Arctic Melt Unnerves the Experts .. [ whew! one more mind-blowing photograph ] ..
Andy Armstrong/National Oceanic and Atmospheric Administration
Retreat A photograph taken in August from an icebreaker research cruise in the Arctic Ocean, about 600 miles north of the Alaska coastline.
By ANDREW C. REVKIN - Published: October 2, 2007
The Arctic ice cap shrank so much this summer that waves briefly lapped along two long-imagined Arctic shipping routes, the Northwest Passage over Canada and the Northern Sea Route over Russia.
Arctic Study Researchers haul a buoy across the Arctic sea ice in August, led by two Coast Guard crew whose job was to ward off polar bears or rescue anyone who slipped into the sea.
Over all, the floating ice dwindled to an extent unparalleled in a century or more, by several estimates.
Now the six-month dark season has returned to the North Pole. In the deepening chill, new ice is already spreading over vast stretches of the Arctic Ocean. Astonished by the summer’s changes, scientists are studying the forces that exposed one million square miles of open water — six Californias — beyond the average since satellites started measurements in 1979.
The pace of change has far exceeded what had been estimated by almost all the simulations used to envision how the Arctic will respond to rising concentrations of greenhouse gases linked to global warming. ..
[.. insert picture from link, because i LOVE 'EM! ..]
[ INSERT: GOOD ON YA, SCIENTISTS! ALWAYS QUESTIONING ]
The world is paying more attention than ever.
Russia, Canada and Denmark, prompted in part by years of warming and the ice retreat this year, ratcheted up rhetoric and actions aimed at securing sea routes and seabed resources.
Proponents of cuts in greenhouse gases cited the meltdown as proof that human activities are propelling a slide toward climate calamity.
Arctic experts say things are not that simple. More than a dozen experts said in interviews that the extreme summer ice retreat had revealed at least as much about what remains unknown in the Arctic as what is clear. Still, many of those scientists said they were becoming convinced that the system is heading toward a new, more watery state, and that human-caused global warming is playing a significant role.
For one thing, experts are having trouble finding any records from Russia, Alaska or elsewhere pointing to such a widespread Arctic ice retreat in recent times, adding credence to the idea that humans may have tipped the balance. Many scientists say the last substantial warming .. http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0442%282004%29017%3C4045%3ATETWIT%3E2.0.CO%3B2 .. in the region, peaking in the 1930s, mainly affected areas near Greenland and Scandinavia.
Some scientists who have long doubted that a human influence could be clearly discerned in the Arctic’s changing climate now agree that the trend is hard to ascribe to anything else.
Experts say the ice retreat is likely to be even bigger next summer because this winter’s freeze is starting from such a huge ice deficit. At least one researcher, Wieslaw Maslowski .. http://www.oc.nps.edu/~pips3/ .. of the Naval Postgraduate School in Monterey, Calif., projects a blue Arctic Ocean in summers by 2013.
In essence, Arctic waters may be behaving more like those around Antarctica, where a broad fringe of sea ice builds each austral winter and nearly disappears in the summer. (Reflecting the different geography and dynamics .. http://nsidc.org/cryosphere/seaice/characteristics/difference.html .. at the two poles, there has been a slight increase in sea-ice area around Antarctica in recent decades.)
While open Arctic waters could be a boon for shipping, fishing and oil exploration, an annual seesawing between ice and no ice could be a particularly harsh jolt to polar bears.
But, she added, that will not last. “Eventually the natural variations would again reinforce the human-driven change, perhaps leading to even more rapid retreat,” Dr. Holland said. “So I wouldn’t sign any shipping contracts for the next 5 to 10 years, but maybe the next 20 to 30.”
While experts debate details, many agree that the vanishing act of the sea ice this year was probably caused by superimposed forces including heat-trapping clouds and water vapor in the air, as well as the ocean-heating influence of unusually sunny skies in June and July. Other important factors were warm winds flowing from Siberia around a high-pressure system parked over the ocean. The winds not only would have melted thin ice but also pushed floes offshore where currents and winds could push them out of the Arctic Ocean.
But another factor was probably involved, one with roots going back to about 1989. At that time, a periodic flip in winds and pressure patterns over the Arctic Ocean, called the Arctic Oscillation, settled into a phase that tended to stop ice from drifting in a gyre for years, so it could thicken, and instead carried it out to the North Atlantic.
The new NASA study of expelled old ice builds on previous measurements showing that the proportion of thick, durable floes that were at least 10 years old dropped to 2 percent this spring from 80 percent in the spring of 1987, said Ignatius G. Rigor .. http://seaice.apl.washington.edu/ .., an ice expert at the University of Washington and an author of the new NASA-led study.
Other Arctic experts, including Dr. Maslowski in Monterey and Igor V. Polyakov .. http://www.iarc.uaf.edu/people/indiv/iarc_all_staff.php?photo=ipolyakov .. at the University of Alaska, Fairbanks, also see a role in rising flows of warm water entering the Arctic Ocean through the Bering Strait between Alaska and Russia, and in deep currents running north from the Atlantic Ocean near Scandinavia.
A host of Arctic scientists say it is too soon to know if the global greenhouse effect has already tipped the system to a condition in which sea ice in summers will be routinely limited to a few clotted passageways in northern Canada.
But at the university in Fairbanks — where signs of northern warming include sinkholes from thawing permafrost around its Arctic research center — Dr. Eicken and other experts are having a hard time conceiving a situation that could reverse the trends.
“The Arctic may have another ace up her sleeve to help the ice grow back,” Dr. Eicken said. “But from all we can tell right now, the means for that are quite limited.”
