Measured sea level rise drops 30% with “pause” greater than half of RSS measurement period.
Guest essay by Larry Hamlin
A paper titled “The rate of sea-level rise” published in Nature Climate Change on March 23 by Cazenave, et al. shows that during the last decade the rate of sea level rise has declined by about 30% during the period 2003 through 2011 to about 2.4 mm/year from the rate of 3.4 mm/year in the period 1992 through 2002. The paper argues that this decrease is the result of short-term natural climate variability which it attempts to remove to reveal the “true” global warming signal with the end result being to “adjust” the lower measured sea level rate upward.
Dr. Judith Curry addresses this new paper in her April 24th post “Slowing sea level rise” where she argues that there is no convincing way to adjust out the effects of El Nino/LaNina events from the measured sea level rise record and that natural variability has dominated sea level rise during the 20th century.
The crux of her arguments are presented below with the figure shown from the UN IPCC AR5 WGI report showing that sea level rise has varied significantly since 1900 in a manner which Dr. Curry concludes demonstrates dominance by natural climate variation forces.
The slowing in the measured rate of sea level rise during the last decade has occurred while the RSS satellite measured global lower-troposphere temperature record now has more than half of its 35+ year temperature record, which began data collection in January 1979, showing no global warming whatsoever since August 1996 as demonstrated in the graph below taken from an article in Real Science addressing this “pause”.
Dr. Curry draws the following conclusions based upon these measured and perhaps interrelated outcomes by noting:
“Once again, the emerging best explanations for the ‘pause’ in global surface temperatures and the slow down in sea level rise bring into question the explanations for the rise in both in the last quarter of the 20th century. And makes the 21st century of sea level rise projections seem like unjustified arm waving.”
Haven’t looked at this in depth, but it strikes me as passing odd that sea level rise has been decelerating if the ocean has been absorbing all the extra heat that was predicted and that we haven’t been seeing in surface/atmospheric data sets. I know, it doesn’t amount to much temperature change over the ocean, but that’s still a heck of a lot of water that’s supposed to be increased in temperature by a very small amount.
Just saying.
Dr. Curry’s point is good though.
the acidic oceans are dissolving the calcium carbonate substrate….
Colorado will have to adjust up for this
BTW…why don’t you just eliminate the first part….when sea levels were below normal
Then there’s nothing happening at all
Same thought I had – would’nt all that heat “hiding” in the oceans cause expansion, hence sea level rise? If so, any idea how much it could account for?
Last night’s Years of Living Dangerously first exploited the human misery of superstorm Sandy suggesting rising sea level could make a storm once a year. To finish the segment, they go to Christmas Island where a researcher suggests the island could be lost rising sea level. But is you look at the PSMSL website for Christmas Island sea level has actually trended lower.
[imgfit]http://www.psmsl.org/data/obtaining/rlr.monthly.plots/1371_high.png[/imgfit]
Essentional, if natural temperature veriations can cause the platue, and slowdown sea level rise, maybe they could also have caused the late 20th century warming?
Questions this brings to mind:
1) What component of sea level rate of change is tectonically / eustatically driven vs thermally driven ? (and how are you going to separate those two components objectively, let alone separate ENSO-PDO-NAO events from the thermal signal to get the AGW signal ? )
2) What’s the cross-correlation of the sea level rate of change & ocean temp / lower atmospheric temp data? The author of the original paper would infer that ocean temps / lower atmospheric temps are driving sea level rate of change – it this were the case , we should expect a very short lag (with ocean / atm temps slightly leading SL rate of change) and a high correlation coefficient. If not ==> theory busted. Has anyone seem this kind of plot?
Didn’t Willis demonstrate the same deceleration in sea level rise here about a year ago? I remember he did a bar graph of sea level rises for 10 year periods (1993-2002, 1994-2003 etc, ) using the data from http://sealevel.colorado.edu/
Hope he was cited in the paper.
strange where these articles take you,
History of the ice trade.
http://en.wikipedia.org/wiki/Ice_trade
It also makes a hash of the egregious claim that SLR is “accelerating” due to AGW, which is generally based on a tiny increase in rate, mostly seen in the still-being-adjusted satellite data, in an absurdly short data chord near the end of the data that anybody publicly posts.
I’m still waiting for someone to update:
http://en.wikipedia.org/wiki/File:Trends_in_global_average_absolute_sea_level,_1870-2008_%28US_EPA%29.png
which carefully preserves the last vestige of the claimed “acceleration” in one of the only places where the normal public can see any compendium of the data. I’m guessing that somebody is waiting for SLR to upturn again, maybe with an ENSO event, rather than honestly publishing the data to let it speak for itself without “interpretation”. I’m also waiting for the latest round of GRACE based corrections to be similarly portrayed in this figure, as I seem to recall that once gravitation and subsidence are more accurately taken into account, the satellite SLR is actually itself diminished even in the thin green line at the end. Of course satellite observations and tide gauge observations, however mismatched they might be initially, are mutually correcting in the long run, just as UAH/RSS LTT is now a hard constraint on what people can do to the global surface temperature anomaly.
I’m actually sad that the top article above doesn’t present the data through 2014 so that we can actually see the data, not a derivative of the data, through the present, not through the early-to-mid 90’s. Telling us about it doesn’t help. Showing us the data does.
I personally have a hard time seeing any hard correlation between SLR rates and ENSO events, BTW. This is a job for Willis, IMO — he seems to cut through the assertions of statistical bullshit by the simple expedient of grabbing e.g. the ENSO data, grabbing some sort of SLR compendium (warts and all) and then using R to, errr, look for correlation with an R^2 that isn’t basically zero. This process is complicated by possible lag, by the short time scale of ENSO events, by all sorts of noise, the limited length of records, confounding and obscuring stuff like uplift/subsidence, and the interesting fact that thermal expansion of water leads to an unusual breakdown of the isothermal assumption of an isostatic surface — warmer water floats, so one can actually support localized bulges of the sea level that have basically zero effect on the overall oceanic level, effects that are limited to the specific location of the warmer water (just as ice floating on water might raise the “level” of water by the height of the ice where it is floating without affecting SLR anywhere else at all).
