Posted on 05/08/2005 8:21:59 AM PDT by velyrorenry
CLIMATE change researchers have detected the first signs of a slowdown in the Gulf Stream — the mighty ocean current that keeps Britain and Europe from freezing.
They have found that one of the “engines” driving the Gulf Stream — the sinking of supercooled water in the Greenland Sea — has weakened to less than a quarter of its former strength.
The weakening, apparently caused by global warming, could herald big changes in the current over the next few years or decades. Paradoxically, it could lead to Britain and northwestern and Europe undergoing a sharp drop in temperatures.
Such a change has long been predicted by scientists but the new research is among the first to show clear experimental evidence of the phenomenon.
Peter Wadhams, professor of ocean physics at Cambridge University, hitched rides under the Arctic ice cap in Royal Navy submarines and used ships to take measurements across the Greenland Sea.
“Until recently we would find giant ‘chimneys’ in the sea where columns of cold, dense water were sinking from the surface to the seabed 3,000 metres below, but now they have almost disappeared,” he said.
“As the water sank it was replaced by warm water flowing in from the south, which kept the circulation going. If that mechanism is slowing, it will mean less heat reaching Europe.”
Such a change could have a severe impact on Britain, which lies on the same latitude as Siberia and ought to be much colder. The Gulf Stream transports 27,000 times more heat to British shores than all the nation’s power supplies could provide, warming Britain by 5-8C.
Wadhams and his colleagues believe, however, that just such changes could be well under way. They predict that the slowing of the Gulf Stream is likely to be accompanied by other effects, such as the complete summer melting of the Arctic ice cap by as early as 2020 and almost certainly by 2080. This would spell disaster for Arctic wildlife such as the polar bear, which could face extinction.
Wadhams’s submarine journeys took him under the North Polar ice cap, using sonar to survey the ice from underneath. He has measured how the ice has become 46% thinner over the past 20 years. The results from these surveys prompted him to focus on a feature called the Odden ice shelf, which should grow out into the Greenland Sea every winter and recede in summer.
The growth of this shelf should trigger the annual formation of the sinking water columns. As sea water freezes to form the shelf, the ice crystals expel their salt into the surrounding water, making it heavier than the water below.
However, the Odden ice shelf has stopped forming. It last appeared in full in 1997. “In the past we could see nine to 12 giant columns forming under the shelf each year. In our latest cruise, we found only two and they were so weak that the sinking water could not reach the seabed,” said Wadhams, who disclosed the findings at a meeting of the European Geosciences Union in Vienna.
The exact effect of such changes is hard to predict because currents and weather systems take years to respond and because there are two other areas around the north Atlantic where water sinks, helping to maintain circulation. Less is known about how climate change is affecting these.
However, Wadhams suggests the effect could be dramatic. “One of the frightening things in the film The Day After Tomorrow showed how the circulation in the Atlantic Ocean is upset because the sinking of cold water in the north Atlantic suddenly stops,” he said.
“The sinking is stopping, albeit much more slowly than in the film — over years rather than a few days. If it continues, the effect will be to cool the climate of northern Europe.”
One possibility is that Europe will freeze; another is that the slowing of the Gulf Stream may keep Europe cool as global warming heats the rest of the world — but with more extremes of weather.
See post #97.
fyi
Underwater volcanic activity in the Arctic Ocean far stronger than anyone ever imagined! (This strongly confirms my belief that underwater volcanic activity is heating the seas; not human activity.)
German-American researchers have discovered more hydrothermal activity at the Gakkel Ridge in the Arctic Ocean than anyone ever imagined.
"The Gakkel ridge is a gigantic volcanic mountain chain stretching beneath the Arctic Ocean. With its deep valleys 5,500 meters beneath the sea surface and its 5,000 meter- high summits, Gakkel ridge is far mightier than the Alps."
Two research icebreakers, the "USCGC Healy" from USA and the German "PFS Polarstern," recently joined forces in the international expedition AMORE (Arctic Mid-Ocean Ridge Expedition). In attendance were scientists from the Max Planck Institute for Chemistry and other international institutions.
The scientists had expected that the Gakkel ridge would exhibit "anemic" magmatism. Instead, they found "surprisingly strong magmatic activity in the West and the East of the ridge and one of the strongest hydrothermal activities ever seen at mid-ocean ridges."
"The Gakkel ridge extends about 1800 kilometers beneath the Arctic Ocean from north of Greenland to Siberia, and is the northernmost portion of the mid-ocean ridge system."