Pools of water form as ice melts atop Jakobshavn Glacier in Greenland. AP Photo/Brennan Linsley
Greenland’s glaciers are melting far faster than scientists expected
By Bill McKibben August 16, 2012 10:10 AM ET
There's no place on Earth that's changing faster – and no place where that change matters more – than Greenland. Late last month, NASA reported that ice all across the vast glacial interior of the world's largest island was melting – a "freak event" that hadn't occurred for at least 150 years. The alarming discovery briefly focused the media's attention on a place that rarely makes headlines. RAPID ICE MELT BAFFLES SCIENTISTS, The Wall Street Journal declared.
In fact, scientists weren't baffled at all – a paper published just weeks before had predicted that an abrupt, islandwide melt was imminent. The rapid loss of ice is only the latest in a chain of events that have upended conventional understanding of how the Earth's "cryosphere" – its frozen places – behave. Taken together, the events offer new insight into how fast the world's seas are likely to rise as a result of global warming – and hence, the fate of major cities like New York and Miami and Mumbai.
Jason Box, a scientist at the Byrd Polar Research Center, has probably spent more time in Greenland than any American of his generation. He began his yearly treks to the island in the 1990s as an undergraduate at the University of Colorado, helping his professor install a series of automated weather stations; last month he was sleeping on a sailboat near the mouth of a huge glacier and traveling onto the ice by helicopter to install yet more sensors. The shift he and his team have measured over the course of the past two decades is startling. "When I took my first course in glaciology," Box says, "conventional thought had the reaction time of the ice sheets to heating on the order of 10,000 years." The ice sheet, scientists believed, was a mostly inert ice cube frozen fast at its bed; if the glaciers melted because of global warming, the process would be, well, glacial.
But in a series of scientific epiphanies beginning in 2002, researchers using GPS have found that melting on the ice's surface can cause large sections of the ice sheet to break free of its moorings in hours, not millennia. In 2006, scientists discovered that ice was suddenly pouring into the ocean at twice the rate previously measured, spurred by a pulse of warm ocean temperatures that undercut the glaciers from below. In two separate instances, Box correctly predicted which sections of a glacier would soon break off – sections, in each case, that were many times larger than the island of Manhattan.
But Box's most crucial contribution to ice science – and the scariest part of his new findings – involves his measurement of Greenland's reflectivity, or "albedo." We know that snow is white: When sunlight hits a glacier, most of it bounces back into space, instead of being absorbed by dark-blue oceans or green forests. But not all ice shines with the same brightness. As snow crystals warm – even before they melt – they lose their jagged edges and become rounder, reflecting less light. "You can see it with your naked eye," says Box. "Think of the way wet sand is darker than dry sand."
Fresh snow bounces back 84 percent of the light that hits it; warm, rounded crystals can reflect as little as 70 percent. Slushy snow saturated by water – which gives it a gray cast, or even a bluish tint – reflects as little as 60 percent. Add dust or soot, and the albedo drops below 40 percent. Box's satellite data has shown a steady darkening in Greenland's albedo, from a July average of 74 percent when the century began to about 68 percent last year.
And then came this summer: Without warning, the line on the albedo chart dropped deep into uncharted territory. At certain altitudes, the ice sheet in Greenland was suddenly four percent less reflective – in a single season. "I confess my heart skipped a beat when I saw how steep the drop was," says Box. "I thought it meant the satellite sensor might have degraded." Instead, weeks of "ground-truthing" – going out on the ice to gather data from imbedded sensors and inspect conditions – verified that it was the ice sheet itself that was darkening. The heat accumulating in the ice sheet year after warm, sunny year was suddenly making it far easier to melt the surface. What's more, in a vicious feedback loop, soot from the wildfires raging in Colorado and Siberia – themselves spurred by climate change – may be helping to darken the surface of the ice. (Box hasn't been able to raise the funds to send a graduate student to do the sampling that would provide a definitive answer.)
Box had conservatively predicted that it might take up to a decade before the surface of Greenland's ice sheet melted all at once. That it actually happened in just a few weeks only underscores how consistently cautious ice scientists have been in forecasting the threat posed by global warming. Now, however, that caution is being replaced by well-founded alarm. "Greenland is a sleeping giant that's waking," says Box. "In this new climate, the ice sheet is going to keep shrinking – the only question is how fast."
The new data from Greenland matters for every corner of the planet. Water pouring into the North Atlantic will not only raise sea levels, but is also likely to modify weather patterns. "If the world allows a substantial fraction of the Greenland ice sheet to disintegrate, all hell breaks loose for eastern North America and Europe," says NASA's James Hansen, the world's foremost climatologist.
But the future, pressing as it is, sometimes gives way to sheer awe at the scale of what we've already done. Simply by changing the albedo of the Greenland ice sheet, Box calculates, the island now absorbs more extra energy each summer than the U.S. consumes in a year. The shape and color of the ice sheet's crystals, in other words, are trapping more of the sun's rays than all the cars and factories and furnaces produce in the world's biggest economy. One of Box's collaborators, photographer James Balog, puts it like this: "Working in Greenland these past years has left me with a profound feeling of being in the middle of a decisive historic moment – the kind of moment, at least in geologic terms, that marks the grand tidal changes of history." Amid this summer's drama of drought, fire and record heat, the planet's destiny may have been revealed, in a single season, by the quiet metamorphosis of a silent, empty sheet of ice.
This story is from the August 30th, 2012 issue of Rolling Stone.
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