New sea level page from University of Colorado now up

Interesting stuff. Wonder why they only plotted the three first weeks of January?
And this basin stuff is just unbelievable! Someday, they will be adding even more mm rise, for the water that is presently in dams, and should be at sea…
Ecotretas

Even though the actual sea level is what they purport to measure, they decide to add a small positive adjustment every year for the fact that some parts of the land are rising due to rebounding from the last ice age. Measurements are measurements where I come from, & if my local tide guage showed a rise of 2.7mm a year because the land is rising by 0.3mm, than that must be the true reading. Do they also adjust for the fact that any rising land areas are also increasing the sea-level rise in those areas which are not rising? I can’t see how this adjustement is anything other than an artifice to satisfy the CAGW believers.

The GIA seems irrelevant to me. As I understand it, sea level is measured in reference to land. If they were reporting on sea volume, then I could see making a case for that. At least they added the caveat that we can ignore the GIA if we want to.

“we have made many improvements to our data (new orbits, new tide model, new corrections)….”
Models are data now? Really?
How do you ‘improve’ data? Data is a recorded physical measurement of some characteristic. Any adjustment to the data, without retaining and disclosing the original data, invalidates it.
“you may notice that the rate of sea level rise is now 0.3 mm/year higher than earlier releases. This is a correction to account for the fact that the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land. ”
Aren’t these same global ocean basins also subject to siltation inflows from river deltas, wind blown dust from desert regions , volcanic eruptions and lava flows directly into the oceans, and even in-falling debris from space? Are these also factored into their ‘global ocean basin models’? All of these natural effects contribute to naturally rising sea levels by making the basins slightly smaller. They should be subtracted from the overall trend.

Aha! So the deepening of the basins is creating a 0.3mm increase? Or zero apparent increase is now actually 0.3mm/yr?
Whatta crock.

Isotasy to the rescue (of rising sea level)! It is now rising the thickness of an ink line faster than before because of….ice that already melted. A new tide model? Does that change how the Bay of Fundy’s tides work?
Regardless, at 31 mm/decade, it’s not rising like Some WTWT catastrophists would have us believe…so why do they keep screaming that it is?

“One important change in these releases is that we are now adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA), ”
How was this calculated given the extent of the glaciations, the total land mass and the area and volume of the oceans?
How was this 0.3 mm/year able to calculated and added to the overall calculation without affecting the prior uncertainty +/- 0.4 mm/year?
It does not seem possible to calculate the affect of isostatic rebound on the global average sea level to 0.3 mm/year with +/- 0.00 mm/year uncertainty.
I don’t buy it. It looks like they added a constant so that the rate did not change.
3.1 mm/year +/- 0.4 mm/year.
“Simply subtract 0.3 mm/year if you prefer to not include the GIA correction.”
It is not a ‘correction’ it is a Constant Value added to have the data match the previously specified trend line.
Does anyone believe that by co-incidence adding the ‘GIA correction’ results in Exactly the same 3.1 mm/year +/- 0.4 mm/year that we saw in 2010_rel4?
I don’t buy it, it smells bad.

One important change in these releases is that we are now adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA),
Translation: “We believe that the recent fall in sea level will decrease the apparent rate of rise by 0.3 mm/year, so we’ve adjusted this out.”

What’s all the fuss? If the ocean basins are getting larger due to GIA then there should be some adjustment so that the decadal/centennial data is self-consistent. And it’s not the fact that sea levels are rising that’s important, but rather the 2nd order differential – any acceleration or deceleration in the rate of rise – that’s crucial.
If it’s feasible to reverse out thermal expansion effects due to ENSO, PDO, AMO et al that’s even better – this will eventually give true self-consistent altimetry data on decadal/centennial timeframes so we can then see whether there is any substance at all in this CAGW scare.
The only really important issue is that all adjustments to the data are properly documented.

vaporware.

