There's an interesting theory that explains these types of findings by the possibility of a polar shift -- the crust of the earth moving from temperate latitudes to the poles from time to time.
In Velikovsky's Worlds in Collision, he basically says that meteor or astroid strikes (or near strikes) may have knocked the earth of its axis in fairly short and violent order.
The earth constantly changes and Al Gore figures it is something bran new.
This could be the cause for current climate change. Who are they going to blame this on?