Guest Post by Willis Eschenbach
Various pundits and scientists keep talking about a threatened acceleration in the sea level rise. Here’s the IPCC Fourth Assessment Report:
Anthropogenic forcing is also expected to produce an accelerating rate of sea level rise (Woodworth et al., 2004).
The usual font of misinformation says:
Church and White (2006) report an acceleration of SLR since 1870. This is a revision since 2001, when the TAR stated that measurements have detected no significant acceleration in the recent rate of sea level rise.
Over at the inversely named “SkepticalScience” blog, which is inadequately skeptical, we find:
The blue line in the graph below clearly shows sea level as rising, while the upward curve suggests sea level is rising faster as time goes on. The upward curve agrees with global temperature trends and with the accelerating melting of ice in Greenland and other places.
The Guardian gets in their licks:
Sea levels are already on the rise as a result of increasing temperatures, because the oceans expand as they warm up, but until now scientists have had a poor understanding of how quickly ice sheets such as those in Greenland and Antarctica will begin to disappear.
Meanwhile, back in the world of reality we have the latest satellite data up to September of 2010:
Figure 1. Satellite-measured sea level rise. Errors shown are 95% confidence intervals. Data Source.
The smaller trend of the recent half of the record is statistically different from the larger trend of the first half. Will this reduction continue into the future? Who knows? I’m just talking about the past, and pointing out that we sure haven’t seen any sign of the threatened acceleration in the satellite record. Quite the opposite, in fact.
We now return you to your regularly scheduled warnings of global inundation from accelerating sea level rise …
w.
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AusieDan says:
January 8, 2011 at 4:06 am
“The Australian government have warned local councils to get ready for much faster ocean rising in the future… provided maps of threatened towns, villages and cities.
That puts many property owners in great difficulty as there are no buyers for property said to be threatened by rising sea levels. Many people will have lost all their assets and be destitute if this nonesence is allowed to continue.”
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Just hope that they do not need to sell. On the other hand this could create an incredible buying opportunity for oceanfront property, temporarily. When no sign of the Great Flood appears things will rebound no matter what the Ministry of Truth says.
So now that the Chicago Carbon Exchange went bust, I wonder if that gang will be moving into real estate development?
Gray Lensman, there’s a couple of videos of interest, here and here. They both show how the surface of the sea is not flat.
There’s one curious thing in those sea level videos that I’ve been intending to write about, but like they say, “So many drummers … so little time”.
Here’s the oddity. Before each El Nino, there is a wave of high water, about a foot high, a small lump of water that runs all the way across the Pacific near the Equator. It starts in the Western Pacific and rolls clear across to South America. It takes about six weeks to make the trip, which means that it is moving at about 8 mph (15 km/hr).
After this wave, there is a second wave, larger and higher, moving in the same direction. Sometimes this wave doesn’t make it all the way across the Pacific, it gets broken up and dies out in mid-Pacific. But when it does make it, as soon as it hits South America the El Niño starts …
Has anyone noted this? What is it? Can we use it to predict an El Niño?
w.
Grey Lensman says:
January 8, 2011 at 11:11 pm
Your full quote does not change the meaning. You’re talking about random short-term variations caused by wind and land shape. I’m talking about 15-year sea-level trends going in different directions, not different amplitudes but one rising and one falling, over 15 years. See my post immediately above this, about waves of water that precede the El Niño and run all the way across the Pacific. That’s neither from “wind, land shape [nor] pressure”.
So adding the rest of your quote would have made no difference … which is why I didn’t include it. Sorry for the omission, but I don’t see the difference.
w.
Willis
This link will tell you the story of the ship behind me, the wave was a monster. over 100 feet. My ship was 30,000 tonnes, disappeared under the sea and the wave went down the funnel. I still dont know how we survived but it left me thoughtful
http://freaquewaves.blogspot.com/2006/08/encounter-of-bencrauchan.html
It sounds to me like those small variations are caused by variations in the current. A lot of them are truly massive, carry a vast amount of water and energy. Sort of like a gigantic bow wave. But they superimpose on the “level”.
Again scale and perception.
If people thought obtaining a global average temperature was difficult, it has nothing on trying to measure sea levels to within x millimetres PER FRIGGING YEAR.
Here is how seriously I consider this subject.
I discounted all the multi-million dollar satellite data, I discounted the thousands of hours of scientific work on the subject and went out to the beach and measured my own sea level. I stuck a 50cent wooden ruler into the water and guess what? Sea level went up, then it went down, then it went up again remarkably in sync with the waves.
Sea level accuracy to within x millimetres. Huh! I fart in your general direction.
> Ric
> Thanks. A brief search for photos yielded
> http://www.pictureninja.com/pages/turkey/image-antalya-coastline.htm
> which seems to show an impressive undercut in the cliff.