Welcome to the new webpages from the University of Colorado sea level group! We apologize for the delay in updating our sea level releases, but the transition to these new web pages took longer than we thought. In addition, we have made many improvements to our data (new orbits, new tide model, new corrections) which ultimately had little effect on global mean sea level, but brought us up to date with the latest advances in the field.
Yeah, right. Do they make adjustments for water extraction?

I notice that much of the Topex trace is below the line – then much of Jason 1 is above the line ?
Has anybody double checked their 2002 join Topex to Jason 1 ?

I just hate it when people tinker with long term data. This looks like hide the decline part 2.

I’ve made a small essay regarding the rate of rise:
http://ecotretas.blogspot.com/2011/05/rate-of-sea-level-rise-going-down.html
It’s going down and FAST! In my opinion, the data was stopped because in cycle 2010.7415 the trend was 2.956158611 mm/year, just enough to round it to 3.0
They have had these months to re-engineer the values so they are at least still bigger than 3.0 mm/year!
Ecotretas

Why don’t they give sea level relative to shorelines where it counts to us inhabitants? Maybe it’s that some are rising and some are lowering due to isostacy and drift and would mean an inconsistent mishmash of positive and negative numbers to average?

I imagine Mike Mann did some decentered PCA to calculate that adjustment for them… When the data is not behaving, they just call in a cleaner from AGW team headquarters.

So La Ninia’s cause a drop but El Ninio’s don’t contribute to the rise?

Why do they insist on adjusting empirical data. Sea level is sea level. If I put water into my swimming pool and measure that level on a regular basis, which I do, I don’t make adjustments for the movement of the walls due to weight of water or the descent of the whole pool relative to the surrounding soil. The level is what it is. The data is what it is. LEAVE THE BLàèDY DATA ALONE! It’s cheating. Nothing but cheating. What are the objectives behind sea level measurement? Is it to calculate the point at which we need to be build our houses further in land or on stilts? Is it to allow us to change the profiles of our ports to keep them open? or Is it to prove that the glaciers are melting and we need more funds.

Buzz Belleville says:
May 6, 2011 at 4:18 am
A 100% transparent adjustment based on legitimate observations and folks here are still complaining. It’s not like the Colorado folks are trying to slip one past you.
Just because it’s “transparent” doesn’t make it right!! Puuleeze!!

More hide the decline pseudo-science.
If this is supposed to be a record of sea level it should be showing sea level. It is not supposed to be a record of ocean volume. GIA is a fraud. This is no longer a measure of sea level but some other metric.
People, governments etc. are concerned about sea level as it relates to land. That is what all the alarmism about sinking atolls and flooded coastal plains is based on.
If we want to infer sea volume from sea level *then* there may be a need to apply some adjustment. At that point we need to look at where these adjustments come from. Let me guess… simplistic computer models.

Regarding the glacial adjustment, the glaciers were primarily on the land. The extra weight pushed down the land and the primarily non-glaciated ocean bottom would have increased slightly or bulged up in compensation.
Now that the glaciers are gone, the land is rising again and the ocean bottom is sinking back to its non-glacier position. There is also the weight of the extra water (which was formerly on land in glaciers) which is now in the ocean which is also pushing down on the ocean bottom.
The overall average depth of the oceans is sinking enough to lower sea level by 0.3 mms per year.
Since sea level is actually measured at increasing 2.7 mms/year, the actual volume change of the water in the oceans must be 3.0 mms/year.
Note that the sea level is actually only increasing by 2.7 mms/year.
(So I think it really shouldn’t count here. If you are going out 100 years and trying to say New York will be flooded by the ocean, you shouldn’t add in the Glacial Isostatic Adjustment because the sea level will not actually increase as a result of this adjustment).

