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Post by socold on Sept 28, 2009 21:15:08 GMT
Uncertainty spreads are given in the figures. The antarctic is more uncertain but for Greenland the uncertainty range is all within mass loss. Slower sea level rise in recent years, but it's still rising The ice sheet mass balance, ocean heat content measurements and sea level rise is balanced for recent decades although the last few years are not. earthobservatory.nasa.gov/Features/OceanCooling/page5.php
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Post by poitsplace on Sept 29, 2009 2:43:33 GMT
I assure you that the even ignoring the fact that the center of greenland and the antarctic are increasing in mass...the 100-200 cubic kilometers of ice "lost" (again, its actually just redistributed) per year would have only a tiny impact on sea levels. It would take 100 years to cause 2.5cm-5cm of sea level increase across the 360 million square miles of ocean. Of course, the ice isn't being lost so that figure is wrong. Essentially all sea level increases are the result of thermal expansion and aren't even uniformly distributed.
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wylie
Level 3 Rank
Posts: 129
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Post by wylie on Sept 29, 2009 2:50:10 GMT
Uncertainty spreads are given in the figures. The antarctic is more uncertain but for Greenland the uncertainty range is all within mass loss. Slower sea level rise in recent years, but it's still rising The ice sheet mass balance, ocean heat content measurements and sea level rise is balanced for recent decades although the last few years are not. earthobservatory.nasa.gov/Features/OceanCooling/page5.phpSocold, I understand that the graph MAY still a small increase, but the problem with the microwave reflectivity of metal ships crossing the sea still applies and the problem with the incredible accuracy claimed when using 3.2 cm wavelength radiation to measure a 1.0 mm /year. The tidal gauges show less increase (will have to look those up for you). Finally, the inaccuracy of the "3.1 mm +/- 0.4mm" almost certainly doesn't include the inaccuracy of the measurement method but rather is a measure of the extrapolation inaccuracy. Also, that assumes one trend. If the last 3 years are now less than 1.0 mm/year (assuming that they are accurate!), then it is a different trend. There is no guarantee that sea level rise should be linear!! Don't understand the second graph on your post. Could you explain it a little more? Ian
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nobodyinparticular
New Member
It use to be days of wine, women and song; now it's beer the ol' lady and the computer.
Posts: 5
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Post by nobodyinparticular on Sept 29, 2009 3:41:35 GMT
I assure you that the even ignoring the fact that the center of greenland and the antarctic are increasing in mass...the 100-200 cubic kilometers of ice "lost" (again, its actually just redistributed) per year would have only a tiny impact on sea levels. It would take 100 years to cause 2.5cm-5cm of sea level increase across the 360 million square miles of ocean. Of course, the ice isn't being lost so that figure is wrong. Essentially all sea level increases are the result of thermal expansion and aren't even uniformly distributed. Ocean area is 361,000,000 square kilometres[/u] (139,000,000 sq mi). Not 360 million square miles. en.wikipedia.org/wiki/Ocean
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Post by slh1234 on Sept 29, 2009 4:40:55 GMT
I just hope the public realizes how badly they've been mislead once all this crap dies down and treats the alarmist leaders the way the alarmist leaders said skeptics should be treated. That probably is too extreme. More to the point the issue needs to be addressed. Requiring complete archiving of data and tearing down paywalls would be a very positive step in the right direction. Additionally the science community should think of putting together an association that promotes licensing, comprehensive peer review, regulation, and set of standards for various levels of services. Working with state and federal governments these standards could be enforced. Doctors have it, lawyers have it, accountants have it. . . .seems to me if we are going to be increasingly putting the public welfare at risk from shoddy science there should be some mechanism to ensure stuff like the following doesn't happen: www.climateaudit.org/?p=7168Climate audit is hard to get to right now with a lot of traffic reading this one. I think government involvement and regulation is a big part of the problem. I can't see them being any part of the solution.
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Post by donmartin on Sept 29, 2009 6:08:47 GMT
How does one determine whether the sea is rising or the land is sinking. Gravity places a limit on the height of land (say, around 49,000 feet), but not the depth, obviously. So the natural tendency of a land mass would be to sink giving the appearance that the water level is rising. Not so?
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Post by poitsplace on Sept 29, 2009 6:28:16 GMT
Ocean area is 361,000,000 square kilometres[/u] (139,000,000 sq mi). Not 360 million square miles. en.wikipedia.org/wiki/Ocean[/quote]Oops, well the math was for kilometers...I just said it wrong.
