March 1, 2004

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  Supervolcanoes could trigger global freeze
  

  
  

  
  

  
  
  

  
  
  
  

  Heat rises from under Yellowstone Park

  
  

  
  By environment correspondent Alex Kirby
  
  Geologists say there is a real risk that sooner or later a supervolcano will erupt with devastating force, sending temperatures plunging on a hemispheric or even global scale.
  
  A report by the BBC on one supervolcano, at Yellowstone national park in the US, says it is overdue for an eruption.
  
  Yellowstone has gone off roughly once every 600,000 years. Its last eruption was 640,000 years ago.

  
  

   

  
  

  "When a supervolcano goes off, it is an order of magnitude greater than a normal eruption. It produces energy equivalent to an impact with a comet or an asteroid."  There have been two such events every 100,000 years for the last two million years.  
  
  "The eruption throws cubic kilometres of rock, ash, dust, sulphur dioxide and so on into the upper atmosphere, where they reflect incoming solar radiation, forcing down temperatures on the Earth's surface. It's just like a nuclear winter.

  
  

  "The effects could last four or five years, with crops failing and the whole ecosystem breaking down. And it is going to happen again some day."

  
  

   

  • 12:55 pm
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