GW: Separating facts from fiction

NASA released new findings this week...
The Antarctic ice sheet shrank significantly during the past three years, according to the findings of a NASA study released on Thursday.

Using data from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE), scientists concluded that Antarctica's ice sheet decreased by about 152 cubic kilometers annually from April 2002 to August 2005.
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You would think that the whole AGW case rests on Mann et Al, and that the controversy around it invalidates all the rest of the science on AGW. It just isn't so. I would have expected if it was so easy to 'debunk' Mann et Al, other published papers would be falling like nine pins. They aren't. The basic science is solid. Carbon Dioxide is a greenhouse gas, it must be, or else the earth would be something like 20C cooler. More CO2 = warmer, less = cooler. It is not that hard to understand. The actual mechanics behind it all are more complex, but the basic theory is simple and sound.
 
Just a note to say that this was/is an interesting thread.

DISCLAIMER: I'm fairly convinced GW is real but on the fence about AGW

This thread almost made me fall off that fence. The Anti-AGW arguments are very convincing while the Pro-AGW arguments are, for the most part, logically flawed in the best of cases. More Adhoms than anything else.

I was thinking of doing an experiment: take every post in this thread, remove every sentence/clause that contains a logical fallacy and every post that is not topical, then recreate the thread from there. Few words/posts would remain. It would likely only be two or three pages instead of eight and I suspect that most of those would belong entirely to the Anti-AGW side.

If I get bored, I might just do that.
 
Rob Lister said:
I was thinking of doing an experiment: take every post in this thread, remove every sentence/clause that contains a logical fallacy and every post that is not topical, then recreate the thread from there. Few words/posts would remain. It would likely only be two or three pages instead of eight and I suspect that most of those would belong entirely to the Anti-AGW side.

If I get bored, I might just do that.
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If you are bored, and you really wanted to get at the truth, don't you think it would be a better use of your time to research the facts presented here and through the links and present your conclusions regarding AGW?
 
DavidJames said:
If you are bored, and you really wanted to get at the truth, don't you think it would be a better use of your time to research the facts presented here and through the links and present your conclusions regarding AGW?
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Probably not. The degree of research/education/skills/talent necessary to fully understand the problem are far beyond my current cabilities. As with many esoteric and politically charged topics, I have to rely on the aspects of the arguments presented to me that I can resonably comprehend. When doing so, I find it best to simply ignore arguments based entirely upon logical fallacies (adhoms, strawment, et al), and concentrate on the remainder.
 
Rob Lister said:
Probably not. The degree of research/education/skills/talent necessary to fully understand the problem are far beyond my current cabilities. As with many esoteric and politically charged topics, I have to rely on the aspects of the arguments presented to me that I can resonably comprehend. When doing so, I find it best to simply ignore arguments based entirely upon logical fallacies (adhoms, strawment, et al), and concentrate on the remainder.
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Yeah, I'm in the same boat. That's what is sometimes nice about these kinds of debates, they go to the heart of the matter and focus on relevant aspects backing up argument with data and explaining the data in a way that helps me make decisions.

I agree that this thread is to some extent bogged down in ego. But hey, far be it for me to complain about ego. That's becoming my middle name. I cringe at some of the threads I've contributed to.

I'm still checking this one out so it's not completely useless.
 
varwoche said:
NASA released new findings this week...

The Antarctic ice sheet shrank significantly during the past three years, according to the findings of a NASA study released on Thursday.
Using data from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE), scientists concluded that Antarctica's ice sheet decreased by about 152 cubic kilometers annually from April 2002 to August 2005.
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I saw this link and wanted to find out more. It sounds pretty bad and would be a very interesting finding; 152 cubic km annual loss in the ice sheet. So, I went on a Google and found out from here:

http://www.aber.ac.uk/~glawww/antarctic.shtml

That the volume of the Antarctic ice sheet is estimated to be about 30 million cubic km. So I got out my calculator and worked out that this study has concluded that the antarctic ice sheet shrank by 152/30,000,000 per annum for the last three years. That is a loss of 0.0005% per year for three years.

This doesn't pass my sniff test. I cannot believe (even with wizz bang satellite technology) that the margin of error of these measurements even come remotely close to 0.0005%. This strikes me to be highly spurious precision.
 
Geckko said:
I saw this link and wanted to find out more. It sounds pretty bad and would be a very interesting finding; 152 cubic km annual loss in the ice sheet. So, I went on a Google and found out from here:

http://www.aber.ac.uk/~glawww/antarctic.shtml

That the volume of the Antarctic ice sheet is estimated to be about 30 million cubic km. So I got out my calculator and worked out that this study has concluded that the antarctic ice sheet shrank by 152/30,000,000 per annum for the last three years. That is a loss of 0.0005% per year for three years.

This doesn't pass my sniff test. I cannot believe (even with wizz bang satellite technology) that the margin of error of these measurements even come remotely close to 0.0005%. This strikes me to be highly spurious precision.
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How can you trust "Centre for Glaciology" when they can't even spell "center" correctly? ;)
 
'Scuse me, but "centre" is the British and Canadian spelling. Considering that the British have been speaking English for far longer than USians, I think it's your spelling that's wrong. ;)
 
Orwell said:
'Scuse me, but "centre" is the British and Canadian spelling. Considering that the British have been speaking English for far longer than USians, I think it's your spelling that's wrong. ;)
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Which is precisely why we need to stop calling it English and start calling it American and bring to an American tribunal and prosecute those who will not conform to American standards. Pissed is angry not drunk. Pants are an outer garment and you go to THE hospital and you study at THE university. The English might have invented the language but we perfected it. You don't need to thank us just learn to use it correctly. I suggest a grace period to bring everyone up to speed.

