Observed sea level rise still is (just) within the 'natural range'

From the University of Southampton

What the past tells us about modern sea-level rise

Researchers from the University of Southampton and the Australian National University report that sea-level rise since the industrial revolution has been fast by natural standards and – at current rates – may reach 80cm above the modern level by 2100 and 2.5 metres by 2200.

The team used geological evidence of the past few million years to derive a background pattern of natural sea-level rise. This was compared with historical tide-gauge and satellite observations of sea-level change for the ‘global warming’ period, since the industrial revolution. The study, which was funded by the Natural Environment Research Council (iGlass consortium) and Australian Research Council (Laureate Fellowship), is published in the journal Scientific Reports

Lead author Professor Eelco Rohling, from the Australian National University and formerly of the University of Southampton, says: “Our natural background pattern from geological evidence should not be confused with a model-based prediction. It instead uses data to illustrate how fast sea level might change if only normal, natural processes were at work. There is no speculation about any new mechanisms that might develop due to man-made global warming. Put simply, we consider purely what nature has done before, and therefore could do again.”

Co-author Dr Gavin Foster, a Reader in Ocean and Earth Science at the University of Southampton, who is based at the National Oceanography Centre, Southampton (NOCS), explains: “Geological data showed that sea level would likely rise by nine metres or more as the climate system adjusts to today’s greenhouse effect. But the timescale for this was unclear. So we studied past rates and timescales of sea-level rise, and used these to determine the natural background pattern.”

Co-author Dr Ivan Haigh, lecturer in coastal oceanography at the University of Southampton and also based at NOCS, adds: “Historical observations show a rising sea level from about 1800 as sea water warmed up and melt water from glaciers and ice fields flowed into the oceans. Around 2000, sea level was rising by about three mm per year. That may sound slow, but it produces a significant change over time.”

The natural background pattern allowed the team to see whether recent sea-level changes are exceptional or within the normal range, and whether they are faster, equal, or slower than natural changes.

Professor Rohling concludes: “For the first time, we can see that the modern sea-level rise is quite fast by natural standards. Based on our natural background pattern, only about half the observed sea-level rise would be expected.

“Although fast, the observed rise still is (just) within the ‘natural range’. While we are within this range, our current understanding of ice-mass loss is adequate. Continued monitoring of future sea-level rise will show if and when it goes outside the natural range. If that happens, then this means that our current understanding falls short, potentially with severe consequences.”

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BS, it makes the GRASS GROW GREEN, BS (basic science), it makes the grass grow tall.
3mm per year… And the satellite accuracy is????
The above introduction is sung to Srgt. Musgrave’s dance (the Bridge on the River Kwai theme.)
After my Father taught me that, in certain “social circumstances” we could walk away from someone who had told us something, and he’d just whistle the tune.

Marcos

are they removing the GIA ‘adjustment’ from the modern sea level rise?

Richard

Hmm, let’s take a look at state of the art equipment put on pacific islands around 18 years ago to measure sea level rise,
South Pacific sea levels Best records show little or no rise?! « JoNova
joannenova.com.au/2010/08/south-pacific-sea-levels-no-rise-since-1993/
18 Aug 2010 – The Seaframe stations are state of the art, and regularly checked to compensate for all these changes. The Seaframe equipment used to measure sea levels is carefully … yet at least in the South Pacific, it’s not clear that sea levels have risen. …. as an exceptionally low year for seal level on all these islands.

Around 2000, sea level was rising by about three mm per year. That may sound slow, but it produces a significant change over time.
Of course it does, but who says that this pace will stay that way over the next 300 years? Perhaps sea level rise also goes in 60 year cycles so a linear extrapolation may not be warranted.

Bloke down the pub

Around the UK there are many settlements that in medieval times were on the coast, but are now many miles inland due to sea level reduction. This is not due to isostacy as in the South the land is sinking. Everything that goes around, comes around, and one day the sea will come to collect the debt owed.

