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As part of an ongoing look at big climate shifts in the Arctic and what they may portend for the rest of the globe, Andrew C. Revkin headed north for the third time in two years to chronicle the shifts on Greenland and researchers' efforts to understand them. Periodically, dispatches from his trip were posted below.

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Heading for Home
Andy C. Revkin/The New York Times
The glacier flowing toward Kangerlussuaq from the interior ice cap.

KANGERLUSSUAQ, GREENLAND | 5.23 12:15AM
Heading for Home
By ANDREW C. REVKIN

KANGERLUSSUAQ, GREENLAND, May 22 -- Most places have rhythms of sorts.

Thank God it's Friday is an American one, the siesta is a Latin American one. Here the rhythm is the "flight period," the week-long stretches in which the New York Air National Guard's capacious, sturdy LC-130's arrive, fly to and from the high ice of the interior, then return to upstate New York.

On Saturday, 19 scientists, leathery ice-core drillers, support staff and others boarded one of three of the planes after a last night of farewells and toasts, some of them made with drinks chilled with "party ice," cracked pieces of faulty cores extracted from high on the glaciers.

Around a couple of tables, a dozen or so of the scientists and workers gathered on Friday night, eating hamburgers and sharing war stories from the planet's two farthest and least trammeled ends.

The "party" in party ice refers to the bubbles of air locked in the frozen water. The deeper the core, the more pressure is on the ice layers and the more compressed the bubbles. As they start to melt, a drink fizzes and pops.

Dr. Joseph McConnell, 45, the ice expert from the Desert Research Institute in Reno, Nev., had brought this batch of ice, useless for science, back from the three-week transect he and his crew had done where the Arctic Circle cuts across Greenland.

They drilled four cores along the way to test whether they can discern different traces of metals and chemicals that indicate whether wind patterns in a particular year were coming from, say, North America or Europe. This information, when meshed with data on temperature and snowfall, could help determine if trends over Greenland were part of regular shifts in air circulation over the North Atlantic.

The sample in the plastic bag on the table was from 144 meters down, and thus was from "before the Civil War," Dr. McConnell said.

Jay Kyne, 45, who had been drilling ice cores since he was an engineering student at the University of Nebraska in 1989, talked of his 11 Antarctic and 13 Greenland expeditions, and a few chasing Dr. Lonnie Thompson, a legendary ice scientist from Ohio State University whose focus is extracting cores for climate clues from the fast-vanishing glaciers on tropical peaks. He had dragged crews across the Andes and Himalayas, working above 18,000 feet a total of 800 days.

Talk also was of summer plans, with a few of the bunch taking a few weeks off before preparing to head to the opposite end of the Earth. Sarah Harvey, 48, the cook from Summit Camp, was taking six weeks "off" to cook on pack trips into Yellowstone National Park.

But all were sooner or later going to return to this frosted island, twice the size of California, heaped with enough ancient frozen water that, if it were to melt or slide into the sea, would raise the global oceans, from Tahiti to Boston, 21 feet.

There was a sense of urgency in the voices of some of the scientists, who still could not tell if their measurements of accelerating melting and iceberg release here were part of some natural cycle or part of a new climate shift on an increasingly human-altered Earth, where carbon dioxide, the main heat-trapping emission from human endeavor, was approaching double the level of traditional levels.

"To the Arctic," said Robin Abbott, the manager of all the research being conducted here under National Science Foundation grants. She had acted all week as a cross between den mother, boss, and old friend to the mostly-veteran polar-science crews coming and going.

"To the Arctic," came a return chorus.

And Saturday morning the planes revved up, their skis raised for now, and prepared to arc over the giant gleaming ice cap one last time before turning south for home.

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Nothing Comes Easy on an Ice Cap
Andrew C. Revkin/The New York Times
A view of the ice cap flowing toward Greenland's west coast. From above, one finally understands what scientists mean when they say that ice is a "hot solid," something plastic, like forge-heated metal.

GREENLAND ICE CAP | 5.21 4:34PM
Nothing Comes Easy on an Ice Cap
By ANDREW C. REVKIN

SWISS CAMP, ON THE GREENLAND ICE CAP, May 21 – The agile Twin Otter aircraft, a legend of the Arctic that can land across a runway in a strong headwind if need be, dipped onto the snow after flying for an hour over the white vastness.

It disgorged four researchers, one journalist, and heaps of plastic and aluminum containers with food, instruments, a tent-repair kit, computers, fuel, and other items needed for three weeks of field work on the globally important puzzle locked in the ice underfoot.

