Hello World, welcome to your global climate change –

Ancient ice shelf snaps and breaks free from the Canadian Arctic

A giant ice shelf the size of 11,000 football fields has snapped free from Canada’s Arctic, leaving a trail of icy boulders floating in its wake.

The mass of ice broke clear from the coast of Ellesmere Island, about 800 kilometres south of the North Pole. Warwick Vincent of Laval University, who studies Arctic conditions, travelled to the newly formed ice island and couldn’t believe what he saw. “It was extraordinary,” Vincent said Thursday, adding that in 10 years of working in the region he has never seen such a dramatic loss of sea ice. “This is a piece of Canadian geography that no longer exists.”

The collapse was so powerful that earthquake monitors 250 kilometres away picked up tremors from it.

… The ice shelf actually broke up 16 months ago, but no one witnessed the dramatic event. Laurie Weir, who monitors ice conditions for the Canadian Ice Service, was poring over satellite images when she noticed that the shelf had split and separated. Weir notified Luke Copland, head of the new global ice lab at the University of Ottawa, who initiated an effort to find out what happened. Using U.S. and Canadian satellite images, as well as data from seismic monitors, Copland discovered that the ice shelf collapsed in the early afternoon of Aug. 13, 2005.

Within days, the floating ice shelf had drifted a few kilometres offshore. It travelled west for 50 kilometres until it finally froze into the sea ice in the early winter.

Derek Mueller, a polar researcher with Vincent’s team, saw that Ellesmere’s Ward Hunt Ice Shelf had cracked in half in 2002. He also saw that sea ice, which creates a buffer zone around ice shelves, was approaching lower and lower levels. “These ice shelves get weaker and weaker as the temperature rises,” he said. “And the summer of 2005 had a combination of high temperatures and strong winds that probably blew the sea ice away, making this ice shelf much more vulnerable.”

[cbc.ca]

Via Boing Boing.

The New York Times reports —

The Ayles ice shelf, as the ancient 100-foot-thick slab was called, drifted out of a fjord along the north coast of Ellesmere Island when the jumbled sheath of floating sea ice that tended to press against the coast there even in summers was replaced by open waters because of the warming, the scientists said.

… The Arctic sea ice has experienced sharp summertime retreats for several decades, adding to evidence of significant warming near the North Pole.

[NY Times]

The NY Times article also states — incorrectly? — that “Neither melting ice shelves nor sea ice contribute to rising sea levels because they sit in the sea already, like ice cubes in a drink.”

If I understand correctly, that melting ice does contribute to rising water levels, when the meltwater warms up enough to expand to a greater volume that the ice from which it melted. (Caveat, I’m not sure I understand this correctly.)

Early warnings: cracks in the Ward Hunt ice shelf, 2002:

Breakup of the Ward Hunt Ice Shelf - In the summer of 2002, graduate student Derek Mueller made an unwelcome discovery: the biggest ice shelf in the Arctic was breaking apart. The bad news didn’t stop there. Lying along the northern coast of Ellesmere Island in northern Canada, the Ward Hunt Ice Shelf had dammed an epishelf lake, a body of freshwater that floats on denser ocean water. This epishelf lake, located in Disraeli Fiord, was host to a rare ecosystem, and it was the largest and best-understood epishelf lake in the Northern Hemisphere. When the Ward Hunt Ice Shelf fractured, the epishelf lake suddenly drained out of Disraeli Fiord, spilling more than 3 billion cubic meters of fresh water into the Arctic Ocean.

[NASA: Earth Observatory]

“Local warming since the 19th century is to blame for the breakup.”

Local warming since the 19th century is to blame for the breakup. Atmospheric warming has been named a cause of a collapsing ice shelf in the West Antarctic, but scientists don’t have enough evidence to link the Arctic melting to global climate change.

Records at Alert, 175 kilometres east of the Disraeli Fjord, indicate an increase of 4/10ths of a degree C every 10 years since 1967. “We figure that there’s about 90 per cent of those ice shelves have been lost over the last 100 years or so,” said [Derek] Mueller. “Most of that happened before 1950 when there were people on-site monitoring the situation.”

Climate change affects ocean temperature, salinity and flow patterns, which can also influence the melting of ice shelves since warmer temperatures weaken the ice.

[cbc.ca]

NASA reports –

The Ward Hunt Ice Shelf breakup comes at the same time as news of unprecedented melting of sea ice in the Northern Hemisphere. “Sea ice cover has been shrinking about 3 percent per decade over the past few decades. We saw a record minimum in September 2002, and the summer of 2003 almost set a new record,” said Mark Serreze, a research scientist at the National Snow and Ice Data Center in Boulder, Colo.

[NASA]

See also Ellesmere Island @ Wikipedia

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I live in Minneapolis, Minnesota. Historically, we have cold snowy winters, starting as early as November, no later than mid-December.

This year, we got November rain, December drizzle. People joked about missing their White Christmas. Well, we did get a dusting of snow, immediately before Christmas. Then more drizzling rain … until New Year’s Even, when we finally got several inches of real snow actually covering the ground without melting away.

On the bright side, I’ll say this for global warming — my heating bill is down, a teeny tiny bit.

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One more time, let’s take a good look at that Ward Hunt shelf breakup, circa 2003 —

“The Ward Hunt Ice-shelf is a remnant of the compacted snow and ancient sea ice that extended along the northern shores of Ellesmere Island in Northern Canada until the early 20th century. Rising temperatures have reduced the original shelf into a number of smaller shelves, the largest of which was the Ward Hunt Ice-shelf on the northwest fringe of the island. Between 2000–2002, the Ward Hunt Ice-shelf began to crack and eventually broke in two. This Standard Beam Mode RADARSAT-1 image, which was acquired September 27, 2003, clearly shows a large crack dividing the ice-shelf in half. The crack runs from the Arctic Sea to the right of Ward Hunt Island and the bright white ice grounded there and back to the rougher, mountainous region.”

[GEO Year Book:]