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Re: Late Cretaceous Arctic Climates

I don't think that ice alone accounts for changes in climate. What is more, the mechanims that govern changes in ice and in climate are dynamically complex, and unstable.

Dora Smith
Austin, TX
----- Original Message ----- From: "David Marjanovic" <david.marjanovic@gmx.at>
To: "DML" <dinosaur@usc.edu>
Sent: Tuesday, July 28, 2009 3:45 AM
Subject: Re: Late Cretaceous Arctic Climates

 Collin... exactly what I'm talkin' about.  Eventually, the myth that
 "it was too warm in the Mesozoic for ice" will melt away.

 Interestingly enough, there's been quite a stir lately in the
 climatology world about how climate models are really, really
 terrible at handling CO2. If we can't get it right for today's and
 "recent" ice-age climates......

Hang on a second. How much ice is necessary to account for the sea-level changes? Does that amount really necessitate inland ice, or are mountain glaciers (like those in southern Alaska which reach the sea through a temperate rainforest) enough to explain the sea-level changes and the Australian glacier sediments?

The sea level is supposed to have changed by 25 m, right? 22 m is the difference between today and 400,000 years ago when Greenland and West Antarctica were ice-free. Is there a way to distribute that much ice over the high-altitude and high-latitude mountains of the Early Cretaceous world?

Finally, how much CO2 was there really in the air in the EK? Some proxies consistently give way too high numbers (for the Cenozoic at least), and the best one -- counts of stomata in *Ginkgo* and *Metasequoia* -- doesn't go that far back.