Guest post by Steven Goddard
One of the most cited “proofs” of global warming is that sea level is rising, as can be seen in the graph below.
http://sealevel.colorado.edu/current/sl_noib_global_sm.jpg
This is a nonsensical argument, because sea level would be rising even if temperatures were going down, as they have been since 2002. The main reason why sea level rises is because the equilibrium between glacial ice and temperature is out of balance, and has been for the last 20,000 years.
http://www.globalwarmingart.com/wiki/Image:Post-Glacial_Sea_Level_png
Note that from 15,000 years ago to 8,000 years ago, sea level rose about 14mm/year – which is more than four times faster than the current rise rate of 3.3mm/year, as reported by the University of Colorado. During the last ice age, sea level was so low that people were able to walk from Siberia to Alaska across the Bering Strait. One of the more stunning pieces of evidence of this is the remarkable similarity of appearance and culture between the indigenous peoples of Eastern Siberia and North America.
In 2002, the BBC reported that a submerged city was found off the coast of India, 36 meters below sea level. This was long before the Hummer or coal fired power plant was invented. It is quite likely that low lying coastal areas will continue to get submerged, just as they have been for the last 20,000 years. During the last ice age, thick glaciers covered all of Canada and several states in the US, as well as all of Northern Europe. As that ice melts, the water flows into the ocean and raises sea level.
http://uk.encarta.msn.com/media_461527006/ice_extent_during_the_last_ice_age.html
The IPCC has stated that sea level may rise two meters this century, which would be a rate of 22mm/year, nearly seven times faster than current rates. Do we see such an acceleration? The simple answer is no. There has been very little change in sea level rise rates over the last 100 years, certainly nothing close to the immediate 7X acceleration which would be required to hit 2 meters.
Sea level is rising, and the abuse of this information is one of the most flagrantly clueless mantras of the alarmist community.
Even if we returned to a green utopian age, sea level would continue to rise at about the same rate – just as has done since the last glacial maximum.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Philip_B (17:11:17)
“There are two main contributions to sea level rises.”
Perhaps climate driven sea level changes, but I would argue the greatest control on sea level is the rate of new ocean floor production. I suppose rates of sea floor spreading happen on much greater time scales.
Geologically “soon” you can expect to see some major changes in the rate of sea floor production in the Atlantic.
But good points none-the-less.
“There are two main contributions to sea level rise”.
No, there is a third more important reason and that is changing land level.
The data I linked to above shows that local land deformations outweigh the sea level rise due to thermal expansion and glacial melt by more than an order of magnitude.
If you are using the satellite data, presumably this is not a factor. But I have seen write-ups that say the satellite data is calibrated to local sea level gauges which are suspected to suffer from land subsidence.
So again, we are just back to square one (as we discovered with the NCEP humidity data as well.)
Steven Goddard (10:24:43) :
I am not just making this up & it is not my theory – it has been known & published in the geological literature for years. See :
http://www.homepage.montana.edu/~geol445/hyperglac/isostasy1/
See bottom of the page – note the relative size of marginal depression & forebulge – they are not equal as I stated before – due to the elastic nature of the deformation of the crust (vs the visco-elastic nature of the mantle)
See:
http://www.earthscape.org/t1/low01/low01d.html#hydroisostasy
Again – ocean basin deformation is not of equal magnitude to continental deformation (and continental shelf deformation – which does effect ocean volume) – as I stated before
See:
http://www.agu.org/books/gd/v001/001GDp0111/p00111-p00128.pdf
Look at figure 3 & how much large an area of the ocean basins were depressed – again because the lithosphere is rigid & that stress field is represented by a much wider strain field. All that ocean is rebounding & with a net decrease in ocean basin volume, driving a subtle world wide sea level rise of the last 8000 years, as seen in your graph. The shape of increased sea level is exponentially decreasing, just as the shape of isostatic rebound curves are exponentially decreasing.
As I said up front, this is not my theory – this is what the geologic data says. I hope you can appreciate that.
The 2002 BBC report has never been verified in any science write up.
