What triggers ice ages? still a puzzle

Have you seen the movie Ice Age? Funny and cute. But the real thing happened. So...

What triggers ice ages?: "by Rasmus Benestad, with contributions from Caspar & Eric

In a recent article in Climatic Change, D.G. Martinson and W.C. Pitman III discuss a new hypothesis explaining how the climate could change abruptly between ice ages and inter-glacial (warm) periods. They argue that the changes in Earth's orbit around the Sun in isolation is not sufficient to explain the estimated high rate of change, and that there must be an amplifying feedback process kicking in. The necessity for a feedback is not new, as the Swedish Nobel Prize winner (Chemistry), Svante Arrhenius, suggested already in 1896 that CO2 could act as an amplification mechanism. In addition, there is the albedo feedback, where the amount of solar radiation that is reflected back into space, scales with the area of the ice- and snow-cover. And are clouds as well as other aspects playing a role.


Martinson & Pitman III's hypothesis states that the fresh water input works in concert with the Milankovitch cycle and the albedo feedback. They conclude that 'major' terminations can only follow fr"