The question comes down to this: Is the miles-high pile of ice cloaking this vast island in balance or not? Are its edges losing more to icebergs and melting than its summit gains each year in snow?

If the answer is yes, Greenland’s meltdown could accelerate the rise in sea levels under way on a warming planet. Or the influx of fresh water into the North Atlantic could disrupt warm currents that keep Europe balmy enough that roses can be grown in Norway at a latitude where, elsewhere, polar bears roam.

One of the best places to find answers was the point about halfway between the heights and the coast. That is where this camp was built in 1990. Its creator was Dr. Koni Steffen, a glaciologist at the University of Colorado in Boulder, and a prime specimen of a subspecies of scientist obsessed with ice.

This was his 29th year of polar research. He had just been down by the sea for about two weeks, studying the floating ice tongue of the giant Petermann glacier, in the northern edge of Greenland, which is melting away from below at a ferocious pace. (Related Map)

With one day of rest, he now brought his team here for a new burst of work through mid-June.

In some fields, science is not much more physically rigorous than doing a crossword puzzle. Arctic science is otherwise.

They found the camp in tatters. Tarps over the three snowmobiles stored there all winter were shredded. Each machine’s engine was packed with snow and ice, requiring gloves to be shed as the men opened air filters and carburetors in the bitter 25-knot wind.

One of the three skylights brightening the plywood vestibule of the half-buried research bunker had been punctured. Snow had filtered everywhere. Icicles festooned the sandals hanging on pegs on the wall.

It took more than an hour but the group was able to free the snowmobiles and get them moving.

The vehicles would soon be used to set out global positioning beacons allowing the subtlest movements of the ice sheet to be tracked.

But about a ton of gear remained to be stowed.

Not all would be grunting and frostbite. Thanks to Dr. Steffen, who is Swiss (and named the camp, no surprise), the camp was equipped with a bread-making machine, a fondue pot, and a sauna. Steaks and sushi were served on occasion.

The first sign of the finer side of Arctic science came as Nicolas Cullen, a team member also from Boulder, proclaimed it was time for tea.

But nothing comes easy here.

The prime ingredient, water, only exists in its frozen state.

Mr. Cullen lit the stove, climbed out through the door in the ceiling, grabbed a shovel and blue barrel, and headed to the nearest drift.

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A Scene from the Ice Age
Andrew C. Revkin/The New York Times
Greenland's ice, some laid down 150,000 years ago, contains an archive of past climate and environmental conditions in its many layers. Here along the edge of the ice cap, spring warmth is melting the ice, forming a flowing milky river.

GREENLAND | 5.20 9:35PM
A Scene from the Ice Age
By ANDREW C. REVKIN

KANGERLUSSUAQ, GREENLAND, May 20 ­ It could have been the tail end of the Ice Age, 13,000 years or so ago, and the scene would likely not have been different.

A carpet of brushy shrubs, lichens and grasses, just showing the first green tinge of spring, ran up a U-shaped valley and over a ridge, ending just in front of the towering frozen walls marking the perimeter of this Arctic island’s giant ice cap, two miles deep at its heart.

As four of us crested the ridge after an hour’s hike, silhouetted against the ice cliffs, just a hundred yards away, a musk ox snorted. Its face was framed by curving horns and its coat was so lush and flowing that it swept the ground as if someone had thrown a shag rug over a boulder. It was a relic of the days when far larger creatures ­-mammoths included -- vied with it for Arctic grazing rights. Musk oxen had been extirpated here by hunters long ago, reintroduced in the 1960’s, and now number more than 3,000 in western Greenland. This one knew what to do when facing humans. It galloped up the ridge, its coat bouncing like a model’s tresses, and vanished.

But the Ice Age was only one of the eras represented in this timeless vista. The ice cap, marked by horizontal bands from top to bottom, was tens of thousands of years old, squeezed out from the depths of the ice sheet by the enormous pressures sustained as fresh snow accumulated on the top.

One of my companions was Dr. Joseph McConnell, a glacier expert from ­ of all places ­ the Desert Research Institute in Reno, Nev., which had devised a host of ways to dissect cylinders of ice extracted from glaciers for clues to past climate and environmental conditions. The ice far above us, he said, spoke in its darker layers of great volcanic eruptions of old. Invisible traces of iron marked the advent of the Iron Age. Traces of lead chronicled the arrival of the industrial age and more recently the invention of leaded gasoline.

