Climate Record From Bottom of Russian Lake Shows Arctic Was (8°C) Warmer Millions of Years Ago

[Yo_Mama]

6. They were. The current ice age is relatively "young"

The Earth has gone through long cycles of warming and cooling before. We are currently in a cool cycle, or an ice age, in which relatively brief periods of warming occur between longer colder stretches with very significant ice sheet expansions.


As the first graph shows, the Earth started cooling millions of years ago and steadily cooled for millions of years. It has done this before, and the current cool cycle is not the coolest such cycle known.

http://news.discovery.com/earth/oceans/snowball-earth-ocean-mixing-130307.htm

One of the theories about the current ice age is that the Tibetan uplift caused a long term change in the Earth's albedo, creating a cooling bias (as an ice/snow cap formed on this area). I think that's wrong, but who really knows.