“NOBODY expects the Glacial Isostatic Adjustment!
Our chief weapon is surprise…surprise and fear…fear and surprise….
Our two weapons are fear and surprise…and ruthless efficiency….
Our three weapons are fear, surprise, and ruthless efficiency…and an almost fanatical devotion to the Pope….
Our four…no… Amongst our weapons…. Amongst our weaponry…are such elements as fear, surprise…. I’ll come in again.”
With respect to Monty Python

We have gone completely bonkers. Our researchers have succumbed to the idea that every natural phenomenon must have human causes. They have even added sacrificial austerity and demands for tithe to the backs of peasants.
Turn the money changing table on its head and kick the tax man out of the courtyard. Else we will be forced to join the masses at this temple of research. Eisenhower had it right all along.

Buzz Belleville says:
May 6, 2011 at 5:32 am
You do understand, fellow posters, that the Colorado page is not just adding 0.3 mm to the current year to show a greater rise in sea levels. It’s adding o.3 mm to all plotted points. It has no effect on the rate of rise.
Buzz, per their website, the GIA adjustment was “-0.3 mm/yr. That’s per year.
The most recent ‘pre-adjusted’ data point for 2010.7415 was 28.119 mm.
This ‘post-adjusted’ data point for 2010.7415 is now 36.996 mm.
So you’re correct that they didn’t just add 0.3 mm to the current year, they added 8.877 mm to the most recent common data point
It does affect the rate of rise!

Hey Buzz.
One important change in these releases is that we are now adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA), so you may notice that the rate!!!!! of sea level rise is now 0.3 mm/year higher than earlier releases.

Buzz Belleville says:
May 6, 2011 at 5:32 am
“You do understand, fellow posters, that the Colorado page is not just adding 0.3 mm to the current year to show a greater rise in sea levels. It’s adding o.3 mm to all plotted points. It has no effect on the rate of rise..”
Buzz, I don’t believe you are correct. The website reads “One important change in these releases is that we are now adding a correction of 0.3 mm/year…”
This means they are adding 0.3 mm every year. Over a period of 10 years, they have added 3 mm. Over 100 years, they have added 30 mm. This does affect the rate of rise. There is nothing scientific about the adjustment. The only solution is to remove the adjustment as they suggest. My question is at what year did this new adjustment begin?

In the article, http://wattsupwiththat.com/2011/04/17/doing-it-yourself-the-latest-global-sea-level-data-from-jason-shows-a-sharp-downtick-and-downtrend/, RomanM had plotted a data point from the Jason-2 data set, showing the most recent measurement was at ~12mm from the 0 line. That data point does not show up on the UofColorado site.
Does anyone know what happened to that data point? Sure it was just one data point, and perhaps it was a spurious reading of some sort, but I’m curious what happened to it.

This is the funniest thing ever. La nina causes the oceans to not rise as much….Its like they look at data that does not follow what the believe/know about so they invent some fairy tale to explain it.
I can see it now, they are all gathered in the lounge and are discussing this. One of the interns pipes up, what if its la nina?
It gets put down. Makes no sense, since la nina has never been shown to do this to sea levels in the past so directly, but why not? Its an explanation….which “is under further research”. Which means that the idea from the peanut gallery is going to be researched with the Government’s money. Of course all tax payer monies belong to the Gov. and are not ours to use….as goes the belief.
And for adjustments, if you are claiming to show the actual data, you DO NOT EVER adjust the data without a good reason to do so.
No case is made about how this changes or skews the data…so in the end the adjustment is spurious, un-needed and just simply put retarded.
Looks like the peanut gallery is alive and well at the University of Colorado with that same peanut gallery running the show.

The GIA model was turned upside down when new GPS data revealed that the ice/bedrock interface of the center of Greenland was sinking rather than rebounding.
This resulted in a 50% reduction from the previous estimation of the ice loss from Greenland. This means that the mass component of sea level rise would also need to be adjusted downward at a time when ARGO is revealing very little thermal expansion.
http://thegwpf.org/the-observatory/1438-ice-sheet-loss-cut-in-half.html
Since the previous estimates were based on gravity changes in time detected from the Grace satellite they must have come up with a crustal explanation due to plate tectonics to explain the gravity changes.
I wouldnt be suprised if they made the correction backwards as the new GIA means less mass component contribution. Gravity is very tricky.

