back to article While sea ice grows, Antarctica sheds land ice

A new satellite survey of Antarctica suggests that some of the continent’s contribution to sea-level rise may be overestimated. However, the land ice melt on the frozen continent is still sufficient to put Australia’s multi-million dollar airstrip at risk. However the University of Tasmania-led study, based on GRACE (Gravity …

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So, what, 3.5cm per century rather than 3.0?

Chicken Little's starting to sound just a bit hoarse.

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Re: So, what, 3.5cm per century rather than 3.0?

I wouldn't know. This article and the two linked in it don't provide any numbers, just vauge statements about other unnamed values.

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Re: So, what, 3.5cm per century rather than 3.0?

That's how Chirgwin likes it.

"breaks almost any records" cracked me up.

Sloppy, sloppy.

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Pint

Re: So, what, 3.5cm per century rather than 3.0?

Your knee-jerk reaction to anything which doesn't match your preconceived ideas is kinda like shouting "Bullshit" to the cry of "Wolf" without even bothering to look up.

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So far the score is a thousand cries of wolf to zero dead sheep

Thus leading me to wonder, on the occasion of the thousand-and-first, whether it's more worthwhile to cramp my neck by looking all round for the wolf which has so far failed entirely to materialize, or instead to give a damn proper walloping to the fellow who won't stop disturbing the peace with frantic yelps of a wolf in every corner.

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Pint

Re: So far the score is a thousand cries of wolf to zero dead sheep

So you haven't seen *any* papers that support the theories that you haven't adopted?

Riiiiight. Because it's a totally one-sided open-and-shut case.

If you're only looking to read things that support your established opinion, and are making knee-jerk reactions about anything otherwise without bothing to look into it further, it begs the question: Why waste precious moments reading and commenting on *any* climate-related articles? Articles that don't agree agree with, you complain about for 'disturbing your peace', and merely reading articles that support your view is simply the intellectual equivalent of masturbation: Pure self-satisfaction.

It seems you'd be happier not knowing and not bothering, and there seems no real point in you continuing to read anything on the subject. (Or y'know: Just read Lewis Page's stuff...)

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Anonymous Coward

Re: So far the score is a thousand cries of wolf to zero dead sheep

@Psyx: This is not an open and shut case at all and there are valid papers on both sides. This doesnt quite sound like one though.

There are a lot of articles claiming the truth while providing very little. This article seems to provide very little except for the most important point which is made in the very first line of Chirgwin's article. Their satalite data was wrong in the first place and took time and effort to prove that they were talking rubbish. As a direct consequence it demonstrates that satellite data is not credible on its own (a single source isnt proof anyway) yet that is what we have.

So we have a method they agree is not a valid source on its own, being used as the source of proof. I am hopeful that the actual study provides more than Chirgwin's article has commented on but Chirgwin's article contains nothing of any value. No data, figures, evaluation, etc except for this statement- melting trends outpaced “almost any records”. That alone makes a joke of the study as there are barely any historical records as usable data and the statement is ALMOST any records.

I will agree with you that lewis page has a very one sided view but at least he reports with information and data. At least you can look at his statements critically. This study sounds shaky and the reporting on it sounds sparse.

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Re: So far the score is a thousand cries of wolf to zero dead sheep

If you'd reviewed my past comments, you'd know that nothing of the sort is true. Instead, though, you (sort of) read one rather dismissive comment of mine, and then your knee jerked up and hit your keyboard. That you immediately go on to accuse me of prejudice on the subject is just funny.

I say "sort of read", by the way, because you misquoted me -- a nice trick, I think, when my comment was right there on the reply page for your copy-pasting convenience. The peace isn't mine in particular; it belongs to everyone, and to disturb it is to make a lot of annoying noise for no very good reason, hence my invocation of the phrase. If it's one with which you're unfamiliar, Google should be your friend here.

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Anonymous Coward

Warmth

Build that airstrip at the South Pole then. At the height of summer you may get a temperature of minus 15 if you're lucky. Enjoy the warmth!

