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Politics : The Environmentalist Thread -- Ignore unavailable to you. Want to Upgrade?

To: Maurice Winn who wrote (8331)	12/2/2006 1:58:26 PM
From: Wharf Rat	Read Replies (3) \| Respond to of 36921

Massive Ice Shelf 'May Collapse without Warning' Published on Friday, December 1, 2006 by the New Zealand Herald The Ross Ice Shelf, a massive piece of ice the size of France, could break off without warning causing a dramatic rise in sea levels, warn New Zealand scientists working in Antarctica. A New Zealand-led ice drilling team has recovered three million years of climate history from samples which gives clues as to what may happen in the future. A New Zealand frigate sails past the Ross Ice Shelf in 1999. An iceberg warning has been issued for ships in the Southern Ocean after more than 100 were sighted just south of New Zealand.(AFP/File) Initial analysis of sea-floor cores near Scott Base suggest the Ross Ice Shelf had collapsed in the past and had probably done so suddenly. The team's co-chief scientist, Tim Naish, told The Press newspaper the sediment record was important because it provided crucial evidence about how the Ross Ice Shelf would react to climate change, with potential to dramatically increase sea levels. "If the past is any indication of the future, then the ice shelf will collapse," he said. "If the ice shelf goes, then what about the West Antarctic Ice Sheet? What we've learnt from the Antarctic Peninsula is when once buttressing ice sheets go, the glaciers feeding them move faster and that's the thing that isn't so cheery." Antarctica stores 70 per cent of the world's fresh water, with the West Antarctic Ice Sheet holding an estimated 30 million cubic kilometres. In January, British Antarctic Survey researchers predicted that its collapse would make sea levels rise by at least 5m, with other estimates predicting a rise of up to 17m. Dr Naish, a sedimentologist with the Institute of Geological and Nuclear Sciences, said one day the drilling team retrieved a core of 83m, far greater than expected, which contained climate records spanning about 500,000 years. "We're really getting everything we've dreamed of. What we're getting is a pretty detailed history of the ice shelf," he said. "You go from full glacial conditions to open ocean conditions very abruptly. It doesn't surprise us that much that the transition was dramatic. "Scientists knew from the collapse of the Larsen Ice Shelf in 2002 that expanses of ice could collapse "extremely quickly". Once dating of the sample was completed, researchers would be able to look at what the ice shelf was doing during periods when scientists knew from other evidence that it was 2degC to 4degC warmer than today, Dr Naish said. commondreams.org

To: Maurice Winn who wrote (8331)	12/5/2006 11:18:44 AM
From: Wharf Rat	Read Replies (2) \| Respond to of 36921

"We are increasing CO2 production rates, but we are not increasing the rate of CO2 accumulation." Oh? Earlier this month, the World Meteorological Organization reported the level of carbon dioxide in the atmosphere reached 379.1 parts per million in 2005, more than 35 percent higher than in the late 18th century Message 23050378 "CO2 levels will drop rapidly." CO2 lasts in the atmosphere for about 100 years. Rapid only in geologic terms. "We have held off the return of the ice age because of huge efforts over a century," You could maybe make the case that the atmosphere mellowed at the beginning of the Antropocene Era, which Ruddiman places back 8K years. (Crutzen only puts it back to 1800 AD.) Ruddiman thinks we wrested control of the methane cycle when agriculture began in Asia, New Guinea, and in SE Australia,where eel massive weirs were constructed. You might argue that. Except for the ice core from Dome C at Vostok. Regardless, the rate of change we are causing now far exceeds anything in the past. Old figures, but in '97, we burned, in one year, the fossilized remains of 422 years of photosynthesis; 400 years of sequestered CO2 in one year. This won't stop until we either use all the fossil fuel,or until we go alternate. Then, if we are lucky, Nature's own positive feedbacks won't come into play. (But it looks like maybe it is already warm enuf for that in Siberia and Alaska.) == Based on current trends, carbon dioxide concentrations are likely to increase to 500PPM this century. The last time the planet experienced levels as high as 500PPM was about 20 or 40 million years ago, when sea levels were 100 metres higher than today. Message 23003170@%20ppm