Flashback 1977: West Antarctic Ice Sheet Melt To Raise Sea Level 20 Ft. – National Science Foundation reveals: ‘It has nothing to do with a warmer climate, just the dynamics of unstable ice’
Ronald Kotulak. The Tribune’s award-winning science editor, recently returned from a reporting trip to Antarctica. This is the first of several. stories reporting what he found there. Others will appear from time to time. In Monday’s Tribune, Kotulak will report on the enormous mineral wealth that may make the frozen, almost inaccessible area near the South Pole the scene of the world s last big land rush.
ROSS ICE SHELF, Antarctica-A huge portion of the Antarctic ice mass appears to be collapsing into the sea, a catastrophe that could raise the levels of the oceans by almost 20 feet.
Scientists have been working feverishly here at this cold, remote site to drill holes through the quarter-mile-thick ice shelf to learn more about the danger. Others have been examining different sections of the ice in search of clues.
They have found startling evidence that the destructive surge in sea levels could occur in the next 300 years, creat ing havoc for New York, Los Angeles, New Orleans, and other coastal cities around the globe.
THE COLLAPSE of part of the Antarctic ice sheet could occur gradually over the next 300 years, said Dr. Terrence J. Hughes, a University of Maine glacial expert brought here to study the unstable ice.
At first it might raise sea levels by a few inches a year with a much bigger increase toward the end of the collapse, he said. But it is impossible to predict how fast the ice might disintegrate.
This threat has caused such concern that the National Science Foundation ], which oversees American interests in the Antarctic, has earmarked one-fourth of our $45 million research effort here to learn more about the threatening condition of the ice sheet.
“We’re doing about the most we can do right now to study the possible collapse of the west ice sheet,” said Dr. Richard Cameron, NSF program manager for glaciology. “It has become an area of concern because we could be on the brink of a rise in sea levels.”
SUCH A RAPID rise is not unprecedented. It may have caused the Great Deluge described in the Old Testament.
The submergence of ancient coastal cities, believed to have occurred about 8,000 years ago, may have been caused by the sudden collapse of a similar ice blanket over the Canadian Hudson Bay area, said Hughes.
“I believe that the collapse of the Laurentide ice sheet [over Hudson Bay] could have caused the flooding of the Great Deluge,” he said.
The Hudson Bay ice sheet was a remnant of the last great Ice Age that gripped the earth. It started about 18,000 years ago and converted so much water into ice that ocean levels dropped 6oo feet.
So much of the continental shelves was drained that the land made up One- third of the earth s surface, compared with only one-fourth today.
Some scientists believe the Hudson Hay ice sheet broke up in about 200 years, possibly less.
THE LAND mass that makes up the Antarctic continent at the bottom of the world is one and a half times as large as the United States.
But it is covered almost completely by ice whose average thickness is one mile. In some places it is up to 2.8 miles thick. Ninety per cent of the earth s fresh water is locked in Antarctic ice,
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Fear of Antarctic ice would flood coastal cities-
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making a gigantic ice cube containing than 7 million cubic miles of ice.
There is so much ice there, in fact, that if it all melted, it would raise sea levels by 215 feet. The water would rise -almost to the chest of the Statue of Liberty.
Sea levels have fluctuated in the past. About 120.000 years ago. the oceans were 20 feet higher than today. leading some scientists to speculate that the same portion of the Antarctic ice sheet now in danger of disintegrating has collapsed once before.
ThE at stake is the West Antarctic Ice Sheet, which is separated from the eastern section by the Trans- Antarctic Mountains. It is much smaller than the ice sheet, which is considered highly stable.
Nevertheless, the western ice sheet is huge, reaching a depth of 10000 feet. It ‘has big glaciers that moee more than half a mile a year.
Until recently, the giant ice sheets have been ignored, primarily because of their inaccessibility but also because scientists had dismissed them as unchanging features.
But a new generation of glaciologists has begun poking around the frozen continent the last 8 to 10 years, and what they are finding has government officials worried.
THE STAGGERING aspect of the research is the discovery of a potentially catastrophic phenomenon that had been totally unexpected.
‘We’re seeing the West ice sheet on its way out,” said Cameron. “It seems to be doing something completely different than the east ice sheet. It has nothing to do with a warmer climate, just the dynamics of unstable ice.”
The evidence turned up so far is convincing from the glaciological and geological standpoint that something dramatic is happening. he said.
“It is a rather rapid change for an area that we thought was so static for such an awful long time.” said Cameren.
“There is no way to stop the disintegration of the ice sheet once it starts.’
