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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 omnicronx on 7/5/2010 1:40:24 PM , Rating: 2
I seriously doubt the US will ever switch. It's too engrained in the society and I don't see switching 300 million people from one system of measurement to another
The only problem I've ever had with this statement is that there are ALOT of Americans in which changing to metric would have little to no effect. I'm not meaning to profile, but how many people in the southern states for example know that there are 5280 feet in a mile? Or sadly 16 ounces in a pound?

This has always had more to do with politics than feasibility.. Nobody wants to be the guy that pulls the switch, it would be political suicide.

RE: When will the US catch up...
By Motoman on 7/5/2010 2:37:50 PM , Rating: 2
People may or may not know how many feet are in a mile, or what a furlong is, or how a nautical mile relates to a regular mile...

...but to say it won't effect them is absurd. All they know is pounds and ounces (even if some don't know there's 16 ounces in a pound) - so they compare products at the grocery store based on that. They know they weigh X number of pounds, that they are X'Y" tall, that their car's gas tank can hold Z gallons of gas, they can understand what 100 yards is, relatively speaking, but couldn't process 20 meters on and so forth.

It would be a HUGE change for EVERY person in America.

Not that I'm necessarily against it. I'd probably have a mildly hard time with it now...but I'd get along fine in short order. But to say that there are "ALOT" (note: not a word) of Americans to which such a change would have little or no effect is ridiculous.

RE: When will the US catch up...
By Ammohunt on 7/6/2010 3:06:03 PM , Rating: 2
I don't think you give Americans enough credit the metric system is taught and has ben for a long time in American schools and know how long it takes to travel 5km or buy a half kg of cheese.

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