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The Woolly Mammoth  (Source: Corbis/Royal BC Museum, British Columbia)

Ancient humans hunted mammoths, which some think contributed to their extinction.  (Source: On Charcoal)

Researchers in a new study claim that the extinctions, possibly triggered by man, caused the birch trees to take over in regions of Siberia, causing a warming effect of as much as 1 degree Fahrenheit.  (Source: EW Birch Builders)
Mammoth extinction 10,000 years ago may have led to as much as a 1 degree Fahrenheit increase in temperatures

Christopher Doughty, a post-doctoral researcher at the Carnegie Institution for Science in Stanford, California, has led a team of researchers that has reached some controversial and unusual claims about mankind's role in changing the Earth's climate.

Doughty, in a paper published [PDF] in the journal 
Geophysical Research Letters, claims that the extinction of woolly mammoths may have triggered a cascade of effects warming Siberia and neighboring Beringia by at least 0.3 to 0.4 degrees Fahrenheit.  If these controversial claims prove true, it would likely be the first example of man influencing the world's climate in humanity's brief history as a species.

The report may change preconceptions about climate change, claims Doughty; "Some people say that people are unable to affect the climate, that it's just too big.  That's obviously not the case. People started to affect global climate much earlier than we thought."

Previous studies had indicated that mankind's development of agriculture 8,000 years ago could have changed the Earth's climate, but the effects of hunting in mankind's earlier days were not thought to have had significant impact.  The new study draws its basis from a previous study in the November 20, 2009 edition of the journal 
Science.  That study indicated that mammoths kept small trees in check, preserving grasslands.  With their extinction, the darker trees grew, increasing the overall darkness of the terrain, absorbing more solar radiation, and ultimately triggering a warming effect.

The issue with that study was that it posed a chicken-and-the-egg sort of conundrum; warming climates would encourage tree growth over tundra grasslands, but tree growth could also 
trigger warming.  Doughty claims in his new study that in the 850-year period where most of the mammoths disappeared from hunting, the levels of birch pollen increased by 26 percent.  Using modern elephant data, it was estimated that 23 percent of this increase came from the death of the mammoths, while the rest was caused by the heating trend itself.

The team then compiled vegetation loss findings and climate simulations to pinpoint how much of an impact the forestation increased had.  They found that it likely raised temperatures from 0.4 degrees F to the nearly 1 degree F.

Doughty admits in the study that it's not been conclusively shown that humans caused the extinction of mammoths in the first place (again, this is a chicken-egg riddle as warming climates could have pushed them to extinction, but their extinction could have warmed climates).  Man did hunt the beasts, and its the prevailing theory that we played at least a small role in their extinction.

The study was funded by NASA and the Carnegie Institution for Science.

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RE: When will the US catch up...
By Nfarce on 7/5/2010 4:02:12 PM , Rating: 3
I remember in 3rd grade (this is in the 70s, mind you) we had this BIG push in school to teach all the kids the metric system, because the USA was *going metric.*

Word up, fellow '70s childhood friend. I also remember the speed limit signs being posted with KHR numbers too. Even better we witnessed the transition on our automobile speedometers to also read KHR. The wildest speedometer that I ever had was in an '84 Z-28 which had one needle that pointed one at MPH and one at KPH on opposite sides, just like a compass needle.

But over the years I've learned distance and the metric system due to my experience with racing and flying (a meter is 3.28 feet, or roughly 3 feet 3 inches, and a kilometer roughly .62 miles). I've also learned the C vs. F difference, especially with PC building and overclocking: I know what 50 degrees Celsius vs. 58 degrees means to my CPU as the voltage goes up.

Now regarding weights, like grams, that's something I'll never get. I know how much a pound is and what 3,350 pounds means to a Nissan 370Z. Don't ask me what 1,600 kilograms means.

RE: When will the US catch up...
By SPOOFE on 7/5/2010 4:07:54 PM , Rating: 2
I learned the difference between metric and imperial by being a Star Wars dweeb back in the day: A Star Destroyer is 1.6 kilometers, or 1 mile, long. Makes many larger distance conversions easier to do in my head. :D

By LordSojar on 7/5/2010 6:07:49 PM , Rating: 2
Now regarding weights, like grams, that's something I'll never get. I know how much a pound is and what 3,350 pounds means to a Nissan 370Z. Don't ask me what 1,600 kilograms means.

Grams is a measure of how massive an object is (mass). Mass is a measure of just the material itself, not including gravity (weight is mass X gravity).

F=m*a, where F=weight, m=mass, and a=gravity (accleration)

So... to calculate weight in the metric system...

F=(mass)x 10 m/s^2. F will be expressed in Newtons.

Thus, a 1kg object weighs 10 Newtons.

"Nowadays you can buy a CPU cheaper than the CPU fan." -- Unnamed AMD executive

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