To their surprise, the researchers found high levels of volcanic activity. Indeed, magmatism was "dramatically" higher than expected.
Hydrothermal hot springs on the seafloor were also far more abundant than predicted. "We expected this to be a hydrothermally dead ridge, and almost every time our water measurement instrument came up, they showed evidence of hydrothermal activity, and once we even 'saw' an active hot spring on the sea floor," said Dr. Jonathan Snow, the leader of the research group from the Max Planck Institute.
No wonder the ice is melting!
See http://www.mpg.de/english/illustrationsDocumentation/documentation/pressR eleases/2003/pressRelease20030718/index.html
I had connections to get my OJ Simpson all White Bronco. It still has OJ's glove in the back. I keep one with red paint on it in the back as part of my long standing joke.
Great data.
We are seeing the beginning of the end of the faux science of the enviral whackos as the real science continues to surface.
BUMP
Why do you assume that the underwater volcanic activity is new? Were it a continuing process, there would be some sort of steady state. Of course, you're right that the seas are heated from crusty activity.
maybe the term "Global" is wrong, but there's no doubt that earth in general is getting warmer. These things can be measured. Why, and what we can do, if anything, is the only debatable point.
so much data from all sides. Hard to trust any of it, unless you see who's funding who.
CO2 prolongs life of 'space junk'~~ And that's bad?
To me it is a real laffer!
"I don't like summer anyway"
I took a group of Boy Scouts up to Blair Athol in August of 2000. In Edinborough, we had to buy fleece jackets, hats and gloves. When the sun went down, they froze. (I fortunately had checked in to a delightful B&B down the road, with an 18 yr old Maccallan)
It is beautiful, but I can't imagine it getting colder.
According to the theory proposed by Felix, the increase in volcanic activity (along with a magnetic reversal of the poles) is linked to the onset of a new ice. This has been going on for millions of years with a new ice age occuring every 10,000 years. We are due for another one now.
Lets see if I understand this.
1st, measurements have shown that (one of) the driving force(s) of the Gulf Stream (melting ice from the Arctic) has fallen from 12 "strong" columns, to 2 "weak" columns.
2nd, without the Gulf Stream transporting all of that nice warm water to the Arctic (and then N. Europe), England and N.Europe will begin to resemble Siberia.
3rd, the Arctic Ice cap will melt in the summer
BUT, if one and two are true, how is 3 possible? What will cause the Ice Cap to melt? AND, if it DID melt, why wouldn't the water then sink in columns, thus replenishing the the Gulf Stream, thus eliminating 1 and, in turn 2 as well?
Maybe I just forgot to drink that dose of nuance this morning!!
A friend and I postulated years ago that if the core has, in effect, a natural nuclear reactor within, or even reactor zones, that these would periodically poison themselves with daughter products and require time to restratify and resume activity. Perhaps this would account for the cylical nature of tectonic activity as evidenced in the geologic record.
We do have distinct periods of mountain building and volcanic activity, followed by relative quiescence, since well back into the preCambrian, recorded in the rocks.
If the 'reactor' theory is correct, even partially, then we could be seeing another cycle of high heat flow from the planet's interior, one which humans cannot affect one way or the other.
Hard to trust any of it, unless you see who's funding who.
I disagree, reproducibility of results and traceability to fundamental physical measurement of actual observed phenomena that any scientist can observe and report on is the measure of all good research.
All funding does, is indicate those who have sufficient need for the research to actually commit resource to doing it so the can use the initial output of the research process. Funding does not at all indicate anything about the reliability of the underlying data or physical research done.
IPPC and global warming research is done by modeling, not physical measurement, and does not reflect the environment it supposedly simulates. They have never been able to demonstrate any ability to track historical data series from first physical principles that a functional simulation model must be able to do to meet objective evaluation against phenomena measured by independent researchers.
All research data is funded, the key is the exposure to true peer review and reproducibility of the results, and in the particular case, the ability track the physical world.
The General Climate Models fail miserably to track the actual global environment as it manifests. In fact no weather model has shown any ability to look forward with any accuracy beyond a window of a few days.
Global warming scenarios and models are not "data", they are results of computer simulations, the models and parameter's, of which have been kept out of an open peer review process by not releasing the programs and their full set of fundamental parameters to open and independent review.
Ok: do most scientists agree that Global Warming exists or not?
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