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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What do you call someone who has the gift of sublety changing a conversation?
A LazyTeenager!
Willis
Forgive me but you are a bugger, you kept me up all night thinking about your paired transient waves. I have some ideas. Do they know the source area?
Secondly I repeat the sea surface is gravitationally flat subject to local effects of a transient or long term transient nature. The global average gravity controlled sea level will only rise if
1. The volume of water rises
2. Sediments added to the water volume
3. Sea floor changes in shape.
This it matters not if it is current, geostrophic or el nino or wind driven, the Sea has a level. Thus if you find a point that is not rising or sinking or subject to transient effects, you have a valid sea level meter. Simply because a one inch rise there will add to all the other effects in force in other places.
To me this seems logical but If I can be directed to where there is a real flaw in this, I will learn
Grey lensman look at point 3 , that alone invalidates all your debate, also the sealevel is fluid (??) and there can be major upsets due to gravitational pull, some places have over 20 foot tides so how would holland fare withe a temporary extra yard or 3 of sea level, a bit like neworleans I would think? so you have some real terminal flaws in your thinking!
Chris
No it does not, the sub surface changes can increase or decrease the surface level constrained by gravity. all the other effects are external and overlay the basic datum level, the gravitational level.
Yes they vary, yes they are complex to measure but if you locate a true datum point, irrespective if it is surface or subsurface influences you have a “mark”
Sorry rushed but so much to do
Grey, thats the problem, there is no datum point.
With all the talk about sea level rise, why are the abandoned WWII facilities on remote Pacific islands still above water?
Surely the gravitational leveling of the oceans applies to the land as well, with a resultant change to the volume of the ocean basins over time. Because rock is heavier than water, on average the land will sink, and the ocean basins will rise, giving the appearance of rising sea levels as a natural consequence of gravity and the relatively thin crust of the earth.
Add to this continental drift, mid ocean spreading, there is no way to conclude the ocean basins are static. The talk of measuring sea level rise at 3 mm per year sounds fishy to me.
Chris, Understand the point that you are making, but I thing there are large areas that are at the datum point, the surface disturbances are localised and directional.
Willis
I think i met something similar to your two waves in the Arabian sea.
I have two thoughts
1. coincidence
2. A sort of whiplash effect but what causes the end of the current to be “whipped” i dont know. To understand that, think of yanking a water hose, thought experiment
Grey Lensman says:
January 9, 2011 at 7:28 pm (Edit)
It appears to be an “non-linear Kelvin wave” bouncing off the coast of South America and returning as a “Rossby soliton wave”. Always something to learn. I find this:
I also find:
As Walter Munk pointed out nearly a decade ago, sea level rise interpretation is somewhat constrained by lenth of day and polar wander observations–a 1cm rise should lead to about a 1ms increase in lod. But the more sea level rise is reportedly accelerating, the faster the earth is spinning, and this long term effect cannot be explained by atmospheric coupling. Core/mantle coupling speculation is based on previous patterns that seem to be falling apart lately. The simplest (hence, most scientific) explanation is that ice is accumulating in Antarctica, and that sea level rise due to thermal expansion or melting–or anything else for that matter–is illusory, the result of imprecise measurement complicated by rebound, etc.
Rebound in fact leads to decreased lod, but only wins when its effect surpasses that of polar melting combined with tidal deceleration, which had not typically been the case until the Little Ice Age. At present, rebound combined with Antarctic snow is overpowering both tidal deceleration and any possible sea level rise. Which of course points to a highly exagerrated AGW threat. –AGF
Serious edit: 1cm corresponds to a .1ms lod increase:
As Walter Munk pointed out nearly a decade ago, sea level rise interpretation is somewhat constrained by lenth of day and polar wander observations–a 1cm rise should lead to about a .1ms increase in lod. But the more sea level rise is reportedly accelerating, the faster the earth is spinning, and this long term effect cannot be explained by atmospheric coupling. Core/mantle coupling speculation is based on previous patterns that seem to be falling apart lately. The simplest (hence, most scientific) explanation is that ice is accumulating in Antarctica, and that sea level rise due to thermal expansion or melting–or anything else for that matter–is illusory, the result of imprecise measurement complicated by rebound, etc.
