Chain Reaction Shattered Antarctica's Larson B Ice Shelf

New submitter Jim McNicholas writes "At the end of the summer of 2002, all 3000 lakes on the Larsen B ice shelf drained away in the space of a week. And then the 2,700-square-kilometre ice shelf, which was some 220 metres thick and might have existed for some 12,000 years, rapidly disintegrated into small icebergs. The draining of one lake on an ice shelf changes the stress field in nearby areas, causing a fracture circle to form around the lake."

Comments

Re:Reporting on events in 2002?

[Jeremy Erwin]

Yes, eleven years ago we knew that it had collapsed, but we didn't know why it had collapsed. This new model might both explain why, and perhaps predict future ice shelf collapse.

Incidentally

[symbolset]

13,000 years ago was the peak of the Holocene Optimum, when the Earth was warmer, glaciers smaller and the seas higher than today.

SCIENCE!

[jeff13]

Yea science, seems slashdot comments are far too concerned with opinions and politics instead of science, facts, and, well evidence. Which, btw, this is actually big chunk of.

Earlier

[dbIII]

There was a major report on the topic sent to President Johnson.

Wait, science...

[theoriginalturtle]

OK, somebody fill me in, here...

3,000 "lakes" on an ice shelf that they state was 2700km^2?

That's a little over a thousand square miles. That's about the land area of Cook County, Illinois, where Chicago is.

3,000 "lakes?" Lolwut? You mean "ponds?" Perhaps "puddles?"

Somebody convince me that I should be runnin' to the hills, because I'm just not feelin' it, here...

A neat maths trick.

[TapeCutter]

Hey professor, did you know that for any curve you can always find a section short enough to approximate a straight line? In the 1600's some maths geniuses built a whole branch of maths from that 'trick' and called it calculus.

Also did you know the best estimates for sea level rise come with rather large error bars which IIRC range from about 20cm to 800cm by the year 2100. The reason for the large error bars is that people who have spent their lives studying this have much less certainty about the shape of the curve than you do. That cautious approach by the "experts" is genuine skeptcisim, fought out in the journals as it should be. Picking a figure at either end of the range and representing it as the "most likely scenario" is simply dishonest.

Re: on a volcano spewing CO2

[Pino Grigio]

Science and political advocacy, which is what you're really about, are incompatible. I suggest you stick to trolling "Skeptical Science" and other political websites to get your kicks.

Whilst I'm at it:

A new NASA study shows that from 1978 to 2010 the total extent of sea ice surrounding Antarctica in the Southern Ocean grew by roughly 6,600 square miles every year, an area larger than the state of Connecticut. And previous research by the same authors indicates that this rate of increase has recently accelerated, up from an average rate of almost 4,300 square miles per year from 1978 to 2006.

Fascinating. I'm sure you'll explain that away as some kind of warming induced cooling, or other moronic hypothesis to keep your failing thesis alive. Please note that the last paper I read about Antarctic temperatures was by Steig et al. It got pole position in Nature (front cover too) but was shown to be complete and utter bollocks soon afterwards by O'Donnell et al. Of course as is normal in Climate Science, it wasn't retracted despite being shown to be rubbish. And you probably won't read about it on the euphemistically named Skeptical Science website.

Re:It would be great

[TapeCutter]

I recall reading about this when it happened. It reminded me of when I was a kid in the 60's I would watch mum heat up the solidified oil in the chip pan (making "fries" if you're American). The solid oil would melt in such a way that a thick flat disc formed across the entire surface (the ice shelf), holes would slowly start to appear in the disc (lakes), then when there were "enough" holes it would suddenly and dramatically break into to small blocks (bergs) which melted very fast. The strange thing was right up until it fell apart the diameter of the disc didn't shrink much at all (ie: it conserved the surface area defined by it's edge). It appears to me that the 200m thick ice shelf had the internal structure of swiss chees and simply collapsed under its own weight, much like the fat floating on top of mum's chip pan. In both cases the trigger is probably the motion of surface waves stressing the entire honeycomb structure and (and in the case of the ice sheet)draining the surface lakes in the early stages of the break up..

Having said that scientists will tell you (with some excitement) that the mechanics of melting ice sheets/shelves is "poorly understood", modelling the behaviour of various slabs of ice is an active research topic but they are a long way from claiming that all ginormous ice blocks melt in a predictable manner, I'd dare say we know even less about modelling small chip pans of melting fat.

Of course they didn't vote for their own requests.

[Von Rex]

That's because Republicans are just like Lucy with her football. Don't know why Democrats keep playing that game. They keep expecting a different outcome, just like Charlie Brown.