Slashdot Mirror

← Back to Stories (view on slashdot.org)

New Ice Age Theory

Posted by samzenpus on from the why-is-it-so-cold dept.

amigoro writes "Most believe that the ice ages are the result of subtle changes in Earth's orbit, known as the Milankovitch cycles. According to one scientist, that is not the case. Robert Ehrlich of George Mason University in Fairfax, Virginia, has developed a model which hypothesizes a dimmer switch inside the sun that causes its brightness to rise and fall on timescales of around 100,000 or 41,000 years, exactly the same period as between ice ages on Earth. The main problem with Milankovitch cycles is that they can't explain how the ice ages go from 100,000 year cycle to 41,000 year cycle. The cycles predicted by Ehlrich's model line up with the observations."

2 of 272 comments (clear)

  1. Re:Ice Age Frequency by DerekLyons · · Score: 0, Flamebait
    It's a neat idea. Are there any observations to support it? Peter Huybers from MIT just presented an alternative model which explains the 40 ky - 100 ky switch nicely without resorting to solar fluctuations. The basic idea is that you start out with ice ages every 40 ky, but at some point the ice accumulation retards heating, and one or even two thawing cycles get skipped. This gives you longer cold periods and a warm period every 80 ky or 120 ky. If you randomly distribute cycles with these two intervals, you can get a peak at 100 ky (but you can't just superimpose the sine curves with those two frequencies).

    How precisely does Huybers model not depend on solar fluctations? His model, as described by you, is merely a frequency analysis of existing data - not really a model as it fails to describe what drives the sine waves. (Furthermore such statements as "you can't superimpose the sine wave" and "randomly distribute the cycles" are somewhat disturbing - it sounds like he trying to make his 'model' match reality without actually modeling anything.)
  2. So basically, he has nothing by GreyFlcn · · Score: 0, Flamebait

    So basically he has nothing to back his arguement.

    "I found this trend on the period of ice ages"
    That's reasonable.

    "And it's caused by something I have absolutely no data for. I'm just guessing"
    That's stupid.

    He might as well blame it on Santa Claus,
    and it'd have the same scientific validity.