Buzz Belleville says:

You do understand, fellow posters, that the Colorado page is not just adding 0.3 mm to the current year to show a greater rise in sea levels. It’s adding o.3 mm to all plotted points. It has no effect on the rate of rise.

Either Buzz is blinded by devotion or does not understand the relationship between rate and position. 0.3 mm/year is a rate of change, NOT an offset as he asserts. Ergo, at some unspecified point on the horizontal axis they decided was the zero of the GIA. Since it is “mm per year“, it is a slope adjustment (i.e., cumulative), not an offset adjustment.
Thus, the sea level point on the graph is 1mm (0.9mm, technically) higher in 2007 than 2004, and the 2011 level is 3mm higher than 2001 purely due to GIA and no other factors. Thus, the actual sea level rise since 1998 is 3.9mm less than graphed, i.e. less than 30mm or 3cm or less than 1.2 inches. For the duration of the graph, it totals 5.1mm in adjustment. Again, who knows what point in time they decided was zero GIA…
(There are some folk who just don’t deserve to live in CO. I’m proud to have RPS & Drs. Gray & Klotzbach, however.)

The rebound adjustment is ridiculous. It is the relatvie change in height of the ocean with respect to land that is important. If oceans were increasing at 50 meters a year, as long as “land” height was aslo increasing at 50 meters per year, you would see no effect at the beach because the net difference is ZERO. In fact, I would maintain that tide gauges are the “Best” measurement for determining relative sea level rise. Expressed another way, if ocean levels are falling at 5mm per year but the land happens to be falling at 1 meter per year, I’d say you should start taking actions to mitigate flooding but the experts based on their logic would be saying just the opposite.

A G Foster says:
May 6, 2011 at 7:44 am
Are you Tamino?

CU must show the data without a hypothesized GIA correction.
Make another graph with the GIA included.
Then TRY to explain the difference. Everyday to everybody.
When CU gets tired of explaining and defending a GIA that is not hidden from view, they’ll decide to deep six it.
This is the Urban Heat Island effect come to sea-level data.

from the original article:
“You may also note that rate of sea level rise over recent years has been less than the long-term average. This is believed to be due to the recent La Nina’s we have been experiencing”
uh, so the previously steep level of rise on the left side of the graph was due to all those El Nino phases we were having then, and now we’re starting to average back out and see the true trend? You can’t just dismiss negative noise without also dismissing the positive noise, can you?

AG Foster,
Your gist of your comment was both accurate and pointless. It seems your intent was to defend the 0.3 mm/ year adjustment, but nothing you wrote came close to defending this indefensible adjustment. It was just more of the same “They’re scientists! You can trust them!” There are a lot of scientists here, Foster. And we call BS.

richcar, FYI if you are not familiar with it, please check the important work by Peltier from Uof T on the subject of glacio isostatic rebound.

Mike Jonas says:
May 6, 2011 at 12:59 am
By my calcs, the overall trend in the new data is less than in the old data, even though they say they have added 0.3mm p.a.
Also, there is a clear downturn in the data in recent years. They say “La Ninas”, I say PDO cooling phase.

Dr. Peter Bromirski of Scipps Institution of Oceanography asserts that if it does turn to a cooling phase it will increase the rate of sea level rise (more of everything proves global warming).

Global sea level rose during the 20th century at a rate of about two millimeters (.08 inches) per year. That rate increased by 50% during the 1990s to a global rate of three millimeters (.12 inches) per year, an uptick frequently linked to global warming. Meanwhile, sea level along the U.S. west coast did not experience the same amount of rise as that seen globally.
…
When the PDO cycle shifts to its cold phase, coastal ocean waters will experience what these scientists call a downwelling regime; that is, the amount of colder, denser water currently brought to the surface will be reduced. The water at the ocean surface will, thus, be warmer, and this warmer surface water is expected to raise sea level.
[Bromirski] suggests that conditions of the past several decades, which were dominated by cold surface waters along the U.S. west coast, could soon flip into an opposite state.