Rebound in fact leads to decreased lod, but only wins when its effect surpasses that of polar melting combined with tidal deceleration, which had not typically been the case until the Little Ice Age. At present, rebound combined with Antarctic snow is overpowering both tidal deceleration and any possible sea level rise. Which of course points to a highly exagerrated AGW threat. –AGF
And I misspelled “exaggerate” –would appreciate reading as follows (since I cannot edit):
As Walter Munk pointed out nearly a decade ago, sea level rise interpretation is somewhat constrained by lenth of day and polar wander observations–a 1cm rise should lead to about a .1ms increase in lod. But the more sea level rise is reportedly accelerating, the faster the earth is spinning, and this long term effect cannot be explained by atmospheric coupling. Core/mantle coupling speculation is based on previous patterns that seem to be falling apart lately. The simplest (hence, most scientific) explanation is that ice is accumulating in Antarctica, and that sea level rise due to thermal expansion or melting–or anything else for that matter–is illusory, the result of imprecise measurement complicated by rebound, etc.
Rebound in fact leads to decreased lod, but only wins when its effect surpasses that of polar melting combined with tidal deceleration, which had not typically been the case until the Little Ice Age. At present, rebound combined with Antarctic snow is overpowering both tidal deceleration and any possible sea level rise. Which of course points to a highly exaggerated AGW threat. –AGF
Thank you Willis
I am excited by the use of the concept of solitions but that does not produce an answer. The relaxation of winds implies a reduction in energy whereas soliton generation implies an increase of energy.
So we are left with what causes the soliton overlay and where does it exactly occur. That is it must have a point of origin or focus.
Grey, one area of LOD variation involves the “inverse barometer” analysis of sea level as it responds to air pressure variation, and such analysis has led to determinations of the variable angular momentum of the earth’s atmosphere. This atmospheric coupling has explained a majority of the non-tidal short term variation in LOD.
A,G, Thanks, seems I am getting further down a rabbit hole. As Antarctica is a very arid desert, increase in snow seems to be well, not right.
Increase in LOD, with no real rise in sea level???????????? dare I mention “expanding Earth”
That would address some questions with perhaps the periodic soliton waves being generated by irregular expansion. An expansion phase triggering the soliton pulse.
My apologies for thinking right outside the box but I hate loose ends
Grey, Willis, correct me if I’m wrong, but I thinks these soliton waves are generated by tides, or are a type of tide. On average of course, it snows as much in Antarctica as it melts, and desert though it be, it still snows considerably in some parts. And does it snow more than it melts at present? LOD behavior suggests that it does, as the earth keeps speeding up in recent years in spite of supposed GW. See Munk at
http://www.pnas.org/content/99/10/6550.full
And keep in mind that we have had only 2 leap seconds in the last decade, following a period of annual and even semi-annual leap seconds. See IERS for details: one example at
http://hpiers.obspm.fr/eop-pc/index.php?index=realtime&lang=en
I would suggest for starters, inputting LOD at 5000 days, deleting tidal effects.
–AGF
Grey, Willis, aren’t these waves of tidal origin? Generally speaking the earth slows down, especially when coming out of ice ages, till rebound overcomes melting. But lately the earth has been speeding up in the face of supposed ice cap melting (see Munk at
http://www.pnas.org/content/99/10/6550.full )
And since he wrote that a decade ago, we have only had two leap seconds as the globe settles around a rotation rate typical of the late 19th century. As for Bangladesh, parts of the delta are still growing at the same time ground subsidence has been exacerbated by the drilling of millions of tube wells. –AGF
A G Foster says:
January 15, 2011 at 4:10 pm
Good question, and I’d say no. The explanation given in the citations seems reasonable. You have wind that sets the entire surface of the tropical Pacific into motion. Then, you get a relaxation of the winds in the central region.
I’d think the moving water behind it could pile up on the stopped water in the middle and create a soliton. It’s reminiscent of the way that the soliton was discovered, when a boat being towed by horses along a canal was suddenly stopped.
w.
The leap seconds was an internet myth, I fully explained this elsewhere. It was greatly misunderstood by many including learned doctors. It was simply a mechanism to realign calenders. No real leap seconds.