ShrNfr

And sea level in the Pacific apparently fell during the Little Ice Age. As we swing from a high level of solar magnetic activity to a low level of solar magnetic activity, extrapolating broken AGW models for 200 years leaves me unimpressed.

Tom G(ologist)

This is a curious conclusion, considering that Conrad (2013, Solid Earth Influences on Tides, GSA Bulletin) found that:
“On the shortest time scales (1–10 yr), elastic deformation [of the crust] causes the ground surface to uplift instantaneously near deglaciating areas while the sea surface depresses due to diminished gravitational attraction. This produces spatial variations in rates of relative sea-level change (measured relative to the ground surface), with amplitudes of several millimeters per year. These sea-level “fingerprints” are characteristic of (and may help identify) the deglaciation source, and they can have significant societal importance because they will control rates of coastal inundation in the coming century.”
In other words, crustal deformation exerts sea level controls on multiple, overlapping time scales ranging from years to billions of years. But, if you put on blinders, the ONLY causes of mm/yr variations in sea level just HAVE to be glacial meltwater and sea water expansion both caused solely by AGW.

rgbatduke

Of course it does, but who says that this pace will stay that way over the next 300 years? Perhaps sea level rise also goes in 60 year cycles so a linear extrapolation may not be warranted.
Yes indeed. In fact one could look at the historical tide gauge data to see that this is precisely the case, and that SLR was as even more rapid than it is today during the first half of the 20th century in good alignment with the thermometric record of post-LIA warming. Gravitation-corrected SLR is currently lower than what the satellites appear to be reporting IIRC, at around 2mm/year, which is almost exactly the long term post-LIA average rate. There is no sign of “acceleration” due to supposed anthropogenic CO_2 effects.
What amuses me about all of these predictions is that they are all — without exception — predicated on some sort of ill-defined mean increase in GASTA predicted by the various GCMs and on a whole raft of assumptions about things like how rapidly Antarctica and the Greenland ice pack are supposed to melt. It’s sort of like “If GASTA increases by 5 C by 2100, and if that increase suffices to cause the melting of a kilometer or so of Antarctic ice pack, and if the ocean expands by thus and such amount due to the warming, then we’ll see X meters of SLR by 2100”. Frequently the claims are literally absurd — melting Antarctica on a timescale of decades shows some sort of serious problem understanding latent heat of fusion (which is huge), high albedo, six months of night and low high-tilt summertime insolation, and surface to volume ratios.
They also seem absolutely impervious to empirical data. “Boiling seas” Hansen was publicly making his wildly speculative 5 meter SLR by 2100 guess well over a decade ago (which is as irresponsible for a scientist to do as showing “fire” in a crowded theater because you have linearly extrapolated the temperature increase inside due to being recently filled with warm bodies to the ignition point of paper in 100 years). Here it is, 2013, one eight of the way through the interval from 2000 to 2100 and the total SLR of the last decade is (drum roll please) at MOST an inch. More likely 3/4 of an inch — a couple of lousy centimeters.
So we have Yet Another Paper — one that lacks even an effort to pretend to analyze the physics of icepack melting on high-latitude plateaus but instead equates things like melt rates in mid-interglacial transition to melting rates today — calling for as much as 80 cm by 2100 and lord knows what by 2200. Hey, I should be glad — at least it’s down from the meter previously being called for in papers of this type as people are beginning to twig to the fact that if we’re going to see SLR of this magnitude it has to start sometime and gee, it hasn’t started yet. Nor is it likely to be starting, as the planet has experienced no significant warming since the burst associated with the 1997/1998 Super ENSO even, and may even be quietly cooling a bit in spite of recent attempts to rewrite the temperature record yet again, this time at the very tail end of inconvenient stasis, so that one can compare infilled kumquats to multiply-adjusted modern era oranges to sparsely sampled, non-infilled thermometric apples in the more distant past (all to get an ANOMALY as we can’t for the life of us actually compute the global average surface temperature TODAY to within a degree K).
Some arithmetic: 80 cm by 2100 is roughly 0.9 cm a year or an inch every 2-3 years. It is over three times the greatest rate observed (on several occasions, not just in the recent past) in the entire reliable historic record (tide gauge data). Every year with only 2-3 mm of rise tacks on an extra 6-7 mm that have to be made up in the following years. Measuring SLR is actually enormously complex — simply determining the current “sea level” is highly nontrivial because it has to be extracted from sparse measurements on a fluid surface with both systematic (but imprecisely predictable) time variation and with an enormous amount of multiple-timescale fractal noise and then corrected for the motion of the Earth’s crust and slow variability in the near-surface gravitational field (both magnitude and direction). The sea level could be rising even if there is no contribution from melting icepack, or it could be rising far more slowly than one would expect from melting icepack because land uplift or subsidence could be cancelling the effect. We barely have the tools to start seriously examining the issue of SLR, and have a pitifully short data secant based on those tools, which are still in the process of showing mutual (e.g. gravitometric) inconsistencies in the whole system.
Why do referees permit the publication of doubly conditional speculation like this? At the moment, the GCMs are busy failing, although there is a widespread effort to pretend that this isn’t the case. Basing physics-free multiply-conditional papers asserting that we are going to have all sorts of SLR that is going to start any decade now because the GCMs say so is a waste of time unless and until the GCMs start exhibiting any predictive skill at all!
So far, they have no predictive skill at all. That doesn’t mean that they won’t in the future, but in the meantime, the paper above is like publishing a paper that says “If superluminal neutrinos are observed, maybe we can build time machines” without even including a single actual equation to explain why, but relying on the fact that in medieval times clocks often ran fast or slow by as much as an hour a day.
Sure, and if pigs had wings, then they could fly, and I’ve got a predictive model for evolution that states that if we continue to throw pigs out of helicopters and breed only the survivors, pigs will have wings in less than 100 years. Maybe I should go ahead and found a pig-hunting club that only shoots pigs on the wing. Yeah. Why not?
rgb
Sigh.

