Wednesday, May 17, 2006
DID GLOBAL WARMING CAUSE MEGAFAUNA EXTINCTIONS?
If a major catastrophe kills 90% of a species then to kill 95% would require a doubly great catastrophe & so on. I find it unlikely that, due to the law of diminishing returns reduction to less than 1 breeding group, of a widespread numerous species could be achieved by anything much short of a meteor that produces continent sized sterilisation.
Hunting on the other hand, since it tends to kill at a fairly flat rate, assuming a flat population of hunters & so long as prey is available. This can quite effectively reduce a declining population to zero.
(14) DID GLOBAL WARMING CAUSE MEGAFAUNA EXTINCTIONS?
The answer to that question is no. Whilst the temperature changes were indeed gradual, easy to cope with for fauna, the precipitation changes were overnight, and that was the real killer. In Siberia the dry steppes changed in marshed and swamps in the Preboreal, following the Younger Dryas causing the last mammoths to go extinct around 11,200 Cal BP (9600 carbion years), The American megafauna perished at the beginning of the Younger Dryas, around 12500 Cal BP (ca 10500 carbon years) with an extreme dry period.
Our paper regarding this theory is under review of Quartenary International.
Non calor sed umor.
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