It Happened Before

It WILL happen again. It's just a matter of when. - Narrator (Chuck Heston), Armageddon

I don't think it's a stretch to say that The Day After Tomorrow might be one of the most ridiculous films ever made.  From a scientific viewpoint, I mean.  In a nutshell, the film is about a massive Ice Age that is brought on by global warming not over a period of centuries or millenia, but over a period of months or days.  The film was greeted with catcalls from those who think they know better.  Massive climate change just doesn't happen that way.

Except, ya know, maybe it does.

Turns out that the last mini-Ice Age called "The Big Freeze" or the Younger Dryas which occurred around 13,000 years ago may have gone from zero to freeze in a period as small as two months.  A bunch of Canadian scientists recently have completed some research in which they have determined that this particular mini-Ice Age was caused by switching off the North Atlantic circulation due to a large infusion of cold, fresh water into the Atlantic. 

This was caused by an ancient lake in Central Canada called Lake Agassiz which grew too fast and broke over it's banks into the Great Lake System and the St. Lawrence River basin.  All of that fresh water screwed up the circulation in the North Atlantic.  Warm water from the tropics that kept temperatures moderate in North America and Europe was suddenly mixed with cold water from Lake Agassiz and it flummoxed our entire weather pattern.  For 1,300 years or so.  And yes...flummoxed is a very scientific word. 

Why did Lake Agassiz, which was formed by melting Canadian glaciers, suddenly overflow it's banks?  Was it rapid global warming of the natural variety or was it caused by the explosion of a comet or meteor in the atmosphere somewhere above Central Canada?  These are questions that are being argued by minds much smarter than mine.  All I know is that it probably won't happen again.  Right?

Er, wrong.

You see, there is this massive ice shelf that covers Greenland.  Huge amounts of fresh water in glacial form that covers the entire island.  And it's melting.  At historic rates.  And it appears to be melting faster every year.  What if there is a sudden tipping point to the fresh water meltage rate that is currently pouring into the North Atlantic from Greenland?  What if the balance of the North Atlantic tropical circulation is about to break?  It would mean that the next Ice Age could be just around the corner.  It could mean that huge swaths of North America and Europe could be plunged into a deep winter that could last for a millennium. 

So...how you feeling today?

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Note: Remember to play the Bug-Eyed Trivia Challenge every day. Flummoxed is indeed a scientific term.