Friday, April 10, 2009

Antarctic ice up close & personal



(photos ©2005 Tony Travouillon, Caltech)


The Antarctic ice shelves (and the Arctic and Greenland shelves) hold the advancing land glaciers at bay, keep them from sliding into the sea (and thus raising the level of the oceans). Here, you can see how an Antarctic ice shelf is supporting upthrusted mountain of blue glacial ice.

(photo: Tony Travouillon used with his kind permission.)

Someone sent me an email with these extraordinary images of Antarctic ice. I was supposed to write s poem a day for Poetry month. Instead, I spent hours hunting the photos down on the internet to find a compelling story behind them. I also found out that they were taken by two different people. One photographer was easy to find and we corresponded, so much of this story is base on his writings.


These photographs are beautiful earth poems and serve as a more powerful testament to the ephemeral beauty of Antarctica than any article I've read, they capture the story of the sublime beauty and fragility of this seventh continent.

(photo: Tony Travouillon) More photos here:

According to the first photographer, Caltech astronomer, Tony Travoullon, this particular formation of sea ice taken near the coastal station of Dumont D'Urville, is what he dubbed a "blue berg," a recycled ice floe flipped on end, possibly thrust up from an earthquake. Though it looks like a frozen wave, it's not. The ethereal blue ice is either formed at the bottom of the sea ice pack or meltwater that has seeped into a crevasse or crack, and was flash frozen, it has no trapped bubbles to refract light, and so it appears an intense blue.


(photo: Tony Travouillon)

Think displacement: what happens when you add a big chunk of ice to an already full glass? Our coastal cities are perched on the edge of that proverbial glass. Last March, a chunk of ice several times the size of Manhattan was set adrift. Around Valentine's Day, 2010, an iceberg that broke off from the Ross shelf in 1987, sheared off the tongue of the Mertz Glacier, creating an iceberg the size of Rhode Island. BTW, those are solid mountains of fresh water, not sea water. Glacial ice melts more slowly than other ice.

The extremely rapid calving of the Wilkins ice shelf is the latest harbinger to a global catastrophe we cannot easily reverse. The shelf is anchored to an island by a narrow shard of ice less than a thousand feet thick. When it breaks free, imagine icebergs the size of Manhattan (but taller), adrift at sea. Then the landlocked glaciers, with nothing to hold them back, will begin to inexorably slide down to the sea like a breach birth. This is where the real catastrophe will begin if global warming continues at the current rate it's been going since 1966.

In a post equinox coitus, the Wilkins shelf is calving into the Wedell Sea with chunks the size of houses. Better pray for an extremely cold winter. Come December, this shelf will probably shear off.

(See amazing photos by: Oyvind Tangen, a sailor aboard a Norwegian research vessel, the G.O.Sars, 660 miles north of the Antarctic. ca. March 2008.)

Blue stripes are created over long periods of time, and are often caused when a crevasse in the ice sheet fills with meltwater and then refreezes so quickly that no bubbles form. The lighter bands are compressed snow, trapped bubbles act as prisms and reflect light. The darker colors in blue ice generally connote extreme age.

There are two kinds of ice formations: land-based glaciers and sea-formed ice shelves, where sea ice coagulates and forms islands of ice, then snowfall and the continued freezing of the sea adds height. On land glaciers, the blue and white horizontal stripes of compressed snow represent a timeline of sorts, a snowfall record similar to dendritic redwood or white pine tree rings, but millions of years old.

Under extremely cold conditions, sea ice crystals forms at -18° C; float to the surface, to create an "oily" slick, called grease ice, which coagulates into pancake ice.

Core ice samples reveal an ancient record of atmospheric conditions including fallout and cataclysmic eruptions and now, modern pollution. Trapped air bubbles also provide a good record of pre-industrial atmospheric conditions. When I studied Irish Medieval manuscripts, I found it helpful to have a glacial timeline in hand. What was the weather like in 800 AD?

In Switzerland, on Jungfrau, there is an early 19th c. ice palace carved out of a living glacier where you can count the ages from inside the glacier. I've also stood at the foot of the great Columbia ice field and gazed into that mesmerizing aquamarine banding. The glacier moaned as it inexorably pushed forward. Now it's retreating.

When I flew over Greenland during the winter of 2007, I was horrified by how much glacial ice had tumbled into the sea. There was clearly far more than the annual global average of two million tons of ice floating on the sea. One suggestion for the accelerated glacial ice calving is due to "bottom melting" not just of icebergs in an increasingly warm sea, but this phenomena, well documented in Antarctica, also threatens Greenland's glaciers by lubricating them from beneath—which causes them to literally lose their icy grip on the land and skid into the sea, unchecked.