So even though ENSO is an anomalous warming of a chunk of ocean water in a specific location, its effect on global SLR is limited to the specific region of the thermal anomaly, over the specific time the anomaly lasts. Only long term, spatially global sea surface warming can really raise SLR via thermal expansion, and of course the only other mechanism for SLR is the melting of non-seasonal land ice or the alteration of the freshwater/sea water balance on a global scale. The anomalous melting (as in an imbalance of new snowfall per year relative to deep melt, since the surfaces of these icepacks basically never reach the melting point) of the major land ice packs — Greenland and Antarctica — is almost non-existent. People make noises of a shift in the ratio of land freshwater and sea water, but I don’t think there is any compelling evidence for it. Basically, nearly all SLR observed is the ocean acting like a great big lagged thermometer that is probably the most precise and reliable direct measure of global average surface temperature in existence.
It is the lack of any compelling acceleration in SLR that is the strongest evidence that we have against the hypothesis of runaway/catastrophic anthropogenic global warming, as well as the natural vs anthropogenic fractions of such warming as has occurred. Both the SLR graph I link and the derivative of the SLR graph republished in the top article show that there is absolutely nothing remarkable about SLR rates post 1950 compared to pre-1950, where 1950 is usually given as the breakpoint year where CAGW due to CO_2 was “launched” by the advent of a steady increase in post-WWII industrialization and civilization worldwide.
This is a profound case of the inconsistency of the CAGW argument. It is so strong that it comes dangerously close to being direct evidence that the argument is unambiguously false! That’s why — IMO — there has been a more or less deliberate delay in the updating of the last “alarming” publicly published figures that the CAGW community was capable of generating. Unchanging SLR rates plus the assertion of hidden heat hiding in the oceans, taken together, suggest that we are completely missing the fundamental drivers of century scale changes in the Earth’s set point, drivers that were responsible for the LIA, the Dalton minimum, and the post-Dalton recovery. The oceans have been warming at a nearly steady rate from before CO_2 could possibly have been a factor through the present. Since we don’t know the causes of the warming or cooling pre-1950, and cannot hindcast any of the significant cooling or warming periods of the thermometric era (see figure 9.8a in AR5, which shows that CMIP5 basically collectively skates over all of the significant 20th century variations outside of the reference period), we cannot even pretend to be able to separate out natural trends from any hypothetical CO_2 linked trend.
But if SLR rates even think of flattening instead of accelerating, especially flattening on a decadal or longer time scale, this is a serious body blow to the CAGW hypothesis. The Ocean has probably been pursuing some sort of global set point, damping the entire planet’s approach to some new “equilibrium” based on the unknown factors that governed the MWP and LIA and post-LIA recovery. CO_2 may, or may not, have modulated that new set point further. But at some point it is quite possible for the ocean to reach the new set point vicinity, in which case SLR will decelerate, not accelerate. Deceleration is anathema.
rgb
According to Trenberth, Hansen and Co., ENSO should be a ‘global warming’ signal i.e. ‘global warming’ increases the frequency and intensity of (warm) El Nino events, and reduces the frequency and intensity of (cool) La Nina events.
Cazenave, et al look at the temp record, and can’t find any ‘global warming’. So they remove Trenberth and Hansen’s ‘global warming’ signal and *poof* – they find ‘global warming’ in what is left over.
Truly, ‘climate science’ is magical.
rgbatduke says:
April 28, 2014 at 11:48 am
Since the longer-term trend has been global cooling for at least the past 3000 years (arguably 5000, since the end of the Holocene Optimum), rising MSL for the past ~150 years might well reverse. As you so aptly note, the causes of decadal & centennial scale fluctuations are not known. CO2 seems not to be the control knob on them, so reversion to the mean millennial scale trend line seems likely.
Orbital mechanics appear to be a major factor on the scale of tens to hundreds of thousands of years, but are not well enough understood to predict how much longer the Holocene might last, whether 300 years, 3000 or 30,000. In any case, the current interglacial has been cooler & so far shorter than the Eemian (MIS 5) or the long, hot MIS 11. Sea level was higher in the Eemian (Scandinavia was an island, perhaps also from lowering by the weight of the big glaciation preceding it), but even with more heat for more millennia, the more vulnerable southern dome of the Greenland Ice Sheet didn’t entirely melt away then, as it may have done during MIS 11 & apparently did in MIS 19 (as shown by DNA recovered from beneath the southern dome & by climatic proxy data). The northern dome has existed for about 18 million years, but has waxed & waned.
The East Antarctic Ice Sheet, as you know, has been around for more than 34 million years, with of course some pretty big mass & area fluctuations. A study last year concluded that the West Antarctic Ice Sheet also probably formed at the Eocene/Oligocene transition:
http://phys.org/news/2013-10-west-antarctic-ice-sheet-earlier.html
@Latitude – Normal seems to be what ever they decide. Not something that is common in the history of the planet.
Damn!
He said he would do it and he did.
All hale POTUS.
Damn!
cn
I struggle really hard to accept any alleged measurement of SLR as serious – after all, it is all relative – but relative to what? an Interglacial ‘average’ – or a (just) pre-glacial ‘high’ – or perhaps a (just) post glacial ‘low’ – or perhaps some arbitrary ‘level’ invented by climate scientists or oceanographers? (I mean, we have an arbitrary avergae temp of the Earth at ’14degC’ despuite the fact it was previously ‘arbitrarily’ 15degC !!) – Can we take any of this stuff seriously when any anthropgenic signal is but a tiny smear on the backdrop of natural variability?
Good ol’ NPI again
http://virakkraft.com/NPI-sea-level-trends.png
I never understood why anybody talks about the sea level rise for the last 100 years as either supporting or refuting global warming.
Eyeballing the graphs on Wikipedia, it seems to me that the noise in the data for the past 8000 year or so is around +/- 1 meter, conservatively: http://commons.wikimedia.org/wiki/File:Holocene_Sea_Level.png
So, when I try to overlay the graph of the past hundred years or so (http://commons.wikimedia.org/wiki/File:Recent_Sea_Level_Rise.png) onto this graph in my mind, it just seems that the tiny 20 cm rise is buried in noise. It seems to me, you could have global warming and still have a sea level decline over the past hundred years, or you could have no global warming but with a rise over the past hundred years. The data is just meaningless to me.
A link to Curry’s site seems to be missing. Not that it is hard to find, but still seems appropriate.
