The paper is currently in press at the Journal of Coastal Research and is provided with open access to the full publication. The results are stunning for their contradiction to AGW theories which suggest global warming would accelerate sea level rise during the last century.
“Our first analysis determined the acceleration, a2, for each of the 57 records with results tabulated in Table 1 and shown in Figure 4. There is almost a balance with 30 gauge records showing deceleration and 27 showing acceleration, clustering around 0.0 mm/y2.”
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The near balance of accelerations and decelerations is mirrored in worldwidegauge records as shown in Miller and Douglas (2006)
Abstract:
Sea-Level Acceleration Based on U.S. Tide Gauges and Extensions of Previous Global-Gauge Analyses
J. R. Houston† and R. G. Dean‡ †Director Emeritus, Engineer Research and Development Center, Corps of Engineers, 3909 Halls Ferry Road, Vicksburg, MS 39180, U.S.A. james.r.houston@usace.army.mil
‡Professor Emeritus, Department of Civil and Coastal Civil Engineering, University of Florida, Gainesville, FL 32611, U.S.A. dean@coastal.ufl.edu
Without sea-level acceleration, the 20th-century sea-level trend of 1.7 mm/y would produce a rise of only approximately 0.15 m from 2010 to 2100; therefore, sea-level acceleration is a critical component of projected sea-level rise. To determine this acceleration, we analyze monthly-averaged records for 57 U.S. tide gauges in the Permanent Service for Mean Sea Level (PSMSL) data base that have lengths of 60–156 years. Least-squares quadratic analysis of each of the 57 records are performed to quantify accelerations, and 25 gauge records having data spanning from 1930 to 2010 are analyzed. In both cases we obtain small average sea-level decelerations. To compare these results with worldwide data, we extend the analysis of Douglas (1992) by an additional 25 years and analyze revised data of Church and White (2006) from 1930 to 2007 and also obtain small sea-level decelerations similar to those we obtain from U.S. gauge records.
Received: October 5, 2010; Accepted: November 26, 2010; Published Online: February 23, 2011
Sea-Level Acceleration Based on U.S. Tide Gauges and Extensions of Previous Global-Gauge Analyses, J. R. Houston and R. G. Dean
Discussion: (excerpt)
We analyzed the complete records of 57 U.S. tide gauges that had average record lengths of 82 years and records from1930 to 2010 for 25 gauges, and we obtained small decelerations of 20.0014 and20.0123 mm/y2, respectively. We obtained similar decelerations using worldwide-gauge records in the original data set of Church andWhite (2006) and a 2009 revision (for the periods of 1930–2001 and 1930–2007) and by extending Douglas’s (1992) analyses of worldwide gauges by 25 years.
The extension of the Douglas (1992) data from 1905 to 1985 for 25 years to 2010 included the period from 1993 to 2010 when satellite altimeters recorded a sea-level trend greater than that of the 20th century, yet the addition of the 25 years resulted in a slightly greater deceleration.
Conclusion:
Our analyses do not indicate acceleration in sea level in U.S. tide gauge records during the 20th century. Instead, for each time period we consider, the records show small decelerations that are consistent with a number of earlier studies of worldwide-gauge records. The decelerations that we obtain are opposite in sign and one to two orders of magnitude less than the +0.07 to +0.28 mm/y2 accelerations that are required to reach sea levels predicted for 2100 by Vermeer and Rahmsdorf (2009), Jevrejeva, Moore, and Grinsted (2010), and Grinsted, Moore, and Jevrejeva (2010). Bindoff et al. (2007) note an increase in worldwide temperature from 1906 to 2005 of 0.74uC.
It is essential that investigations continue to address why this worldwide-temperature increase has not produced acceleration of global sea level over the past 100 years, and indeed why global sea level has possibly decelerated for at least the last 80 years.
Full paper available online here
WUWT download (faster) here: jcoastres-d-10-00157.1
h/t to John Droz and to Dr. Willem de Lange
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Magnus says:
March 28, 2011 at 2:30 pm
How important is this finding for the AGW theory? Im asking bc it sounds pretty important in light of the scary sea level rise scenarios Ive read about…
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Its not really a bombshell
the IPCC notes that globally sea level rise shows a rise in some places and declines in others. It should not come as no surprise that you can select areas and find no acceleration. See the chart I posted above that shows the difference between the west coast and the east coast of the US. This study focuses on the US. Next, there is some disagreement in the literature about whether the rate is increasing or not ( accelerating) The rate for the century is about ~1.7mm, but sat data shows that since 1993 the rate appears to have increased.. accelerated. The real question is this:
if it continues to warm, we know the sea level will go up ( in places) how much is the question.
