Community | December 02, 2009 | 29 comments

The "Little Ice Age" 12,800 Years Ago was Triggered in Months, Not Decades

source: http://www.dailygalaxy.com/my_weblog/2009/12/little-ice-age-12800-years-ago-was-triggered-in...

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http://www.dailygalaxy.com/my_weblog/2009/12/little-ice-age-12800-yea...

William Patterson, from the University of Saskatchewan in Canada, and his colleagues have shown that switching off the North Atlantic circulation can force the Northern hemisphere into a mini 'ice age' in a matter of months. Previous work has indicated that this process would take tens of years.

Around 12,800 years ago the northern hemisphere was hit by a mini ice-age, known by scientists as the Younger Dryas, and nicknamed the 'Big Freeze', which lasted around 1300 years. Geological evidence shows that the Big Freeze was brought about by a sudden influx of freshwater, when the glacial Lake Agassiz in North America burst its banks and poured into the North Atlantic and Arctic Oceans. This vast pulse, a greater volume than all of North America's Great Lakes combined, diluted the North Atlantic conveyor belt and brought it to a halt.

Without the warming influence of this ocean circulation temperatures across the Northern hemisphere plummeted, ice sheets grew and human civilisation fell apart.

Previous evidence from Greenland ice cores has indicated that this sudden change in climate occurred over the space of a decade or so. Now new data shows that the change was amazingly abrupt, taking place over the course of a few months, or a year or two at most.

Patterson and his colleagues have created the highest resolution record of the 'Big Freeze' event to date, from a mud core taken from an ancient lake, Lough Monreach, in Ireland. Using a scalpel layers were sliced from the core, just 0.5mm thick, representing a time period of one to three months.

Carbon isotopes in each slice reveal how productive the lake was, while oxygen isotopes give a picture of temperature and rainfall. At the start of the 'Big Freeze' their new record shows that temperatures plummeted and lake productivity stopped over the course of just a few years. "It would be like taking Ireland today and moving it up to Svalbard, creating icy conditions in a very short period of time," says Patterson, who presented the findings at the European Science Foundation BOREAS conference on humans in the Arctic, in Rovaniemi, Finland.

Meanwhile, their isotope record from the end of the Big Freeze shows that it took around two centuries for the lake and climate to recover, rather than the abrupt decade or so that ice cores indicate. "This makes sense because it would take time for the ocean and atmospheric circulation to turn on again," says Patterson.

Looking ahead to the future Patterson says there is no reason why a 'Big Freeze' shouldn't happen again. "If the Greenland ice sheet melted suddenly it would be catastrophic," he says.


http://www.dailygalaxy.com/my_weblog/2009/12/little-ice-age-12800-years-ago-was-...
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29 comments // The "Little Ice Age" 12,800 Years Ago was Triggered in Months, Not Decades

  • mckcall
    • 0
      mckcall  

    • I think it's funny that people keep going on about saving the planet.
      The planet will always be here, no matter what.
      The whole global warming thing is about saving us, the human race.
      We are the ones that need saving, from ourselves.

    • 3 years ago
  • MajorMajorMajorMajor
  • stonefree87
    • 0
      stonefree87  

    • Damn global warming. Those ancient people 12,800 years ago should have seen it coming with all those fossil fuels they were recklessly burning.

    • 3 years ago
  • Rubens_Diman
    • 0
      Rubens_Diman  

    • ...one thing lid's to another...chain reaction, with no hope for reversal...NEW WORLD ORDER in the making for real is eminent!!! All the the segments are there to make a firm "base-ground" for it!!! ALL WE NEED IS LOVE and whap pa rubba daaaa!!

    • 3 years ago
  • frimer
  • Lurkistan
  • maurajriordan
  • ras_menelik
  • RoxieLeigh
    • 0
      RoxieLeigh  

    • As long as Earth is in an icehouse period an ice age is possible it is just the way the planet works .. I doubt Earth is going change its habits just to accommodate humans .. it wasn’t to accommodating to the dinosaurs.. if it happens it happens.

    • 3 years ago
  • wowfan2009
  • good_stuff
    • 0
      good_stuff  
    • Image

    • See the map for tempretures over the last 400,000 years. Ice ages occur many times and show no sign of slowing. We are currently in a pretty high tempreture period. Perhaps global warming would be helpful to the survival of the human race?