If all those Hiroshima bombs of heat have been absorbed by the oceans, why is the sea level rise rate declining? I know. Answering that question is like wrestling a muddy pig.
http://www.osdpd.noaa.gov/ml/ocean/J2_handbook_v1-3_no_rev.pdf
OSTM/Jason-2 Products Handbook
2.3.1. Accuracy of Sea-level Measurements
Generally speaking OSTM/Jason-2 has been specified based on the Jason-1 state of the art,
including improvements in payload technology, data processing and algorithms or ancillary data
(e.g: precise orbit determination and meteorological model accuracy). The sea-surface height shall be provided with a globally averaged RMS accuracy of 3.4 cm (1 sigma), or better, assuming 1 second averages.
I tend to avoid commenting on most of these sea level posts because unlike most of the world I find the satellite sea level data to be a complete crock. If history is any indicator I will have almost no chance of turning anyone here to my point of view and I can live with that, but i would suggest that before you choose to be an epistemological mattress back for what is admittedly an amazing bit of technology, that you spend some time with the data products handbook I linked above. Try to keep a tally of the various approximations, models, adjustments and other fudge factors involved in assembling this data, bearing in mind that each of the first order “corrections” is itself based on its own ensemble of fudge factors and the logical chains extend to third and fourth orders for most of them.
With that in mind, try to recall the ubiquitous stock footage of the Southern Ocean that has been a hallmark of the wall to wall coverage of the missing Malaysian airliner and ask yourself how a satellite pinging that surface from 800 miles up could resolve its height to tenths of a millimeter, especially since in the table that provides a summary of specifications and error budget, which appears just below the paragraph I quoted above, there is a line for Significant wave height which is 10% or 0.4 m whichever is larger.
I have heard over past decade the following…..
The glaciers are melting, Antarctica and Greenland are losing mass balance, the oceans ate my global warming, the hottest decade evaaaaah, global warming hasn’t stopped etc. And now this!
I know, it doesn’t amount to much temperature change over the ocean, but that’s still a heck of a lot of water that’s supposed to be increased in temperature by a very small amount.
The point is that thermal expansion is proportional to the length of the system that is expanding. Assume that this length is (say) 1 km, or 10^6 mm. Even temperature changes that are one part in 10^5 absolute could then produce changes of several mm over 1 km. As I said in an earlier reply, that’s why the oceans are an exquisite thermometer for the Earth.
rgb
at least they didn’t try to hide the decline…
The trend lines in the RSS temperature graph have no merit whatsoever because their ends do not connect. Displaying such lines is a stain on this website, viewed with disdain by any practicing scientist including me. Anyone who knows their stuff, when encountering such sham “science” will immediately turn off to the website. Don’t do this to me.
The Cazenave, et al people are probably kicking themselves in the butt about now… they missed a big chance here. They should have subtracted to influence of the El Nino years from the previous data, which would have dropped that SLR rate to around 2.5mm/year. Addition of the El Nino correction to the data post 2000 like was done, then they would be able to claim that sea level rise is rapidly accelerating…… it is MUCH WORSE THAN WE THOUGHT could have been the headlines all around the world. Sea level rise went from 2.5 mm/yr in the 1990s to 3.3mm/yr rise in the 2000s (after corrections), an increase of 30% in a single decade.
@Kev-in-Uk says: April 28, 2014 at 12:27 pm
+100
SLR of 2 or 3 mm per year is so far below the noise level as to be in-credulously irrelevant.
First JJ refers to Trenberth, Hansen, and Co. opinion that ENSO should be a ‘global warming’ signal. That is because they are ignorant of the origin and history of ENSO. ENSO is a resonant oscillation of ocean water from side to side in the Equatorial Pacific, powered by trade winds, and has a period of five years. This resonant period can be temporarily changed by other oceanic happenings but it will always return when the disturbance is over. One such disturbance was the super El Nino of 1998 that carried far more warm water across the ocean than any regular ENSO oscillation is capable of. If you look at any of the long-term temperature curves you can trace that five year resonance back to the early nineteenth century. I just counted the frequency of occurrence of El Nino peaks recorded by HadCRUT3 and found that for approximately sixty percent of the cases peak-to-peak distance between El Ninos was close to five years. This has been going on as long as the present equatorial current system in the Pacific has existed, which is to say since the Panamanian Seaway closed. As to sea level, what is missing in all this talk is correction for water held in storage by reservoirs. This was done only by Chao, Wu and Li [Science 320:212-214 (2008)]. They corrected all available sea level data for the effect of 29,484 reservoirs built since 1900. They found that the GSL curve, so corrected, became linear for the last 80 years with a slope of 2.46 millimeters per year. Anything that has been linear that long is not likely to change anytime soon. This gives us a centennial rise of 24.6 cm, or just under ten inches. It is lower than any predictions from IPCC I have seen and is likely to be closest to real sea rise when the results come in.
Dave Wendt says:
April 28, 2014 at 12:59 pm
I tend to avoid commenting on most of these sea level posts because unlike most of the world I find the satellite sea level data to be a complete crock.
===
LOL…you’re not alone Dave
Here you go….. http://www.aviso.oceanobs.com/fileadmin/documents/calval/validation_report/EN/annual_report_en_2009.pdf
philjourdan says:
April 28, 2014 at 12:24 pm
@Latitude – Normal seems to be what ever they decide. Not something that is common in the history of the planet.
====
pretty much…..who decided where that little zero line goes anyway
http://www.foresight.org/nanodot/wp-content/uploads/2009/12/histo3.png
ZombieSymmetry says:
April 28, 2014 at 12:47 pm
…
Eyeballing the graphs on Wikipedia, it seems to me that the noise in the data for the past 8000 year or so is around +/- 1 meter, conservatively: http://commons.wikimedia.org/wiki/File:Holocene_Sea_Level.png
…
It is far worse than that. There is very respectable evidence of mid-Holocene high stands that are between one and two meters ABOVE the present stand. Evidence of this comes from both northern and southern hemispheres. High stand strand lines have been mapped in Texas, Brazil, Australia, and various Pacific islands. There numerous methodological problems with trying to track sea level shanges, but there is wide support for the mid-Holocene highstand.
A good overview is Woodroffe and Horton 2005:
One point that the mid-Holocene marine highstand suggests is that the “Holocene” peaked at that time, and since then, we have been sliding slowly and unsteadily into the next glacial.
Lookie here smuck.
