This is not cheery news. So far, this story seems to be running only on BBC:
UK scientists working in Antarctica have found some of the clearest evidence yet of instabilities in the ice of part of West Antarctica. If the trend continues, they say, it could lead to a significant rise in global sea level.
The new evidence comes from a group of glaciers covering an area the size of Texas, in a remote and seldom visited part of West Antarctica.
The “rivers of ice” have surged sharply in speed towards the ocean.
David Vaughan, of the British Antarctic Survey, explained: “It has been called the weak underbelly of the West Antarctic Ice Sheet, and the reason for that is that this is the area where the bed beneath the ice sheet dips down steepest towards the interior.
“If there is a feedback mechanism to make the ice sheet unstable, it will be most unstable in this region.”
There is good reason to be concerned.
Satellite measurements have shown that three huge glaciers here have been speeding up for more than a decade.
The biggest of the glaciers, the Pine Island Glacier, is causing the most concern.
Julian Scott has just returned from there. He told the BBC: “This is a very important glacier; it’s putting more ice into the sea than any other glacier in Antarctica.
“It’s a couple of kilometres thick, its 30km wide and it’s moving at 3.5km per year, so it’s putting a lot of ice into the ocean.”
It is a very remote and inhospitable region. It was visited briefly in 1961 by American scientists but no one had returned until this season when Julian Scott and Rob Bingham and colleagues from the British Antarctic survey spent 97 days camping on the flat, white ice….
Throughout the 1990s, according to satellite measurements, the glacier was accelerating by around 1% a year. Julian Scott’s sensational finding this season is that it now seems to have accelerated by 7% in a single season, sending more and more ice into the ocean.
“The measurements from last season seem to show an incredible acceleration, a rate of up to 7%. That is far greater than the accelerations they were getting excited about in the 1990s.”
The reason does not seem to be warming in the surrounding air.
One possible culprit could be a deep ocean current that is channelled onto the continental shelf close to the mouth of the glacier. There is not much sea ice to protect it from the warm water, which seems to be undercutting the ice and lubricating its flow.
Julian Scott, however, thinks there may be other forces at work as well.
Much higher up the course of the glacier there is evidence of a volcano that erupted through the ice about 2,000 years ago and the whole region could be volcanically active, releasing geothermal heat to melt the base of the ice and help its slide towards the sea.
David Vaughan believes that the risk of a major collapse of this section of the West Antarctic ice sheet should be taken seriously.
“There has been the expectation that this could be a vulnerable area,” he said.
“Now we have the data to show that this is the area that is changing. So the two things coinciding are actually quite worrying.”
The big question now is whether what has been recorded is an exceptional surge or whether it heralds a major collapse of the ice. Julian Scott hopes to find out.
“It is extraordinary and we’ve left a GPS there over winter to see if it is going to continue this trend.”
If the glacier does continue to surge and discharge most of it ice into the sea, say the researchers, the Pine Island Glacier alone could raise global sea level by 25cm.
That might take decades or a century, but neighbouring glaciers are accelerating too and if the entire region were to lose its ice, the sea would rise by 1.5m worldwide.
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“This is not cheery news. So far, this story seems to be running only on BBC”
There may be a reason BBC is in the forefront of this, they’re on a self-appointed Mission from God to inform the heathen. I fail to see how Chicken Little prophecies that “the sea would rise by 1.5m worldwide” in a century’s time is anything to get excited about. Perhaps if you were to step back from the precipice a moment and direct weigh some other scientific evidence you will feel less concerned.
I direct your attention to Gordon A. Macdonald’s “Volcanoes in the Sea,” second edition, 1983, by the University of Hawaii Press (ISBN 0-8248-0832-0) as just one source. The eight main Hawaiian islands are anywhere from half a million (Big Island) to 5.7 million years old (Kauai), mere infants in geological terms (p.303). On page 278 of Macdonald’s book is Table 14.1 listing “Ancient shorelines in the Hawaiian Islands.” The 18 shorelines listed are each given names. They range from the Mahana, at +365 meters to the Waho, estimated to be –915 to –1,100 meters below current sea level. Again, these two figures, along with the others, show that in a mere blink of an eye (no more than 5.7 million years), the sea’s level has changed up or down nearly 1,400 meters or over four thousand feet! (Yes, the islands themselves may or may not have risen or sunk in that period as well. But the net effect is as stated in Macdonald.) Why, then, this fear mongering about a one-point-five meters rise in a century? Yawn.
Thank you for letting me direct your attention away from the less than informative BBC for a few minutes. A different point of view often illuminates.
You tag this as “Global Warming” but the scientist in the article does not draw that conclusion. In fact, the piece reads:
“Julian Scott, however, thinks there may be other forces at work as well.
Much higher up the course of the glacier there is evidence of a volcano that erupted through the ice about 2,000 years ago and the whole region could be volcanically active, releasing geothermal heat to melt the base of the ice and help its slide towards the sea. “
Yes there is a mention that warm ocean currents could be a cause but search the piece for “climate change” or “global warming” and you find neither. I myself believe in global warming. But I encourage people to be careful with their understanding and reporting of the science because accuracy is critical to effective communication of the problems we face.
Great site.
Guys, it may not technically be the best tag, but “ice falling into the ocean and increasing sea levels” is one of the consequences of global warming that scientists AND the Pentagon are most worried about. I wouldn’t create a “rising sea level” tag just for this post if this were my blog.
In reference to the earlier “Don’t Worry, SeaLevel were much higher millions of years ago,” the poster is quite right. But that will not help me if my house is in on Galveston or Clear Lake, by NASA in Houston, and it is covered in water.
Hansen, the climate scientist at NASA, has publishes recently several articles critiquing the IPCC reports for underestimating risk of Greenland glaciar melt and Antarctic rate (on which the overall melt/new snow&ice rate is much more difficult to measure, currently).
See Hansen, http://www.iop.org/EJ/article/1748-9326/2/2/024002/erl7_2_024002.html .
I saw him speak in Houston last November.
and see a good Washington Post overview at
http://www.washingtonpost.com/wp-dyn/content/article/2006/03/02/AR2006030201712.html
If you’re really interested, that is; it is being covered but noone is paying much attention. The Japanese, Scandanevian resarch groups working on Artic/Greenland melt have been publishing reports on the internet for the last 3 years.