@Bloke: An excellent point, Sir! The land around the Solent has dropped about 20 feet since the pre-Roman settlement was occupied, but in the days of King John, the Wash was a tidal zone.

A link to the paper itself is needed.
The paper appears to be Rohling, E.J, Haigh, I.D., Foster, G.L., Roberts, A.P., and Grant, K.M., A geological perspective on potential future sea-level rise. Scientific Reports (12 December 2013 in press), see http://www.highstand.org/erohling/ejrhome.htm
Scientific Reports appears to be part of Nature Publishing Group.

From the same author, E J Rohling:
Gavin Foster & Eelco Rohling
Proceedings of the National Academy of Sciences, 22 January 2013, Pages 1209-1214
Abstract:
On 103- to 106-year timescales, global sea level is determined largely by the volume of ice stored on land, which in turn largely reflects the thermal state of the Earth system. Here we use observations from five well-studied time slices covering the last 40 My to identify a well-defined and clearly sigmoidal relationship between atmospheric CO2 and sea level on geological (near-equilibrium) timescales. This strongly supports the dominant role of CO2 in determining Earth’s climate on these timescales and suggests that other variables that influence long-term global climate (e.g., topography, ocean circulation) play a secondary role. The relationship between CO2 and sea level we describe portrays the “likely” (68% probability) long-term sea-level response after Earth system adjustment over many centuries. Because it appears largely independent of other boundary condition changes, it also may provide useful long-range predictions of future sea level. For instance, with CO2 stabilized at 400-450 ppm (as required for the frequently quoted “acceptable warming” of 2 °C), or even at AD 2011 levels of 392 ppm, we infer a likely (68% confidence) long-term sea-level rise of more than 9 m above the present. Therefore, our results imply that to avoid significantly elevated sea level in the long term, atmospheric CO2 should be reduced to levels similar to those of preindustrial times. []
My comment : It looks like Eelco Rohling makes the simple error of coming into this subject with an unverified assumption, namely that the observed sea level rises were caused by CO2. We know that in fact a warming ocean releases CO2, so Rohling’s observed relationship between CO2 and sea level is likely to be caused by temperature. For Rohling’s observations to support the “ dominant role of CO2, the alternative explanation – that temperature is the driver – needs to be eliminated.
This latest paper places sea level rise “(just) within the ‘natural range’“. I wonder whether another simple error has been made, namely comparing high-resolution modern data with low-resolution geological data. Without a link to the paper I can’t tell.