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Post by radiant on Sept 29, 2009 10:31:41 GMT
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Post by poitsplace on Sept 29, 2009 11:08:34 GMT
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Post by woodstove on Sept 29, 2009 14:47:06 GMT
Technical problems that they are still working on according to the latest e-mail I received this morning.
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Post by inverse on Sept 30, 2009 0:51:12 GMT
I worked for a contractor in 1983 that helped build the Thames barrier in London and at the time it was given a 25-50 year lifespan due to the Southern part of the UK sinking. Now over 25 years later this theory has changed to rising sea levels due to climate change and that a new barrier would be required in 2030, 50 years!!!
The trouble with internet articles is that they dont go back far enough to prove what was said over 25 years ago.
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Post by slh1234 on Sept 30, 2009 3:31:29 GMT
A while back, someone posted a link here talking about the land rising around Juneau, AK. The article attributed it to melting of the Mendenhall glacier. I responded to the posting, and called it ridiculous, and I still think it was for a number of reasons (not the least of which is the area the glacier occupies as compared to the total area they were claiming was rising as it was getting relieved of the weight of the Mendenhall Glacier). Most of all, though, the article was just ridiculous because they just found an explanation they liked for something they didn't really research.
But now, with the article about Antarctica, it looks to me like they are measuring the height of the elevation of the ice, and since it is (as they say) lower, they are only considering that this could be due to ice melting. But since the ice there covers the continent (if not, please correct me), and has been expanding, would it not also be possible, following theories put down about Alaska, that the weight of the ice is pushing the level of the underlying land down? I don't see any consideration given to that in that article.
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Post by nonentropic on Sept 30, 2009 4:05:58 GMT
In geological deposition it is quite normal to talk about compression from loading and in those instances the quantity of material can be quite modest say 500m plus of material.
Ice in a major glacier will be 1000m plus and in a glaciation much more.
The plasticity of the earth's crust is often not considered in these issues. I would say that the Antarctic loading and consequent alteration of the apparent earths shape is a bit of a wild card.
In a sense the consequence of a lift via ice at some point say the Antarctic will result in a lift of land at some other point possibly the bottom of the sea. How do they get such precise sea levels out of all this is a point of concern.
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Post by radiant on Sept 30, 2009 11:23:07 GMT
A while back, someone posted a link here talking about the land rising around Juneau, AK. The article attributed it to melting of the Mendenhall glacier. I responded to the posting, and called it ridiculous, and I still think it was for a number of reasons (not the least of which is the area the glacier occupies as compared to the total area they were claiming was rising as it was getting relieved of the weight of the Mendenhall Glacier). Most of all, though, the article was just ridiculous because they just found an explanation they liked for something they didn't really research. But now, with the article about Antarctica, it looks to me like they are measuring the height of the elevation of the ice, and since it is (as they say) lower, they are only considering that this could be due to ice melting. But since the ice there covers the continent (if not, please correct me), and has been expanding, would it not also be possible, following theories put down about Alaska, that the weight of the ice is pushing the level of the underlying land down? I don't see any consideration given to that in that article. serc.carleton.edu/NAGTWorkshops/geomorph/vignettes/25106.htmlin Glacier Bay, ...... new post-LIA uplift rates as high as 25 cm/yr have been measured And it seems the rapidly rising ground is catching some people out? link.brightcove.com/services/player/bcpid1243604764?bctid=1653635032www.juneauempire.com/stories/070808/loc_301334527.shtml ;D
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Post by slh1234 on Sept 30, 2009 14:49:07 GMT
Those are good articles Radiant. The first is a very reasonable explanation, and the second a news strory (I can't watch the video right now - I'm on my air card on the train, so bandwidth is a little bit limited). That is very different from what was written in the article I said was ridiculous. And it is something to think about with respect both to what can be happening in Antarctica, and why sea levels may not necessarily rise that much even if there is a melt of Antarctica and Greenland.
My thought on the second is that as the land rises, there is a change in the shape of the sea basin and that will change its capacity. The constantly changing shape and capacity of the sea basin is something that I don't think can be measured with any significant accuracy, so I don't think any change of sea level upward or downward can really be attributed in any quantifiable way to specific causes like climate change (regardless of what Many And Varied's "Pocket Protector People" may say.)
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