Volcanoes and the Little Ice Age

We wrote in SuperFreakonomics about how past volcanic eruptions have resulted in a temporarily cooler planet, thanks to the release of sulfuric ash into the atmosphere. New research indicates that a series of volcanic eruptions may have caused the Little Ice Age:

The study, led by the University of Colorado Boulder with co-authors at the National Center for Atmospheric Research (NCAR) and other organizations, suggests that an unusual, 50-year-long episode of four massive tropical volcanic eruptions triggered the Little Ice Age between 1275 and 1300 A.D. The persistence of cold summers following the eruptions is best explained by a subsequent expansion of sea ice and a related weakening of Atlantic currents, according to computer simulations conducted for the study.

According to Bette Otto-Bliesner, one of the study’s co-authors, the volcanic eruptions may have “triggered a chain reaction”:

The model showed that sustained cooling from volcanoes would have sent some of the expanding Arctic sea ice down along the eastern coast of Greenland until it eventually melted in the North Atlantic. Since sea ice contains almost no salt, when it melted the surface water became less dense, preventing it from mixing with deeper North Atlantic water. This weakened heat transport back to the Arctic and created a self-sustaining feedback on the sea ice long after the effects of the volcanic aerosols subsided, according to the simulations.

(HT: Naked Capitalism)

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  1. Allen Hughes says:

    Hidden due to low comment rating. Click here to see.

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    • James says:

      Change “scientist” to “denialist”, and “government” to “oil company”, and you’d have a semi-accurate statement instead of a load of organic fertilizer :-)

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  2. John Caro says:

    I don’t believe in global warming because of things I have read or heard. I believe in global warming because of the 15 foot tall wild palm trees now growing in my back yard. My mother was a botanist who showed me the “Palm Tree Line” That is the line about 100 miles south of our home in Florida that was warm enough for palm trees to grow wild. In 50 years the “Palm Tree Line” has moved north about 100 miles. Every time any thing about global warming comes up on the internet the first comments are by someone or some automatic program spouting nonsense. The penalty for believing nonsense is very harsh. BE CAREFUL WHAT YOU BELIEVE

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    • Wow says:

      All I can say is, wow. So your argument is a “Palm Tree Line”? How about you take a look at all of the ice that has melted in the last 50 years; or all of the statistics on how much impact we have had on the climate. So your comment about not believing in global warming, then believing in global warming because you have a 15 foot tall palm tree growing in your back yard? You are obviously reading the wrong things.

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