[blam]

"TWC “It Could Happen Tomorrow” are interesting vignettes, but they are only regional, climate/weather related events, based on our current circumstances. They are relatively insignificant and make no mention of long-term effects, recovery or adaptation."

Ahem, I beg to differ.

Late Pleostocene Human Population Bottlenecks. . . (Toba)

"The last glacial period was preceded by 1000 years of the coldest temperatures of the Late Pleistocene, apparently caused by the eruption of the Mount Toba volcano. The six year long volcanic winter and 1000-year-long instant Ice Age that followed Mount Toba's eruption may have decimated Modern Man's entire population. Genetic evidence suggests that Human population size fell to about 10,000 adults between 50 and 100 thousand years ago. The survivors from this global catastrophy would have found refuge in isolated tropical pockets, mainly in Equatorial Africa. Populations living in Europe and northern China would have been completely eliminated by the reduction of the summer temperatures by as much as 12 degrees centigrade. "

[sodpoodle]

Now you’re talking - and I shall be reading.

I know what you’re thinking - and it isn’t nice;)

sod

[KayEyeDoubleDee]

The six year long volcanic winter and 1000-year-long instant Ice Age that followed Mount Toba's eruption may have decimated Modern Man's entire population. Genetic evidence suggests that Human population size fell to about 10,000 adults between 50 and 100 thousand years ago.

I was about to posit that the most likely common reason for the simultaneous split of elephant and primate lines (obviously a few orders of magnitude older than the event you mention) would be some catastrophic event that isolated groups. Weather-induced seems more likely than geographic, but who knows.