Geography and global climate

BBC NEWS | Science/Nature | Fossil gives clue to big chill

The above article points out that the disconnection of South America from Antartica some 41 million years ago is believed to have played (and still play) a very large part in the global climate:

The world was a very different place then. Levels of carbon dioxide were three to four times today's levels and it was so warm that alligators sunned themselves in the high Arctic.

But some 30 million years ago, there was a dramatic shift in climate from "greenhouse" to "icehouse".

The rapid cooling swept over the Antarctic and, over the course of several million years, its pine trees were replaced by glaciers.

Interesting. Global warming is obviously good for alligators and pine trees. Pity polar bears and penguins are so cute.