The white cap on Greenland also marked human triumphs, like the ban on lead that caused a drop of 85 percent in the the amount in layers of young compacting snow compared to earlier toxic peaks.

But today’s scene spoke mainly of those days longest ago when North America had its own great miles-high ice sheath, when humans saw ice only as an advancing peril not as one whose threat in a warming world lay in its retreat.

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Biology Revealed
Andrew C. Revkin/The New York Times
The ice has pulled back from the shores of Lake Ferguson in western Greenland, signalling the arrival of spring in this Arctic wilderness.

Bottom: Bill Burnham, the founder of the Peregrine Fund, with a captured well-worn female falcon.

GREENLAND | 5.19 8:12 PM
Biology Revealed
By ANDREW C. REVKIN

KANGERLUSSUAQ, GREENLAND, May 19 - Greenland, flushing with spring around the edges, showed its biological side on Wednesday.

Fingerling Arctic char, and one keeper of 15 inches, darted in the glass-clear shallows of Lake Ferguson, whose white winter sheath was in full retreat under the unfiltered Arctic sun and 60-degree noontime temperatures.

Several musk ox, distant woolly lumps, slowly nuzzled through still-leafless willow and birch. But this was no forest. In the Arctic, plants that are elsewhere familiar as trees grow no higher than your thigh.

Snow bunting flitted along the soaring glacier-polished bluffs lining the fjord that runs from this town of Lego-like buildings for 100 miles to the west coast. Northern wheatear flashed their white and black backs as they darted and twittered in the brush, which was just beginning to show some green. The brief full explosion of vegetation (and, thankfully, mosquitoes) was another week or two away.

The bird's caution was well advised. Even as these songbirds arrived in mid-May, so too did their nemesis, peregrine falcons, migrating here to breed after spending the winter as far away as Cuba and Brazil.

They were cached in nooks high on the cliffs, some marked by a "whitewash" of centuries of guano, but ready to stoop and kill at the first glimpse of fluttering wings below.

My guide to the ways of Greenland's birds, and especially its sharp-beaked, sharp-eyed raptors, was Bill Burnham, the founder of the Peregrine Fund, a nonprofit group in Boise, Idaho, devoted to restoring peregrine populations and studying and conserving many other birds of prey. He, his son and their faded red Volkswagen minibus had been flown here by the 109th Tactical Airlift Wing of the Air National Guard so they could start capturing and tagging peregrines and gyrfalcons.

More than 30 years ago, when Mr. Burnham began his work, peregrines, decimated by DDT, had vanished from the United States east of the Mississippi.

An American airman who was an amateur falconer had spotted peregrines here while stationed at the airfield when it was an American Air Force base. Mr. Burnham first came to have a look in 1972. Starting in 1993, his group started a full-time project studying Greenland's falcons. Now Mr. Burnham's son, Kurt, a biologist who was literally weaned 29 years ago alongside captive-reared falcons, navigated their creaking van up a 20-mile dirt track leading inland toward the transition point between brown bedrock and dust and the white looming walls of the ice cap.

Lest anyone need proof that this part of Greenland is, well, a bit unusual, this road was built a few years ago by Volkswagen so it could establish a secretive test track for auto prototypes up on the ice sheet, far from the prying eyes of industrial spies.

And then there was the local golf course we passed while peregrine tracking, built on a sandy river floodplain, with colored flags marking the tees and holes and rushing torrents of glacial meltwater constituting the water hazards.

And the shiny, dispersed carcass of a small airplane remained where it had disintegrated long ago after smashing into a gravelly hillside.

Along the way, the Burnhams pointed out some of the 150 peregrine eyries, or nesting spots, they had mapped over the years.

Now it was time to turn the tables on the swift predators and catch one. The first attempts attracted no falcons. But after two hours of driving and hiking to known or suspected nesting spots, the Burnhams moved to a spot just a few hundred yards from the airfield, on a flat gravelly spot beneath a looming gray bluff. They set out the lure, a pigeon shielded by a hard sheath covered with loops of nylon that entangle the falcon's talons. This time, a female plunged like a gray streak to the target. The hunter, now quarry, was trapped (And the pigeon unscathed.)

The elder Mr. Burnham, showing no signs that his 57 years were an impediment, pounced on the fluttering two-pound female. In an instant, a talon perforated the fleshy end of his left middle finger, but he clenched his teeth and held on.

"You can see she's not scared, she's angry," Mr. Burnham said. The birds large black eyes pierced those of each person they glared at.