AleaJactaEst

rgbatduke says:
December 12, 2013 at 12:08 pm
“flying pigs….”
can I help out there during the flying pig season?? I don’t seem to be having too much luck with the pheasants here in Scotland at the moment, flying pigs sound more in my league.

Brian R

Just more of the “sea level rise is accelerating” nonsense. If you look at the the record, sea level rise has a long term average of 3-4mm per year. So for the level to increase another 80cm by 2100 the average rate of increase would have to double or triple over the next 84 years. Then it would have to triple again to hit their 2.5 meter increase by 2200.
Complete and utter nonsense!

There is no such thing as “normal times.”

JJ

“The team used geological evidence of the past few million years to derive a background pattern of natural sea-level rise. This was compared with historical tide-gauge and satellite observations of sea-level change for the ‘global warming’ period, since the industrial revolution.”
Yet another example of someone tacking a modern instrumental record onto the end of a proxy dataset and pretending the result is meaningful.

NemoFinder

Wow…you can smell the bias in his words. Sea level rise is within the natural range…but he had to insert a “just” in there to make it sound less “natural”. This directly contradicts his “quite fast by natural standards” statement too. Which is it? If the rise is within the natural range, it cannot also be “quite fast by natural standards”. He really really wants to say sea level is rising “too fast”, doesn’t he?

boondoggle9945

How the heck do you define normal and natural? Is it before, during or after the various ice ages we have had over the last million years ? How has the rate varied during those various periods ? Based on this summary, this does not make any sense at all.

davidmhoffer

rgbatduke;
so that one can compare infilled kumquats to multiply-adjusted modern era oranges to sparsely sampled, non-infilled thermometric apples in the more distant past (all to get an ANOMALY as we can’t for the life of us actually compute the global average surface temperature TODAY to within a degree K).
>>>>>>>>>>>>>>>>>>>>>
I have to learn to keep my coffee cup out of reach when reading your comments. The cost in coffee and ruined key boards is starting to mount. In this case, I had just done cleaning up from that quip when I encountered the flying pigs quip and had to start all over again.

Auto

Hat tip to RGB!
Magisterial.
=====
“Continued monitoring of future sea-level rise will show if and when it goes outside the natural range. If that happens, then this means that our current understanding falls short, potentially with severe consequences.”
The last two sentences from the abstract appear to translate as ‘Send more money’.

SMC

If you want flying pigs, head to Cincinnati, Oh. They’re all over the place in good’ol porkopolis.

davideisenstadt

rgbatduke says:
December 12, 2013 at 12:08 pm
I so look forward to reading your posts….

Jimbo

Researchers from the University of Southampton and the Australian National University report that sea-level rise since the industrial revolution has been fast by natural standards and – at current rates – may reach 80cm above the modern level by 2100 and 2.5 metres by 2200.

That’s one take on things. Here are some other take on things.

American Meteorological Society – Volume 26, Issue 13 (July 2013)
Abstract
Twentieth-Century Global-Mean Sea Level Rise: Is the Whole Greater than the Sum of the Parts?
………..The reconstructions account for the observation that the rate of GMSLR was not much larger during the last 50 years than during the twentieth century as a whole, despite the increasing anthropogenic forcing. Semiempirical methods for projecting GMSLR depend on the existence of a relationship between global climate change and the rate of GMSLR, but the implication of the authors’ closure of the budget is that such a relationship is weak or absent during the twentieth century.
http://dx.doi.org/10.1175/JCLI-D-12-00319.1
Abstract – 2011
It is essential that investigations continue to address why this worldwide-temperature increase has not produced acceleration of global sea level over the past 100 years, and indeed why global sea level has possibly decelerated for at least the last 80 years.
http://www.jcronline.org/doi/abs/10.2112/JCOASTRES-D-10-00157.1

So what are we to conclude?