Got a good, confirmed example? Cambay Bay isn’t a city under water.
Smokey: Try http://tidesandcurrents.noaa.gov/sltrends/sltrends.html for Sea Level Trends. The page you linked to shows sea level anomalies: “A sea level anomaly, as defined by NOAA’s National Ocean Service, occurs when the 5-month running average of the interannual variation is at least 0.1 meters (4 inches) greater than or less than the long-term trend. ” ie, the reason you don’t see any long-term sea level rise is because the long-term sea level rise has been detrended out!
Steven Goddard: Ok. So your State of New Jersey study disagrees with other studies. The other studies claim a “high rate” of sea level rise followed by a slowing at about 2500 year before present. I personally trust the IPCC collection of references more than a single New Jersey reference, but lets take your reference at face value:
They state that for the past 7000 years New Jersey has averaged 2 mm/year of rise – of which _half_ was subsidence, meaning that their best estimate for the last 7000 years was 1 mm/year. Therefore, the reference you cite concludes “Thus, human-induced effects on sea-level in New Jersey are 1-2 mm/year which is up to one-half of the total observed rate of sea level rise”.
So: have we seen long-term sea level rise at the current rate in the past several thousand years? If we believe the state of NJ, the answer is no, the past couple thousand year rate was half of current. If we believe the IPCC the answer is also no, it was 1/10th of current rates. Now, does sea level rise rate vary? Yes. Both on a decadal scale (eg Holgate et al., and the IPCC chapter too) and on a longer term scale. But the long-term variations of sea level rise occur on the same time scale as long-term variations in temperature. Therefore, IF CO2 can lead to temperature increases, then CO2 can lead to increased sea level rise. (Note that if some other factor leads to a temperature increase, that would also lead to sea level rise – no one is pretending that CO2 emissions are the _only_ thing that can cause SLR)
Finally, on the “70% of SLR is thermal expansion”: that is an estimate for _current_ sea level rise, and potentially, for sea level rise over the next century depending on what Greenland + Antarctica do. Yes, the immediate post-glacial period was dominated by ice sheet melt, but for the past decade we have various measures of G&IC and ice sheet mass loss, and they only add up to about 30% of SLR.
I suggest you actually read the IPCC chapters on sea level rise. You don’t have to take it all at face value, but you should at least try to be familiar and understand the logic behind the consensus statements before you toddle off into left field and make your own random statements about the “basic geology” of interglacial sea level rise.
ps. I still stand by my previous statement “Basic logic can be applied to show that a claim of <1 mm rise for the last several thousand years can be perfectly consistent with your concrete archeological evidence if your concrete evidence comes during the time period that alarmists and skeptics alike agree was having extremely large SLR changes.” Let’s try some simple logic: if we suppose that between 9000 and 6000 years ago sea level rose by about 30 meters (seems reasonable from your long term SLR graph), then between 6000 years ago and present sea level rose by <1 mm/year. Voila! Consistency!
Philip_B,
You say that 70% of sea level rise is due to thermal expansion? That would imply that nearly 300 feet of the 400 feet of sea level rise since the last ice age was due to thermal expansion.
I meant recent (last 100 years or so) sea level increases. The 70% contribution from thermal expansion is generally accepted. Although that doesn’t make it correct.
Anyway, my main point was that climate changes over the last 50 to 100 years have had little impact on recent sea level changes. So the whole discussion, while interesting, has little or nothing to do with AGW.
Similarly, claims of substantial sea level rises from melting icesheets have no scientific basis, without introducing extraordinary (IMHO) mechanisms to transport the ice somewhere warmer.
Benjamin P.,
As one ocean gets larger through sea floor spreading, another gets smaller through subduction. If this weren’t true, the area of continents would shrink over geological timescales and they don’t. Sea floor spreading per se has no longer term effect on sea levels and any shorter term effect could be in either direction, ie to raise or lower sea levels.
Bill Illis (18:56:46) :
“But I have seen write-ups that say the satellite data is calibrated to local sea level gauges which are suspected to suffer from land subsidence.”
