The Big Frosty

It might surprise you to know that we are in an ice age.

Have been for the last 3 million years or so. Currently we are in a short warm period between ice advances. The last advance of the ice ended about 10,000 years ago. At that time the ice sheets were near the Ohio river and our part of the world was much cooler than now. The BIG question is when will the next ice advance start? Most recent interglacial periods have lasted around 10,000 years..So this one may be getting long in the tooth.

Visible life appeared on Earth about 600 million years ago in a period of Geological time called the Cambrian.. For most of that time, the earth has been a very warm place. Sea levels were much higher than they are now and Alabama and much of North America was under water much of the time.

For some reason earth started cooling about 50 million years ago. This almost certainly had to do with Antarctica drifting over the South pole. Ice ages do not spontaneously develop when a continent is over a pole, but it is thought that they DO NOT happen when there is not one there.
So!
When there is a continent over the pole we have a series of glacial advances and retreats.
There are some good theories about why this is happening, but there is no consensus. (See my blog on Milutin Milankovitch).

The PBS program NOVA has a great Ice age fact sheet online.

It's called:

The Big Chill

(Here's to NOVA, one of the best science programs in North America)

Here is another link to
Continents adrift


Many global warming doubters use these facts to say that global warming is a fallacy. That we should be more concerned about keeping warm!
This is almost certainly bad logic and in the next blog I will tell you why.

More later,
Dan