Yes, that’s the one.
But if that cliff has been there in that condition for 600 years, and the sea level is exactly on the undercut, then sea levels have not changed in 600 years. Remember there are no tides in the Med to confuse the issue.
Some might try to argue that the land is rising at exactly the same rate as the sea, but I think that is stretching the bounds of possibility.
.
Baa Humbug scoffs
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Sea level accuracy to within x millimetres. Huh! I fart in your general direction
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No doubt that’s only one of the reasons your arguments stink.
It’s really simple Baa. Even a noisy/ periodic signal like wave action has an average value. And each and every square cm of water has a pretty good idea that it would like to get there and it would if not stirred up by a bit of wind.
AussieDan sympathises
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That puts many property owners in great difficulty as there are no buyers for property said to be threatened by rising sea levels. Many people will have lost all their assets and be destitute if this nonesence is allowed to continue.”
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Sorry don’t see it. If you bought beach front you are probably pretty well off. So no sob story there.
They still have the property and it’s only of no value if the sea level actually rises significantly in the time scale of their residence. Since you claim that it will not why panic.
Most people will take the time scale and actual height above sea level into account if they intend to buy this property so there will be some devalue but not much.
Storm surges could be a problem. But they should have factored that in when they bought the property. So it’s their own fault.
Ralph claims
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And these undercuts are precisely at sea level. There was a glass sea a couple of months ago, and the sea was sitting just on the lower platform of the undercut. Within 5cm.
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This is not making much sense to me. If the undercuts are caused by erosion then if the sea level rises the undercut will rise to. If the sea level falls a gap wil be produced between the current sea level and the undercut representing the previous maximum sea level. Am I missing something here.
Gray Lensman informs
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In the bay of Naples, far above the sea sits a large Roman villa. In the cliff face under the villa sits a sea cave containing a fish farm designed to hold and breed lampreys. A Roman delicacy. These need the circulation of fresh sea water and indeed function today, at sea level as designed and operated by the Romans. There has only been one modification to the set up, they no longer feed recalcitrant slaves to the lampreys.
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If memory serves there are both sunken and elevated Roman and Greek ports at various places around the Mediterranean. This suggests that on the millennium time scale the coast has moved quite a bit. I would not count on one instance as being representative.
Willis gets defensive
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I know I didn’t say Wikipedia’s satellite data is wrong, because I didn’t even know they had satellite data. Where is it accessible?
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Willis your article is about sea level trends.
The Wikipedia article you reference is about sea level trends.
You show a graph of satellite data.
The wikipedia article you reference also shows a graph of satellite data.
I was alluding to the possibility that you preferred one lot of satellite data over another because it provided a more comforting story.
Now you claim that you are unaware some portion of the contents of the Wikipedia article. That does not make much sense to me.
Lazy
A fish farm in a cave at sea level is not a port.
It is a just small example that sea level is not the disaster we are informed.
Ports move in or out for various reason, sea level being a minor one. Alexandria and Port Royal being just two examples of ports that fell into the sea. A port at Manaus in Brazil fell spectacularly into the river, again nothing to do with sea level
Grey Lensman says:
January 8, 2011 at 11:11 pm
The subject of the post is changes in mean sea level over the years, i.e. a few centimeters per decade. When you said “slight variations” I read that as “less than the subject at hand” when it’s clear the changes are much greater than a few cm.
While a variation in mean sea level in the middle of the Pacific of a few meters would have a slight effect on vessels at sea (but play havoc on islands), that’s not the subject.
> I also forgot sea bed changes effect sea level as well, and they can be quite dramatic
… affect …. Pet peeve.
LazyTeenager says:
January 9, 2011 at 3:31 am
Yes, your reading comprehension skills.
First, note “the sea was sitting just on the lower platform of the undercut.” Erosion needs wave action, and that means on shore (on cliff!) wind driven waves. The erosion zone would from trough to wave top plus splash effects around the back wall. If the sea level rises, that lower platform will be under water.
Second, Ralph also posted:
In shorter sentences:
There are no exposed undercuts out of reach of current wave action.
Spot checks show no submerged undercuts out of reach of current wave action.
>>Lazy teenage
>>This is not making much sense to me. If the undercuts are caused by
>>erosion then if the sea level rises the undercut will rise to. If the sea level
>>falls a gap wil be produced between the current sea level and the undercut
>>representing the previous maximum sea level. Am I missing something here.
Missing quite a lot, I would say.
If the sea level rose, then another undercut would be formed above the previous one, which is not the case, for there are no sunken undercuts that I could see. Or, the sea level would rise well above the ‘platform’ of the older cut and make the undercut much deeper, which again is not the case. The sea level lies exactly on the level of the platform of the undercut, to within a few cm.