Pamela Gray

Yep. Another example of magnified significance. Take a small but fine tuned segment of data and scale it so all the wriggles show up than wave hands wildly at the obvious significance of the dangerous rise (or fall, or whatever you imagine the dangerous wriggles are telling you). I echo others here. Stop comparing find grained data with historical WAG data.

Pamela Gray

oops…fine grain. Not find grain.

Jimbo

They keep trying on willing the rate of sea level rise to accelerate. They keep trying on willing Antarctica to go into thermal, spiral meltdown. Here is their latest effort in Antarctica.

Esa’s Cryosat mission detects continued West Antarctic ice loss
http://www.bbc.co.uk/news/science-environment-25328508

Yet Antarctica denies them to the East while extent stays stubbornly near record highs. Now here is a finding that has bearing on East Antarctica and sea levels for 2100.

Abstract – 7 June 2013
Recent snowfall anomalies in Dronning Maud Land, East Antarctica, in a historical and future climate perspective
Enhanced snowfall on the East Antarctic ice sheet is projected to significantly mitigate 21st century global sea level rise. In recent years (2009 and 2011), regionally extreme snowfall anomalies in Dronning Maud Land, in the Atlantic sector of East Antarctica, have been observed. It has been unclear, however, whether these anomalies can be ascribed to natural decadal variability, or whether they could signal the beginning of a long-term increase of snowfall. Here we use output of a regional atmospheric climate model, evaluated with available firn core records and gravimetry observations, and show that such episodes had not been seen previously in the satellite climate data era (1979). Comparisons with historical data that originate from firn cores, one with records extending back to the 18th century, confirm that accumulation anomalies of this scale have not occurred in the past ~60 years, although comparable anomalies are found further back in time. We examined several regional climate model projections, describing various warming scenarios into the 21st century. Anomalies with magnitudes similar to the recently observed ones were not present in the model output for the current climate, but were found increasingly probable toward the end of the 21st century.

Remember, the IPCC projects more snow for Antarctica towards the end of 2100.

Proud Denier

OK…Who else has had it with being told that you can look at a bunch of rocks and measure isotopes and calculate that sea level or temperature or whatever changed 0.000003 between the years of 1,004, 209 BCE and 1,004, 003 BCE? It’s bad enough that people sell these rotten apples, let alone proceeding to authoritatively compare them to the oranges of actual measurements taken over the last 30 years.

Christopher Hanley

The use of the phrase “since the industrial revolution”, presumably another term for the neologism ‘Anthropocene’, exposes the circular reasoning that inevitably bedevils climate change™ research.

kwinterkorn

Given the dramatic changes in sea level moment to moment (waves), hour to hour tides, and month to month (seasons, currents, winds, eg ENSO) measurement thought to be accurate to the mm seem dubious at best. I would think every statement on this subject should include error bars referring to the uncertainties of measurement and of the arithmetic chosen to average out the ongoing changing position of any point of the sea surface.
And reference also must be made to the reference point, given that the land rises and falls as well.
Perhaps satellites can be as accurate as claimed, but maybe there are problems with their measuring systems that limit mm-level resolution as well.
Any experts out there on this?

Jimbo

Opps. The last sentence was my comment and not meant to be indented. Here is the link:
http://onlinelibrary.wiley.com/doi/10.1002/grl.50559/abstract;jsessionid=5529DEBFBF5E41AC06765B65861C8492.f04t04

I believe the explanation for not seeing it now but seeing it later in other skeers was that it was inappropriate to assume a linear SLR because the rise would be exponential. Therefore you wouldn’t notice it now but you would be treading water by 2100 if you live on the coast. I don’t recall how they handled melting a kilometer or so depth of ice in places where the sun shine is limited and temperatures are usually below freezing other than handwaving at black soot and increasing global temperatures.
This seems to be one in a continuing series SLR scare stories.

