JULY 13, 2000
REPORTER'S NOTEBOOK
Unraveling Climate's Mysteries atop an Arctic Summit | A visit to Greenland, where scientists at a polar lab focus on the ozone hole above and the ice below
| Two hours ago, I felt slightly foolish, waiting for my flight on the airstrip at Kangerlussuaq, Greenland. I was overdressed, in a heavy, fur-lined Arctic parka, snow pants, and big, white, cold-weather boots. With the sun beaming down from a clear blue sky and the temperature pushing into the 80s, shorts and T-shirts were the appropriate attire for Kangerlussuaq, a former strategic air base at the head of the second-longest fjord in the world.
But I don't feel so silly now. The ski-equipped U.S. Air Force C-130 "Hercules" has slid to a stop on an ice runway on the vast Greenland ice sheet, 700 miles to the north. At more than 10,000 feet above sea level, I've arrived at the highest point above the Arctic Circle. Nice weather here as well. The sun beats down from that blue sky, and the flat snowfield stretches to a distant circular horizon. Temperature: 14F. Now I'm glad I have my winter gear on.
WEATHER WATCH: Geologist Konrad Steffen has placed 20 automated weather stations across the Greenland ice cap
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CREDIT: Alan Hall, BW |
This remote speck on the terra incognita of Greenland is called Summit, a research station operated by the U.S. National Science Foundation. Located at 72 degrees North latitude, it sits atop more than a mile of undisturbed packed snow that holds a record of earth's climate stretching back more than 125,000 years -- through the warm period that preceded the last great Ice Age.
CRASH AND BURN.
Overhead is the mysterious Arctic ozone hole, where concentrations of the curious grouping of three oxygen molecules, which shield life on earth from harmful ultraviolet radiation, declined as much as 60% from November, 1999, through March, 2000. In the 24-hour daylight of summer, sunblock is a necessity -- unprotected faces can sunburn in a matter of minutes. And higher up, charged particles from the sun follow the earth's descending magnetic field and crash into the upper atmosphere. Although they're invisible now, the spectacular displays of the resulting aurora light the winter darkness.
Summit is among a small elite of polar research laboratories where scientists are attempting to understand the inner workings of the immense engine that controls weather and climate. Calling this place home in the summer months is an international team of up to 50 glaciologists, geologists, meteorologists, and atmospheric chemists, sleeping in orange tents on the snow and taking their meals in a blue prefabricated building known as the Big House (see BW Online, 7/13/00, "Bedding Down on an Ice Cap"). "We are coming up with even more questions," says Jack E. Dibb, a photochemist from the University of New Hampshire.
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The average annual temperature here is indeed rising -- and at the rate of about 2F each year
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Summit is where the first two ice cores to reach bedrock were drilled in the early 1980s as part of a joint effort of the U.S., Denmark, and Switzerland known as the GRIP, for the Greenland Ice Coring Project. The site was selected because scientists surmised that ice would flow away from the highest point, leaving a vertical cross section below undistorted.
THIN AIR.
Unfortunately, though, the scientists drilling at Summit guessed wrong -- the deepest parts of the cores, marking the last period in the world's climate similar to ours, an interglacial period called the Eemian, were distorted. So the Danes selected what they hope will be a better site about 200 miles north of Summit. This season, the team at North GRIP, as it's known, hopes to complete an even more detailed core.
So these days, research at Summit focuses on what's happening in the atmosphere and the ice in the present. "The ice-core community needs to know the present climate and how it's changing," says Konrad ("Koni") Steffen, professor of geology at University of Colorado at Boulder.
Steffen, for one, is clearly at home in the thin air of Summit. He skates back and forth between the Big House and the black tent that serves as his lab on cross-country skis. I follow him on foot, and slowly. It's icy up here.
MAJOR MELTING.
Since 1990, Steffen has dotted the Greenland ice sheet with 20 automated weather stations that continuously monitor incoming solar radiation, snowfall, melting and evaporation of the ice, temperature, wind speed, and other parameters. Measurements are taken every 15 seconds and then beamed to Colorado by a satellite, where they're automatically posted to the Web. The data can measure the most minute changes in the thickness of the ice sheet across Greenland.
The observations have been unsettling so far. The average annual temperature here is indeed rising -- and at the rate of about 2F each year. "That's a huge increase," says Steffen. "We're seeing enormous fluctuations in warming in each season."
