[colorado tanker]

I agree with you guys. Of course it was warmer in the Pliocene. The characteristic of the beginning of the Holocene is our cycle of glacial and interglacial periods. Taking the climate as a whole we've been in a kind of ice age the whole time.

Most scientists think this happened when the isthmus of Panama closed blocking global ocean currents.

So, the pattern is unlikely to break until plate tectonics breaks up the North/South America land mass.

Aren't geologists supposed to know this stuff?

[muawiyah]

I think the closing of the Isthmus was about 7.5 million years ago and that coincides with the development of the present ice sheet on that continent.

The North American deal is more recent ~ 3 million years or so ~ and it moved into position to support year round ice and also to restrict the flow of warmer water into the Arctic ocean basin.