Posted on 05/24/2010 5:46:13 PM PDT by Free ThinkerNY
The rapid decline of mammoths and other megafauna after humans spread across the New World may explain a bone-chilling plunge in global temperatures some 12,800 years ago, researchers reported Sunday.
The 100-odd species of grass-eating giants that once crowded the North American landscape released huge quantities of methane -- from both ends of their digestive tracks.
As a heat-trapping greenhouse gas, methane is 30 times more potent than carbon dioxide (CO2).
It was not enough to trigger runaway global warming. But when all that gaseous output suddenly tapered off, it caused or at least contributed to a prolonged freeze known as the Younger Dryas cold event, they argue.
If so, the "Anthropocene epoch" -- the era of major human impacts on Earth's climate system -- began not with the industrial revolution in the 1800s, but the large-scale influx of two-legged predators to the Americas more than 13,000 years earlier.
Calculations by a trio of researchers led by Felisa Smith of the University of New Mexico, published in Nature, show how all the pieces of this previously unsolved puzzle might fit together.
Extrapolating from data on cows and other modern-day ruminants, the scientists estimated the total methane output of pre-historic megafauna at nearly 10 trillion grams per year.
(Excerpt) Read more at news.discovery.com ...
Nope. See post #9.
Great book. Even explains why humans were wiped out in North America at the same time.
cause and effect, class, cause and effect
Thanks for highlighting that for me, as I had skipped over it. I will check that out.
The periodic ‘dark ages’ that overtake human history have always fascinated me. I feel I have a front row seat on one of those right now . . .
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