If you have bought, built, a luxury apartment – or any other kind of dwelling – near to the shores of San Francisco Bay – you may be having Al Gore as your neighbour – (rumours have it that Al has acquired a property, at a cost of $$$£££££££$$$$ gazillions – or maybe just a few millions) so, be afraid, be very afraid, cause our Al has only spent his “own money” in the public’s interest. – – – –
Al and his (Cocktails at dawn) friends are only there to monitor, at close quarters, the rapid sea level rises. Your property, however, will definitely be waterlogged by Christmas. And you, will have lost your money. SSSSSSSSSSSSSSSSSShi
The link disappeared there for Woodroffe and Horton. Here it is:
http://repository.upenn.edu/cgi/viewcontent.cgi?article=1022&context=ees_papers
Someone gets data from Wikipedia?
Thanks Dr. Brown.
> The paper argues that this decrease is the result of short-term natural climate variability
I’m really getting tired of this old phrase. I wish that warmists who can’t find the correlation they want with CO2 would go out and study what makes up “natural climate variability” instead of whining (or whinging) about it. They might learn something useful about the many sources of natural climate variability….
And if anyone sees Trenberth, suggest he dig under Hawaii to look for his missing heat. It might keep him busy for a while.
The absurdity of the “team” to actually believe that we can actually measure SL/R to the 1000th of an inch/meter is overwhelming. They would have us believe that the earth is a static perfectly proportioned ball and it’s just so darn easy when in fact it is anything but. As RGB notes the lack recent datum from GRACE (with all its warts) is telling. And this video from minute physics puts in all in perspective as the geodesists can only model SL to within ONE meter.
What the paper says: ” that during the last decade the rate of sea level rise has declined by about 30% during the period 2003 through 2011 to about 2.4 mm/year from the rate of 3.4 mm/year in the period 1992 through 2002″ contradicts the graph from Colorado which shows about a linear trend of 3.2 mm/year, no deceleration:
http://sealevel.colorado.edu/content/global-mean-sea-level-time-series-seasonal-signals-removed
However Colorado’s own data contradicts their graph if one looks at the historical values.
The overall increase was between 3.0 – rose to 3.5 in 2007 and then down to 3.2 in 2009.
The 3.5 mm/year in 2007 was the average computed/adjusted for the entire satellite data until then:
http://wattsupwiththat.com/2009/04/06/sea-level-graphs-from-uc-and-some-perspectives/
When I look now at the new data and it is again 3.2 mm/year for total:
http://sealevel.colorado.edu/content/global-mean-sea-level-time-series-seasonal-signals-removed
however including the additional GIA adjustment of 0.3 mm/year added in retrospect for the whole period ( I think this was done in 2011 or 2012 if I remember correctly – too lazy to check now…).
http://stevengoddard.wordpress.com/2014/03/24/the-global-isostatic-adjustment-scam/
So with the additional adjustment of more then 6 mm added in the last couple of years it cannot show the linear trend over all the data?
With the additional 0.3 the trend before 2007 should now show 3.8 mm/year and after 2007 should show less, something like 1.5 or 2 mm/year?
Gonzo says:
April 28, 2014 at 3:04 pm
The absurdity of the “team” to actually believe that we can actually measure SL/R to the 1000th of an inch/meter is overwhelming.
====
but they can measure temperature, CO2 (13CO2), etc…..the same way
/snark
Looks like an analysis of El NINO.
Noise In, Noise Out.
In response to:
“shows that during the last decade the rate of sea level rise has declined by about 30% during the period 2003 through 2011 to about 2.4 mm/year from the rate of 3.4 mm/year in the period 1992 through 2002.”
What has not been made public is the recent satellite data shows the ocean level is now dropping slightly. The increase shown based on satellite data is due to adjustments. There is a climategate type problem and there is a genuine significant scientific mystery.
If we were not in the middle of the climate wars, the sea level rise ( higher than can be explained by thermal expansion or melting glaciers or ice sheets) and then fall would be acknowledged to be an unresolved paradox.
As the warmists do not understand the missing mechanism (that can caused the mid ocean level to rise or fall) and we are in the middle of the climate wars, they have hidden the dropping of the mid ocean surface by adjustments to the depth of the ocean which enables them to state the ocean level is increasing when the net ocean level is in the last 6 or so years is dropping slightly.
Early indication that there is a missing mechanism that is causing anomalously more mid ocean rise in level, is the fact that the tide gauge measure is less than ocean level measured by satellite. The satellite measurement is too high and cannot be explained by thermal expansion of the ocean.
ftp://falcon.grdl.noaa.gov/pub/bob/2004nature.pdf
Mass and volume contributions to twentieth-century global sea level rise
The rate of twentieth-century global sea level rise and its causes are the subjects of intense controversy1–7. Most direct estimates from tide gauges give 1.5–2.0 mm/yr, whereas indirect estimates based on the two processes responsible for global sea level rise, namely mass and volume change, fall far below this range. Estimates of the volume increase due to ocean warming give a rate of about 0.5mmyr21 (ref. 8) and the rate due to mass increase, primarily from the melting of continental ice, is thought to be even smaller. Therefore, either the tide gauge estimates are too high, as has been suggested recently6, or one (or both) of the mass and volume estimates is too low.
Looks like data for about 1.5 to 2 main cycles or so folks with some shorter periodicities overlaid plus some noise. Definitiely not linear, quadratic or even just monotone increasing.
Come back in 2050 or 2100 and we should have a robust data set and some preliminary analysis. In 2500 we should have enough data for a robust preliminary report and in 3000 we will have it nailed. No further comment at this time thanks.
Can someone PLEASE stop the children waving their arms?
Link to Dr. Curry’s article.
http://judithcurry.com/2014/04/24/slowing-sea-level-rise/
And this video from minute physics puts in all in perspective as the geodesists can only model SL to within ONE meter.
I’m glad you posted that, as my attempt to post it myself (in the middle of a much longer reply) got eaten by demons from hell — again — and I didn’t have the energy to repost. It is actually a fabulous video, and it explains a lot of the difficulty with trying to build the satellite measurements.
The good thing is that the satellite measurements and tide gauge data are basically independent and from now on will act as mutual sanity checks. As is the case with RSS/UAH LTT and the various GASTA measurements, it is simply no longer acceptable for any sort of growing divergence to exist between the two. So regardless of any growing pains or initialization or algorithm problems in the satellite measurements, they will fairly rapidly either agree in general with the tide gauge measurements or nobody will believe them, including the scientists responsible for them. So they’ll fix them.
