A scientist at the British Antarctic Survey announced today that an Antarctic ice shelf the size of Connecticut is "hanging by a thread" and may soon break up. The collapse of the Wilkins Ice Shelf will be the largest event of this type ever observed by scientists.

Satellite images processed at the US National Snow and Ice Data Center revealed that the retreat began on February 28 when a large (41 by 2.5 km) iceberg calved away from the ice shelf's south-western front. In a series of images, the edge of the shelf proceeded to crumble and disintegrate in a pattern that has become characteristic of climate-caused ice shelf retreats throughout the northern Peninsula, leaving a sky-blue patch spreading across the ocean surface compose [sic] of hundreds of large blocks of exposed old glacier ice. By 8 March, the ice shelf had lost just over 570 km2, and the patch of disintegrated Antarctic ice had spread over 1400km2. As of mid-March, only a narrow strip of shelf ice was protecting several thousand kilometres of potential further break-up.

The area behind the "hanging thread" comprises 13,680 km2, five times greater than the Larsen B breakup.

When the initial iceberg separated from the ice shelf's southwestern front on February 28, it triggered "a runaway disintegration of 405 square kilometers (160 square miles) of the shelf interior..."

[See image to right]

For video of the breakup, click here.

Professor [David] Vaughan, who in 1993 predicted that the northern part of Wilkins Ice Shelf was likely to be lost within 30 years if climate warming on the Peninsula were to continue at the same rate, says,

"Wilkins is the largest ice shelf on the Antarctic Peninsula yet to be threatened. I didn't expect to see things happen this quickly. The ice shelf is hanging by a thread - we'll know in the next few days or weeks what its fate will be."

The professional climate denialists, the propaganda producing minions of global warming's true villains the climaticidal coal and oil corporations, love to claim that climate models are wrong.  As the data rolls in it is becoming increasingly obvious that the models are wrong, but not in the way the climaticides claim, for far from overestimating the rate of climate change, the models actually underestimate it.  

James Hansen, probably the world's preeminent climate scientist now believes that climate sensitivity for a doubling of CO2 from pre-industrial levels (that is 550 ppm) is 6 degrees Celsius twice the estimate of the IPCC.  For this reason Hansen is now calling for a rollback to 350 ppm (currently we are at 385 ppm). Read the draft version of his latest paper on the subject here (PDF).

Joseph Romm summarizes Hansen's position in this way:

... if we stabilize at 450 ppm (or higher) we risk returning the planet to conditions when it was largely ice free, when sea levels were higher by 70 meters -- more than 200 feet!

We are now living through the first stage of rapid climate change. What climate scientists 20 years ago predicted might happen in 50 years is happening today: more intense droughts, floods, hurricanes, tornadoes, sea ice and glacial melt, species extinction and the spread of disease. When the rest of the Wilkins ice sheet falls into the sea in the next few weeks or months it will simply be the latest and most spectacular example to date of our blind march to disaster.

[Thanks to Deadicated Marxist whose diary today on Daily Kos provided the inspiration for this one].

[Crossposted at Daily Kos]