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Saturday, November 14, 2009

Younger Dryas began in just few months

Research by scientists of the University of Saskatoon (Canada) has found that the arrival of the last cold phase of the late Ice Age, known as the
Younger Dryas stadial, took place in few months.

Submilimetrical slicing of fossil sediments at Lough Monreagh in Ireland showed that biological activity stopped within months, a year at most. It would be like taking Ireland and moving it up to Svalbard, in the Arctic Ocean, said led researcher William Patterson.

This is even shorter than the time suggested by less precise measurements in Greenland's ice sheet, that suggested an onset of the big freeze in one to three years.

It is believed that this cold period was triggered by melting of ice sheets due to global warming at the end of the Ice Age, causing the Gulf Stream, which keeps Europe quite warmer than normal for its latitude, to stop flowing. The Younger Dryas period lasted some 14 centuries, from 12,900 to 11,500 years ago.

Source: New Scientist.


Ken said...

I'm not sure about that explaination for the late Ice Age, Wikipedia entry and other sources say the Gulf Stream only adds a few degrees to the temperature of Britain, the warm climate is said to be the result of the wind.

Forget about the Gulf Stream: Britain is really kept warm in winter by the Rocky Mountains.

I suppose the wind patterns could have altered back then (and they might in the future).

Maju said...

Hmmm... it's a hypothesis (that I'd like to see explained in further detail before I take a stand). Western Winds anyhow follow the same path as the Gulf Stream more or less.

In my experience, the sea does indeed warm and cool depending on the season and does store warmth for the autumn and early winter.

And in my experience, regions closer to the ocean in Europe are both warmer and rainier than those to the interior. This has always been attributed to the warm and wet influence of the Ocean.

Those western winds are dominant here too and they normally bring fresh weather and rain. Only when the southern winds from the Sahara arrive it causes a significative warming. Dry cold instead is caused by the Siberian winds from the NE.

Air circulation anyhow doesn't seem to be something radically different from water circulation, right? Wouldn't there be a warm Ocean there the western winds would be cold.

Ken said...

It seems that what the scientific balance of opinion - 'it is believed' - is, depends on who is asked. The calculations about the rate and consequences of Global Warming ought to be presented with the warning that they have a very big stochastic element in that light.

If something as basic as the main trigger of the Younger Dryas is not agreed on one wonders what is. Global warming causing a rapid cooling in Europe might be more likely than any of the currently accepted predictions.