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"We are seeing very weird stuff in the snow," says one scientist
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Increasing rates of melting have major implications. The summer flush of ice and freshwater flowing south from Greenland is reflected two months later in changes in the course of the great ocean rivers -- the Gulf Stream, which swings westward to warm Northern Europe, and the cold Labrador current that brings nutrient-rich waters south to the fishing grounds off North America. Moreover, the added water raises sea levels, threatening to inundate coastal areas.
BREAKING THE ICE.
The big question: Is this an isolated event or part of a pattern over eons? Evidence from the ice cores indicates that Greenland's ice sheet shed armadas of icebergs at intervals of 1,000 years or more during the last period of glacial advancement, which extended from about 60,000 to 20,000 years ago. Between these outbursts were extreme climatic periods that, over Greenland, resulted in as much as a 60F rise in atmospheric temperature in 50 years.
It doesn't seem to take much of a temperature increase to trigger these events, however. When the ice surface is cold, the dry snow reflects most of the incoming solar radiation. But if it melts just a little bit, the small amount of water changes it rapidly from being reflective to being absorbent. And the rate of melting accelerates. "It can go very fast," observes Steffen.
Worse yet, the climatic cycles in Greenland seem to be mirrored by the even vaster ice sheet of Antarctica. Using cores of ocean sediment drilled by the research ship JOIDES Resolution, a team from the University of Florida reported in early June that parts of the Antarctic ice sheet were unstable during the warming spikes in the Northern Hemisphere, possibly because of rising sea levels or changes in ocean currents. And so far this summer, four massive icebergs have broken off from the Ross Ice Shelf -- the largest was the size of Rhode Island.
L.A. SMOG.
Just as the ice affects the oceans, it also has an important influence on the atmosphere. The snow contains trapped air and chemicals -- those spewed out by volcanoes, growing plants, and forest fires, and those made by humans. Some stay and others leave as the ice is compacted. By analyzing the chemistry of the snow, scientists hope to allow the core chemists to correlate the composition of the ice with what the real atmosphere looked like at the time.
More intriguing, the snow, which covers half the northern hemisphere in the winter, doesn't just lie there. It shapes the atmosphere above it by altering its composition and creating thermal gradients that direct the course of the great air currents like the jetstream. "We're trying to find out what the snow is doing to the atmosphere," says Dibb of the University of New Hampshire.
And from what Dibb and his colleagues are finding, the snow seems to be doing quite a bit. When the sun strikes nitrogen compounds trapped in the ice, light-activated chemical reactions involving the ice crystals convert the compounds into common nitrogen oxide pollutants, known as NOx. The result is Arctic smog. When the sun isn't shining -- as in the winter -- the reaction ceases. "It looks like Los Angeles smog chemistry is being transported to Summit," says Dibb, who adds, "we are seeing very weird stuff in the snow."
WINTER CREW.
Then there's the ozone issue. Just as nitric acid and ice crystals seem to be the agent of ozone's destruction in the upper atmosphere, so do nitrogen compounds in the ice sheet. The effects of ultraviolet radiation are apparent nearly three feet into the ice -- and it seems to destroy ozone as effectively on the snow surface as aloft.
These and other riddles won't be solved this season. And preparations are already under way for the next. There's one more building here -- it's known as the Greenhouse. It's smaller than the Big House and holds just a four-person crew, which will remain here over the winter to take readings and tend instruments.
Last winter, the Greenhouse was buried by the annual fall of new snow and drifting. Now, a trench has been dug around it, and in a few weeks, a construction crew will arrive and drag it onto the surface to serve as a home for the isolated scientists for another long Arctic winter.
IDEA OF NORTH.
Our small party is scheduled to fly out tomorrow morning to North GRIP on a tiny Twin Otter aircraft to spend a day and night with the Danes at their coring site, an hour's flight away. We're looking forward to the visit -- the North GRIP team is notorious in Greenland for its hospitality and respected for the quality of its science.
Steffen and some of the other scientists are also heading out and will be picked up by an Air National Guard C-130 tomorrow for a flight back to Kangerlussuaq and then home. But like the Arctic explorers who came here before them, the frozen North is a place that grips the minds of the team. Like many of the others here, Steffen has been at Summit every year for more than a decade.
Later, I e-mail Steffen in Colorado and ask if his trip home went well. Yes, he replies, but "it's too damn hot here in the mid-latitudes." He'll be back.
Further Information:
Background about the National Science Foundation's Arctic Program
Information about the science being conducted at Summit
Program in Arctic Regional Climate Assessment (PARCA)
CIA
factbook about Greenland
Hall reports on science and technology for Business Week Online
EDITED BY DOUGLAS HARBRECHT
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Copyright 2000 , by The McGraw-Hill Companies Inc. All rights reserved.
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