Posted on 12/10/2007 4:05:10 PM PST by sourcery
Two researchers spent months scouring through old expedition logs and reports, and reviewing 70-year-old maps and photos before making a surprising discovery. They found that the effects of the current warming and melting of Greenland 's glaciers that has alarmed the world's climate scientists occurred in the decades following an abrupt warming in the 1920s.
Their evidence reinforces the belief that glaciers and other bodies of ice are exquisitely hyper-sensitive to climate change and bolsters the concern that rising temperatures will speed the demise of that island's ice fields, hastening sea level rise.
The work, reported at this week's annual meeting of the American Geophysical Union in San Francisco , may help to discount critics' notion that the melting of Greenland 's glaciers is merely an isolated, regional event.
They recently recognized from using weather station records from the past century that temperatures in Greenland had warmed in the 1920s at rates equivalent to the recent past. But they hadn't confirmed that the island's glaciers responded to that earlier warming, until now.
“What's novel about this is that we found a wealth of information from low-tech sources that has been overlooked by most researchers,” explained Jason Box, an associate professor of geography at Ohio State University and a researcher with the Byrd Polar Research Center. Many researchers, he says, rely heavily on information from satellites and other modern sources.
Undergraduate student Adam Herrington, co-author on this paper and a student in the School of Earth Sciences, spent weeks in the university's libraries and archives, scouring the faded, dusty books that contained the logs of early scientific expeditions, looking primarily for photos and maps of several of Greenland 's key glaciers.
“I must have paged through more than a hundred such volumes to get the data we needed for this study,” Herrington said.
They concentrated on three large glaciers flowing out from the central ice sheet towards the ocean – the Jakobshavn Isbrae, the Kangerdlugssuaq and the Helheim.
“These three glaciers are huge and collectively, they drain as much as 40 percent of the southern half of the ice sheet. All three have recently increased their speed as the temperature rose,” Box said, adding that the Kangerdlugssuaq, at 3.1 miles (5 kilometers) wide is half-again as wide as New York's Manhattan Island .
Digging through the old data, Herrington found a map from 1932 and an aerial photo from 1933 that documented how, during a warm period, the Kangerdlugssuaq Glacier lost a piece of floating ice that was nearly the size of New York 's Manhattan Island .
“That parallels what we know about recent changes,” Box said. “In 2002 to 2003, that same glacier retreated another 3.1 miles (5 kilometers), and that it tripled its speed between 2000 and 2005.”
The fact that recent changes to Greenland's ice sheet mirror its behavior nearly 70 years ago is increasing researchers' confidence and alarm as to what the future holds. Recent warming around the frozen island actually lags behind the global average warming pattern by about 1-2 degrees C but if it fell into synch with global temperatures in a few years, the massive ice sheet might pass its “threshold of viability” – a tipping point where the loss of ice couldn't be stopped.
“Once you pass that threshold,” Box said, “the current science suggests that it would become an irreversible process. And we simply don't know how fast that might happen, how fast the ice might disappear.”
Greenland 's ice sheet contains at least 10 percent of the world's freshwater AND it has been losing more than 24 cubic miles (100 cubic kilometers) of ice annually for the last five years and 2007 was a record year for glacial melting there.
Source: Ohio State University, by Earle Holland
Yes. Even though the "reporter" thought they were helping the GW cause, they actually undermine it, don't they?
How can that be???
Then we need it to be "shipped" into the Lake of Okeechobee, that is our major water supply in South Florida, which level is low because they let water from it by wrong calculation!!!
I always wondered where the former Florida chad counters would find a job.
Water, water, water... I need fresh water...
Somebody get me a cup of North Pole Ice.
The system used to measure temperature kind of fell into some serious disrepair (check all the FreeRepublic stories over the last 6 months about weather stations ~ just incredible stuff).
I don't know whether to worry, or say, "Hey, another 70 year cycle, and what does that mean?"
While driving past my old neighborhood (which was recently destroyed by an expansion of I-70 and the consequental burying of an openly accessible Clovis hunting site) just the other day I realized there were "ripples" ranging from just South of there about a mile and a half to somewhere around Noblesville.
These "ripples" were low glacial moraines formed as the 2 mile high ice sheet that used to loom over Central Indiana retreated in fits and starts, that is, in "cycles".
If cycles existed during that sort of climate, why should today's far less robust climate be exempt?
It's that third kind that represents the greater part of the Antarctic ice.
Since it's not currently "floating", if it melts it raises the ocean level worldwide. In fact, it can do the same trick if it's somehow launched into deeper water where it can float.
If you want a tabletop demo try this. Fill a glass with water. Freeze it. Fill another glass with water. Freeze it. Then, worry the ice out of the first glass (being careful not to break it) and place it on top of the second glass. Once all of it melts you will have a very wet table top.
So Greenland warmed before it cooled, then it’s warming again? Shades of Kerry/flip-flopping! ;-)
Problem, Greenland isn't melting it's gaining Ice
From the European Space Agency ERS altimeter survey shows growth of Greenland Ice Sheet interior
Greenland ice-sheet elevation change in cm/year (see colour scale) derived from 11 years of ERS-1/ERS-2 satellite altimeter data, 1992-2003, excluding some ice-sheet marginal areas (white). +5.4 cm/year, or ~5 cm/year when corrected for bedrock uplift.
“Global warming” hoax BUMP!
So far he and the Clintons are at the top of my list.
Quick! Throw another virgin into the volcano to appease the volcano gods before it erupts!
Oh, nevermind. Global warming is going to require a larger sacrifice than a virgin.
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