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What's up with this?

There is much excitement among the green fraternity this morning over a new paper that claims to have found an acceleration in sea-level rise that is even more dramatic than previously thought.

Stop yawning at the back there.

As usual, a brief perusal beyond the headlines reveals a considerably more nuanced story. The paper is based on tide gauge records and finds a slow increase over the 20th century of just over 1mm/year. This is rather less than some previous estimates.

However, the authors go on to say that:

Our analysis, which combines tide gauge records with physics-based and model-derived geometries of the various contributing signals, also indicates that GMSL rose at a rate of 3.0 ± 0.7 millimetres per year between 1993 and 2010, consistent with prior estimates from tide gauge records4. The increase in rate relative to the 1901–90 trend is accordingly larger than previously thought; this revision may affect some projections11 of future sea-level rise.

I'm a bit bemused by this. Why would they use a different methodology for 1993-2010 to the one they used for 1901-90? Why would they want to combine data with "physics based and model-derived geometries"? Do the tide guages show any acceleration or not?

Perhaps the text of the paper will explain if someone can send it over or leave a comment.

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Reader Comments (64)

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Jan 15, 2015 at 10:38 AM | Unregistered Commenterkim

More alarmist nonsense from two juvenile researchers, trying to make a name for themselves with another man-made hockey stick, a la Mann.

Jan 15, 2015 at 10:42 AM | Registered CommenterPhillip Bratby

This technique has great power for the development of narrative. Tacking model output onto observational series can be made to show anything, well, anything only limited by the human power of imagination.

This is analogous with tacking observations on at the end of proxy series, and is fraught with even more corrupting power.

Jan 15, 2015 at 10:42 AM | Unregistered Commenterkim

Over and over again, lately, Phillip, I've noticed that an alarmist paper comes out to fill some need in the ongoing narrative of catastrophism, and over and over again, lately, the paper is blown up in days if not hours.

A hallmark of the dying march of a false narrative.

Catastrophism, what a catastrophe.

Jan 15, 2015 at 10:46 AM | Unregistered Commenterkim

This is pretty much what alarmists have been reduced to; scaremongering and speculating about, followed by the inevitable revision of, historical trends.

It's padding, treading water, running to stand still.

They don't have rising temperatures.They don't have runaway warming. They don't have collapsing polar ice and they don't have validated models. In fact, until actual temperatures start increasing to a statistically significant extent they really don't have very much at all apart from a multi-faceted bogey man. Hence the frantic end-of-the-world-is-nigh arm-waving.

Jan 15, 2015 at 10:46 AM | Unregistered Commentercheshirered

Could be that the physics based stuff does a bugger-all job at fitting data from 1901-1990 and gives about 3 mm for that period too.

Jan 15, 2015 at 10:47 AM | Unregistered CommenterDEEBEE

New paper finds that climatologists are stupider than previously thought.

Jan 15, 2015 at 10:47 AM | Unregistered CommenterMikeB

This has also been picked up at WUWT.

Jan 15, 2015 at 11:00 AM | Registered Commenterperry

Gauges not guages please ! [Done! Just spotted it myself]
Sorry to nit-pick. Keep up the great work.

Jan 15, 2015 at 11:03 AM | Unregistered CommenterGillespie Robertson

I was just going to enquire what had happened to the three years between 1990 and 1993. Infilled as well.

Jan 15, 2015 at 11:07 AM | Unregistered CommenterMessenger

"Stop yawning at the back there"

Your Grace, we are amused.

Jan 15, 2015 at 11:08 AM | Unregistered CommentersHx

I assume this was reviewed by Clacton pier before publication.

The moment they mentioned models you know the conclusions don't add up and the real data doesn't fit the story.

Jan 15, 2015 at 11:09 AM | Unregistered Commenterivan


No, I don't understand the 3-year gap either. I can't see an explanation in the text.

Jan 15, 2015 at 11:14 AM | Registered CommenterBishop Hill

I think Jo Nova is discussing the same paper. I've just copied this from her site:

"... the tide-gauges don’t show any acceleration, and nor did the raw recordings from satellites. The 3mm rising sea claims apparently come from satellites that were calibrated to one subsiding tide gauge in Hong Kong.

It’s cherry picking par excellence. We might finally accept tide gauges up to 1990, but after that the tide gauges don’t count — bring in the “adjusted” satellites. "

Jan 15, 2015 at 11:24 AM | Unregistered CommenterSchrodinger's Cat

Take them back to Tulsa, they're too young to bake a pie.