Satellite altimetry Topex/Poseidon data is adjusted by the University of Colorado for NASA to match the rate of sea level rise measured by a set of 64 tide gauges. Any difference between the raw satellite measurement and the tide gauge measurement is assumed to be the sum of satellite measurement drift error and the vertical land movement at the tide gauge location. A separate estimate of land motion is made. The difference is assumed to be altimeter drift, which is applied to the raw satellite data.
Therefore, the slope of the reported satellite sea level data is determined by the 64 tide gauges and the accuracy of the vertical land movement estimates of those tide gauges. This doesn’t mean the estimate is wrong. But it is wrong to think the sea level rise from satellite data is independent of tide gauge measurements.
The calibration is described here:
http://sealevel.colorado.edu/calibration.php
Folks here spend a lot of time intently looking at a specific square inch of bark on a specific tree in this particular forest.
When was the last time anyone here took a look at a ruler? More importantly, when was the last time anyone here went down to the ocean, stuck a stick in the sand/mud and was able to measure a millimeter of change in the ocean? Do it with a stick; do it with a laser; do it with a satellite – the result is the same.
Adding useless noise on top of useless noise does NOT add up to a legitimate result (it’s a variation of two wrongs equalling a right).
More importantly, what 23 tidal gauges are these? Where are they? Who monitors them? WHO, exactly, was measuring a MILLIMETER of change in sea level in Holland on August 8, 1888? What are these guages made of? If wood, does it expand or contract? What are the guages stuck in? Mud? Sand? Is there no erosion or silting where these are located? Did the guages ever move left? or right? or forward? or back? or TILT? Did anyone notice? Are all the guages measured by the same people? At the same times? With the same MILLIMETER level of precision?
In short, it’s all utterly preposterous.
Imagine yourself in a highschool science class and asked to conduct a SCIENTIFIC experiment. Would ANY highschool (or elementary school) science teacher accept data gathered in this way? I know that kids don’t get “F”‘s anymore, but this kind of garbage would have warranted an “F” when I was a kid. But that was back when SCIENCE required observations gathered in a SCIENTIFIC fashion – not some cobbled together mishmash of two dozen different sources, each of which is as questionable as the next.
There is NO CREDIBLE evidence of ANY sea level rise. Why? Because of the ridiculous way in which this data was compiled. Yet everyone accepts it and tries to figure the why’s and wherefore’s of it. IT’S JUNK. USELESS. MEANINGLESS. And anyone who would accept this 100+ years of sea level measurements as serious scientific data is a PUTZ.
Keep tilting at invisible windmills guys, I’m sure you’ll win someday.
mörners claim was that the satellite data showed no trend and was later adjusted with poor gauge data.
http://www.climatechangefacts.info/ClimateChangeDocuments/NilsAxelMornerinterview.pdf
the other side wrote this reply:
http://www.imedea.uib.es/goifis/OTROS/VANIMEDAT/documentos/intranet/Bibliography/Nerem_et_al_Global_Planet_Change_2007.pdf
they confirm that there was no trend in satellite data.
however they say, there were errors in the satellite data due “to drift in the TOPEX Microwave Radiometer” and “A second major error was
introduced when the redundant TOPEX altimeter was
turned on in early 1999”.
it is not clear from the article, to what extent gauge data was used to quantify these errors and to correct them, or anything about the quality of the possibly used gauge data.
Steven,
So you are now taking the first plot you posted, from which you previously used the trend of 3.3 mm/year in your article and are claiming it actually has a slope of 2.4mm/year for the last fifteen years and shows no change at all in the last three years. I invite any interested readers to draw your suggested trend lines on this plot. I certainly had difficulty seeing it as an improvement to the initial linear fit of 3.3 mm/year – who is playing with the data here?
Please can you give me your derived trend for the data from 7000 years ago to present? You keep on stating the current trend is within historical variation, but do not give any values.
