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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."
Ok, this happened some years ago. Is useful to predict what will happen maybe soon if there are big ice shelves in similar conditions? Are we walking in thin ice, and could happen from a week to the next that a very huge amount of water is added to the oceans? I don't think nothing of this scale will be enough to make the ocean level rise in a noticeable way, but if we are in that scenario will be pretty bad, maybe we can adapt to the oceans rising a meter in a whole century, but no that that kind of change is so fast.
Hey, 11 is better than 10 ... because it's 11.
Mandatory XKCD: Extrapolation
If they report it immediately, then there are complaints that we don't have all the facts in. If it's reported after the facts are in, someone will point to an unsubstantiated guess that happened to be right, but beat Slashdot by years. The best is when Slashdot does both, and gets bashed for the initial report, the "delayed" report and the dupe.
Learn to love Alaska
I didn't realize she'd told you about me! So you're cool with that?
#DeleteChrome
The problem with extrapolating the same rate... is you assume that nothing is reliant on each other, nothing affects anything else, and everything is a closed system.
Icebergs calve off a glacier on the Larsen B Ice Shelf at a rate of x amount per year, meaning that the Larsen B Ice Shelf will exist for about 300 thousand years. But yet... it didn't. One lake drained away at a given rate on this ice shelf... one could extrapolate that to be that it would take decades for all the other lakes to drain away, and further say that one lake draining has no effect on other lakes, and that it will be replaced by the formation of many other meltwater lakes just like it was formed. One could also say one small lake draining would NEVER affect a large ice shelf.
But yet... it did have an effect that was not explained by a purely flat rate per time extrapolation. It wasn't quite exponential, but it definitely came in somewhere between. It was an example of how one thing happening in one place... can effect and increase speed of other nearby items.
Or, from another source... http://en.wikipedia.org/wiki/File:Trends_in_global_average_absolute_sea_level,_1870-2008_(US_EPA).png. Sea levels rose 0 inches between 1910-1930. A lot different than the 2.4 millimeters per year rise that you claim. But yet... it did happen. I think you're trying to scare us by using measurable facts.
No, the 4 foot rise number is an upper limit... and not 4 foot per year. The actual is anywhere from 7 inches to 4 feet, depending on how things cascade. The biggest concern is the ice melt from the Greenland Ice Sheets, and the continued ice melt of large Antarctic ice sheets.
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.
13,000 years ago was the peak of the Holocene Optimum, when the Earth was warmer, glaciers smaller and the seas higher than today.
Help stamp out iliturcy.
I agree. Statistics are lies and science is the enemy.
We need to fight this anti-capitalist socialist encroachment by eliminating all traces of science from our nation. We must ban science from the classroom from tomorrow. It's nothing less than child-abuse to expose innocent young minds to science. Next all military and other government funding of any projects in any way science related must be cut off immediately! Finally we should impose an additional tax burden on any company spending share-holders money on science related R&D. Make them see sense!
Only in this way can we stop icebergs from melting and save the world from communism. Listen to common sense, you know it's RIGHT!
No, it wasn't "the same so-called scientists," it was a couple of guys who were out of the mainstream, although it got some sensationalist play in the mainstream media. Even back then, the consensus favored warming due to CO2 release, although there was a lot more uncertainty about how much. Anybody who cares about facts rather than propaganda can easily verify this for themselves--the original scientific literature of the time is available in any major university library and much of it, or at least the abstracts, is available online.