As far as measuring mm-scale stuff regarding the sea level “anomaly” given the difficulty of establishing SL itself within less than about a meter, with tide gauge data it is probably in principle possible as long as one doesn’t overextend one’s prediction from what it is — “relative” SL measured at a variety of coastal sites, over time, averaged in a not-completely-insane way into an estimate of the non-isostatic component of SLR change. However, ultimately, one faces exactly the same difficulties when trying to compute GASTA (the surface temperature anomaly) to supposed 0.15C precision when the same models one uses to do so cannot estimate GAST — the actual average surface temperature — closer than about a degree C, and where e.g. HADCRUT5 and GISS LOTI often differ by several times 0.15C. SLR hadn’t reached that point as of 2007, but I suspect that by 2014 it has some pretty serious disparities (hence the lack of actual figures released to the public).
rgb
“””””…..NZ Willy says:
April 28, 2014 at 1:20 pm
The trend lines in the RSS temperature graph have no merit whatsoever because their ends do not connect. Displaying such lines is a stain on this website, viewed with disdain by any practicing scientist including me. ……”””””
Well if it was up to me, I would draw the first trend line from 1978 to 1994, which would be dead flat like the second line; and that would demonstrate that a step change occurred around 1996-7.
To draw a single straight “trend line” for that complete graph would be totally insane.
But then this practising scientist would never draw a trend line any how.
Why make up fiction, when you have the facts ??
And trend lines are pure fiction.
If you are unhappy with two trend lines; then make it three trend lines, and join them all; that would put my third trend line from 1994 to 1997.
From rgb
“””””…..As I said in an earlier reply, that’s why the oceans are an exquisite thermometer for the Earth……”””””
Professor; one can even make the argument that the oceans (sl) are an exquisite measure of total ocean heat.
If one assumes that the temperature coefficient of (linear expansion), is constant over the temperature range (from surface to bottom), and also the specific heat, then the sea level rise due to added heat in the sea, is essentially independent of how the heat distributes versus depth.
You can heat a lot of water a little, or heat a little a lot, and the total length change is the same, under the conditions I gave.
It appears to me that the overall trend in sea-level rise (SLR) is derived by averaging many, perhaps thousands, of data points over many years. This masks the areas of the ocean where sea level is falling. That alone should raise serious concerns.
Yet there is a bigger issue. I recently found that rainfall over the ocean correlates very well with SLR. Also a lack of rainfall correlates to sea level falling.
For the two graphics that show this, see
http://sowellslawblog.blogspot.com/2014/04/sea-level-rise-and-annual-rainfall.html
The question becomes, then, what effect does rainfall over the oceans have on the SLR? Is the dramatic increasing SLR graph at all valid?
rgbatduke: “Assume that this length is (say) 1 km, or 10^6 mm. Even temperature changes that are one part in 10^5 absolute could then produce changes of several mm over 1 km.”
Thanks a bunch. That’s something that had never occurred to me.
Since you’ve obviously thought about this, though, perhaps you could also let us know how big you think the confounding factors you know of are. If we assume (contrary to fact) a uniform coefficient of expansion, then a 2-mm/yr trend over a century means 0.2 m out of 4267 m average depth, and that ratio, divided by 2.14 x 10^(-4) %/K, yields only 0.22 Celsius degrees of ocean-temperature change over the past century if I haven’t made another calculator error.
Now, you scientist types use words like “thermocline” that, in addition to frightening us natives, makes us wonder whether things aren’t more complicated. If we’re talking about using the ocean to bound radiative forcing plus feedback, as they’re talking about today over at Dr. Curry’s, I’d be willing to accept that it doesn’t much matter; if the ocean heats less somewhere, it heats more somewhere else. But as to the effect on temperature up here where we live, well, that’s something else; there must be some kind of multiplier that results.
And what about the non-uniform coefficient of expansion? Perhaps it’s not too non-uniform at the depths where most of the temperature change occurs. Or maybe it is.
:Finally, when you say, “People make noises of a shift in the ratio of land freshwater and sea water, but I don’t think there is any compelling evidence for it,” I take it you’re not convinced by what Leonard Weinstein is (or may be) saying http://judithcurry.com/2014/04/28/an-alternative-metric-to-assess-global-warming/#comment-535465 at Dr. Curry’s?
In any event, might you conclude that as far as what Pielke, Sr., McNider, and Christy are proposing today at Dr. Curry’s the Argo system isn’t all that necessary if we have good sea-level information?
Corrigendum in my comment:
“2.14 x 10^(-4) %/K” includes the percent sign erroneously .
As mentioned in one of the blogs above the “powers” started adjusting the reported sea level rise by considering the subsidence at the bottom of the sea. This correction is misleading since it adds the subsidence (which reduces actual sea level) to the measured sea level ignoring the fact that subsidence creates more volume to store more water. I believe this mis- represents the impact/risk of sea level rise.
My question is: do the plots above incorporate the soil subsidence thus exaggerating the risk.
By the middle of this century sea level will likely be falling, it would almost be almost impossible for it not to happen.
Odd sentence structure:
“But in a puzzle to climate scientists, the rate slowed to 2.4 millimetres (0.09 inch) a year from 2003 to 2011 from 3.4 mm from 1994-2002,”
Surely it would be clearer to write “slowed from 3.4 mm from 1994-2002 to 2.4 millimetres (0.09 inch) a year from 2003 to 2011″. This structure is more logical, in that the path of thought in the sentence is in the same direction as the movement or change.
How about the impact of sucking water out of the ground and sending it to the ocean. Is it significant in adding to the volume in the ocean? Areas outside Houston are experiencing significant soil subsidence from this
jim Steele says:
April 28, 2014 at 11:28 am
The same for Kiribati and the Maldives
Never mind trying to figure out the level of a constantly moving body of water … The US Canada border is supposed to follow the 49th parallel but the original and subsequently relocated “official” boundary markers are generally several hundred feet north or south of the 49th due to the “accuracy” of the original survey and failure to account for the gravitational pull of the Rocky Mountains on the plumb bobs and variations in the surface elevation gravity and so on. The gravity issue with the mountains was discovered early and corrections made. Now with GPS we can more accurately determine where the border “should have been”. But it is all still based on “agreed to” calculations and marks that we once put on the ground as reference points and our agreed Geodetic surveys. We now have the technology to electronically measure straight lines very accurately but since we live on a spheroid with lots of bumps and dips, we have to apply adjustments. Many of us will remember many measurements are adjusted to “STP”.
