Friday, 19 October 2012

Interglacial climatic instability - an introduction


I am sure many of you have seen or at least heard of the movie "The Day After Tomorrow". For those of you who haven't, here is a short summary...

A paleoclimatologist Jack proposes a theory that anthropogenic global warming has caused a major melting of polar ice, which in turn disrupts the North Atlantic current and will lead to a major fall in temperatures over the next few hundred or thousand years. Jack turns out to be slightly wrong with his predictions, a new ice age hits the Earth within a week and this is how our planet ends up looking:


There is also a love story and a (relatively) happy end, but the apocalyptic vision of the Earth's abrupt climate change is what I want to draw your attention to.

The response of the scientific community to the film can be summed up in the words of Andrew Weaver from the University of Victoria: "I'm not losing any sleep over a new ice age, because it's impossible"... but surely the film director must have got the idea of such a sudden cooling event from somewhere?

The history of our planet has plenty of examples of rapid climate fluctuations, most of which fit into a roughly 1500 year cyclical pattern. This pattern is known as Bond cycles when referring to Holocene, or Dansgaard-Oeschger cycles in the context of the last glacial. Not being as extreme, perhaps, as shown in the movie, some of these events can still boast an 8 degrees increase in temperature over just 40 years!

In this blog I am going to look at the science behind Holocene abrupt climate change events, explore and critically assess various hypotheses for their occurrence, see what impact they had on human populations so far and, finally, try and predict how likely are we to experience such a rapid climate change event in the future. I really hope you will enjoy this blog and will greatly appreciate any feedback you may have for me!

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