It seem to be two errors in the Introduction:
“…and add as much as 0.20 cm to the upper limit if melting of
ice sheets increases…” should be 20 cm?
“The current sealevel
trend of about 1.7 mm/y will produce a rise of about 19mm
over 110 years from 1990 to 2100, …” should be 19 cm?
Rob Z:
Random, ever heard of the southern hemisphere?
True, true. My follow-up is if it is winter in the US what season is it in NZ or Australia. IIRC closest approach of Earth to Sun was 3 January. But you know what they say about broken clocks 😉
As I am a bit uncertain about how to start on a least square quadratic analysis I recently took the easy way out and checked the water mark on the fence post at Wellington Point in Brisbane. The spot has the advantage that it is on the lee side of a long headland protected by offshore mangroves so there is no wave action- a natural tide gauge. The spring tide mark is exactly where it was in 1941! Those who doubt such simplicity can check the records that at that time the Pacific Ocean was in imminent danger of breaking through to the Nerang River at aptly named Narrowneck which opening would have endangered the Main Beach at Southport. Heavy wooden groynes saved the day and the road connection is intact. Any sort of sea level rise would have eroded this narrow sand connection long ago- the groynes are long gone and there is no current threat. A careful check of the salt crystal erosion rock platforms at Point Danger and the Kiama -Woolongong coast of New South Wales adds confirmation. My private bet is that a lot of these alleged climate scientists would not know what salt crystal erosion was let alone its significance. If anone wants to know ask me. Geoff Broadbent
I lived in Boulder from 1972 to 1983 and was registered as a student at the U. of Colorado for most of that time. The concept of CU researchers measuring sea level conjures up an image of grad students leaning out of upper-story windows in Gamow physics tower, dropping lines into the water.
I sincerely hope that this isn’t what they’re doing, as when I lived there, Boulder was a good 1600 m above sea level! {grin}
Well, Random’s question works regardless of which hemisphere you’re in. It’s just that summer is in July in the Northern and in January in the Southern.
steven mosher says:
March 28, 2011 at 2:52 pm
It is believed that on average, over the period from 1961 to 2003, thermal expansion contributed about one-quarter of the observed sea level rise, while melting of land ice accounted for less than half.
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Mosh, your charts stop 8 years ago, in 2003.
This paper goes up to 2010, 7 years after your chart stops.
Since sea levels have not risen in the past few years, you got a newer chart?
Glad to see that they didn’t cooked the books, but this reads like they were really trying to find acceleration. Maybe for the reason others have suggested, to get funding.
This is actually not new. Chao, Yu & Li (Science, 11th April 2008) proved that sea level rise had been linear for at least for the last eighty years, with a slope of 2.46 millimeters per year. Theirs was the sea level rise corrected for all water held in storage by every dam built in the world since the year 1900. You don’t need to be rocket scientist to figure out that for a century this amounts to a little under ten inches, not twenty feet that Al Gore is dreaming about, or any other number that is periodically trotted out by various climate “scientists.” I am glad that these guys were able to publish because of the hold warmists have on scientific publication these days.
How can sea level rise not be accelerating when it is one of the great truths of the Doom Twins, Hansen and Gore, that sea level rise will accelerate due to global warming?
SØREN BUNDGAARD says:
March 28, 2011 at 5:59 am
“Danish meteorological institute has measured the water level since 1890
and have measured only small fluctuations…”
It’s always good to see data on a time scale appropriate to questions of eustatic sea-level, rather than short-term “trends” that impress rank amateurs in the science. Because of its location, however, sea-level fluctuations off Denmark are more indicative of run-off in the Baltic basin, than of global levels.
BTW, between the two, Jim Houston and Bob Dean have “only” a century of experience in dealing with real-world coastal data. They are not the typical academic “climate scientists.”
“Magnus Olert says:
March 28, 2011 at 3:53 pm
It seem to be two errors in the Introduction:”
I was going to say the same thing. One mistake might be forgivable if its subtle but if they cant get the introduction right the I suspect the rest of the paper is going to be rubbish too.
“ClimateForAll says:
March 28, 2011 at 9:32 am
You know what I predict.
Alarmists will find a way to account for this analysis.”
Global warming is causing the rate of sea level rise to decelerate because the warming is even worse than we predicted. As the earth gets warmer more water evaporates from the oceans, making the rate of sea level rise decelerate.
However, this will lead to increased precipitation over the polar regions, leading to increased melting of the arcitic, which will make the flooding if the shorelines even worse and kill millions of polar bears.
This is another clue that catastrophic sea level rise is a ruse, but it’s not enough to convince me fully since at first glance I don’t see spacial consideration. If a hundred tide records were located along a coast that was expanding upwards, tectonically and due to vulcanism, and another hundred were scattered randomly over the planet, then a strong rise in sea level would not be detected in their histogram.
