Wednesday, February 25, 2015

Antarctic Glacial Stability At Risk

Another Blow to Antarctic Glacial Stability-Larsen C Shelf Cracking In Half

There’s a 30 kilometer long and hundreds foot deep crack running through West Antarctica’s massive Larsen C ice shelf.

It’s a rift that now stretches from the Weddell Sea — where winds and currents have driven human-warmed ocean waters to up-well along the ocean-contacting faces of the great Antarctic ice sheets — and deep into the interior of this 49,000 square kilometer and 600 to 700 foot tall block of ancient, floating ice.

Over the past few years this rift has been rapidly advancing at a rate of about 2.5 kilometers each year. Given that the rift has already traversed more than half of the Larsen C ice shelf calving face, a very large break-up could now occur at almost any time.

Larsen C Destabilizing

This evolving situation now threatens to destabilize the entire Larsen C ice shelf — resulting in major losses to a very large block of ice that has been a permanent feature of the Antarctic coastline since at least the last interglacial period 150,000 years ago. Such rapidly evolving risk was the subject of a February 5 communication by a group of glaciologists warning that “significant threats” to “Larsen C ice sheet stability” now existed.

The report notes:

"In a change from the usual pattern, a northwards-propagating rift from Gipps Ice Rise has recently penetrated through the suture zone and is now more than halfway towards calving off a large section of the ice shelf (Figs. 1 and 2). The rate of propagation of this rift accelerated during 2014. When the next major calving event occurs, the Larsen C Ice Shelf is likely to lose around 10 % of its area to reach a new minimum both in terms of direct observations, and possibly since the last interglacial period (Hodgson et al.2006)"


Larsen A and B Shelves have already disintegrated due to human induced global warming. Yet all we hear from deniers is that there is no global warming because Antarctic "extent" is larger without explaining reasons for it which are also attributable to warming and changing wind patterns. This is the type of misleading that is leading us over the cliff. People need to read about this and understand the physics and dynamics behind it and the consequences of it on a global scale. I am really disappointed to see that so many people refuse to do this even though it means our very survival as a species.

Also see:

Massive Glacial Melt and Sea Level Rise-Antarctica

Collapse Of Parts Of West Antarctic Ice Sheet Has Begun

NOAA: Record Antarctic Sea Ice Due To Global Warming

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