Never mind trying to figure out the level of a constantly moving body of water … The US Canada border is supposed to follow the 49th parallel but the original and subsequently relocated “official” boundary markers are generally several hundred feet north or south of the 49th due to the “accuracy” of the original survey and failure to account for the gravitational pull of the Rocky Mountains on the plumb bobs and variations in the surface elevation gravity and so on. The gravity issue with the mountains was discovered early and corrections made. Now with GPS we can more accurately determine where the border “should have been”. But it is all still based on “agreed to” calculations and marks that we once put on the ground as reference points and our agreed Geodetic surveys. We now have the technology to electronically measure straight lines very accurately but since we live on a spheroid with lots of bumps and dips, we have to apply adjustments. Many of us will remember many measurements are adjusted to “STP”.
Wayne Delbeke at 10:05 regarding borders –
The border of Kentucky and Tennessee was supposed to be a smooth line also. Have a look!
NZ Willy Apr 28 1:20 pm says “The trend lines in the RSS temperature graph have no merit whatsoever because their ends do not connect.“. This is the graph you need:
http://members.iinet.net.au/~jonas1@westnet.com.au/RSSTLT20140429.JPG
It’s a least-squares fit of a two-phase trend to RSS TLT global monthly data downloaded today from http://data.remss.com/msu/monthly_time_series/RSS_Monthly_MSU_AMSU_Channel_TLT_Anomalies_Land_and_Ocean_v03_3.txt
The point of intersection is optimised both vertically (temperature) and horizontally (date).
RoHa: “Odd sentence structure.”
I know what you mean; I always have to re-read that construction when I encounter it. But others’ mental equipment must differ and find it more logical; if you notice, that approach seems to be in the Wall Street Journal’s style manual.
rgbatduke says:
April 28, 2014 at 11:48 am
…
It is the lack of any compelling acceleration in SLR that is the strongest evidence that we have against the hypothesis of runaway/catastrophic anthropogenic global warming, as well as the natural vs anthropogenic fractions of such warming as has occurred. Both the SLR graph I link and the derivative of the SLR graph republished in the top article show that there is absolutely nothing remarkable about SLR rates post 1950 compared to pre-1950, where 1950 is usually given as the breakpoint year where CAGW due to CO_2 was “launched” by the advent of a steady increase in post-WWII industrialization and civilization worldwide.
This is a profound case of the inconsistency of the CAGW argument. It is so strong that it comes dangerously close to being direct evidence that the argument is unambiguously false!
I agree, very important point. Sea level is a good integrating indicator of heat in the ocean. Its rise is slowing, not accelerating. Trenberth’s missing heat is not in the ocean.
Anyone know why the seasonal rise in sea level, which peaks in mid Spring, is much higher in the Nth hemisphere than the in the Sth hemisphere?
re my last comment I meant to say sea level peaks in mid Autumn / Fall not Spring.
If one assumes that the temperature coefficient of (linear expansion), is constant over the temperature range (from surface to bottom), and also the specific heat, then the sea level rise due to added heat in the sea, is essentially independent of how the heat distributes versus depth.
inverse K. Thus:
K/year. Over a decade, this is order of a millidegree. Over a century it is still not resolvable with any but our best thermometers, maybe, at around a hundredth of a degree. In that same century, SLR would be 30 cm.
Excellent point, A+ in fact. I hadn’t really thought of that, but I do believe you are right.
As for Joe’s comments — one actually has to look up the volume expansion coefficient, which is probably approximately linear between 10 C and maybe 80 or 90 C. At 20 C it is around
Assuming that we should be using linear instead of volume (arguably we should use $\alpha^3$, but I’m assuming the ocean is essentially constrained horizontally at all but one surface) and that we’re talking temperature change averaged over only the top kilometer and an annual change of 3 mm:
Ignoring factors of order unity, this means that
This is, actually a very serious argument both in favor of and against Trenberth’s assertions of oceanic warming. On the one hand, yes, the ocean is warming, at around 0.1 millidegrees per year (averaged over the top km). On the other hand, it takes a century of such warming to become (maybe) resolvable at the instrumental level, and longer than that to rise above the noise. The only way we actually know the warming is occurring is because of SLR (because there is no way in hell that they are measuring this with only a few thousand ARGO buoys), and that same phenomenon puts strict limits on how large it could be.
rgb
Wayne Delbeke says:
April 28, 2014 at 10:05 pm
“…for the gravitational pull of the Rocky Mountains on the plumb bobs..”
Good points Wayne, but, counterintuitively, the plumb bob is “pushed away” from the mountains. The mountains are lighter crustal rocks, and like an iceberg, have deep roots and are ‘floating’ in denser mantle rocks. This results in a deficiency of mass in the direction of the mountains. This of course doesn’t negate your point.
http://www.britannica.com/EBchecked/topic/296537/isostasy
In fact, the theoretical basis for SL rise is not there. The last warming trend ended long ago and the thermal expansion of the ocean has stopped. Greenland ice melt is more than compensated by the growth of the Antarctic shelf ice. NOAA guages on the Gulf coast (where subsidence is the rule) show no increase in SL in the last 16 years (see NOAA mean sea level trends). One exception is grand Isle. La., where subsidence gives a gauge of a false SL rise.
rgbatduke and others touch on SL gauging. It is instructive to see how many of these show no SL rise this century. To utilize this source, see NOAA mean sea level trends gulf coast, or the individual guage charts for Galveston, Sabine Pass, Port Mansfield, Freeport, Port Isabel, Rockport, etc. The data is accurate because of the special conditions of that particular coast.
Willis, for one, will greatly benefit by utilizing this resource.
“””””…..rgbatduke says:
April 29, 2014 at 7:01 am
If one assumes that the temperature coefficient of (linear expansion), is constant over the temperature range (from surface to bottom), and also the specific heat, then the sea level rise due to added heat in the sea, is essentially independent of how the heat distributes versus depth.
Excellent point, A+ in fact. I hadn’t really thought of that, but I do believe you are right……”””””
Robert, I have known of this for some time, but had never posted it anywhere.
It first occurred to me, when thinking about sea level “rise” during the floating ice melt season.