I’m not sure what PDO phase charts he’s working with my all the ones I’ve seen clearly indicate the PDO has definitely shifted into a cooling phase. I guess he’ll need some more grants to be certain.
Article here: http://earthsky.org/earth/will-sea-level-begin-rising-more-rapidly-along-u-s-west-coast

Jason F says:
May 5, 2011 at 11:40 pm
they always correct upwards don’t they
You mean center the deviations? Only actual scientists do such things, this is climatology.

A G Foster says:
May 6, 2011 at 9:26 am
Re. Ron Cram at 8:42.
“But no one here has attacked the adjustment on any scientific basis whatever.”
Not true. Qualitative arguments have been put forward here, including the neglect of silt. When researchers only look to make adjustments in one direction, they lose credibility.
In this comment you make a qualitative argument the the adjustment may be reasonable. This is not the same as making a scientific case for the adjustment. It would be far more reasonable to increase the uncertainty range (even if it was increased only on one side) because you have identified a source of uncertainty.
An adjustment of 0.3 mm/ year in a straight line is not physical. Nature does not operate in a straight line. The adjustment has an appearance of being goal-oriented. It is not scientific and should be condemned by all scientists.

to wayne and Jason F:
“they always correct upwards don’t they
You mean center the deviations? Only actual scientists do such things, this is climatology”
Yeah, when you give one guy unilateral control over an official source and he can make any change he wants without having to subject what he does to any kind of peer review you can do all kinds of neat little “tricks to hide a decline”. Hmmm, and they think better communication will make people trust them more? Right.

Is it sea level that is measured or sea volume?
Sea level is relative to the ground around. So there is no value in adding the constant.
For sea volume they need to make a proper analysis, again the constant is just addressing a small part of the sea volume question – so adding it adds no value to the result.
As DirkH said in some previous posting:
“May 4, 2011 at 2:58 pm
If current trends continue, dishonesty in science will have wrecked the reputation of *ALL* scientific fields by summer 2015. /sarc”

Bruce has some interesting data there. If the trend suddenly changed, there is something seriously wrong with the “new and improved” corrections…
That something wrong is adjustments that instead of showing reality show someone’s belief. Science and belief should be seperated for obvious reasons…this data used to be something to take to the bank with, but I am no longer so sure anymore.

I would like to see comparative data on the number adjustments, up vs down, to various climate related data.
My guess is, the ‘ups’ have it.

I am not sure if you know . . . . but this is my contribution to the subject . . .
“Dyke Swarms: Keys for Geodynamic Interpretation”
http://www.springer.com/earth+sciences+and+geography/geophysics/book/978-3-642-12495-2?cm_mmc=NBA-_-May-11_WEST_7952377-_-product-_-978-3-642-12495-2
at the end of the page you will see some other articles that may be of interest to some . . .
like:
“Geochemical and Petrological Characteristics of Mesozoic Dykes from Schirmacher Oasis (East Antarctica)”
and others . . . .

I grabbed a copy of the msl_ib_ns.txt (inv barometer, seasonal adjusted) a couple of weeks ago when Anthony first posted the delayed update issue.
Now plotting its differential with that of the current dataset , they are clearly different data but have the same trend (within a knat’s cock).
It appears the “old” data had already been pre-adjusted for GIA at that stage.
Could anyone with a pre-adjustment copy pastebin it somewhere and post a link?

One important change in these releases is that we are now adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA), so you may notice that the rate of sea level rise is now 0.3 mm/year higher than earlier releases. This is a correction to account for the fact that the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land.

If the above statement [bold] is referring to geological plate subduction [and it is not clear to me that that IS what they mean], it seems to me that this basin enlargement would, on long time scales, be offset by all the natural forces of erosion tending to fill the ocean basins. So why this correction factor?

