Tuesday, June 10, 2008

Toba Eruption (History Channel Mega-Disasters): "Volcanic Winter"

Today (June 10) the History Channel Mega-Disasters series presented “Toba Volcano”. About 75000 years ago in Indonesia, on the island of Sumatra, a supervolcano erupted, leaving a lake today in the caldera. The volcano was probably ten times as Tambora, also in Indonesia, that produced “the year without a summer” in 1815 and even inspired literature (the Frankenstein story). The ash cloud circled the world, and even worse, sulfur dioxide built up into the stratosphere. The result would not be just acid rain, but a volcanic winter. At the time, an ice age may have been underway, but the result was at least 1000 years with much expanded ice caps. Snow fell at low elevations even in Africa, and people and animals starved. Mammalian life on earth might have become extinct. The Toba eruption was 100 times as large as the Mount Pinatubo eruption in the Philippines in 1991, the largest volcanic eruption in modern industrial age history.

There may have been a million people before the eruption, but the world’s population may have shriveled to 30000. This created a “genetic bottleneck” meaning that the world’s people today are unusually consistent genetically relative to other animal species. This means that the world’s races are reproductively compatible, and (even given the tragedy that race has caused in history) that there are no significant differences between races in terms of basic human skills. One can imagine other planets like ours (maybe within a few hundred light years or so) where this is not so, and the enormous social and political consequences of larger genetic variations in a species of about our level of civilization. It’s possible to trace the mitochondrial DNA of every human today to female ancestors, perhaps only 10000 or so, surviving the eruption.

A supervolcano results from a large dimple of magma under the Earth’s crust. Tora is showing some vague signs of reawakening today, but there are alarming areas in western US that cover supervocalno calderas, such as in the Owens Valley near US 395 in California, and in Yellowstone in Wyoming. A supervolcano eruption would cover the US with an average of 4 inches of ash and would wipe everyone out for several hundred miles, as in Las Vegas. But a volcanic winter would ensue. Unlike local catastrophes like Hurricane Katrina, there would be no where to go for help. Civilization as we know it would probably perish, and there is nothing we can do to prevent a mega-disaster on the scale of a supervolcano (even though we could probably stop an asteroid). This would be The Purification, not just “The Happneing”.

Update: May 5, 2009

Tonight the History Channel rebroadcast the program renamed as "Volcanic Winter". The link is here.

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