"Were going to borrow ten minutes of her time here, then she's going back to her eyrie and do what she needs to do," he said. Soon she would lay one egg every other day until she had a clutch of four. After a few weeks, the young would hatch, and 45 days later they would take flight.

The bird, wearing faded ankle bands with codes the biologists would look up later, was clearly a veteran of many migrations that the Burnhams estimated to be 12 to 14 years old.

Kurt Burnham placed a leather hood over its eyes and weighed, measured, and drew a few drops of blood from the falcon for genetic tests.

He noted a broken middle toe on the left foot.

"Diving at 200 miles an hour into a pigeon or duck flying at 60 miles an hour is bound to do damage," the father said.

Overall, the bird was strong and healthy, like the species itself having weathered tough times.

Peregrine numbers here have greatly increased, the father said, apparently a reflection of the general recovery of the species after the ban on DDT.

Now they were also showing up in rising numbers in the far north of Greenland, possibly expanding their range as a response to climate change, Mr. Burnham said.

This bird, quieted by the hood, was ready to go free. Mr. Burnham gingerly handed the falcon to Toby Travelstead, a science technician on a break from research on the high ice, so he could have the honor of releasing it. He counted to three and gently flung it into the air. With a series of quick chirps, the falcon blasted away, arced over the minibus and soared back toward the bluffs, which were stained dark with water seeping from the melting ice far above.

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Seeking Clues in a Vast Frozen Mystery
Andrew C. Revkin/The New York Times
Bob Hawley, a glaciologist at Summit Camp atop Greenland's ice cap, heads into the deeply buried room where the composition of the air over the ice is monitored.

SUMMIT CAMP | 5.18 6:43 PM
Seeking Clues in a Vast Frozen Mystery
By ANDREW C. REVKIN

SUMMIT CAMP, GREENLAND, May 18 – Two kinds of edgeless whiteness confront those who fly over the frozen, two-mile-high, 1,200-mile-long hump called Greenland: layers of low clouds and the horizon-to-horizon sprawl of the ice cap itself. It is important to recognize the difference.

As they made a supply run on Tuesday to the highest point, where scientists are probing for clues to climates past and future, one of the Air National Guard’s bipolar LC-130 crews – fresh from Antarctic duties – described how more than a few pilots had flown straight into the ascending convexity of Greenland in years past, presuming it was just another cloud bank.

But the pilot, David Koltermann, was having no such troubles on this sun-splashed day. From six miles away, no radar required, he saw the cluster of dark dots, like fleas on an albino elephant, marking where scientists had been pricking Greenland with motorized drills for nearly two decades to extract a climatic timeline going down 10,000 feet and back 100,000 years and more. He lowered the sturdy skis mounted beneath the fuselage of the 45-ton Hercules cargo craft and touched down softly on the 15,000-foot “skiway” – not a runway – maintained by workers at the research camp.

Among those arriving for a four-month stint on the high ice was Sue Novak, the new cook, fresh from her job at the Belton Chalet resort, just outside of Montana’s Glacier National Park. No Atkins-obsessed tourists here. She would be feeding between 15 and 25 scientists and camp workers somewhere around 4,000 or so calories a day. The outgoing chef packed a box lunch for the Air Guard crew of pepperoni and jalapeno pizza, dense brownies, and palm-size chocolate-chip cookies.

Food is important in the Arctic.

Ms. Novak watched to be sure the arriving boxes with fresh produce were quickly moved out of the 28-degree-below zero air and into the “Big House,” a building that had originally stood above the surface on stilts. Because of accumulating snow in Greenland’s midsection, it had been jacked up 15 feet but now peeked out from a depression.

The science here was originally focused on unveiling a record of conditions long past, archived as each year’s accumulation of snow was buried and compressed and – after 200 years and a descent below the surface of 200 feet – became ice.

In the last few years, though, scientists have begun to focus on what appear to be big changes in the overall balance of accumulation and loss of ice here, with the difference – if any – representing Greenland’s contribution to changing sea levels.

At elevations as high as 6,500 feet, where for decades it had always been too cold for ice to melt, ice was now trickling away as water in the spring and summer, and some glaciers along the coast were falling apart because less ice was flowing down from the interior to sustain them.

Aerial and satellite maps of the ice were showing its surface in many places was descending, meaning more mass was being lost around Greenland’s perimeter than gained through all that annual snowfall up high.

Many scientists have already concluded this is one consequence of global warming from building atmospheric concentrations of heat-trapping smokestack and tailpipe discharges.