(Calving glacier in Greenland, mid-winter. Photo: © 2007 Maureen Hurley)

(Greenland from 40,000 feet, those little white dots are thousands of very large glaciers, some stand as many as 400 feet above the waterline (and triple that below) that have calved off and are adrift in the open sea, mid-winter, Jan. 2007. Double-click to enlarge. Photo: © 2007 Maureen Hurley)


TEDTalks Photographer James Balog shares new image sequences from the Extreme Ice Survey, a network of time-lapse cameras recording glaciers receding at an alarming rate, some of the most vivid evidence yet of climate change in Alaska, Greenland and Iceland. The Greenland glacier (that I photographed above) is so enormous, it boggles the mind. This is a MUST WATCH in order to grasp the severity of the ice melt! To read more on James Balog go to TEDTalks © distributed under a Creative Commons (CC) license.

Antarctica's Lambert Glacier, the world's largest, at 40 by 400 kilometers; is moving from 100 to 1200 meters per year onto the Amery ice shelf, which impedes its headlong rush into the sea. Dramatic unprecidented ice collapses occurred in 2008, 2002 and 1995.

(See photo: Øyvind Tangen) See HoaxSlayer story here:

As for the candystripe banding, it's real, when an iceberg falls into the sea, a layer of salty seawater freezes to its underside. If the water is rich in algae, it will form a green stripe. Brown, black and yellow lines are caused by sediment and pulverized rock picked up when a landbased glacier inexorably grinds downhill towards the sea and picks up debris enroute.

(See photo: Øyvind TangenNorwegian sailor 


After 12,000 or so years of stability, three vast Larsen ice shelves on the east side of the Antarctic Peninsula that extends toward Chile, and Wilkins' neighboring ice shelf, the Wordie ice shelf have completely vanished, in some cases, fracturing up within three weeks, during 2008. Ice shelves are extremely sensitive to temperature change, and over 11% of Antarctica's mass is shelf ice. The Antarctic holds 91% of the world's glacial ice. The loss of the ozone layer is a major contributing factor to the 5• temperature rise.
(See photo: Øyvind Tangen) This striped iceberg towered 30 metres above the surface of the ocean. Only one-tenth of an iceberg lies above the water. The tallest recorded iceberg towered 551ft above sea level - that's the height of a 55-storey building.

During 2000 to 2005, 150 trillion liters of icemelt have rushed headlong into the sea. I would guess an equal, if not accelerated amount has melted into the sea since then.


GOOD FRIDAY REQUIEM FOR ICE

Imagine a vast archipelago of icebergs
larger than Manhattan, unseasonably set adrift.
This is how it begins. The mad race to the end.

Too late I am learning the complex language
of ice: firn, ogive and swale, iceberg ballast,
the secret emerald tear and Tanzanite heart,
strange unfathomable blues: lapis & sapphire,
azurite & aquamarine, cerulean & cobalt.

Precocious tongues of fresh water
150 trillion tons float on a salt brine sea
as scientists try to translate and explain
and decipher the final symphony of ice
playing it fast-forward at both ends of the earth,
before it's too late. For whom the bell tolls.

They say that frozen breath rings in small knells.
A song of ice islands adrift on a final migration.
For the continent at the ends of the earth,
the western ice shelf is disappearing into the sea.
Sweet tongues of ice speak in a new sea dialect.
Things are heating up: Mt. Erebus is erupting:
fire and ice. Fire and ice and floods.

But hey, a new species of krill was discovered.
The krill shall inherit our flooded cities.

Meanwhile in the far north, beneath Ursa Major
the ice melt has accelerated out of control,
the first ice free summer in the Arctic
is predicted to arrive midsummer, 2013.
Who's going to explain that to the polar bears?

Break out the beach chairs and sunblock
and lead us on to the new Riviera.
We'll sip Manhattans on polar ice.
I hear the aurorae borealis and austrailalis
are spectacular this time of year.

Too bad about the penguins, though.

No resurrection likely, or in sight.

mayday mayday mayday

4/10/09

(For a glimpse into the rich ecosystem beneath the ice, see Norbert Wu's Life Beneath Antarctic Ice). It is reported that the rise in temperature is creating an explosion of vegetation, which in turn, raises the temperature.

Friday poem


Øyvind Tangen's photos are listed on several sites as being in the public domain—I have tried to contact him, and have written to the publications where the photos have appeared, to no avail. So I have made links back to those sites. These photos have been widely published under Hoaxslayer,  Snopes, Digg, The Daily Mail. The Telegraph, UC Santa Barbara Dept. Of Geology, A Fish Blog, etc. If anyone knows how to reach Øyvind Tangen I would be most appreciative if you would forward his contact info.




Update on Arctic ice—I didn't have the heart to write about the North Pole but this NASA photo of the Petermann ice island, four times the size of Manhattan in 2010, drifting toward Labrador puts it into a global perspective.

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