Little Ice Age


Little ice age
. NASA defines the term as a cold period between AD 1550 and 1850

“The period between 1400 and 1850 was marked by an average temperature drop of just less than 1 degree C (1.8 degrees F), but not just in the Northern Hemisphere. Scripps graduate student Anais Orsi and colleagues found evidence of the same cooling trend in samples of ice from the West Antarctic Ice Sheet. That contradicts prevailing theories that the Little Ice Age was not globally synchronized, but a regional cooling possibly triggered by changes in ocean circulation that created a temperature see-saw effect between the hemispheres.”

QUOTE from

Thanks to
JAMIE JESSOP and his google blog for linking this interesting info’


2 comments on “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.
    The study, which used analyses of patterns of dead vegetation, ice and sediment core data, and powerful computer climate models, provides new evidence in a longstanding scientific debate over the onset of the Little Ice Age. Scientists have theorized that the Little Ice Age was caused by decreased summer solar radiation, erupting volcanoes that cooled the planet by ejecting sulfates and other aerosol particles that reflected sunlight back into space, or a combination of the two.
    “This is the first time anyone has clearly identified the specific onset of the cold times marking the start of the Little Ice Age,” says lead author Gifford Miller of the University of Colorado Boulder. “We also have provided an understandable climate feedback system that explains how this cold period could be sustained for a long period of time. If the climate system is hit again and again by cold conditions over a relatively short period—in this case, from volcanic eruptions—there appears to be a cumulative cooling effect.”
    What it says: The Little Ice Age was initiated by a series of volcanic eruptions then ocean circulation and sea ice changes caused a positive (ie cooling) feedback that lasted for centuries.
    more from the link below
    thanks to for this link

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