Schrodinger's Cat

This is a suggestion/appeal to Anthony that I think fits with (some of) the subject of this post.
I met with a group of old colleagues for a few beers last night. All are retired scientists from industry and some I hadn’t seen for 20 years. When I mentioned I was sceptical about climate change, they regarded me with incredulity and amusement. I obviously didn’t realise that the Arctic ice was melting, sea temperatures were rising, sea levels were rising. The gulf stream had changed course – one of the others corrected this to the jet stream. Global warming was happening…
Reducing fossil fuel usage was obviously good, so was reducing the carbon footprint, … They had an understandable and sensible view of climate change as portrayed by the media.
I had lots to say, about the Antarctic and the pause, and though I tried to explain all the sceptical points, the conversation had moved on. I felt that I had missed an opportunity to communicate the sceptical case.
Realising that setting the record straight is at the heart of this site, I wonder if this could be the subject of a future post. A sort of question and answer format that addresses commonly contested issues would be good. I realise that this is not new, but it always needs updating and I’m sure even regulars at this site will benefit from some up to date advice.
I must admit that I have been living in a sceptical bubble involving the best sceptical sites and was a bit shocked when I realised that all my old friends were totally convinced by popular propaganda from the BBC and MSM. WUWT would be doing a great service if it provides a “service pack for sceptics to convince believers in a window of opportunity of 15 minutes”.
Now there is a challenge.
(I wouldn’t put this to a sceptical site that wasn’t scrupulously fair with the data.)
[Reply: this request should be posted in Tips & Notes. ~mod]

Jimbo

Even IF they showed that sea level rise is accelerating (which they have so far failed to do) who says it has anything to do with global warming? More people in the world means a greater demand for fresh water. And how do some people get at that water? Do farmers irrigate their fields? Do bears sh###$$ in the woods?
Groundwater abstraction is about “one fourth of the current rate of sea level rise of 3.3 mm per year.”
Here is the paper’s abstract

Neville

Just to back up the SLR problems for the alarmists here are the ALL MODELS graphs AGAIN as used by the IPCC. This is from the Royal Society.
This accounts for about 99% of the planet’s ice, 89% in Antarctica and 10% in Greenland. Antarctica is negative until 2300 and Greenland is positive.
So where is all this future SLR to come from? Yes perhaps some thermal expansion and the 1% from melting mountain glaciers.
But the problem is the much bigger Antarctica ( 89%) will be storing more ice for centuries to come and act as a decelerator for future SLR.

Neville

Sorry here’s that link to the RS all models graphs.
http://rsta.royalsocietypublishing.org/content/364/1844/1709/F4.large.jpg

R Babcock

When the water gets over my dock on the Chesapeake, I’ll start to worry.

Bill Illis

The full paper is now available at Nature. (I believe it costs quite a bit to make these open access).
http://www.nature.com/srep/2013/131212/srep03461/full/srep03461.html

