What Killed the Great Beasts of North America? 214
sciencehabit writes "Until about 11,000 years ago, mammoths, giant beavers, and other massive mammals roamed North America. Many researchers have blamed their demise on incoming Paleoindians, the first Americans, who allegedly hunted them to extinction. But a new study points to climate and environmental changes instead. The findings could have implications for conservation strategies, including controversial proposals for 'rewilding' lions and elephants into North America."
Re:It's the orbit, stupid (Score:5, Interesting)
My personal theory is that the pleistocene has been so cold because of the historically (4 billion years) high oxygen levels and the significant amount of historical carbon that has been sequestered underground.
Humans are changing that, we're sucking all the sequestered carbon out and putting it into the atmosphere where it hasn't been since the dinosaurs. Before all the science deniers reply, this is scary because humanity was born in the ice ages of the Pleistocene we've never experienced a planet as warm as the dinosaurs where there weren't any ice caps and it was 100 degrees in the northern reaches of Canada (yes I know the continents were in different places so Canada was at a lower latitude).
Humans will survive a warmer earth I have no doubt, but the potential for massive disruption to the food supply is there and if that happens there's going to be some really ugly war that humanity might not survive. The reason to be scared of global warming is because of those changing fertile zones, humanity goes batshit crazy when starvation is eminent.
Re:It's the orbit, stupid (Score:4, Interesting)
That bit about continents *is* a standard theory... but it has nothing on 11k years ago. Same thing goes for the orbit. So no, it isn't the orbit, and it isn't the landmasses.
Let's see... you have the North American Clovis Point [wikipedia.org] people going extinct at the same time. So it isn't *who* killed them either. If the Clovis people had killed them off, you wouldn't have had them going extinct.
Also, at the same time, you have wildfires throughout North America. That soot contains microdiamonds. [sciencedaily.com]
You also have mammoths in Siberia at that time, flash frozen (Alaska Science Forum November 1, 1976. Mystery of the Mammoth and the Buttercups Article #122 by J. Holland).
You also have great areas in Alaska of jumbled up, blasted fauna caracases, many of them torn apart. [s8int.com]
Now, all told, I'm going to posit -- and I doubt I'm the first to do so -- that an asteroid hit a glacier up against the south side of a mountain in Northern Alaska. The first thing it did, was melt/throw the ice of the glacier in a great parabolic trajectory. The water of the glacier went into near space, froze to extremely low temperatures, and came down. But meanwhile, the asteroid impacted the south side of the mountain, and vaporized, causing a fireball to project back into North America.
Thus the soot, thus the extinctions (animal and Clovis culture), thus the flash-frozen mammoth, thus the tectites, thus the great boneyards.
And no, for those creationists here, I extremely doubt that ANY of this had to do with Noah's flood. Noah's flood dates to about 5000 ya, and seems to match the Madagascar chevrons and 8' of river mud, pretty well. This is something different.