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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 Murloc on 7/5/2010 1:18:03 PM , Rating: 2
you teach it in the schools and impose that all the new scholars will use the metric system from now.

Eventually the other system will go extinct.

You can still use the imperial system to measure your garden and how large your door has to be, but you begin by using the international system in scientific papers, the rest will come.


RE: When will the US catch up...
By omnicronx on 7/5/2010 1:45:05 PM , Rating: 2
quote:
You can still use the imperial system to measure your garden and how large your door has to be, but you begin by using the international system in scientific papers, the rest will come.
Exactly, even in countries that use the Metric system, this still happens. Construction for example is a field where the imperial system is still used in many countries. I.e a 2x4 is still a 2x4 ;) Everything for the most part is still measured in inches.

Another Example is with Scales (KG may be the secondary measure, but the default is still pounds)


By Arlosaurus on 7/6/2010 11:59:29 AM , Rating: 2
But a 2x4 isn't actually 2x4 now is it? We all know that a 2x4 is actually 1.5 in × 3.52 in or 38 mm × 89 mm.

You can't justify a mesurement system with an example that is a label and not a actual measure.


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