But many of those who know Greenland best say that, while they are convinced humans are contributing to warming and serious problems lie ahead, the dynamics maintaining this impossibly vast island of ice remain a puzzle.

Bob Hawley, a 34-year-old glaciologist from the University of Washington, was leaving Summit Camp today on the return flight after weeks of work testing characteristics of ice cores from different depths and ages. But his plan was to turn around almost immediately and fly to a lower ice camp, called Raven.

There he would drill shallow boreholes – just 50 or 100 yards deep – and drop video cameras down them to assess whether some of the estimated ice loss was actually simply the uppermost layers of snow compressing on themselves.

If this were the case, then the vast sloping ice sheet could be shrinking but not necessarily losing any mass of water. This might eventually show that Greenland was contributing less to rising sea levels than some experts thought, he said. Or it might not.

Mr. Hawley said one of his favorite professors was once thrilled to have a pet theory proved wrong, because in that proof lay new knowledge about how the world works.

And that drive to understand this vast frozen mystery was what was keeping Mr. Hawley up here, far from his geologist wife back in Seattle, who wouldn’t have much to do should she accompany him here, seeing that the nearest rock was 10,000 feet straight down.

The pilots, who never shut down the plane’s engines, signaled that it was time to go, to avoid the risk of the plane’s skis freezing fast to the ice.

As it turned out, they nearly did so anyway. Initial thrusts of the throttles failed to budge the plane.

But some quick thinking by Shad Gray, the flight engineer, liberated the Hercules, named “City of Cohoes,” and she lumbered along until, at around 70 knots, the crew ignited the eight rockets tucked along her flanks that spewed flame for 10 or 15 seconds, adding four tons of thrust and pushing the portly craft into the air.

She rose above the ice cap, and I suddenly appreciated what it was: an inverted sea of frozen water, measured in height instead of depth.

Its losses would be our liquid oceans’ gain.

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No Better Location to Study the Dimensions of Climate
Andrew C. Revkin/The New York Times
Big stretches of coastal Greenland are not covered with snow or ice, but the interior is piled so high with it that, should all the island's ice melt, it would raise seas worldwide more than 21 feet.

GREENLAND | 5.17 7:42 PM
No Better Location to Study the Dimensions of Climate
By ANDREW C. REVKIN

KANGERLUSSUAQ, GREENLAND, May 17 -- The polar science season has switched ends of the Earth. The powerful four-propeller LC-130 cargo transports of the 109th Tactical Airlift Wing of the New York Air National Guard that for five months had been ferrying supplies and scientists to and from Antarctica are now heading here.

Along with 18 scientists, Air Guard personnel, and research support staff, I was tucked into the belly of one at dawn as it left its home base in Scotia, N.Y., a dozen or so miles from Albany, to make the six-hour, 1,800-mile flight north northeast to the world's largest island (presuming you don't count Australia, of course).

The plane's cargo bay was easily big enough to hold a city bus, but in this case, along with the passengers and crew, held several pallets of scientific gear and supplies, an aging red Volkswagen minibus — and several perforated boxes loaded with softly cooing pigeons.

The pigeons and the VW were to be used in a research project of the Peregrine Fund, a private group, studying migratory patterns and populations of the fast-flying raptors.

But most of the people heading to Greenland this spring and summer are focused on the climate, past, present, and future.

There is no better place to understand all of those dimensions than Greenland, where an extraordinary volume of ice — a tenth of all the frozen fresh water on Earth — both contains clues to the past in its layers and, in its melting, could contribute to one of the costliest anticipated impacts of global warming.

Greenland is, after all, where scientists nearly 20 years ago first pierced the ancient two-mile-deep ice sheet and extracted slender cylinders providing a record of climate changes over 120,000 years. In so doing, they discovered some of the most compelling evidence that conditions could change abruptly sometimes in a matter of a decade. The two biggest upheavals came 8,200 years ago and nearly 12,000 years ago, sending the northern hemisphere into prolonged cold spells well after the last ice age had ended.

But this was not just about climate history. Greenland's ice could play a powerful role in shaping the impacts of future climate shifts, particularly if warming continues from building concentrations of heat-trapping greenhouse gases.

Were it all to melt, Greenland's two-mile-high ice sheet would raise sea levels worldwide more than 21 feet — and that is just Greenland's contribution, not counting Antarctica or other terrestrial glaciers. Of course, even in a worst case, it would take centuries for the sprawling ice sheet to disappear, leaving Greenland's undulating long-hidden surface exposed for the first time in 125,000 years or so.