"You're in America, speak Spanish!" --Paul Rodriquez
 
Geckko said:
I cannot believe (even with wizz bang satellite technology) that the margin of error of these measurements even come remotely close to 0.0005%. This strikes me to be highly spurious precision.
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Perhaps you could look into the accuracy of side-looking radar, multiple-pass imaging, and GPS, and get back to us, then?
 
Geckko said:
I saw this link and wanted to find out more. It sounds pretty bad and would be a very interesting finding; 152 cubic km annual loss in the ice sheet. So, I went on a Google and found out from here:

http://www.aber.ac.uk/~glawww/antarctic.shtml

That the volume of the Antarctic ice sheet is estimated to be about 30 million cubic km. So I got out my calculator and worked out that this study has concluded that the antarctic ice sheet shrank by 152/30,000,000 per annum for the last three years. That is a loss of 0.0005% per year for three years.

This doesn't pass my sniff test. I cannot believe (even with wizz bang satellite technology) that the margin of error of these measurements even come remotely close to 0.0005%. This strikes me to be highly spurious precision.
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WGAF about the percentage? The quantity is the important feature. The ice-mass in the centre (sic) of Antarctica is statistically overwhelming, but that's not where things vary much. Were all of that to melt we'd be looking at silly sea-rises on the hundreds of metres. The variability occurs on the seaward side of the continent - which is twice the size of Australia - where the oceans bring in the heat of more balmy climes. The loss of ice-mass in those regions is what matters, and the subsequent rise in sea-level will have an absolute value, irrespective of the ice still locked-up (as it has been for 3 to 4m years) in central Antarctica.
 
CapelDodger said:
WGAF about the percentage? The quantity is the important feature. The ice-mass in the centre (sic) of Antarctica is statistically overwhelming, but that's not where things vary much. Were all of that to melt we'd be looking at silly sea-rises on the hundreds of metres.
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I don't think I've ever seen "hundreds of meters" before. Any source for that?

Usually I see estimates of six to thirty meters - which is bad enough as I live more or less on the beach - but "hundreds"?

From http://pubs.usgs.gov/fs/fs2-00/

tbl1.gif
 
CapelDodger said:
WGAF about the percentage? The quantity is the important feature. The ice-mass in the centre (sic) of Antarctica is statistically overwhelming, but that's not where things vary much. Were all of that to melt we'd be looking at silly sea-rises on the hundreds of metres. The variability occurs on the seaward side of the continent - which is twice the size of Australia - where the oceans bring in the heat of more balmy climes. The loss of ice-mass in those regions is what matters, and the subsequent rise in sea-level will have an absolute value, irrespective of the ice still locked-up (as it has been for 3 to 4m years) in central Antarctica.
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I don't know what WGAF means. I am not saying it wouldn't matter if the Antarctic Ice sheet melted. Clearly it would be a big problem.

But the percentage is particularly pertinant as a measurement of what is observable, which is what this particular study is about.

What if I told you I weighed myself this morning and I had lost 0.04 grams in weight. You would most likely say to me that it is highly questionable whether I am able to measure my weight with that level of precision. Same with this study in my mind. I just don't think this paricular study is worth anything given the scale of the findings.

Another reservation I would have about this study is that this scale of variation over an extremely short time span doesn't seem like it would be outside expected variations from year to year. Again, take my weight analogy. There would be something wrong if our weight didn't vary by 0.0005%, or around 0.04 grams from day to day. I would think the same about the Antarctic Ice sheet from year to year.

I think the more correct conclusion should be that the measured variation in the ice sheet over the short period of study has been too small to draw any conclusions about whether it is growing or shrinking.
 
An excellent 'history' of the scientific investigation of CO2. It was understood in the 19th century that CO2 was a greenhouse gas.

http://www.aip.org/history/climate/co2.htm

From Scientific American

1. What is the greenhouse effect?
The Sun's warmth heats the surface of the Earth, which in turn radiates energy back to space. Some of this radiation, which is nearly all in the infrared spectrum, is trapped in the atmosphere by greenhouse gases. For instance, water vapour strongly absorbs radiation with wavelengths between 4 and 7 micrometres, and carbon dioxide (CO2) absorbs radiation with wavelengths between 13 and 19 micrometres.
The trapped radiation warms the lower atmosphere, or troposphere. Some heat then finds its way back down to the Earth's surface, making it hotter than it would otherwise be. This is the greenhouse effect.
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Geckko said:
But the percentage is particularly pertinant as a measurement of what is observable, which is what this particular study is about.
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If NASA's methods are not reliable then surely you should have little problem finding a citation to support your point.
 
varwoche said:
If NASA's methods are not reliable then surely you should have little problem finding a citation to support your point.
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Admittedly I haven't been around here very long. But don't people on this forum use their own facilties to assess the information, or is it the accepted practice to simply throw links around?
 
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