They probably did notice it was a volcano
http://www.skepticalscience.com/Measuring-CO2-levels-from-the-volcano-at-Mauna-Loa.html
>But how about gas from the volcano? It is true that volcanoes blow out CO2 from time to time and that this can interfere with the readings. Most of the time, though, the prevailing winds blow the volcanic gasses away from the observatory. But when the winds do sometimes blow from active vents towards the observatory, the influence from the volcano is obvious on the normally consistent records and any dubious readings can be easily spotted and edited out (Ryan, 1995).
or this one
http://earthobservatory.nasa.gov/blogs/climateqa/mauna-loa-co2-record/
>Most of the time, the observatory experiences “baseline” conditions and measures clean air which has been over the Pacific Ocean for days or weeks. We know this because the CO2 analyzer usually gives a very steady reading which varies by less than 3/10 of a part per million (ppm) from hour to hour. These are the conditions we use to calculate the monthly averages that go into the famous 50-year graph of atmospheric CO2 concentration.
We only detect volcanic CO2 from the Mauna Loa summit late at night at times when the regional winds are light and southerly. Under these conditions, a temperature inversion forms above the ground, and the volcanic emissions are trapped near the surface and travel down our side of the mountain slope. When the volcanic emissions arrive at the observatory, the CO2 analyzer readings increase by several parts per million, and the measured amounts become highly variable for periods of several minutes to a few hours. In the last decade, this has occurred on about 15% of nights between midnight and 6 a.m.
If you follow either link there is a graph showing data from other sites and Mauna Loa's readings perfectly align with them.
Think about this another way... if the results were skewed by the volcano it could be fairly easily proven and that scientist would get a lot of publicity. It is not for want of trying. But the fact is that the effects are known and accounted for and in the second link you can see someone actually studying the CO2 outgassing of the volcano.
There are many thousands of scientist around the world studying this topic. If there were big holes in the theory then the denier community would make sure that people knew about it. But there is not, their responses are mostly wrapped in ignorance of the science.
And the science is not all built on one single data point (eg atmospheric temperatures) but instead a wealth of data, all of which supports that CO2 is rising, that human activity is the major contributor and that there are effects on the climate.
They're not reporting the fact that Larsen B broke up because it was well reported at the time. I saw pictures. This post is reporting the results of a just published study of why it broke up as it did.
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.
Kind of like how carbon dioxide passed 400 parts per million for the first time in human history yet the effect was much less than predicted.
The effect has not been "much" less than predicted. It's still within the 95% confidence range of the predictions, albeit on the low side. If you factor in things like the lowest solar cycle in a century and the predominance of La Nina years since 2007 it's not surprising temperatures are running on the low side of predictions..
there is no such thing as man made "climate change" (they had to change the name since the warming wasn't happening).
No, "climate change" has been around since at least 1970 as shown in an October 1970 paper by George Benton titled "Carbon Dioxide and its Role in Climate Change"
Here we go again. Tell me then, what's your own personal definition of science that's better than the one the scientists and the dictionary uses?
There was a major report on the topic sent to President Johnson.
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...
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Rotate the pod, please, HAL....
OK. It doesn't sound like you're trolling, so I'll give a more useful post this time:
Check out this site. It has some really good material and references about the science behind this stuff.
You might also find this interview with one of the key scientists interesting.
I don't profess to be a climate change guru, but this stuff looks reasonably legit to me.
No confusion. Antarctic sea ice is growing, due to increased calving. There is some increase in land ice due to increased moisture. Normally the centre of Antarctica is a very dry place. The increased moisture is from the warming of the oceans, the same process which is increasing the calving. Of course, denier sites focus on the increase sea ice, saying that is a good thing, and the increase in snowing, also saying that is a good thing. They conveniently ignore the fact that these are bad things, not good and that overall the antarctic is losing ice. A triumph of spin over science.
Almost everyone here says that Slashdot was so much better ten years ago. Now, the editors listened.
PlusFive Slashdot reader for Android. Can post comments.
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.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
Who needs facts when we can engage in massive hyperbole? Obama's nothing special. He ain't great. He's failed to change things that needed to change since Bush. A lot of the stuff you're complaining about is simply a continuation of existing policies or slight expansion. I'm not happy about it, but let's not pretend that he's some sort of Hitler, seizing power and single-handedly changing the shape and function of our government. Hardly. Get over yourself.
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.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
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.