question with profound consequences because clouds regulate the amount of solar 
energy that runs the entire climate show. Increased temperature means more 
water evaporates from the sea, but it also means the atmosphere can hold more 
water before it is forced to form clouds. So who wins this tug of war? Nobody 
knows, its too complicated. Water vapor is a far more powerful greenhouse gas 
than CO2 and unlike CO2 it undergoes phase changes at earthly temperatures, it 
can be a solid a liquid or a gas which makes it much more complicated than CO2 
which is always just a gas, at least on this planet. ? 

And then there is the important issue of global dimming, the world may be 
getting warmer but it is also getting dimmer. For reasons that are not clearly 
understood but may be related to clouds, at any given temperature it takes 
longer now for water to evaporate than it did 50 years ago.

? John K Clark










-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To post to this group, send email to everything-list@googlegroups.com.
To unsubscribe from this group, send email to 
everything-list+unsubscr...@googlegroups.com.
For more options, visit this group at 
http://groups.google.com/group/everything-list?hl=en.

-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To post to this group, send email to everything-list@googlegroups.com.
To unsubscribe from this group, send email to 
everything-list+unsubscr...@googlegroups.com.
For more options, visit this group at 
http://groups.google.com/group/everything-list?hl=en.

Reply via email to