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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.
yeah....and also those who believe and show others that they know but really don't. They are the ones with the most degrees, usually.
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Good, I don’t have to sweat this amnesty bill then ...
We all die, eventually.
Chandler’s Wobble Causes Earthquakes, Volcanism, El Nino, and Global Warming
Michael Wells Mandeville | 2004 | Michael Wells Mandeville
Posted on 01/18/2005 11:58:05 PM EST by IGBT
http://www.freerepublic.com/focus/news/1323583/posts
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