Jan 15, 2015 at 11:33 AM | Unregistered Commenterkim

Hasn't there been a pause in the acceleration since 1990 on their data? Are they arguing that sea level rise will resurge from the deep oceans and reach 6mm/a?

Jan 15, 2015 at 11:40 AM | Unregistered CommenterIt doesn't add up...

Are these rather alarmist papers ever corroborated by other independent studies?

Jan 15, 2015 at 11:40 AM | Unregistered CommenterPeter Stroud

Nils Axel Morner stated that the average sea-level rise over the last century was 2.3mm/year. 3mm - 0.7 = 2.3mm/year! Am I missing something?

Jan 15, 2015 at 11:44 AM | Unregistered CommenterAlan the Brit

A while back I had a look at the Newlyn tide data and calculated a long term trend of about 0.15mm per month and 1.8mm per year for the whole period from 1915-2013. That rate does increase to 0.37mm per month or 4.5mm per year. OMG. But I then calculated the deviation from a rising trend of .15mm per month and plotted the result. This gave a trend of zero. There were clearly periods where sea level rise exceeded the average and others where they fell below. The early 90s was one of the dips. It's worth remembering the Newlyn is also sinking. What effect ocean phase has on all this I don't know but clearly start and stop dates of any trend make a big difference.

Jan 15, 2015 at 11:46 AM | Unregistered CommenterTinyCO2

The paper is a classic case of 'effective but crap' in other words its actual science is poor, little better than speculation , but has its being pushed has unquestionable truth by the media , the BBC and the Guardian leading the charge .Its certainly been positive for the researchers own futures .

Unfortunately the self correcting mechanisms that in other areas of science would cut to ensure that poor science has bigger baring then good headlines simply does not exist for this most special of 'sciences' . Indeed within climate 'science' poor science can be and is reward if its 'effective '

Jan 15, 2015 at 11:46 AM | Unregistered CommenterKnR

It's amazing, isn't it?

All sorts of studies by experts in the field, incl Bruce Douglas, and Church & White have over the years come to similar conclusions - that sea levels rose by around 6 to 8 inches during the 20thC.

Now, all of a sudden, this work is just cast aside (and not actually disproven, I note) in favour of some model based nonsense.

Would this happen in any other field of science?

Jan 15, 2015 at 11:46 AM | Unregistered CommenterPaul Homewood

I think when considering miniscule changes, in the rate of sea level rise, we should remember the number of stones thrown into the sea, by climatologists, with nothing better to do.

Jan 15, 2015 at 11:47 AM | Unregistered CommenterGolf Charlie

A reminder of recent sea level trends via the satellite record:

The rate of increase appears to be decellerating.

Jan 15, 2015 at 11:58 AM | Unregistered CommenterIt doesn't add up...

It's the usual climate activist BS that we've come to expect from Nature. The measurements painstakingly taken over the last century don't match our theory, so they must be wrong, and need to be adjusted by a "reanalysis" using computer models.
The abstract claims that they "revisit estimates of twentieth-century GMSL rise using probabilistic techniques".
Here's what they really do, buried in the detail of the methods section, under the misleading heading of 'Karman smoother'

The KS methodology is divided into four steps, the first three of which are repeated by employing the spatial fields of GIA and ocean dynamic models from all possible combinations of 161 different Earth rheological models and 6 global climate model (GCM) simulations from CMIP5...

Also in Nature is the more interesting editorial Ocean 'calamities' oversold, say researchers, saying that disasters such as coral reef die-offs are not observation-based, and scientists have not been sufficiently sceptical, and that some of the blame lies with journals like Nature! Though this is a report from another journal, and apparently Nature editor Philip Campbell disagrees (he would say that wouldn't he).

Jan 15, 2015 at 11:59 AM | Registered CommenterPaul Matthews

It's called progressive enlightend liberalism, or political propaganda to promote their policies.

Jan 15, 2015 at 12:02 PM | Unregistered CommenterSanta Baby

As was pointed out by Stephen Fry on QI during the 10th series, they like to include many nice new research facts from peer-reviewed literature in the program to surpise and confuse the panel.

But after 10 years, the programs researchers revisited the first series and found the 5 out of 6 of the new "facts" had since been shown to be wrong in subsequent published research.

And that's for all research - imagine what proportion for just CAGW would be?

