Tuesday, April 7, 2009

Wilkins Ice Shelf Floats Free

In March of last year, portions of the Wilkins Ice Shelf, now no longer connected to land, showed signs of accelerating disintegration. Image: National Snow and Ice Data Center.

The following video is one year old. It shows an event almost one year ago to the day when a piece of the Wilkins Ice Shelf the size of the Isle of Man (221 sq.mi.) broke free and floated into the ocean to slowly melt into oblivion. This video shows the aftermath of the pictures above.

The blue ice you see is pollutant-free water that was frozen before it became contaminated with any of our modern-day cocktails of pollutants.

Many, many years I lived in New Brunswick. This was before pollution reached even there. I had always believed (as most people do) that snow is white. I had a friend who kept telling me I was wrong - that uncontaminated snow is blue. Of course, I didn't believe her; and, then I moved to New Brunswick. Guess what? It's true! Pollution-free snow is blue. It was like living in a wonderland - everywhere you looked was a hint of blue - made you forget there was 6' of the stuff everywhere you looked.

As long as there has been recorded history, the Wilkins Ice Shelf has been held in place by a massive ice bridge which ruptured on Saturday, April 4, 2009.

The 25-mile long bridge connecting the ice shelf to Charcot Island broke at its narrowest point (about a 1/3 mi. wide) making Charcot a true island for the first time in its history. The Wilkins Ice Shelf has been retreating since the 1990s; but, this bridge rupture will now allow the ocean water to wash away even more of the shelf even faster.

"It's amazing how the ice has ruptured. Two days ago it was intact," David Vaughan, a glaciologist with the British Antarctic Survey, told Reuters of a satellite image of the Wilkins Ice Shelf on the Antarctic Peninsula. "We've waited a long time to see this," he said.

The loss of the ice bridge, jutting about 20 m (65.5 ft) out of the water and which was almost 100 km (62.14 mi) wide in 1950, may now allow ocean currents to wash away far more of the Wilkins shelf.

"My feeling is that we will lose more of the ice, but there will be a remnant to the south," said Vaughan.

Ice shelves are formed by ice spilling off Antarctica with many being hundreds of meters thick. Nine other shelves have receded or collapsed around the Antarctic Peninsula in the past 50 years, often abruptly.

"We believe the warming on the Antarctic Peninsula is related to global climate change, though the links are not entirely clear," Vaughan said. Temperatures in the Antarctic have risen 3° C (5.4° F) in the past 50 years. This is the fastest rate of warming in the Southern Hemisphere.

We only wait and see what ramifications this episode has.

1 comment:

miranda.ann said...

Hello Pippa,
I couldn't find your contact info., so I figured I could leave you a message on here. first off, my name is Miranda Mullett and it seems we have a lot of the same interests. I will be going to Beijing in 4 weeks to somehow use myself to help sustain the environment. Do you have any ideas? My e-mail address is mam376@nau.edu Thanks!!