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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Beesaman says:
January 8, 2011 at 5:49 am
…I’ve visited quite a few seaside places here in the UK and the sea is still were I found it many, many years ago as a child…
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Same here in tiny Malta, middleof the mediterranean sea. No indication of any visually identifiable signal of any sea-level changes whatsover, positive or negative. Our old traditional fisherman would definitely notice since these have made many markings, boat hooking points on the rocks, steps cut in granite etc…. NO CHANGE.
Sarc on: Maybe it’s because we do not have glaciers….LOL.
SL is very important issue and it will probably be the issue to wake people up. It is obvious that it already stopped rising and it will be dropping soon, much faster than it rose in the last few decades.
re ‘acceleration’ as used by the warmists – this is typical ‘get out of jail free’ card used by propagandist types to ensure the original fact of continuous (i.e. since LIA) sea level rise is ignored. Instead of describing decadal (or whatever) changes in rates of SL rises, they use the term acceleration to be deliberately alarmist. The truth is (from this article) that acceleration is slowing – but I wonder how many MSM articles will ever say that!
I suspect the satellite data is pretty useless (+/- 20mm is not that useful when one can do real measurements at harbours etc) but yet again it doesn’t exactly get prime media coverage because it does not show what the alarmists want!
Sea level rise seems to be more policy than science. Will the earth they claim to be saving cooperate? We know tax hungry politicians will, if elected.
Please see:
TOPEX-Poseidon Radar Altimetry:
Averaging the Averages
by John L. Daly (5 Dec 2001)
John Daly died 2004. This article is very well written and informative. I have some knowledge of radio and radar and think most of what John wrote almost 10 years ago is correct.
Agust
The link is here:
http://www.john-daly.com/altimetry/topex.htm
If you separate the Topex data from the Jason data and plot trend lines you can see that there has been a lowering of the rate of rise. The change may be due to the satellite differences.
hotrod ( Larry L ) mentions sine wave plots. I was just thinking of a slightly more general question about trends. If, hypothetically, you have several independent climate phenomena, each following a natural sine wave, then mathematically one fourth of these will be accelerating upwards at any point in time. Similarly, one fourth will be accelerating downwards. So given the various natural climate cycles, the odds should be pretty good of finding a trend that either seems to be increasing exponentially or looks like it’s in a “death spiral”. It’s almost surprising that the best example anyone can find is arctic sea ice.
I will post this again, if you don’t mind.
The evidence from the Mediterranean (which no tides to confuse the issue) counts against sea level rise.
There are deep undercuts on the cliffs around Greece and Turkey, which lie precisely on the sea level (caused by wave action). Now I did think these cliffs may be ‘recent’ due to erosion. However, I have now found deposited curtains of calcite deposits, from streams flowing over the cliff-top, with layered deposits 25cm deep. This means these cliffs have been a feature in this state (with undercuts at sea level) for many centuries.
Now unless one proposes that land movement is exactly in synch with sea level rise, for the erosion to be exactly at sea level, the evidence seems to suggest that sea levels have not changed for between two and five centuries (depending on how long it takes to deposit 25cm of calcite, from a stream that can only flow in the winter months).
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.
.
This is in addition to Greek and Roman ports being at or above sea level, all over the eastern Med. Now you might argue land rise for the above sea level ancient ports – but you cannot argue the same for the cliff undercuts, otherwise you would have other undercuts left high and dry above the present sea level.
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onion says:
January 8, 2011 at 5:10 am
I guess people might want to check the SkepticalScience article that the article quotes but does not link to:
How much is sea level rising?
http://www.skepticalscience.com/argument.php?p=3&t=104&&a=68
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As with mjk, I suggest you look up the definition of acceleration. The chart in the article you link to clearly shows EXACTLY the point Anthony was making, i.e. that there is no acceleration in the rate of sea level rise.
As tarpon pointed out in the first comment, the VERY SMALL rate of rise at this point, relative to the significant change over the recent (in geological terms) past is measurement error. Now even that rate seems to be slowing, so where’s the concern?
Oh, and interesting that the article you linked to only shows the data up to 2005, omitting the data since then. I wonder if that could be because the data since then, as shown by Willis above, shows even More clearly that the rate of sea level rise is DECELERATING, not accelerating?
Hmmmmmmmmmmm… a bit of cherry picking methinks.
KD
mjk says:
January 8, 2011 at 4:17 am
Sea levels are headed in one direction: UP.
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and there’s not one thing we can do about it…..
….does that make you wet your pants
Over the satellite record, the rise rate is trending down and perhaps the ocean cooling of the last decade accounts for some of that?
Rather than getting all geeky about how closely we can measure sea level to mm precision, why not take some clues from geology and look at the big picture?
Search “Holocene sea level” and follow some of the links. The rapid melting of continental ice sheets after the glacial maximum actually peaked about 6000-4000 years ago when sea level was roughly 2 METERS higher than today.
This evidence comes from wave-cut terraces and stranded corals that are presently sitting high and dry above the surf. These sites were not affected by isostatic rebound or tectonic uplift.
The Antarctic probably held substantially less ice during that Holocene Climatic Optimum when “global temperatures” were several degrees warmer than today.
Look at this graphic graphic showing sea level rise since the end of the last ice age. Initially it looks quite alarming then gets less so over time.
Very interesting, but if you take the longer period of observed decadal sea level rise, even the figures quoted are a slight exaggeration I would suggest. According to S. J. Holgate, a recognised world authority in geophysical research at the UK-based Proudman Oceanographic Laboratory in Liverpool, in his paper published in 2007, the following results represent the most comprehensive measurements of decadal sea-level change rates during the 20th century.