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Re: Warmth

I hope you were making a joke. Casey Station (where the melting airstrip is) is 2,635 kilometres from the South Pole, so getting sleds from one place to the other would be very non-trivial. Also, the South Pole already has an airstrip so it makes no sense for you to suggest building one there.

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They are *weighing* the ice cap

Is that not just a *bit* impressive?

Note this appears to be another one of those nasty non-linear effects which should be *properly* allowed for.

Thumbs up for tightening up the calibration on theory.

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Black Helicopters

Wolf!

Oh wait no, there's no evidence of wolves round here. Just hearsay, conjecture and competiting statistics (and we all know how many of those are made up on the spot - that's right, 22.8% of them).

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Anonymous Coward

Hang on

This could be for real and could potentially prove there is a problem. Its possible

So this brings a much larger problem and that is credibility. When the first line reads "A new satellite survey of Antarctica suggests that some of the continent’s contribution to sea-level rise may be overestimated". We could translate that to "we saw what we wanted to see and didnt question it. Then we added to the figure to scare people to action".

So after admitting their satellite data lied (not mistake, lie) they bring more satellite data showing again a scary situation we should worry about. Since the first lot of data was proven rubbish ages ago by ground sensors is there any collaboration to actually prove their data this time?

Then as already noted, there is a lack of anything in the study. Where is the data and proof which can be checked and verified to try against the models? The only figure I see is part of a £600,000 ($940,000) project funded by the UK’s Natural Environment Research Council.

So it is possible there is a problem. But who is going to believe them when we have more evidence of lies than truth? The casualty of the MMCC cult is science

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Reality

This was discussed over at Bishop Hill a couple of days ago.

One commenter looked at the reality of what was said, I quote:

Thoughts on the reported figure:

Daily ice loss: 190,000,000 Tonnes = cu m , roughly.

Wow that's a lot of tons, if you're an innumerate liberal-arts grad reading the Age in Starbucks .

And that ice loss is going on 365 days a year. Terrifying

That's 69,350,000,000 cu. m per year.

Antarctic ice cover area, sez Wikipedia 13,720,000 square clicks.

Times a million, for square metres: 13,720,000,000,000 sq. m.

So, annual depth of ice lost: 0.005 m.

That's, yup, five millimetres a year of Antarctic ice, folks. Every year.

WE'RE ALL GOING TO DIE!!!!

Oct 22, 2012 at 11:31 AM | Unregistered CommenterThon Brocket

When looked at like that and considering the several kilometres thickness of said ice it's going to be a very long time to see much of anything happening.

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Re: Reality

"When looked at like that and considering the several kilometres thickness of said ice"

Wikipedia says there's 30 million cubic km of ice in Antarctica. Dividing that by the km ice cover area the Bishop Hill poster claimed gives an average thickness of just over 2 meters. It implies that if the loss of 5 mm a year continues then all the ice will be gone in just over 400 years, raising sea level by tens of meters!

This is far too quick though, last thing I read was that scientists think it'll take at least 1000 years to go at current rates, so either this new data suggests it's sped up or one of the numbers here is wrong. I suspect the 5mm/year figure is the rate of ice loss, but not net ice loss.

In any case this is an example of why not to assume a small number is insignificant just because it looks small. 5mm/year loss would actually be a very significant amount of loss!

The Bishop Hill commenter could have avoided this by taking a less round-the-houses approach. I have no idea why he decided to convert the loss into depth loss. Why not stick to mass?

It would have been far easier to take the Antarctic mass figure from wikipedia (30 million cubic km) and divide that by the alleged rate of mass loss of 190 * 365 cubic km per year:

30,000,000/69350 = 432.5883201153569

That would have instantly told him the loss figure was suspiciously high. All gone in just over 400 years.

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Re: Reality

"Dividing that by the km ice cover area the Bishop Hill poster claimed gives an average thickness of just over 2 meters. It implies that if the loss of 5 mm a year continues then all the ice will be gone in just over 400 years, raising sea level by tens of meters!"

Quality, quality post. Would you enlighten the rest of us how losing 2m of ice over 14m square kilometres causes a "tens of metres" increase in seal level across the 361m square kilometres of ocean?

