Ghost of a flea

End to snowball glaciation

The evolution of sea-critters with carbonate shells may have prevented "snowball glaciation" this last half-billion years or so through a regulatory effect on the oceans (via A Voyage to Arcturus).

The researchers used a computer model describing the ocean, atmosphere and land surface to look at how atmospheric carbon dioxide would change as a result of glacier growth. They found that, in the distant past, as glaciers started to grow, the oceans would suck the greenhouse gas -- carbon dioxide out of the atmosphere -- making the Earth colder, promoting an even deeper ice age.

When marine plankton with carbonate shells and skeletons are added to the model, ocean chemistry is buffered and glacial growth does not cause the ocean to absorb large amounts of carbon dioxide from the atmosphere.

Posted by Ghost of a flea at November 5, 2003 06:34 AM