Supervolcano Rained Acid on Both Poles -- But Wasn't So Bad After All?Scientists have long debated just how extensive and enduring those effects were. One study, for example suggested the Toba blast spawned a thousand-year ice age that only some 10,000 individuals survived. Another has found evidence of humans thriving in relatively nearby India shortly after the eruption.
by James Owen
National Geographic News
November 7, 2012
The new study -- based on acid rain-tainted ice cores from Antarctica and Greenland -- suggests Toba's fallout wasn't quite as catastrophic as might be expected.
The Antarctic ice core, for example, even bears traces of a warming event just after the Toba eruption -- contrary to a strong cooling signal seen in the Greenland cores.
"That means there's no long-term global cooling caused by the eruption," study co-author Anders Svensson said. If there had been, you'd expect to see evidence of a chill at both Poles.
In fact, the post-Toba Antarctic cooling spike looks well, relatively ordinary. "There may have been shorter [global] cooling of a duration of maybe 10 or 20 years, like we see for more recent" -- and much less powerful -- "volcanoes," said Svensson, of the Niels Bohr Institute's Centre for Ice and Climate in Copenhagen.
There are shorter warm spells in the midst of the icy periods ~ Toba might well have occurred during such a period, or could have influenced it in some way.