Posted on 10/11/2006 11:43:56 PM PDT by MadIvan
If you are the kind of person who worries about the future, this might not make happy reading.
Scientists have found that on average mammal species enjoy only 2.5 million years of life before being wiped out because of the Earth's "wobble."
They say when the tilt and orbit reach key points it can spark dramatic global cooling - and the last time this happened was 2.6 million years ago.
This suggests we are overdue a wave of extinction.
However, before you panic, scientists say our planet has changed beyond all recognition in the last 3 million years.
The new research published in the journal Nature (must keep) however sheds new light on just why individual mammal species seem to come and go with mysterious regularity.
The study, conducted by researchers at Utrecht University in the Netherlands, involved looking at 22 million years of data on rodent species to see which ones appeared and died out at key points.
They then studied the pattern of the Earth's wobble, which is caused by two factors, our orbit around the sun and the tilt of the planet.
Both of these can be slightly altered by the gravitational pull of other planets, in the case of the tilt it can adjust by as much as two degrees, and the orbit can vary from a circle to an ellipse.
Lead researcher Dr Jan van Dam said when the tilt reaches a certain point and the orbit is almost a perfect circle it can trigger ice sheet expansion.
This could then lead to colder summers, changes in humidity and significant climate cooling.
He found a clear pattern between the Earth's wobble and mammal species dying out.
There were two distinct cycles of species turnover, one with peaks every 2. 5 million years and the other every million years.
Dr van Dam said the last peak was 2. 6 million years ago.
However he said this does not necessarily mean we are on the brink of dramatic global cooling.
'The last three million years are not representative of those we studied,' he said.
"Northern hemisphere glaciation is fully developed and that also affects the climate system."
He said global warming and destruction of habitats could also change the patterns of the past.
He also thinks people may well be able to survive global cooling, give the way our ancestors coped with past Ice Ages.
"Humans have survived ice ages which were quiet extreme and are well adapted to survival," he said.
Based on the fossil record it appears on average we have lost around 10 to 100 species - including insects, bacteria, fungi and mammals - each year.
There are currently around 5,000 known species of mammal at present and in the past 400 years 89 mammals have died out.
"He made a mistake by giving a specific timetable"
Exactly! This global warming stuff that Gore is talking about is kind of like saying that we are in global warming because July is warmer than January to it's getting warmer on earth. The earth has seasons, just as our solar system and the galaxy has seasons. No need to cry out that the sky is falling!
This sounds like a croc. The only wobble I am aware of is what they call the "precession of the equinoxes" which the earth goes though about every 26 thousand years. The axis wobbles like a top that has slowed down.
Well sure. It gets a little colder we make more muskrat coats, beaver hats and bunny slippers. Of course the rodent populations are going to be affected.
Thanks for the heads up! I'm after buying up some beachfront property in the Himalayas!
can we panic now?
"If the Earth wants to lose humanity, all it has to do is fart". A saying I read somewhere, although I can't remember once.
One of the reasons I don't buy into global warming is simply that the Earth does a lot more by itself than we could manage in millenia of oil-burning.
And, hell, if we're all going to die due to the wobble anyway, why do we care about global warming in any case?!
BUMP
Bush Did it.
love.
This time around we'll have jackets to wear.
"So if I start my Alaskan seal farm now, I'll have enough pelts to make a killing?"
Doogle
Do as you like, but I am not going to drink the Kool Aide tomorrow.
7:07am...first laff-o-the-day .... I's thanks you
There was a science fiction story ("Fallen Angels", by Niven & Pournelle), what posited that we were overdue for an Ice Age, and the only thing holding it off had been global warming. So when the enviro-weenies finally won ...
I just got off the phone with Al Gore.
He said the is also a man made problem due to gravitational pull of water spinning in toilets in the northern hemisphere.
His said Global "Turd Spin Cooling" is our next, most critical problem to resolve. He wants everyone to lighten their load, or shall we say our "Turd flush footprint".
Well, that settles it. We need to outlaw hybrids and require everyone drive a Suburban to get enough CO2 in the atmosphere to prevent this from happening.
I don't keep up technically the way I used to when I worked professionally, but as far as I knew that theory of pole reversal has never been refuted.
I find it curious that no one in the pop science world has ever written extensively about it. It seems odd to me that something which has the potential to wreak all sorts of havoc on civiization is simply ignored; maybe it's because one can't blame anyone for the situation.
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