Jan 15, 2015 at 12:09 PM | Unregistered Commentersteveta_uk

It was all planned by the Club of Rome and we are seeing the continuing nonsense

Jan 15, 2015 at 12:26 PM | Unregistered Commenterferdinand

The rate of change of sea-level increase has now been changed.

Richard Nixon was briefly famous for using a third-derivative when he stated that "the rate of increase of inflation is now now falling". He came to a sticky end.

Jan 15, 2015 at 12:27 PM | Unregistered Commentermichael hart

It's the same with global temperature trends. When the recent increases fail to give the required trend, then they have to go back in the records and reduce past readings.Fewer people are likely to notice if you say sea level was a foot lower thirty years ago, than if you claim it rose an inch last year.

Jan 15, 2015 at 12:32 PM | Unregistered CommenterBloke down the pub


Jan 15, 2015 at 12:32 PM | Unregistered CommenterMars Shmallow

As I commented on Unthreaded yesterday evening, it is odd that the alleged sudden acceleration in sea level rise from 1990 to present doesn't show up in individual tidal gauge station data - e.g Honalulu which does not have any tectonic complications:

NOAA, Mean Sea Level Trend 1612340 Honolulu, Hawaii

On EM's recent 'sea level is a threat to civilisation' debate thread, to make the point that you can't trust the satellite data (from which the alarmists derive their 3.2mm rise pa), I spent an hour or so looking at random tide gauges - and found only came across only one station with a rise of over 3mm per year (Aden, Yemen, at 3.02mm +/- 0.22 mm/yr) e.g.:

Aberdeen 0.72 millimeters/year -

Chile -0.80 millimeters/year -

Denmark - 130-081 Aarhus, 0.63 millimeters/year -

220-011 Algeciras, Spain, 0.43 millimeters/year -

9455920 Anchorage, Alaska, -0.75 millimeters/year -

9439040 Astoria, Oregon, -0.34 millimeters/year -

290-065 Alexandroupolis, Greece, 1.78 millimeters/year

485-001 Aden, Yemen, 3.02 millimeters/year with a 95% confidence interval of +/- 0.22 mm/yr

Argentine Islands, Antarctica, 1.43 millimeters/year with a 95% confidence
interval of +/- 0.45 mm/yr -

The gauge at Battery (New York), also confirms no change in rate since 1950: NOAA, Mean Sea Level Trend, 8518750 The Battery, New York, (and NY is apparently sinking at 1.26mm pa.)

Gauges in the southern hemisphere also show that that there has been no increase in the rate of sea-level rise in recent years, e.g. Dr. Sebastian Lüning and Prof. Fritz Vahrenholt recent review of tide station data which concluded no acceleration in rise since 1940. (ave. 1.6mm/yr) in North Atlantic). New Zealand, Arctic, Australia, Pacific.

Using satellites 200 miles up which pass over a fluid surface subject to tides of up to 7m and waves up to 20m high, at 20,000mph? Give me a post stuck in concrete or a solid harbour wall any day. John Daly said all this many moons ago.

Jan 15, 2015 at 12:33 PM | Registered Commenterlapogus

The idea there is a single rate of sea level rise around the world is rubbish.
Even the idea of using linear trend to establish SLR is questionable given there are cycles of about 60 years and also the odd volcano (Pinatubo) which cause see levels to fall.

I have fitted a linear trend to every tide gauge record held by, around 1/3 show falling sea levels.

Sea level rise (or fall) can happen very quickly, for example Myake Sima, Japan where levels increased about 1/2 metre around 2000 following a volcano eruption.

More gory details

Jan 15, 2015 at 12:37 PM | Unregistered CommenterJeremy Shiers

Calamity Jam.

Jan 15, 2015 at 12:43 PM | Unregistered Commenterkim

Hide the design
Calamity jam,
Climate science,
That's what I am.

Jan 15, 2015 at 12:45 PM | Unregistered Commenterkim

Tidal guages are not discriminating, they take no acount of ground movement. Gravity has a lot to do with tide movement and this has been ignored. the Indian Ocean is some 140m lower than the Pacific purly due to gravity changes over the earth's surface.

Jan 15, 2015 at 12:50 PM | Unregistered CommenterJohn Marshall

Which bit of coastline would be best for the downhill water skiing speed record?

Jan 15, 2015 at 1:02 PM | Unregistered CommenterGolf Charlie

That's Slartibartfast's bailiwick, Golf Charlie ye be.