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Re: Reality

looks like we both made the same mistake with the units. It's kms not meters. So average thickness is 2km not 2m as I claimed and loss is 5m per year not 5mm per year as he claimed.

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Re: Reality

wait it might just be my error. how many m3 in a km3? 1,000,000,000?

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Re: Reality

yes just my error. It's 5mm per year as the original commented stated and total average height is **2 kilometers**, not 2 meters. Sorry about that.

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Re: Reality

And, to continue the poking, where do you get figure of 5 metres depth of ice being lost each year?

The reposted arithmetic from Bishop Hill looks OK (if the quoted 190 million tonnes per day is accurate) in terms of the figures for loss of ice equivalent to thickness lost, so we're talking about 5mm of thickness lost out of 2km vertical thickness.

That's going to take a very long time to melt.

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Linux

Re: Reality

Best work out everything in km, km^2 and km^3 to avoid confusion... and the result surprised me so much that I re-checked it

(so sod's law it's even more likely I screwed up a conversion somewhere)

Density of ice - 916.7 kg/m^3 = 0.9167 tonnes / m^3 = 916.7 million tonnes / km^3

Daily / Yearly ice loss*

190 million tonnes/day = 69350 million tonnes/year = 75.6 km^3 /year

Quantity of ice in Antartcica**

30 mil km^3 / 13.7 mil km^2 = 2.18km average depth (of course - 2m average depth seemed immediately strange)

Long - term ice loss

30 mil km^3 of ice divided by 75.6 km^3 /year rate of ice loss = 396825 years of ice melt for it to all melt away - Which seems like a huge number but in fact on geological scale is quite quick compared to probably tens of millions of years it took to build up.

@Fellow commentards - that number still doesn't seem quite right to me - please enlighten me as to where I went wrong - or maybe the quoted ice loss of 190 million tonnes/day is off?

* 190 million tonnes / day figure quoted from post by Ivan4

** from post by Ivan4 / Nomnomnom, Wikipedia caveat applies

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Boffin

Re: Reality

Hmmm.... juding by teh later posts my calculations seems to have been correct - hooray!!

According to NASA site, Antarctic is losing about 100 km^3 a year, quite a bit more than the 75.6 I calculated above, but that's still only 7.3mm a year on a 2km + depth, and that means 300000 years before complete meltdown.

Cue the shock tabloid headline - Antarctic ice to melt 96825 years before previous estimate!!!

:)

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Re: Reality @James M

400,000 years for it all to melt doesn't seem unreasonable as a projection of current (claimed) melt rates. But why will this continue for 400,000 years? The current (laughable) state of climate science is all predicated upon man made CO2 emissions, but the stock of fossil fuels is running low. Shale gas and unconventional oil might buy a few decades, but the basic maths of per capita energy use, population, and known and probable reserves push to the same conclusion that CO2 emissions will rise, and then fall off over the next fifty years.

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Re: Reality @James M

The problem is the CO2 drawdown is thought to follow a curve like this:

http://www.acamedia.info/sciences/sciliterature/globalw/reference/joos_shine.jpg

Yet until CO2 falls below a certain level Antarctica is expected to lose mass. That level might be 360ppm, 340ppm or even 300ppm.

There are enough fossil fuels to keep CO2 levels rising well beyond the next 50 years. Emissions are roughly proportional to the rate of CO2 rise. So even if emissions fall that just causes the rate of CO2 rise to slow. It would take a substantial reduction in emissions to stabilize let alone reduce CO2 levels.

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Melting???

According to this, on the continent proper, only the Antarctic Penninsula sees weather that reaching temperatures above freezing. Some islands close to the continent do see "warm" temperatures annually. The point is, if the temperature never gets above freezing, then that ice is not melting. It is subliming, and if there is a loss of mass, the annual precipitation has declined enough that the loss from sublimation is not compensated for by precipitation. This the same reason the ice fields on Kilimanjaro have declined. Drier air over the continent is far more likely to be due to cooler air then to warmer air.

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Boffin

Re: Melting???

Melting, sublimation, and.... slipping off into the sea. You forgot that third way Antarctica can lose ice mass.

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