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Politics : Sioux Nation -- Ignore unavailable to you. Want to Upgrade?

To: T L Comiskey who wrote (75312)	8/4/2006 3:48:46 AM
From: Wharf Rat	Read Replies (1) \| Respond to of 362004

What is supposed to happen with this? They say that, as it melts, sea levels go up. But what about sudden collapse and sliding into the ocean? Wouldn't that be a tidal wave situation compounding the rise in ocean levels?

To: T L Comiskey who wrote (75312)	8/4/2006 4:32:09 AM
From: Wharf Rat	Read Replies (1) \| Respond to of 362004

1883 volcano eruption's legacy is cooler planet Keay Davidson, Chronicle Science Writer Wednesday, August 2, 2006 Thanks to a spectacular volcanic explosion in the late 19th century, global warming and sea-level rise over the last century haven't been quite as severe as they might have been otherwise, scientists at Lawrence Livermore National Laboratory and elsewhere say. The 1883 eruption of Krakatoa in the Sunda Strait of Indonesia spewed so many particles into the sky that the world's sunsets turned an eerie reddish color, inspiring painters as far away as Europe. The explosion's gases and dust also blocked sunlight and cooled the planet by an average of about 1 degree well into the 20th century. Now the scientists have reported a surprising finding. A legacy of the explosion persists beneath the ocean surface: a vast layer of cold water chilled by the nuclear-bomb-class volcanic detonation of 1883. Cold water is denser than warm water, so the chilled water sank beneath the waves. According to the scientists' computer model, the cold water is still there 123 years later -- a climatic leftover from the decade when President James Garfield was assassinated and the first Sherlock Holmes story was published. The scientists discovered the deep-sea pocket of cold water indirectly, while modeling the long-term climatic and ocean effects of the Krakatoa blast. They will report their findings in a forthcoming issue of the scientific journal Geophysical Research Letters, the American Geophysical Union in Washington announced Tuesday. The volcanic explosion unleashed millions of tons of particles -- including sulfur dioxide -- into the stratosphere, a relatively warm layer of the atmosphere that begins about 6 miles above the ground. Stratospheric winds quickly blew the gases and other particles around the world. The sulfur dioxide interacted with oxygen and water vapor in the atmosphere to form sulfuric acid, which blocked some sunlight and caused the climate to cool. The scientists involved in the research said they were surprised how long the cold-water layer has endured. If it hadn't persisted so long, the sea-level rise driven by global warming would have been slightly higher -- about one centimeter -- than it has been. The persistence of the deepwater cold anomaly "really stunned us," said Tom Wigley, a leading expert on global warming at the National Center for Atmospheric Research in Boulder, Colo. Wigley co-authored the article with four Livermore lab scientists and a researcher in England. When Wigley analyzed the computer printout, his first reaction was, "This has got to be a mistake," he said. But after some reflection, he realized it was just another reminder of the complex ways in which the ocean and atmosphere interact. The Krakatoa eruption counterbalanced the global warming trend that has been under way at least since the early-to-mid 19th century Industrial Revolution, when human burning of fossil fuels began filling the skies with greenhouse gases that warm the climate. Humans certainly can't count on future Krakatoa-style explosions to significantly delay the effects of global warming, Wigley cautioned. Present models indicate that average planetary temperature will rise by 5 to 6 degrees over the next century, he said. Indeed, according to the study, subsequent volcanic eruptions -- such as the 1991 explosion of Mount Pinatubo in the Philippines -- had minimal cooling effects because of the human-caused planetary warming already under way. The evidence that humans are largely to blame for global warming is "overwhelming," Wigley explained, and "feedback effects" like temporary coolings induced by volcanic eruptions are comparatively minor factors. Still, scientists are trying to include volcanic phenomena in their computer models of global warming for the sake of comprehensiveness. Asked if he thinks global warming is to blame for the latest California heat wave, Wigley said that for statistical reasons, it's "very difficult" to know whether global warming triggered a specific short-term weather event. Even so, global warming is like "weighting a dice" -- it increases the odds of heat waves, he said. And in a world where more and more cars and industries are burning fossil fuels, "we're adding more weight as time goes by." The article's lead author is Peter J. Gleckler of Livermore. Besides Wigley, neither Gleckler nor the other co-authors -- three from Livermore and J.M. Gregory of the University of Reading in England -- could be reached Tuesday. Livermore lab spokeswoman Anne Stark issued a statement: "For years, the laboratory has been developing the most-advanced models to help interpret current and predict future climate change. In this recent research, scientists were able to interpret the effects of volcanoes on past climate. In fact, ocean temperatures dipped and offset a large percentage of sea-level rise caused by humans." sfgate.com