The 2004 Interim New Jersey State Report you cite was work done by a team at Rutgers and was included in a Science article published in 2005. This article specifically studies the current and historical rates of sea-level change along the New Jersey coast. The associated press release is at http://ur.rutgers.edu/medrel/viewArticle.html?ArticleID=4858
“In an article published in the Nov. 25 issue of the journal Science, Rutgers professor of geological sciences Kenneth G. Miller reports on a new record of sea level change during the past 100 million years based on drilling studies along the New Jersey coast. The findings establish a steady millimeter-per-year rise from 5,000 years ago until about 200 years ago.
In contrast, sea-level measurements since 1850 from tidal gauges and more recently from satellite images, when corrected for land settling along the shoreline, reveal the current two-millimeter annual rise. “Without reliable information on how sea levels had changed before we had our new measures, we couldn’t be sure the current rate wasn’t happening all along,” said Miller. “Now, with solid historical data, we know it is definitely a recent phenomenon.
“The main thing that’s changed since the 19th century and the beginning of modern observation has been the widespread increase in fossil fuel use and more greenhouse gases,” he added. “Our record therefore provides a new and reliable baseline to use in addressing global warming.””
Manfred,
You state:
“mörners claim was that the satellite data showed no trend and was later adjusted with poor gauge data.
http://www.climatechangefacts.info/ClimateChangeDocuments/NilsAxelMornerinterview.pdf
the other side wrote this reply:
http://www.imedea.uib.es/goifis/OTROS/VANIMEDAT/documentos/intranet/Bibliography/Nerem_et_al_Global_Planet_Change_2007.pdf
they confirm that there was no trend in satellite data.”
I read the article and the authors make no such confirmation. Rather they write:
“In light of this, the statement by Mörner that “This means that this data set does not record any general trend (rising or falling) in sea level, just variability around zero plus the temporary ENSO perturbations” is completely false and is based on his erroneous data processing.”
The main thing that’s changed since the 19th century …
is that the little ice age had ended – the coldest period in several thousand years, that was accompanied by a massive buildup of glaciers. melting of these hase increased the rate.
I’m no historical sea level rise denier, but this field is complicated too. (Of course the thermal expansion is real, and should have effect on century time scale.)
I’m no geology professional either, but google is fun! 🙂 Here’s some maybe interesting links:
1) Daily Tech article about University of Colorado, Boulder data, but where also Vincent Gray mention calibration errors:
http://www.dailytech.com/Defying+Predictions+Sea+Level+Rise+Begins+to+Slow/article13679.htm
2) Till Hanebuth made a study (“Rapid flooding of the Sunda Shelf – a late-glacial sea-level record” (2000)) , and I think it shows sea level rise almost continually (maybe with a few centuries during the last ~5000 years of temporarily declining level?). But I found this chart which — I don’t know why — shows declining sea levels during this interglacial period:
http://www.geoscience-environment.com/es551/back_ground.html
3) India’s National Institute of Oceanography present data measured at the west coast of India (which in the chart don’t seem to be that trust-worthy…) of almost constant sea level since 5000 year ago. they say “After 7,000 years B.P. it fluctuated to more or less the present level.”
http://www.nio.org/WaterFront/Civilization/SeaLevel.jsp
Any skeptics here? 😉
Tom P (01:31:35) :
Mörner obviously referred to the satellite raw data.
the other side writes:
“Because the details of the analysis are not presented in his paper, we are left to speculate on how this result could have been obtained, based on our years of experience as members of the T/P and Jason-1 Science Working Team. Mörner was apparently oblivious to the corrections that must be made to the “raw” altimeter data in order to make correct use
of the data.”
this is again just one of these lengthy unnecessary explanations used to make somebody look stupid. actually they acknowleged, that mörner used uncorrected raw data.
as has been written in a previous posting, the satellite data slope was and is still generated from gauge data. there is no independant satellite trend measurement.
graphs produced by these offices are still lacking a comment or footnote, that the satellite data slope is not measured but adjusted to match some gauge data trend.