Jan 15, 2015 at 1:06 PM | Unregistered Commenterkim

Look, folks - it really doesn'y matter what 'it' is - sea level; polar ice; number of storms/hurricanes/droughts; diameter of squirrel sh*t - you know that the alarmists' stance is going to be: 'Its worse than we thought....'

By the way - 'physics based and model-derived geometries...' - what the hell are they when they're at home..? Not actual readings, that's for sure....

Jan 15, 2015 at 1:14 PM | Unregistered Commentersherlock1

Kim: Tide and dime wait for no man.

Jan 15, 2015 at 1:24 PM | Unregistered CommenterHarry Passfield

The mysterious kim
Whose comments are slim
And crafted to cryptic perfection
Has produced what I am
Sure is, in 'calamity jam',
A mighty insightful conception

Jan 15, 2015 at 1:29 PM | Registered CommenterJohn Shade reality slr is not increasing. But the climate obsessed are desperate for new constructs to hide behind.

Jan 15, 2015 at 1:40 PM | Unregistered Commenterhunter

"The science is settled."

"It is worse then we thought."

The amount of cognitive dissonance that you need to sustain to be a climate scientist is truly staggering. Surely, if the science is actually settled then it must be exactly as bad as we thought? No more and no less.

This paper uses models to help with estimating the sea level. I seem to recall that Trenberth found his missing heat in the oceans only after he had used a model to help him process the original data.

I sense opportunities for some circular reasoning here.

Jan 15, 2015 at 2:31 PM | Unregistered Commentergraphicconception

If the sea level rise keeps accelerating like this I'll have to buy a bigger yacht because the sea will start slopping in over the side of the old one.

Jan 15, 2015 at 2:45 PM | Unregistered Commenterivor ward

Andrew wrote:

There is much excitement among the green fraternity

Ahem..............may I suggest - "green sorority"?

Jan 15, 2015 at 2:50 PM | Unregistered CommenterAthelstan.

For a good study of the influence of data quality, and analysis of all the factors influencing the concept of "sea level rise", there's a paper by Van Onselen, split into two parts, here:

My feeling: if anyone would know about sea levels, it would be the Dutch (or Netherlanders, to avoid offence)

Jan 15, 2015 at 2:56 PM | Unregistered CommenterSensorman

Here is a nice discussion of the National datums. At the Battery NY,NY the change from the '29 Datum to '88 was about 0.78 ft + Not clear that the tidal benches are on rock. Or that the rock is not moving.

Jan 15, 2015 at 3:52 PM | Unregistered CommenterATMJ

It's the same issue as with the temperature records. There simply is no practical datum against which to measure changes of millimetres in global sea level. It is changing relative to what? No landmass surface is that stable.

They are certainly measuring something, but who the hell can know what it is? Problem is the concept of datums and relative movement is something the general public subjected to the barrage of greenwash don't generally have the ability to parse.

Couple that with the clear preference to analyse the data in such a way as to identify an increase which guarantees a seat on the Green Gravy Train...

Jan 15, 2015 at 4:31 PM | Unregistered CommenterNW

British Geological Survey detected the explosion on the Submarine Kursk and underground Nuclear testing in North Korea

Rising Sea levels pull the records for Under Sea Earthquakes

If the Sea Floor is moving up and down the Sea Level must be moving with it.

Jan 15, 2015 at 4:32 PM | Unregistered Commenterjamspid

Kim, I think Slartibartfast would be most disappointed with the effects of plate tectonics, on his award winning coastline designs (particularly the Norwegian fjords).

Closer to home, we have some of the Kent ports, and of course Harlech Castle, where the sea level does appear to have retreated, in complete denial of the existence of computer models, which clearly state the opposite. No wonder that Frankie and Benji Mouse were a bit tetchy with Arthur Dent.

Meanwhile, climatologists have to use creative writing techniques, to explain how The Earth, the galaxiy's biggest computer model, defied mankinds pathetic attempts to model it.

CliSciFi makes me smile!

Jan 15, 2015 at 4:35 PM | Unregistered CommenterGolf Charlie

Tore this apart at WUWT yesterday. No need to repeat details here. The paper is junk, regretably from Harvard.
The authors used a model they built for other purposes, fed it sparse sketchy early data (their own statement) to produce a model result that supposedly refutes a century of observational tide gauge data from around the world. Such as NOAA Historical SLR. It gets NYT and Guardian coverage the very next day, evidencing yet again media bias and
lack of quality control.

Jan 15, 2015 at 5:25 PM | Unregistered CommenterRud Istvan

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