I have always believed that when the sea ice melts, the source of the “heat” energy, including the latent heat (80 calories per gram), is the surrounding warmer sea water, and not the air above the ice. So when the ice melts, it cools the surrounding sea water, which shrinks, since salt water of ocean salinity, still has a positive Tc down to its freezing point. So the level falls instead of rise. I realized, I had no data at all, about the path that heat would take in getting to oblivion, so I couldn’t begin to calculate the shrinkage. Then it dawned on me that it wouldn’t matter if Tc and specific heat were both constant.
But of course, near the freezing temperature, the Tc gets really wonky, so the constancy assumption is not good. So I gave up on it, and just said, it goes down on ice melt, and NOT up.
But elsewhere, the deep oceans evidently don’t go below about 4 deg. C; unrelated of course to the max density temperature of FRESH water.
So I figure Tc of ordinary sea water warmer than deg. C is not too variable.
Ocean coastlines have variable steepness, and some of it is very low slope so the area might expand quite a bit with increased height. I’m too old to figure out such non-linear three dimensional integrations, but since the temp changes are small, I figure it is actually somewhat linear, so the volume Tc and linear Tc should be roughly 3:1. I believe the three dimensional distribution of the heat, is also irrelevant to the resulting volume or depth change.
Get your students to think on it.
Somebody at the U of A (Auckland) was doing some study of sound propagation over long distances in the ocean, and evidently the velocity is temperature related in such a way that the propagation time over a long distance varies linearly with the AVERAGE temperature over the path; regardless; or irregardless, as the case may be, of the temperature profile of the path. I somehow got the idea they were pinging from NZ to Hawaii; but maybe just from the dock to Rangitoto. I do NOT want to know how far someone can listen through water.
So they were using that to observe ocean temperatures. I could probably find out about that from the head of the dept (Physics). I have connections of a sort.
G
rgbatduke comments on the difficulty of obtaining accurate SL data via tide guages. This difficulty is due, of course, to tides, storms, and isostatic adjustments.
The Gulf coast offers more reliable data because its tidal fluctuation is small, normally about one foot or so from low to high tide and it is characterized by subsidence, from very slight on the Texas coast to acute at Louisiana, and thus guage readings on that coast are an upper constraint on actual SL rise. The NOAA mean SL trend charts show a good consistency for some six stations from the southern tip of Texas to the La. border. These all indicate little or no SL rise this century, uncorrected for sunsidence. For those who are interested see NOAA Mean Sea Level for Sabine Pass, Galveston (2 stations), Freeport, Rockport, Port Mansfield, and Port Isabel. For a false sea level rise due to acute subsidence, see Grand Isle, La.
NOAA 2012 report of sea level using all available data from 2004 to 2012 shows about 1 mm per year. Link to report and comments
http://hockeyschtick.blogspot.com/2012/12/noaa-2012-report-finds-sea-levels.html
For a false sea level rise due to acute subsidence, see Grand Isle, La.
====
Or Galveston too….
Figure 1 shows the sea level trend for Galveston Pier 21, Texas, which has been rising at a rate of
6.5 mm/yr due to land subsidence from oil, gas, and water extraction
http://oceanservice.noaa.gov/outreach/pdfs/sea_levels_online.pdf
At last an article reporting land subsidence as a bigger problem than sea level rise:
Megacities contend with sinking land
http://www.bbc.co.uk/news/science-environment-27202192
“Subsiding land is a bigger immediate problem for the world’s coastal cities than sea level rise, say scientists.
In some parts of the globe, the ground is going down 10 times faster than the water is rising, with the causes very often being driven by human activity.
Decades of ground water extraction saw Tokyo descend two metres before the practice was stopped.
Speaking at the European Geosciences Union General Assembly, researchers said other cities must following suit….”
“…The most rigorous solution and the best one is to stop pumping groundwater for drinking water, but then of course you need a new source of drinking water for these cities. But Tokyo did that and subsidence more or less stopped, and in Venice, too, they have done that.”
The famous City of Water in north-east Italy experienced major subsidence in the last century due to the constant extraction of water from below ground.
When that was halted, subsequent studies in the 2000s suggested the major decline had been arrested.”
thus guage readings on that coast are an upper constraint on actual SL rise.
Or, sadly, not.
The problem is this. Let’s suppose that this is, as some expect, a big ENSO year. Let’s imagine that a huge patch of the Pacific ocean warms by several degrees C over its usual temperature, to some reasonable depth. Let us imagine that — since this water expands as it warms and is buoyed up by the cooler water underneath it — local sea level in the middle of the ENSO warming is a whole centimeter higher than usual.
How much does one expect SL at Galveston to vary, assuming that it is rock solid, stable, not moving?
The answer is “not at all”. The water that was warmed was “floating” (neutral buoyancy) before it warmed. It is “floating” (neutral buoyancy) after it warmed. It displaces exactly the same amount of water that it did before everywhere outside and beneath the local warming.
So, coastal gauge readings “can” actually be significantly disconnected from average SL over the entire ocean. Note that this disconnect can occur either way. If coastal temperatures are warming, coastal SL will (on average) rise, even if ocean temperatures far from shore are falling and the actual mean SL is falling. Or vice versa. Coast tidal gauges are actually subject to “UHI”-linked false SLR to the extent that they live in harbor waters around major urban sites that dump a lot of waste heat or heat absorbing silt into the water. If coastal waters at (say) the Beaufort Inlet in NC (where I live all summer teaching at the Duke ML are (say) a degree or two warmer than the surrounding ocean upcoast, downcoast, and out away from the coast because of silt, trapped haze and pollution from the urban centers around, waste heat coming down the various rivers or sounds that drain in and out there, or because the bay bottom at the inlet was recently carpeted and raised several feet by the sand from around a third of a mile of the tip of Shackleford Island because of Hurricane Sandy, and shallow water warms much faster than deeper water — the tide gauges there will read a teensy bit higher from thermal expansion that is entirely local — the surface water will float a bit higher on the cooler water beneath than it would if it where cooler, and as SL rises from thermal expansion at Beaufort it has no effect on SL anywhere else.
This is the same trick question involving melting sea ice. The ice floats before it melts. It “floats” (displaces the existing water) by exactly the same about — its weight in water — after it melts. So the net displacement everywhere else does not change. I’ve spent the day explaining this to students.
