How Global Catastrophe Could Make Us Smarter | LiveScience »

When supervolcanoes blow their tops, the world's climate is altered and life is snuffed out regionally and challenged globally. Such an event is thought to have occurred 74,000 years ago when the Toba supervolcano erupted in what is now Sumatra with a force estimated to be 1,000 to 10,000 times that of Mount St. Helens.

The timing of Toba's tempest fits with an interesting bottleneck known to exist in human evolution, as seen in DNA evidence. The population became very small sometime between 90,000 and 60,000 years ago. And a new idea floating around suggests that the eruption may have contributed — by necessity — to our supreme intelligence today. Further, it has been suggested, we may be undergoing the next great leap in smarts right now.

More on all that lower down. First, some fresh research on the eruption:

Scientists have theorized that Toba triggered plunging global temperatures that caused ice sheets to grow for a thousand years and led to a mass die-off of plants and animals. Perhaps only a few thousand early humans survived, the thinking goes, and that's why all human DNA today is so remarkably similar — though we branched off from other primates millions of years ago, we all come from the same few folks who survived Toba, and we've had only 74,000 years to evolve, an eyeblink in the grand billions-year scheme of evolution.

Neat idea, but climate model simulations of the eruption have been unable to produce the glaciation to the satisfaction of all those who study this stuff, and there are no climate observations to adequately support the volcanic winter.

A new study offers another mechanism to explain the great human bottleneck.

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