Between 1904 and 1953 global sea levels rose by 2.03 mm per year, whereas from 1954 to 2003 they rose by only 1.45 mm per year, giving an annual mean rate of 1.74 mm per year over the 100 years to 2003, or seven inches per century. Importantly, there was no increase in the rate of change over the whole century, indeed, they slowed down in the fifty years to 2003. These numbers have, incidentally, been fully accepted by the scientific establishment!
mjk says:
January 8, 2011 at 4:17 am
Absolutely spot on Willis. It is clear from the satellite measurements (when viewed upside down) that sea levels are in decline. I wish my share portfolio graph showed such a lack of acceleration. I would be rich!!! Must be a slow news day at WUWT to publish this analysis. Sea levels are headed in one direction: UP.
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As stated earlier, congrats to David L for showing a predictive prowess and having a finger on the pulse of alarmists. Also to MJK for having a desire to be posted on WUWT over a desire to type “acceleration define” in his/her search bar.
I’m feeling a bit generous this morning, so MJK, this is your lucky day.
Definitions of acceleration (n)
ac·cel·er·a·tion [ ak sèllə ráysh’n ] Audio player
1. increase in speed: the rate at which something increases in velocity
2. increase in rate of progress: an increase in the rate at which something happens or develops
3. act of accelerating: the act of accelerating, or the process of being accelerated
Synonyms: speeding up, stepping up, hastening, hurrying, quickening, rushing
Please note the synonyms (words that have same or similar meanings).
In Willis’ graph, did you see any quickening or speeding up? No? So sea level rise isn’t accelerating. But, you’re probably more focused on the sea level rise. The fact that the sea level is rising at all probably causes you much concern and alarm. This is a sad but known phenomenon. You see, when we exit a glaciation, (that’s where much of the earth is covered with glaciers), the dastardly glaciers melt on us! In spite of some heroic efforts to sequester the melted ice from the sea, inevitably, we fail, and the melted water making it to the sea raises the sea level.
Go here and scroll down to see a graphical representation of historic sea levels.
http://www.johnstonsarchive.net/environment/sealevel.html
There you go again, ruining a perfectly good narrative with that silly “data” stuff. If any of the sea level rise is due to warmer ocean water (and I think we know the answer to that…) then the flat to cooling temperatures of the ocean (Loehle, C. 2009. Cooling of the Global Ocean Since 2003. Energy & Environment 20:99-102.) would make the sea level rise curve start to turn down, as you show.
Jim Cole says: January 8, 2011 at 7:24 am
Rather than getting all geeky about how closely we can measure sea level to mm precision, why not take some clues from geology and look at the big picture?
Search “Holocene sea level” and follow some of the links. The rapid melting of continental ice sheets after the glacial maximum actually peaked about 6000-4000 years ago when sea level was roughly 2 METERS higher than today.
I know I have read of archeological digs along the Gulf Coast c.>2000 years ago, and the shore line was ~50 miles north of today’s as the Gulf was 2 meters higher.
David wrote: “… the Universty of Colorado graph you show does not look as flat as the Universitry of Colorado graph shown on the ENSO section of WUWT. Maybe my eyes are off , but if not WUWT?”
What gets me is the ‘diagonal black line’ on that graph…to me the trendS look like this:
http://sitelife.runnersworld.com/ver1.0/Content/images/store/13/9/dd8b7779-094f-4350-8980-aedf0c0f542b.Medium.jpg
One thing that is always missing from these discussions is the fact that coastlines are not static. Even if we leave out subsidence and uplift, other factors have an impact on the ‘height of the coast. Plants are constantly trying to build up the land along the shore. Waves can can deposit sediment along the coast or take it away, depending on many different factors.
Bangladesh, one of the supposedly more vulnerable places on Earth to sea level rise, has seen a tremendous gain in ‘dry’ land area due to these processes.
It is not scientifically feasible to take the current rate of sea level rise, project it out hundreds of years, then draw maps of flooded regions. It won’t happen that way.
Do continents “float” ?? . . . . I know clouds do . . . and they are heavy especially right before it rains!
Methinks the gloom and doom crowd have decimal dust emitting from their carbon wands. BOO!!!!!!!!!!!!!!!!!!
onion says: what’s more funny, that this article is missing the slower sea level rise before 1992, or that some readers won’t even accept the article because they refuse to accept sea level satellite data.
Orion, you clearly have little understanding if you make that type of comment. Let me give you a very simple example of the problem. I was recently trying to find the level of the sea at the Eastern Terminus of the Antonine wall when it was built. After contacting the best authorities on the subject they were unable to tell me whether the sea level had risen or fallen. The problem is that the last ice age depressed the area of Scotland and the land mass itself has been rising. In addition there have been sea level changes. The result is that not only should you expect long term sea level change, but you should also expect long term land level change – particularly in a region close to plate boundaries.
If you want to see evidence for land level change just pick up a rock. There’s a 100% certainty that it was formed when the land was at a different level – otherwise how e.g. would limestone rise above sea level? Or granite, or metamorphic stones, or sandstone become compacted – and if it’s mudstone then where is the mud now?
Land level is constantly changing. Some land masses are rising and some are falling and how anyone thinks it is possible to get an accurate measure of sea level from a few tide gauges is beyond me because there is no way to tell whether a change in the level of the gauge is due to a rise/fall in the land and/or a rise/fall in the sea level.
Its more understandable if you use ‘Rate of change’ instead of acceleration.
And the rate of change is decreasing.
Here is one reference to higher sea levels in the Holocene, geologic, not archeologic.
http://academic.research.microsoft.com/Paper/13400808.aspx