Sea ice is, of course, multiple tricky — as sea ice forms, it desalinates. That’s because salt water has a lower freezing point, so as freshwater crystals form, they grow at the expense of ever saltier residual water that melts its way down through the formed ice to rejoin the sea. Icebergs are invariably fresh water because of this process, even if they were formed directly from freezing salt water. But this is almost a zero sum process. In the winter, freezing sea ice forms, drops its salt into the underlying water, boosting its salinity. In the spring and summer, it melts, adding freshwater to the extra-salty water underneath and diluting it back towards “normal”. It may or may not be a zero sum process because at the same time the thermohaline circulation currents may sweep the extra-dense winter salinity down into the low level return current, replacing it with comparatively less dense water brought in by the top current. Or not. This is, no doubt, one of the forces that drives the THC in the first place. Either way, it is nearly zero sum, so the matched pair of freezing sea water to make sea ice and melting sea ice to make sea water very likely has almost no effect on net displacement.
The only two things that affect global SL are average thermal expansion — which is absolutely dominant in the process at least at the moment — and land ice melt. Land ice melt is definitely not zero sum — it can cause a real rise in sea level. Thermal expansion is ultimately zero sum — SLR measured in one place due to thermal expansion will not generally mean (as one might naively expect) SL to rise somewhere else because of isostatic displacement. The whole SL can rise — because the whole ocean can warm — but as soon as it cools it will shrink right back down, locally, to its normal depth or wherever.
The slow tide gauge SLR observed over the last 140+ years is not, in all probability, a very good measure of true SLR. In fact, it doesn’t guarantee that SL on average has risen at all. It also doesn’t help us understand at all what, if any measurable, fraction of that rise was due to actual melting land ice (and hence is “irreversible” SLR at least until glaciation starts up again globally). What it does indicate, though, is that whatever the “average” ocean is doing (and still neglecting a lot of possible factors that work on geological time, such as tectonic drift, changes in ocean volume due to uplift or opening of ocean floor rifts or the movement of continents or growth of volcanic islands underwater) there is little evidence that we should be alarmed by SLR at the moment. Whether or not we should be alarmed in the future depends a lot more on how warm it has to get to melt Greenland and/or Antarctica, and how long it would take to melt either one even if the air above them both went up by 2-3 C. Since the air above them both is basically well below freezing pretty much all year long (and this would not substantially change if there were a small temperature shift) I’m guessing the answer is “a really, really, really long time”. As in centuries to millennia. Their response might even be counterintuitive — warmer air might come with more moisture, more snow, and net icepack accumulation per annum, on average. With a nonlinear, chaotic system, with complex coupled feedbacks, it is really difficult to make any sort of simple linear response statement and have it work out to be true.
rgb
What pause are you seeing? The sea level rise has been remarkably stable on 3.2 mm/year since 1992.
See: http://sealevel.colorado.edu/
The report which claims a pause stops in 2011 when we saw a short dip.
/Jan
@Joe Born
I never read WSJ (not a popular newspaper here in Brisbane) but I’ll take your word for it. I am quite prepared to believe any insanity associated with the crooks of Wall Street.
I had a horrible experience today on this subject. I had an otherwise intelligent young man tell me that he had read that the recent spate of earthquakes was caused by global warming. The worst part was that until I explained to him why that was not true, he was willing to believe it.
We really must have sites like Anthony’s to counter such rot.
Perhaps, rgbatduke, but study the NOAA mean SL trends for The Tx Gulf Coast and you will see a curious spike at around 1998 on these.
That SL gauges do not give reliable indications of SL or SL trends and therefore should not be relied on seems to me to be rather an extravagant statement. What I have heard about Satellite data and instrument drift and theoretical corrections to avoid such and those who operate such, who may or may not subscribe to rigorous principles of science or ideology and so forth, it seems that there is a large degree of uncertainty there, and the rest of us have no means whatsoever of ascertaining any such “drift” or factor of verity.
I prefer gauge data which you can always try for whatever corrections that might seem necessary. Which is not to say that one can remove absolutely all degree of uncertainty.
mpainter
I prefer gauge data which you can always try for whatever corrections that might seem necessary. Which is not to say that one can remove absolutely all degree of uncertainty.
Actually, it is lovely to have both. It would also be fun to have deepwater gauge measurements but alas, it is a bit difficult to create a rigid rod down to the ocean floor and not have it subject to all sorts of confounding influences from currents that bend it sideways (submerging the tip) to thermal expansion of the rod itself as surface temperatures vary, so that it out-expands the thermal expansion of the ocean due to local surface warming (lots of materials have thermal expansion coefficients as large or larger than that of water). No matter how you slice it, measuring SLR is a bitch. In one sense SLR at the coasts is what we really care about, so tide gauge measurements at the coast, whether or not they accurately reflect overall average SLR, are what matters. OTOH coastal tide gauges are subject to a range of local errors or confounding influences — uplift/subsidence of the land, silting, local warming, alteration of the tidal gap leading to the station due to construction, beach migration or storm-erosion (a BIG factor at Beaufort, for example). Satellite data is relatively global and relatively immune to most of this by simply out-sampling the confounded sites with (more) “randomly” selected ones. People don’t put tide gauges down via random site selection, or systematic grid — they put them where they live, and they live in places that are not necessarily “typical” of the (any) coast in general. And they don’t/can’t put them into the deep ocean.
But together they give us a better picture than either one alone. Sadly, the problems of isostasis and gravity and coriolis force and the non-sphericity of the globe mean that AT BEST the picture they give us is highly imperfect and imprecise.
Fortunately, until and unless the major continental-scale ice packs melt, it is pointless to be concerned about SLR. Seriously pointless. That, at least, is a simple consequence of physics, because the oceans are really, really big and take a really, really long time to substantially change their temperature. Without additional water we’re talking thousandths of a degree and millimeters/year of SLR at most, almost independent of what happens in the air or on the land surface.
rgb
I agree: “seriously pointless”.
Unfortunately the alarmists have used this issue with much advantage and so it must be refuted. It is for this purpose thatI have an interest in the issue.
Jan Kjetil Andersen:
The U of Colo. is entirely unreliable for sea level information. NOAA data show no sea level rise for this century.
I read some time ago that it actually dropped two years in a row – I believe 2010 and 2011…
If 9000 years ago, it was 4.5 deg F warmer than today and the oceans were 2 meters higher. Then 2000mm/4.5= 444mm SLR per deg F of SLR. So, 3.2 mm per year times 100 years, a century, =320mm. 320mm/444mm = 0.72 deg F temperature rise per century. No, this can’t be that simple???