THE MAJOR U.S. effort to understand – more about the ice sheet started this year with the Ross Ice Shelf Drillin Project [RTSP1.
The Roes Ice Shelf, an incredible hunk- of ice that bottles up the Ross Sea. is the size of Spain and up to 1.409 feet thick. Scientists believe it was formed by glaciers pouring !ce into the sea.
Three holes were to be drilled into the shelf during the 1976-77 summer season here, which runs from October through January.
One hole would have provided core samples to tell the age and history of the ice. Another would have been drilled all the way through to find out what is going on underneath the shelf. All would have shed new light on the condition of the shelf.
BLUT ALL hol-s failed. The biggest enemy was the ice, which closed in on the holes or froze the drill bits so they couldnt be removed.
Cameron, who was visiting the Ro s project when the last attempt fizzled,
said the project is of such importance that it will be resumed next season.
An even bigger prog-am is planned next year with the start of the West Antarctic Ice Stream Project . he said. The terrain of the high ice sheet is rugged and dangerous. but Sci- will be sent there to study’ the condition of the ice and the movement of the powerful glaciers.
THE REASON for the is that it has been only in the last two to three years that scientists began to realize that giant ice sheets could break up rapidly.
They used to believe that these huge glaciers retreated timidly, slowly melt- ing and creeping as they shrank. The retreat was thought to take thousands of vears.
Now there is evidence of a new proc- eQs of 7-tion that ‘ekes the form do cs a tea prt sta–. In the new break- .p . “.” the ice sheet flows rapidly forward like a slov- motion avalanche,
In an avalanche, one rock falling from the top of a causes many oth- er rocks to fall. In the same , calv- ing starts with big icebergs breaking off the main sheet. A bay is formed in the sheet where the ice falls off. reducing the structural integrity of the sheet and encouraging even more ice to break off.
One reason for the increasing speed of th’ ?wr2 lc that the movement of the glacier produces friction. generating heat at the bottom. A layer of water is formed that acts as a lubricant to accel- erate ice flow.
THEltE ARE indications that the -on Bay ice sheet broke up this wav and that it may be happening to a gla-
cier near Greenland in the Arctic Circle.
The Jakobshavn Glacier in Greenland is moving into the sea at the incredible rate of 4.25 miles a year. Fortunately this does not pose muck danger to ocean levels because the Arctic contains very little ice, compared with the Antarctic.
Scientsts; will study the Jacobshavn Glacier flis summer to learn about the calving proce -. sa d.(‘Cnt on.
The Byrd Glacier. ‘ – “i!t of the West Ice Sheet. is murch more slowly, about one-tenth the sp2ed of the Jakobshaavn Glacier.
Its progress, however, may he slowed by the Ross Ice shelf. which is acting like a gigantic stopper, said Hughes. The glacier is hitting the shelf at the rate of 1,650 feet a year.
IF TIlE ROSS Ice Shelf loose. then it could uncork the glaciers, lead. ing to a rapid collapse of the West Ice Sheet, he said.
Another big ice shelf. called the Ronne Ice Shelf, is blocking the Weddell Sea on the opposite side of the ice sheet. Al- though smaller than the IHoss shelf, it. too. may be acting like a stopper.
But how long can the ice shelves hold back the immensely powerful glaciers?
Evidence uncovered at the Ross drill- ing site revealed that in the last 30 to 40 years, some sections of the Ross shelf have thickened, indicating that the tre: mendous pressure from the glaciers is causing it. to buckle in the middle.
Measurements made with orbiting sat- show that the Ross Ice Shelf may be yielding, moving out into open water at the rate of 3.2 feet-a day, said Camer- on.
DR. GEORGE Denton, another Uni- versity of Maine glacial expert, recently has found evidence that the Ross shelf is rapidly disintegrating.
His research shows that at one time the shelf extended all the way across the Ross Sea to the present site of the
McMurdo station and that it was once so thick that it on the sea floor.
Within the. last 6,000 years,. the shelf has shrunk and no longer rests on the sea bottom; it is now floating.
Another piece of evidence is the shape
of the West Ice Sheet. A stable ice sheet looks somewhat like a dome with nicely rounded sides.
But the west ice sheet has sides like slides, indicating that a lot of ice al- ready has fallen away, Hughes believes
the dome of the shelf was at least 1,300 feet higher about 20.P.0 years ago.
As the Ross shelf disintegrates, the forces holding the ice sheet are reduced, possibly leading to a cata- strophic surge of the sheet. he said.