A G Foster says:
May 6, 2011 at 7:44 am
“Lots of misplaced skepticism around here. I see only 2 or 3 posters who understand the problems involved. ”
It seems a lot of the problems involved is a case of understanding just what GMSL actually refers to after all these adjustments.
Many we now need a global mean land level against which to compare it.

That’s a new one.
Sea level drops are due to La Ninas while sea level rises are due to manmade global warming.

That GIA correction seems rather dodgy to me. The two major areas of isostatic readjustment in the northern hemisphere (northern Europe and eastern Canada) both have shallow seas at the center of the rising areas (Hudson bay and the Baltic respectively). These seas are steadily being decanted into the oceans as the land rises, so it seems likely to me that the correction for GIA should be opposite to what they claim.
Of course it is possible that the isostatic adjustment under the Greenland and Antarctic Icecaps is going the other way and is large enough to outweigh this. However this is guesswork (a k a modelling) since there is no way of measuring what is happening under the icecaps with sufficient precision.

One important change in these releases is that we are now adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA), so you may notice that the rate of sea level rise is now 0.3 mm/year higher than earlier releases. This is a correction to account for the fact that the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land.

If glacial rebound is reducing sea level rise by .3mm/yr below what it would otherwise be (due to melting and warming etc.), that means that coastal areas have that much less sea level rise to worry about. So there is no point to the “correction”, other than to mislead the public a little about the extent of the problem (if there indeed is one).

Hey Foster, whats the problem, you can’t talk about the noticeable decline is sea level rise, but you have go off on some GIA tangent, as if you are the leading authority on the subject, so you don’t have to notice that sea levels are declining, even with the GIA correction..
Hows that working out for ya….
Somebody give that guy a binky.
Remember this, satellite altimetry is not an exact science. The data is suspect, the basis function is suspect. Spatial variance causes problems in qualitative measuring.
The whole thing is a guess.
The issue of validity grows exponentially with each correction added to the
super model of sea levels.
How about we go back and look at each individual tide guage in the PSMSL and see if we find any GIA correction there.

“After Climategate etc, there is a huge amount of scepticism about all data.”
You’re damned right about that.
I’m an engineer and I am massively sceptical about any data coming out of “climatology” (which clearly cannot be regarded as a science).
UEA and other pseudo scientists traded on the reputation of real science which had been built up over centuries – they should be strung up (figuratively, if not actually).
No real scientist could admit to have ‘lost’ the original, raw data. Let alone their other shenanigans (peer review, foi, baseless chicken little claims etc etc).
These clowns have set back science by centuries

Why don’t the scientists also calculate a Global Mean Coastal Level (GMCL) to compare to the GMSL? Or even better, show the specific points where coastal ground elevations are stable, and then show which other areas have land that is rising versus where the land is dropping in elevation. Then compare global or local sea level variations against land levels. The eggheads have tide gauge data plus satellite info (Jason, Topex, GRACE, GPS, yadda, yadda). How hard can that be?
Also, if La Nina’s drop GMSL levels, then El Nino’s raise GMSL levels, right? But if these trends just reflect upwelling of warm/cold water to the surface, how does that change the net ocean density and thus the net ocean volume?
And we now know that isostatic effects have overestimated the amount of melt water from Greenland and the West Antarctic Peninsula so that scientists now have to admit that any melt water contributions to GMSL have been, well, overestimated.
And next we hear that massive fresh water impoundments have prevented GMSL from rising as much as it would have otherwise. But we also now hear that massive acquifer depletions are forcing the GMSL to rise faster than it would have otherwise. Why don’t the eggheads do a mass balance for these two effects? Or can they?
Last, the GMSL has risen about 7 mm in last 4-5 years, or about 1.40-1.75 mm/year. That’s a helluva acceleration from 3.1 mm/year. Oh, wait – that’s not an acceleration, is it?

What strikes me is how the “adjustments” are always upward, NEVER downward.