Maybe there is something to the idea that the temperature rise in the last century has been greatly overstated? Well duh. Most everybody on here except Mosh has come to that conclusion. I mean don’t forget that the temperature ten years ago is already a few tenths warmer than it was back then and getting warmer every year. And the temperature 60 years ago is a few tenths lower now than it was 10 or 11 years ago and getting cooler. Subtract the negative tenths from the positive tenths and there ain’t much actual warming left to melt any ice that wasn’t already in the process of melting from the LIA warmup.
Throw in some tenths to account for bad siting and some more tenths for UHI effect and maybe the decline in the treemometers isn’t so far from the actual temperature trend after all.
This is an umpteenth introduction to the 105-year trend of sea level at the Japanese coast:
http://www.data.kishou.go.jp/kaiyou/shindan/a_1/sl_trend/sl_trend.html
Our MET says (1) there is no long-term trend, and (2) a 20-year oscillation is evident.
OT, but we are still having a hard time with the Fukushima nuke plants.
Hope things are getting better in coming months.
It’s like I already said, AGW is simple:
If the world were warming, the ice would be melting.
If the ice were melting, the sea would be rising.
The sea is not rising.
Therefore the ice is not melting.
Therefore the world is not warming.
Really, I don’t see what all the fuss is about. Seems simple enough to me.
Again, what in the hell do these guys have to gain for lying like this?
@ur momisugly David Archibald and others looking for recent Global Mean Sea Level data ….
Aviso, http://www.aviso.oceanobs.com/en/news/ocean-indicators/mean-sea-level/products-images/index.html has data into early 2011.
There are multiple versions of data available, with and without inverse barometer corrections, seasonal signal removal. and global isostatic rebound corrections.
Face meet Palm – So Trenberth’s heat is still missing???
There is a new GMSL dataset from Church and White now available at CSIRO.
It is associated with a paper due to be published later this year. It extends the tide gauge based dataset through 2009. See the section titled “Reconstructed GMSL for 1880 to 2009” on page http://www.cmar.csiro.au/sealevel/sl_data_cmar.html
The Houston and Dean paper, the subject of the headpost, analyzed the Church and White 2006 and 2009 datasets, but the 2011 dataset was only recently released. They found deceleration from 1930 through 2001 of -0.0066 mm/y2. For the 2009 update, they found increased deceleration 1930-2007 of -0.0130 mm/y2.
For the most recent update the data has been changed so that the deceleration from 1930 through 2001 had dropped in by about 40% to -0.0039mm/y2. What was once a relatively sharp change of slope around 1930 has become less evident with each successive data update.
For the 1930 through 2009 period, GMSL now shows an acceleration of +0.0036mm/y2.
Taking the second derivative of a noisy data set is difficult at the best of times…I would be very, very surprised if any were to come up with a robust measurement of this figure, acceleration of rate of change of sea level, at a level of significance good enough to rule out or confirm any of the IPCC scenarios in the coming decade. But kudos to the authors for trying:)
Latitude:
Mosh, your charts stop 8 years ago, in 2003.
This paper goes up to 2010, 7 years after your chart stops.
Since sea levels have not risen in the past few years, you got a newer chart?
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That chart is from the IPCC Ar4. I suppose one could go to the dataset and recompute. However, the lesson of that chart should be clear. You have to be careful picking coastal locations.. the sats look at the entire ocean and starge as it may seem
you’re see major variability. Note also, that sea level varies WAY MORE than temperatures. So, people who complain about the fact that there are only several thousand temperature sites, should HARDLY glom on to a study that looks at less than 100 stations, all in the US and all on the coast.
Still, The question of ACCELERATION in the last 20 years or so, is interesting, but its not really the main concern. The main concern is projecting the future. Note, that since we see some places that go up and other places that go down, the regional impacts become much more important. Note also, that GCMs have been criticized lately for their lack of regional precision. So the real skeptical position is not about
acceleration. Its about the future rise and where it will occur and what we can or should do about it, if anything.
In the last 7000 years, sea levels have been pretty stable, rising about 2m (2000mm) in that time. The rate of rise averages out to 2000/7000 ~ 0.3 mm/year.
The rate of increase over the past 100 years is about 10 times that. But I forgot about the little ice age………
Oh, and with the dams argument, its got nothing to do with flow in and flow out – just the total volume of dams (i.e. the water is in the dam, not in the sea), which I rather imagine is increasing.
The satellite data from Jason shows deceleration. If the rate of deceleration remains constant for the next 100 years (89 until 2100), then the sea levels will peak in 2025 and will drop almost 40 cm in 2100.
http://theinconvenientskeptic.com/2011/02/determining-the-true-acceleration-of-sea-level-rise/