Posted on 02/04/2008 4:55:40 PM PST by NormsRevenge
OSLO (Reuters) - Global warming this century could trigger a runaway thaw of Greenland's ice sheet and other abrupt shifts such as a dieback of the Amazon rainforest, scientists said on Monday.
They urged governments to be more aware of "tipping points" in nature, tiny shifts that can bring big and almost always damaging changes such as a melt of Arctic summer sea ice or a collapse of the Indian monsoon.
"Society may be lulled into a false sense of security by smooth projections of global change," the scientists at British, German and U.S. institutes wrote in a report saying there were many little-understood thresholds in nature.
"The greatest and clearest threat is to the Arctic with summer sea ice loss likely to occur long before, and potentially contribute to, Greenland ice sheet melt," they wrote in the journal Proceedings of the National Academy of Sciences.
"Tipping elements in the tropics, the boreal zone, and west Antarctica are surrounded by large uncertainty," they wrote, pointing to more potential abrupt shifts than seen in a 2007 report by the U.N. Climate Panel.
A projected drying of the Amazon basin, linked both to logging and to global warming, could set off a dieback of the rainforest.
"Many of these tipping points could be closer than we thought," lead author Timothy Lenton, of the University of East Anglia in England, told Reuters of the study.
Other sudden changes linked to climate change, stoked by human use of fossil fuels, included a dieback of northern pine forests, or a stronger warming of the Pacific under El Nino weather events that can disrupt weather worldwide, they wrote.
A possible greening of parts of the Sahel and the Sahara, if monsoon rains in West Africa were disrupted, was one of the few positive abrupt shifts identified by the scientists.
CLOSER
Even a moderate warming could set off a thaw of Greenland's ice sheet that could then vanish in 300 years -- raising sea levels by 6 meters (20 ft), or 2 meters a century and threatening coasts, Pacific islands and cities from Bangkok to Buenos Aires.
The U.N. Climate Panel foresees a rise in world sea levels ranging up to about 80 cms this century and reckons that a thaw of Greenland would take hundreds of years longer.
The new study said a disappearance of Arctic sea ice in summertime could happen in coming decades -- earlier than projected by the U.N. panel. That could stoke further global warming as dark water soaks up more heat than ice and snow.
The report also identified risks such as damage to northern pine forests -- widely exploited by the pulp industry -- because of factors such as more frequent fires and vulnerability to pests in warmer, drier conditions.
But it played down some other fears, such as of a runaway melt of Siberian permafrost, releasing stores of methane which is a powerful greenhouse gas.
And it said a shutdown of the Gulf Stream in the Atlantic Ocean that brings warm water north to Europe "appears to be a less immediate threat."
You’re right about thse kinds of reports always being chock full of weasel words. None of these eco-whores wants to stand behind any of their doomsday predictions.
[IT’S THE END OF THE WORLD AS WE KNOW IT!!!!]
Ooooohhh. Will it hurt?
Actually, the biggest threat to the polar regions is when the ships that the greenies use to gawk at the seals’ mating grounds sink and leak diesel oil for the next twenty years.
Is that proof of global warming or proof that Batman is gay?
Change that to 20% and you'll find that Arctic "sea ice" can last for centuries longer.
So far the Greenland ice pack has been all talk and no action.
Go ahead and melt -- I double-dog dare ya....
Scientists have recently discovered that there has been a paradigm shift and people who use terms like "tipping point" have reduced gravitas and suffer from a disenfranchising lack of empowerment.
Have these climatic tipping points ever actually been observed?
Coulda, woulda, shoulda when will the tipping point come when these morons give it a rest. It is never something that is happening now or has happened, but happening at some undefined time in the future and if it doesn’t happen then oh well they will have a reason other than that they might just be wrong.
I think I’ll start investing in houseboat companies.
According to these scare mongers, about 18 seconds.
I guess after 30 years of not teaching science in the public schools, they feel confident in preaching their junk science to the ignorant.
...
From the link,
The scheme would involve flooding a natural depression in the Western desert (the Qattara) through a canal or tunnel from the Mediterranean Sea, 56 km away (fig. 2.52). At its lowest point, the depression is 134 m below sea level. The plan envisages generating power utilizing the difference in elevation to the lake that will eventually be formed, whose surface will be 60 m below sea level, with an area of 19,500 km2;. The scheme could supply 670 MW of basic load without pumped storage (WPDC 1978).
2.11.2 Topography of the Qattara depression
The Qattara depression is located in the north-western part of Egypt and is the world’s fifth deepest natural depression. The depression is bounded to the north and west by deep escarpments but becomes comparatively flat towards the south and the east (fig. 2.53). The lowest point is found at a level of 133 m below sea level. The depression has a length of about 300 km at sea level, a maximum width of 145 km, and an area of 19,500 km².
...
So, what’s the potential volume? 19,500 km^2 at some average depth of 70 meters? (134 max depth minus water level of -50 meters?) Or use all of the -134 meters?
Good find!
No science in the story at all: Merely scary words based on extremist guesses. (Hoping for disaster, rather?)
Greenlands HIGHEST temp at its HOTTEST station is -5 degrees C. Global warming is +1/2 of ONE degree, and that over the last 40 years. The last ten years of “global warming” have not had any temp increase at all.
So, to get Greenland’s HOTTEST temp up to zero (and it will get to zero for only one week of the year) will require 500 years of increasing temperature.
During the heyday of Hannibal, a mere 2300 years ago, most of what is now arid North Africa was tropical and semi-tropical Numidia. So pre-industrial climate change is hardly a modern issue.
Let Not Your Heart Be Troubled! The End of The World As We Know It Will Leave You Feeling Fine! In Fact, You’ll Be Singing Along With REM:
http://www.youtube.com/watch?v=zeo0_3gN190&feature=related
It is 26 miles from the Med to the dead sea, and drops 800 m ...
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