    • 3 years ago
  • Alex_Ram
    • 0
      Alex_Ram  
    • good_stuff:

      I'm not entirely sure how serious you are by that final question. The mentioned Ice Age was caused by increased freshwater caused by increased melting caused by increased temperatures. Get educated.

    • 3 years ago
  • echoz
    • 0
      echoz  
    • good_stuff:

      if it's not a "serious" question then all the nonanswers must be at least as flippant as the question so dismissed. Scientists who've proposed this very hypothesis have met with much the same, though SETI and other "questionable" purposes remain untouchable...the blind irony abounds.

    • 3 years ago
  • mindcruzer
  • Lurkistan
  • good_stuff
    • 0
      good_stuff  
    • good_stuff:

      Yes, it is kinda backwards, since time increases from right to left on the graph. It is all relative though, and just a matter of how the info is presented.

      I guess you could look at the graph in a mirror if that makes you more comfortable.

    • 3 years ago
  • RoxieLeigh
  • ny_nj_soulchild
    • 0
      ny_nj_soulchild  

    • This is interesting enough...So what we were worried about was a huge flood but it turns out to be another ice age. In that case...Didn't ADAM YAMAGUCHI go to GREENLAND...ILLULISAT and report about global warming? He did shed some light about how rapidly the glacier is breaking apart over there.

      Im going to watch that again and put this article into perspective....

    • 3 years ago
  • tommic
    • 0
      tommic  

    • Maybe people should start to be alarmed that the Gulf Stream is slowing, that if it stops so does the ocean currents that brings warmer weather to the northeast United States and northern Europe. By the way its not global warming its climate change.

    • 3 years ago
  • Mike_Johnston
    • 0
      Mike_Johnston  

    • There is a lot of evidence that it was a meteor/comet impact that caused everything that happened 12,800 years ago. The impact is thought to have been in North America and to have been the cause of the extinction of the megafauna like mammoths that existed at the time.

      What makes this rapid climate change theory interesting is that it is supported by all of the frozen mammoth carcasses in Siberia. The animals died and froze suddenly and many pseudoscience theories have been put forward over the years to explain why these temperate region animals suddenly died en-masse in an arctic region..

      Now that we know about the comet impact/detonation and the resulting rapid climate change that ensued it all makes sense. They died because their formerly temperate environment suddenly changed and they couldn't escape.

      Also interesting from this perspective are the global flood stories. The comet impact would have caused immediate destruction and the climate change more. The oldest man made temple dates back to 12,800 years ago (in Turkey) and weirdly enough Plato's Atlantis story happened (according to the story) 9,000 years before his time which would put it right around 12,800 BC. There may be a lot more to learn from old legends as new science starts to shed some light on previously unknown events...

    • 3 years ago
  • dancore
    • 0
      dancore  
    • Mike_Johnston:

      what peer reviewed scientific journal was these findings of a meteor impact published in?? a reference would be helpful.

      This disruption of the circum-haline cycle n the atlantic ocean was originally proposed by Wally Broeker from Columbia in the early 90's (or around that time) and a lot of workhas been done on it; but we've never discussed anything about any meteorites in any of my classes....

    • 3 years ago
  • Mike_Johnston
  • schobiz
  • echoz
    • 0
      echoz  
    • schobiz:

      ...since birth, you may recall. Insightful nonetheless. Thanks schobiz.

      "Science says the first word on everything, and the last word on nothing."
      --Victor Hugo, Things of the Infinite...

    • 3 years ago
  • KevinFederline
  • CalgarC
    • 0
      CalgarC  

    • we burn up all the ice and the water, the planet becomes unstable, so it freezes up gains stability, then humans just shrug their shoulders and continue to fuck up the planet...

    • 3 years ago
  • krazykizza
  • Lurkistan
    • 0
      Lurkistan  
    • krazykizza:

      No kizza what its saying is that if the Earth warms and melts the arctic ice too fast, this might mess up the ocean currents and cause another ice age. So if the Earth heats up too fast it could actually cause an ice age that could happen in a matter of months, rather than over a few decades.

    • 3 years ago
  • asherp
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