If the sea level fell, then a dry undercut would be left above the present undercut, which is not the case. Or, the undercut would be widened into a much deeper undercut, which again is not the case.
Thus the sea and land have been in this same position for some considerable time. All one needs to do, to see how long the sea levels have been stable, is estimate the length of time the cliffs have existed in this form. My estimate is 500 years.
.
Willis I appreciate your response to the comments but you can easily go to the ENSO page on this site and scroll down to the Colorado graph. I am talking about the period from sometime in 2005 / 2006 to current. Visually the rise looks flatter on the WUWT version. http://sealevel.colorado.edu/
I looked up the Wikipedia article on sea level. The graph is very hard to analyze, but seems to be the usual stuff, just at lower resolution and not as current. An up-to-date presentation of the same data is shown on the NASA site http://climate.nasa.gov/keyIndicators/ in easier to read form.
Willis is not picking “his” satellite data. It’s pretty much everybody’s data online. NASA gets its data from Aviso’s site. There doesn’t seem to be a lot of dispute as to what the standard data for the last 18 years is.
A reasonably skeptical person might note that the rate of rise changes from one reasonably straight line to another at a sharper angle at exactly the moment that the method of measurement changes. But it no longer matters. 18 years is long enough to analyze on its own. Over 18 years, sea level generally continues to rise but the rate at which it rises shows no acceleration. Possibly the reverse, but certainly no acceleration.
Lightrain has a problem with the definition of acceleration. As a meaningful physical property, it’s instantaneous. The instantaneous rate of change of the rate of change. You can no more say that sea level rise is accelerating now because it was slower on average during some earlier period, than that it is now decelerating because it was rising faster at the start of the present interglacial.
Bottom line is that since the start of reliable satellite data, the observed increase in sea level has followed something very close to a straight line and if anything is starting to flatten. It’s very difficult to get alarmed at a steady inch per decade and that’s all the data supports.
More panic-mongering over sea levels in an article in the Guardian this evening (Sunday), under the heading ” Glacier shrinkage will hit European Alps hardest, study claims”.
Apparently melting glaciers and ice caps will contribute sea level increases of 8.7 -16.1 cm by 2100: and that’s not counting Greenland and Antarctic ice sheets.
If you can’t reach the politicos by any other means, threaten their winter skiing!
LazyTeenager says:
January 9, 2011 at 4:05 am
I “prefer one lot of satellite data over another”? As far as I know, there’s only one satellite up there taking sea level measurements, and it only provides one datastream. If you don’t like the University of Colorado numbers, which ones would you prefer I use?
I’m not clear about your point. If you think my data is wrong, talk to the University of Colorado folks, where (as I clearly indicated) I obtained the data. If you think my analysis of the data is wrong, you’ll have to say exactly where and why.
Finally, you are trying to attack my numbers by impugning my motives, which is a most unpleasant technique. You are not claiming, but “alluding to the possibility” that I picked one dataset merely because it was “more comfortable”. That’s a non-starter of an argument. Doesn’t matter if I did what I did because I woke up with a hangover. All that matters is whether the numbers and the logic and the math are correct, my state of mind is not an issue. You lose points around here by trying that kind of stuff.
w.
PS – In regards to not using the Wikipedia graph, I make it a practice to obtain the data and create my own graphs. I would strongly recommend that you or anyone interested do the same. I cannot tell you how many times I have found errors or, on the other side of the coin, previously unknown relationships by going and looking at the data myself. This is particularly true of information coming from Wikipedia, where William Connoley has been distorting facts for a decade or so …
David says:
January 9, 2011 at 9:45 am
I suspect the difference is that they have used the data without the inverse barometer correction, and I have used their data with the inverse barometer correction applied. As you may know, the sea level rises when the barometer drops, so they provide both datasets. I prefer the one with the IB correction, as the more variables I can remove from the data the better.
w.
Willis,
A couple three weeks back there was a report done on modelling accuracy and sea level rise. Basically, it had to do with the problem with using one number for the whole globe, since the level varies by region. Hmm cant recall were I read it
A new assessment of the error budget of global mean sea level rate estimated by satellite altimetry over 1993–2008
Sometimes interestingly related pairs of articles appear close together on WUWT, perhaps random clustering. A few posts back we have:
http://wattsupwiththat.com/2011/01/06/new-paper-on-argo-data-trenberths-ocean-heat-still-missing/
describing upper 700m ocean cooling, which is the reason for the sea level rise decelleration that Willis is reporting here.
I do not see why any barometric adjustment is desirable if using satellite data as all pressure will do is move the water around, if the data is extensive enough it will equal out, if the data is not comprehensive then it is valueless. As for local observations they need to find out of the land is rising or sinking and barometric and wind action. How does the fantasy predictions of the IPCC compare to the scientific analysis of half of a volcanic island falling in to the ocean? that would solve the problem of beach front property values!