rgbatduke

I have to learn to keep my coffee cup out of reach when reading your comments. The cost in coffee and ruined key boards is starting to mount. In this case, I had just done cleaning up from that quip when I encountered the flying pigs quip and had to start all over again.
Your keyboard has my apologies. I have to ask, though, why you are drinking coffee while working at a keyboard. It is well known that beer cleans off of keyboards much better, and is less likely to cause permanent damage to its internal circuitry. It also makes it a lot easier to read badly written science fiction, which is an essential skill if one is following WUWT (in both directions;-).
Just more of the “sea level rise is accelerating” nonsense. If you look at the the record, sea level rise has a long term average of 3-4mm per year. So for the level to increase another 80cm by 2100 the average rate of increase would have to double or triple over the next 84 years. Then it would have to triple again to hit their 2.5 meter increase by 2200.
Sorry, could you give any sort of backing to this statement? I mean, I sort-of-agree (and said much the same thing) but when I visit my favorite readily-available SLR link:
http://en.wikipedia.org/wiki/Current_sea_level_rise
and
http://en.wikipedia.org/wiki/File:Trends_in_global_average_absolute_sea_level,_1870-2008_%28US_EPA%29.png
To be specific, total SLR from 1870 to the present is just under 9 inches (inches, Jeeze, why not use barleycorns instead?) Following a tedious conversion to metric and division, that is an average of 1.6 mm/year. The peak rate in this entire graph (unsurprisingly) came in the late 1930s following the dust bowl — the 1930’s by strange chance was the decade when almost exactly 1/2 of the state high temperature records were set and, I suspect, the actual Global Average Surface Temperature (if we were ever able to accurately and retroactively measure it) was actually higher than it is at the present, regardless of what the heavily adjusted “anomaly” from the unknown absolute average temperature might be.
There is at least some evidence to support this, BTW. Arctic ice reportedly disappeared over roughly this same time frame, much as it did over the last decade. The clustering of state high temperature records. The great dust bowl itself, which was indeed a catastrophic climate event although not one that anyone can tie to CO_2. This is all the more surprising since high temperature records don’t correct for the UHI effect which alone should cause more high temperature records in the present and since we sample so many more locations at the present (making it even likelier still that the 30’s temperature records should have been broken long ago if the current temperature was in fact higher).
But either way, you’re off by over a factor of 2 in your assertions of SLR rates. They are 1-3 mm/year over most of the tide-gauge record, average of 1.6, and they show a strong correlation to the 50-60 year cycle visible in GASTA as well (possibly linked to the PDO). You can’t quite fit a linear trend and single sine wave to it though, probably because the SLR rate lagged the initial temperature rise at the end of the LIA by 30-40 years.
rgb
rgb

rgbatduke said @ December 12, 2013 at 12:08 pm

Basing physics-free multiply-conditional papers asserting that we are going to have all sorts of SLR that is going to start any decade now because the GCMs say so is a waste of time unless and until the GCMs start exhibiting any predictive skill at all!

Not to mention also a waste of money that could have been used for some useful purpose!

Went up the Maine coast last week end. We walked down to the Atlantic & marvelled at the ocean (& stepped in, & boy was it cold!). The next day we walked down & there was a good 40ft (12192mm) of shingle beach exposed that hadn’t been the day before. The water was obviously 5 or 6ft (1524 to 1828.8mm) lower than it had been the day before. According to my calculations you should be able to drive a 1968 Holden from Providence, RI to Scunthorpe, N. Lincolnshire (though you’re going to have to jog way north to Greenland to stay out of the water, I’d guess) by sometime mid-June 2014, if the current sea-level fall continues, right?

Richard

Bloke down the pub,
City of Troy, when it was actually a thriving city the sea was pretty much at the city walls, now the sea is a couple of kilometres away.

Richard

Though to be fair to alarmism the Thames barrier was built to stop the increase flooding.

Jimbo

Schrodinger’s Cat says:
December 12, 2013 at 1:00 pm
This is a suggestion/appeal to Anthony that I think fits with (some of) the subject of this post.

While at the Guardian some time back I was astonished at the number of people who said that co2 was the most important greenhouse gas. I referenced them to the IPCC which said water vapour. Many keep saying that sea levels are rising, I suspect they think sea level has been stable during the Holocene and only started rising in the last 30 odd years. Many believe in runaway warming even though the IPCC says this is not supported in the literature and so on. I second your suggestion: it’s time for the LOW DOWN PAGE.

80 cm by 2100 is ~9.3mm a year. last few decades is 3.3 mm a year or is it 3.1mm a year? No matter. The rate would have to be about 3X what is observed to meet that forecast. Perhaps they used a model. Heidi Klum would be my choice. For now.

