SUPERVOLCANO WILL THREATEN CIVILIZATION GEOLOGISTS WARN

by Never_Surrender, Tuesday, April 19, 2005, 03:27 @ Never_Surrender

Super Volcano Will Challenge Civilization, Geologists Warn

March 8, 2005

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The eruption of a super volcano "sooner or later" will chill the planet and threaten human civilization, British scientists warned Tuesday.

And now the bad news: There's not much anyone can do about it.

SNIP...

super eruption is a scaled up version of a typical volcanic outburst, Sparks explained. Each is caused by a rising and growing chamber of hot molten rock known as magma.

"In super eruptions the magma chamber is huge," Sparks said. The eruption is rapid, occurring in a matter of days. "When the magma erupts the overlying rocks collapse into the chamber, which has reduced its pressure due to the eruption. The collapse forms the huge crater."

The eruption pumps dust and chemicals into the atmosphere for years, screening the Sun and cooling the planet. Earth is plunged into a perpetual winter, some models predict, causing plant and animal species disappear forever.

"The whole of a continent might be covered by ash, which might take many years -- possibly decades -- to erode away and for vegetation to recover," Sparks said.

SNIP...

The next super eruption, whenever it occurs, might not be the first one humans have dealt with.

About 74,000 years ago, in what is now Sumatra, a volcano called Toba blew with a force estimated at 10,000 times that of Mount St. Helens. Ash darkened the sky all around the planet. Temperatures plummeted by up to 21 degrees at higher latitudes, according to research by Michael Rampino, a biologist and geologist at New York University.

Rampino has estimated three-quarters of the plant species in the Northern Hemisphere perished.

Stanley Ambrose, an anthropologist at the University of Illinois, suggested in 1998 that Rampino's work might explain a curious bottleneck in human evolution: The blueprints of life for all humans -- DNA -- are remarkably similar given that our species branched off from the rest of the primate family tree a few million years ago.

Ambrose has said early humans were perhaps pushed to the edge of extinction after the Toba eruption -- around the same time folks got serious about art and tool making. Perhaps only a few thousand survived. Humans today would all be descended from these few, and in terms of the genetic code, not a whole lot would change in 74,000 years.

Sitting ducks

Based on the latest evidence, eruptions the size of the giant Yellowstone and Toba events occur at least every 100,000 years, Sparks said, "and it could be as high as every 50,000 years. There are smaller but nevertheless huge eruptions which would have continental to global consequences every 5,000 years or so."

Unlike other threats to mankind -- asteroids, nuclear attacks and global warming to name a few -- there's little to be done about a super volcano.

"While it may in future be possible to deflect asteroids or somehow avoid their impact, even science fiction cannot produce a credible mechanism for averting a super eruption," the new report states. "No strategies can be envisaged for reducing the power of major volcanic eruptions."

The Geological Society of London has issued similar warnings going back to 2000.

Rest at link....

http://www.his-forever.com/super_volcano_will_challenge_civilization.htm

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and here is another warning from 2000....

3 February 2000

Scientists warn of supervolcano that could blot out the Sun and bring a global winter

By Steve Connor, Science Editor

Geologists will warn MPs today of the threat posed by a supervolcanic eruption that could devastate the global climate, disrupt agriculture and cause severe food shortages.

Senior members of the Geological Society are to give evidence to the House of Commons Science and Technology Committee, claiming that a massive eruption could emit enough gas, dust and debris into the atmosphere to block out sunlight and cause a global "volcanic winter".

"Given the climatic impact of volcanic eruptions ... and the likelihood of future eruptions, the society recommends that the committee investigate the extent to which the Government has explored the agricultural, economic and political consequences of volcanic winters," the Geological Society says in its written submission.

Geologists are particularly concerned about so-called "supervolcanoes", which can erupt with a force powerful enough to eject thousands of cubic kilometres of debris and hundreds of thousands of tons of sulphuric acid, which can form a reflective shield, cutting out sunlight.

Historical records of eruptions big enough to have a global effect show they are more common than many people imagine and have had a serious impact on human existence.

"For example, a powerful eruption of the Indonesian volcano Tambora in 1815 was followed by one to two years of unusually cold climate around the world," the society says. "In Europe, annual mean temperatures were 1°C to 2.5°C lower than normal, harvests were late or failed altogether, grain prices were at their highest and famine was widespread."

Tambora measured seven on the eight-point volcanic explosion index. The explosion in 1991 of Mount Pinatubo in the Philippines was 10 times smaller, registering six points on the index, which was 10 times bigger than the five-point explosion in 1980 of Mount St Helens in the United States.

SNIP...

A Horizon documentary to be broadcast tonight on BBC2 reveals that one of the biggest eruptions, 74,000 years ago at Toba in Sumatra, may have pushed man to the brink of extinction. Toba, which is estimated to have been a maximum eight-point explosion, caused a volcanic winter lasting several years and reduced the population to a few thousand, resulting in a genetic "bottleneck" that can be observed in our genes today.

"There's nowhere to hide from the effects of a supervolcano. When one goes off it will be like a nuclear winter without the radiation," Professor McGuire said.

http://millennium-debate.org/ind3fe2.htm

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