The simple chart in my previous comment may give Hanebuth bad reputation, so this sea level chart is based on Hanebuth et al., 2000:
http://tetide.geo.uniroma1.it/igcp464/Brazil/Immagine%208.jpg
So it’s inconsistent with the simple chart, and presented on this page:
http://tetide.geo.uniroma1.it/igcp464/Brazil/Brazil%20conference.htm
It appears that the sea level record is as hopelessly flawed as the temperature record. Those who feed at the public trough can (and do) make of them what they will.
Tom P,
It is pointless explaining things to you, because you obviously have an agenda.
CU shows 3.3 mm/year Aviso shows 2.4mm/year Both are within the normal range for the last 7,000 years. Are you claiming that Aviso is incorrect? Based on what data?
The New Jersey study stated unequivocally an average 2mm/year for the last 7500years. Instead of reading the study, you quote a press release.
Hansen claims 55mm/year. IPCC claims 11-22mm/year. Both are completely out of line with observations. You choose not to think about this, and instead quibble over a few tenths of a millimeter..
This is my last message to you, because it is a waste of time trying to get you to think rationally.
Steven Goddard,
It is pointless explaining things to you, because you obviously have an agenda.
The New Jersey study stated unequivocally an average ONE mm/year for the last 7500 years after correcting for subsidence, and noted that in the last 100 years there was a definite human signal. Instead of reading the whole study, you cherry pick one sentence out of it.
The IPCC claims a sea level rise rate of 0.18 to 0.59 meters over the next century (1.8 to 5.9 mm/year average), not including dynamical changes to ice sheets (and for these estimates, Antarctica is assumed to be a net negative contributor due to increased snowfall in the interior). Go and READ THE IPCC REPORTS ALREADY instead of lying about what they claim. Pfeffer et al. (not the IPCC) stated a possibility of 2 m sea level rise if all the uncertainties in dynamical processes were resolved in the high-melt direction, but did not claim it was likely. In either case, neither the IPCC nor Pfeffer nor even Hansen (whose claim of a possible 5 m rise in an interview, not a published article, I don’t defend at all) claim that sea level rise is expected to be linear for any of these scenarios. As temperatures increase, both thermal expansion and glacier/ice cap melt are expected to increase, and ice sheet melt rate may change but we do not have a good handle on ice sheet dynamics yet. Therefore, an SLR of 2.4 or 3.3 mm/year today or whatever can be consistent with an SLR of 1 m over the next century under high scenarios of temperature change. If you want to argue about temperature projections, fine, but that’s a different issue entirely.
This increase of sea level rise over the next century would be consistent with the increase in sea level rise observed during the last century’s temperature increase, as compared to the smaller rate of sea level rise increases over the past 2 millennia.
FYI: Aviso: http://www.aviso.oceanobs.com/en/news/ocean-indicators/mean-sea-level/ estimates 3.045 mm/year sea level rise since 1993 (with inverse barometer correction). Which is within the error bars of the CU estimate of 3.3 plus/minus 0.4 mm/year.
This is my last message to you, because it is a waste of time trying to get you to think rationally.
Steven,
I’m very unclear as to why you feel you have to bow out of the discussion. You leave hanging my repeated question of why you feel the recent trends of 3.3+/-0.4 mm/year lies within the normal range for the last 7,000 years.
The most AVISO data is here: http://www.aviso.oceanobs.com/en/news/ocean-indicators/mean-sea-level/
and gives a current trend of 3.0 mm/year, so consistent with the trend you first used from the University of Colorado analysis. I don’t think either dataset is incorrect.
Instead of using data from an interim report, I presented the data from the peer-reviewed Science article, which states the background rate over the last 5,000 years of 1mm/year from the New Jersey sea level analysis. There is a clear difference between this rate and the current rate.
The IPCC and Hansen figures you quote are projections based on various models. They are not relevant to a discussion of the historical data.
If you feel unable to discuss why the current sea-level rise rate is two to three times the prior historical rate for the previous 5,000 years, I wonder why you brought up this data for discussion at all.
Steven Goddard (05:46:48) : “Hansen claims 55mm/year. IPCC claims 11-22mm/year.”