1sky1

rgb:
Indeed, the most credible empirical estimates of the long-term rate of SLR are below 2mm/yr and what we have here is physics-free projections inexplicably predicated upon future rates several times higher. Your suspicion that GAST in the 1930s was actually higher than today, however, is likewise lacking in solid observational basis. As best as can be determined from available non-urban station records world-wide (which I’ve been gathering, vetting and updating scrupulously since the 1970s) GAST actually peaked somewhat earlier in the 20th century at a level ~0.2K below that experienced during the 1997-98 El Nino. It’s In the contiguous USA that the average peaked in 1934 at a level effectively indistinguishable from that seen in 2012.

Gary Hladik

rgbatduke says (December 12, 2013 at 12:08 pm): [snip]
RGB, the Babe Ruth of WUWT!

Rhoda R

This was compared with historical tide-gauge and satellite observations of sea-level change for the ‘global warming’ period, since the industrial revolution.”
Last time I checked, the Industrial Revolution began in the late 1700s to early 1800s; ie. early Little Ice Age. Talk about moving goal posts.

rgbatduke

Indeed, the most credible empirical estimates of the long-term rate of SLR are below 2mm/yr and what we have here is physics-free projections inexplicably predicated upon future rates several times higher. Your suspicion that GAST in the 1930s was actually higher than today, however, is likewise lacking in solid observational basis. As best as can be determined from available non-urban station records world-wide (which I’ve been gathering, vetting and updating scrupulously since the 1970s) GAST actually peaked somewhat earlier in the 20th century at a level ~0.2K below that experienced during the 1997-98 El Nino. It’s In the contiguous USA that the average peaked in 1934 at a level effectively indistinguishable from that seen in 2012.
That is very interesting. Do you have this published?
rgb

ROM

It seems the satellite guys might have a different view on the rate of sea level rise compared to the sea level experts;
From NASA’s GRASP mission conference 2011 [ Geodetic Reference Antenna in Space ]
http://www.gps.gov/governance/advisory/meetings/2011-06/bar-sever.pdf
From Frame 4 of this presentation;
[quote]
Impact of TRF on GMSL Record from Tide Gauges: competing approaches for TRF
realization yield estimates for sea-level rise ranging from 1.2 to 1.6 mm/yr.
[ TRF= Terrestrial Frame of Reference ]
[ GMSL = Global Mean Sea Level ]
Also a paper win which a table of sea level data points are included;
Global sea-level rise and its relation to the terrestrial reference frame
http://sas2.elte.hu/tg/msc_gravi/collilieux_sealeverise.pdf
For those who would like to have a look at the global tide gauge data for locations around the Earth;
PMSL / Permanent Service for Mean Sea Level
http://www.psmsl.org/data/obtaining/
To find the sea level tide gauge data for a location in the tables just click through the “ID” numbers.
The locations of the tide gauges are grouped into their national groupings which then run meridionally from a start in Iceland and Europe, eastward into the Pacific and America’s.

rgbatduke

Last time I checked, the Industrial Revolution began in the late 1700s to early 1800s; ie. early Little Ice Age. Talk about moving goal posts.
Especially when there was no significant CO_2 increase until the middle of the 20th century, especially not on a log scale. Of course there still hasn’t been a significant increase on a scale of decibels, which is likely the relevant one — around 1 dB over the entire industrial era.
rgb

Clinton

Is land reclamation factored into sea level rises?
There are many projects around the world reclaiming land/forming new land

Seems odd to be fussing about an ill-understood event or trend which started in the late 1700s and seemed to slow after the 1860s. Here in Australia you can get for free any amount of alarm over sea level rise, but you couldn’t buy an actual, discernible sea level rise. I’m sure somebody can find a shack on a sand spit between swamps which has sunk, but otherwise…
Maybe it’s cheaper to blame erosion on CO2 than to pay more attention to tedious coastal maintenance and regulation. No doubt the clever New Yorkers who dumped all that rubble into the Hudson mouth to make more low lying real estate in a notorious hurricane belt would love to change the subject from local responsibilities to coal mines in Queensland or factories in Poland.