But the rate at which ice below a mile or so in elevation has been melting and moving toward the sea has picked up sharply in recent years, glaciologists working here have reported. Aerial and satellite surveys using lasers and radars and global positioning beacons have measured the shifts with growing precision.

Still, paradoxes abound. Even as the pace of melting has increased, temperatures around the island, surrounded by chill currents, have been cooling even as most of the rest of the Arctic has seen a record warming trend.

All the more reason for scientists to spread out on these ice sheets and the shelves that jut into the dark cold sea, which is so thick with icebergs in some places that, from an airplane's height, they resemble a dusting of white pepper.

We flew into this former military base 100 miles up a fjord from the west coast, in a region with a remarkably mild climate, where the ground was already free of snow and ice for many miles around. Arriving here and stepping out of the plane, still chilly from its miles-high cruising height, the passengers -- some of whom had donned their parkas -- were jarred to feel spring warmth of 50 degrees or so.

The ancient brown and gray bedrock hills, bereft of soil, baked in brilliant unfiltered Arctic sunshine along with ranks of reindeer antler racks lined up in front of one of the barracks-style hostelries near the runway.

Out of the belly of the plane came strapped bundles of silvery tubes that would soon hold newly-cut cylinders of ancient ice extracted from the depths of Greenland's white cloak.

Out, too, came coveted fresh produce — tomatoes, lettuce, fruit — that would soon be sent to various research camps to provide a break from canned goods and camp fare.

And out came the newbies, myself included, workers and visitors and Guardsmen who were setting foot on Greenland's shores for the first time. The novice Guardsmen would face a blue nose ritual later in the week, their veteran colleagues announced. The ritual had something to do with blue chalk and drinking.

Tuesday, I plan to fly on the LC-130 with a group of workers and scientists to the 10,626-foot summit, the highest spot on the island's continental divide from which all the ice — formed as accumulating snowfall compresses — slowly flows toward one coast or the other.

This makes it the perfect place to drill deep and find ice that has not migrated anywhere and has lain there, holding climate secrets in its chemistry, its air bubbles, its traces of radioactive isotopes.

Unraveling the mysteries of this part of the Arctic is not an academic exercise, but a vital means of improving the still-murky picture of how further global warming could reshape our world, climate scientists say.

Particularly because of its potential impact on sea levels, Greenland must be paid attention to, said Dr. Richard B. Alley, the glaciologist from Pennsylvania State University who helped drill some of the first deep cores here and whose book on that work, "The Two Mile Time Machine," was my reading material for the long flight.

In an interview a few days before I flew north, he told me the importance becomes clear when you consider the world you hope to leave for generations yet unborn.

If you really want to give Miami to your great-great-great-grandchildren, he said, then you've really got to worry about Greenland.

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5.13
Ice Trends on Greenland
By ANDREW C. REVKIN

Around the edges, Greenland's great mass of ancient ice, which has piled up nearly two miles high across the world's largest island over 120,000 years, is both melting and sliding into the sea at a disturbingly accelerating rate. Already in some places, the coastal erosion of the great ice sheet has been fast enough to cause interior ice fields to measurably slump.

The changes are forcing theorists who had once seen the island's ice as relatively stable to rethink their projections for how the ongoing global warming trend, driven partly by human actions, could affect sea levels in coming decades and centuries.

Understanding Greenland's ice trends is vital, scientists say, because it accounts for 10 percent of the Earth's total bank of frozen water — enough to raise seas more than 22 feet should it all flow into the sea.

The changes have come to light through the application of new, extremely precise measurements of the ice that allow its motion, both horizontal and vertical, to be tracked to the scale of inches. The seaward flow of some glaciers along the west coast has increased from about 7 yards a day to 24 yards a day in just the last 10 years, say scientists from NASA, the University of Colorado, and other institutions and agencies working there.

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READERS' OPINIONS
Forum: The Environment
A question was posed by cohen004b in the Environment Forum: I know that Antarctica is very dry with the South Pole getting maybe one inch of precipitation a year. What is the average annual precipitation in various parts of Greenland and does almost all of it fall as snow?
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RELATED RESOURCES
Greenland Ice Sheet Flows Faster During Summer Melting (www.gsfc.nasa.gov)
Recent Warming of Arctic May Affect Worldwide Climate (www.gsfc.nasa.gov)
Arctic and Antarctic Sea Ice Marching to Different Drivers (earthobservatory.nasa.gov)
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