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New Ice Age Theory
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."
No one tries the old venerable "Frost Post"
This guy's theories are all wrong. Obviously people are causing the 100,000 - 41,000 year cycles. Someone should take away his meterology license...
The party of stupid and the party of evil get together and do something both stupid and evil, then call it bipartisan.
So the new model is heliocentric instead of geocentric. I thought we made this switch centuries ago.
sophism [sof-iz-uhm] -noun
a specious argument for displaying ingenuity in reasoning or for deceiving someone, e.g. beginning with a conclusion and finding reasons to justify it, regardless of where the evidence points.
shouldn't that be:
that's like writing
THE EARTH IS FLAT!!!! according to some guy somewhere.
instead of
some guy somewhere thinks the earth is flat!!
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). He suggests that the 100 ky cycle isn't real, and just an effect we see from skipping some thaws. This is supposedly supported by oxygen isotope measurements, but I'm not enough of a geochemist to verify that.
I thank God the scientists keep looking for patterns and physics to try to explain what we see in the geologic and solar record & current observations of the sun, as that is the ONLY WAY we will ever have a chance of really knowing what long term cycles are caused by. There may be 50 models and theories, but it will likely be a stew of dozens of researchers that finally get a theory that is solid enough to be verified and called a Proof, or tentative Proof.
Fact is, no one can yet show a proof of why, but we do know that Ice ages occurred dozens of times and when, but we can not yet prove what the underlieing factor is that causes the repetition (excluding the major "accidental" supermassive volcano or mega-asteroid).
That is what true science is for, which is to keep digging, sometimes literally, until you uncover the data and principals that can be independently verified and eventually acknowledged as fact.
But that is not convenient for politicians who want power, and bureaucrats who can manage whole new divisions of government if they get funding to try to act on something with the citizens money, when there is only speculation as to what is going on and to what degree, let alone whether we can actually do anything about it.
"The climate depends more on atmospheric composition than on any variation in the sun or even our proximity to it. That's why venus is hotter than mercury."
That's less "difference in atmospheric composition" and more "has an atmosphere or not."
One competing viewpoint with this theory is that these events were caused by a solar "Clapper" which flipped the sun when bombarded with echoes and reverberations from the big bang. This non-viewpoint is endorsed by non-dimmer switch oriented non-scientists but these non-scientist find it more plausible...in lots of ways.
Yeah, it definitely could be a combination of all manners of cycles. That's the thing about climate shifts- there are so many variables interacting, that some interact in very different ways. I wrote a summary paper a few years ago for a seminar about a theory of frequency modulation of the Milankovitch cycles to help solve some of the classic Milankovitch "problems". Here's a link for it: http://www.sciencemag.org/cgi/content/abstract/285 /5427/564. Looking at the followup research, Dr. Rial has done both frequency modulation to see what he can do with the three main Milankovitch cycles (that being orbital eccentricity (changing in how "oval" the Earth's orbit is, every 100,000 and 400,000 years), planetary precession (changing the location of the seasons, so that the Northern Hemisphere winter moves from January to January over the course of 21,000 years) and the planet's obliquity (changes in the tilt of the earth from 22.5 degrees to 24.5 degrees, over a course of 41,000 years).
Through this frequency modulation, he was able to produce a signal very close the delta-O 18 ratios found for the Vostok core in Antartica. His theory also was able to "demodulate" the Vostok core to get peaks at 41kyr (kyr = 1000 years), 100kyr, and 21kyr as predicted by the classic Milankovitch cycles.
While these solar fluctuations may exist (and I'm not an astronomer, just a meteorology/atmospheric science/climatology PhD student) I'd prefer to firm them up before they replace the classical orbital mechanisms that we know exist. Whether they cause the Ice Ages or not, they are present in the orbital path.
>> a model which hypothesizes a dimmer switch inside the sun
No, seriously? That must be how they get it to be all dark and stuff at night.
Yes, the Himalayas are the youngest mountain ranges on earth, but the timescale is still way too long to explain the occurence of ice-age cycles.
We actually did a simulation using a coupled GCM to remove the Tibetan pleateau all together, to see its influence. The result was that some aspects of the current climate system, for example the Asian monsoon, or the western Pacific warm pool has weakened dramatically. The jet stream did change dramatically, but that alone was not enough to trigger a continental ice sheet.
We then changed the orbital parameters to see which impact is greater. The result was that a slight change in orbital parameters is far efficient in changing the northern hemispheric surface temperature in the order of 7-8 degC.
So the parent is correct in some respect. I guess he just didn't bother to explain in detail.
I was wondering why he kept sending his annoying employees to ask me for money.