I agree that not only Hansen but also AGW promoting IPCC exaggerate sea level rise prediction. But if IPCC claims 11-22mm/year it means between 1.1 and 2.2 m/century! That’s not exactly right, is it? I believe they say between 0.4 and 0.6 m this century. That’s “only” two or tree times as fast sea level rise as we’ve had (0.2 m/century, which I rather think may drop this century if a Gleissberg cycle with low solar activity brings cool climate for 60-100 years:
http://ncwatch.typepad.com/dalton_minimum_returns/2009/02/no-warming-until-after-2014-and-maybe-not-then-.html .)
Marcus,
IPCC lead author David Randall told me personally that he expects “1 to 2 meters” this century, and Gavin at Real Climate defends that and Hansen’s 5m prediction here. That is the standard position in the AGW community.
http://www.realclimate.org/index.php/archives/2008/09/on-straw-men-and-greenland-tad-pfeffer-responds/
The New Jersey paper states-
Data from NJ (all sources) and the reefs are consistent with a constant rate of rise of 2 mm/y since ~7,000 yBP. This suggests a background, preanthropogenic sea-level rise of 2 mm/y for the entire east coast of the U.S.
Is this somehow confusing to you?
Marcus,
You are quoting outdated Aviso data. Their latest number is 2.4mm/year.
http://www.aviso.oceanobs.com/fileadmin/images/news/indic/msl/MSL_Serie_J1_Global_NoIB_RWT_PGR_NoAdjust.png
Steven,
You state:
“You are quoting outdated Aviso data. Their latest number is 2.4mm/year.
http://www.aviso.oceanobs.com/fileadmin/images/news/indic/msl/MSL_”
Your figure is for the seven year trend. You first quoted the University of Colorado fifteen year trend on 3.3+/-0.4 mm/year. Marcus and I are quoting the AVISO analysis, which is right up to date, for the fifteen year trend of 3.0 mm/year. Do you agree there is no discrepancy between the two trends for the same time period?
You further write:
“The New Jersey paper states-
Data from NJ (all sources) and the reefs are consistent with a constant rate of rise of 2 mm/y since ~7,000 yBP. This suggests a background, preanthropogenic sea-level rise of 2 mm/y for the entire east coast of the U.S. Is this somehow confusing to you?”
What is confusing is that the original data in the interim report you cite has not been corrected for subsidence effects. This is what is written in the Science paper which reports on the same data:
“Sea-level rise slowed at about 7 to 6 ka. Some regions experienced a mid-Holocene sea-level high at 5 ka, but we show that global sea level has risen at 1 mm/year over the past 5 to 6 ky. We present new core data from New Jersey covering the past 6 ky that show a rise of 2 mm/year over the past 5 ky. This New Jersey curve is remarkably similar to sea-level records from Delaware (46) and southern New England, with a eustatic rise of 1 mm/year over the past 5 ky once corrected for subsidence effects, virtually identical to that obtained from Caribbean reef localities accounting for subsidence.”
Science 25 November 2005:Vol. 310. no. 5752, pp. 1293 – 1298
What we are still left with is a current rate of sea level change which is more than twice the background level.
Tom P,
You have just stated that according to Aviso, sea level rise rate has declined recently to 2.4mm/year. This despite rapidly increasing CO2 levels and unprecedented warming according to Hansen, who expects a record high global temperature this year or next.
What is interesting from the NJ study is the raw data which showed 2mm/year for the entire East Coast for the last 7,000 years. Their theoretical analysis of the much less interesting. Glacial rebound in Florida is not a concept that is going to fly.
For the last 7 years, sea level rise (2.4mm/year) has been scarcely different from the 7,000 year trend. Hansen believes we are headed for 5000mm this century. If you want to argue with someone, take it up with him.
POP QUIZ
Sea levels are…
__RISING?
__FALLING?
__STATIC?
__ALL THE ABOVE?
Crib sheet…
http://www.john-daly.com/ges/msl-rept.htm