So the data are no longer actual measurements. They have been ‘adjusted’ upward to account for glacial rebound, or something that sounds really cool and requires a few PhDs to understand. I can think of reasons to adjust the data downward, such as silting and fresh water aquifer draining, but that won’t make it look scarier.
I get really tired of government agencies adjusting what previously were actual measurements.

I think this is what the bottom line is all about:
Rate of change plot before and after.
Taking the slope across three data points (d/dt) and fitting a straight line to the whole record we see where the difference lies. GIA assures that there is an ever mounting sea level. The non-adjusted data shows sea rise would stop around 2024.
Now I’m not suggesting that fitting a straight line is particularly meaningful, nor that there is any reason to say that is a trend that will continue. But if someone wants to play “if the current trend continues and we fail to act to stop CARBON emissions NOW ….” they will want their data to show continued rising sea levels not a trend showing it will stop in ten years.

A G Foster says:
May 6, 2011 at 1:49 pm

Look, the problem is to figure out whether the mass of the ocean is changing. To know this you have to keep track of sea level, and you have to know if it’s warming and if the basins are changing. If the mass is not changing, then the ice caps are not melting, on average. LOD history suggests that polar ice is increasing (or that melting has decreased lately), in which case sea level rise remains an enigma, as it was in the last millennium.

Right, so if that’s what you are trying to work out, *one* of the things you need to know sea level. If you want to know total mass or total volume you have other things to look at and the result will NOT be called GMSL.
This issue here is that what is posted as a record of GMSL is no longer that. It’s some kind of half-way-house towards finding something else. It’s neither one nor the other but it’s still called GMSL.
Of course if you want to know if coastal plains are going to be submerged in 100 years and the Maldives are going to join their underwater government you’ll be seriously mislead by looking at what is being called GMSL, or trends thereof.
You don’t need a crystal ball to see what is going on here. In 2014 the new IPCC report will be crapping on about the dangers of accelerating sea rise based on this data and other distortions of reality pretending to be science.
Enough!

Just a note on my nomenclature of those plots. Each d/dt is done over an interval of three data points and stored at the mid point date. Effectively a two month average slope. This is repeated to the second differential.
This is then smoothed by a 6 sigma gaussian filter which on this data will have a 6x2x2 month ( two year) corner frequency. No mannian padding anywhere, hence the data stops short of 2011 in the raw data.

A G Foster, What’s the academic mainstream rationale for assuming constant GIA?

Paul Vaughan says:
May 6, 2011 at 9:09 pm
“P. Solar, They probably don’t even realize. You should write to them.”
What bit do you think they don’t realise?
That they have redefined sea level, that they have converted a receding rate of change into a positive one or that they have smoothed out 1998 to give the impression of a steady rate of increase when there is a fall?
I’d be fairly sure with the extended period that they have been working on all this that they are well aware of what they have achieved are busy writing papers to submit to Science and Nature in time to 2014 IPCC.
They probably have the arrogance to think no-one else has the brains to see through it, or think that the odd few that do don’t matter.
What would you suggest I say?

A G Foster says:
May 6, 2011 at 9:26 am
“But no one here has attacked the adjustment on any scientific basis whatever.”
==============================
Email me at sharkhearted@gmail.com and I will send you a pretty decent attack on this “adjustment” and its “scientific basis.”
Tamino loves to try to overwhelm with about 60% truth and 40% quasi-intellectual spin….such technique attempting to “outsmart” the opponent. (Cue the smoke and mirrors).
The good thing is…there are individuals on here who are on to that game.
Chris
Norfolk, VA, USA

Some sharp eyes there. Best documented, documented and archived for history.

@ P Solar: afraid you are seeing a conspiracy where there just isn’t one. It’s all about comparing like with like. Due to GIA the ocean basins are physically getting larger which – just by itself – is reducing apparent sea levels by about 1.2 inch/century (0.3 mm/year). It is entirely consistent with scientific principles that this effect is recognised for what it is and dealt with in the data.
Now the awkward part: there are two ways of handling this. Every 100 years (pro rata for part) CU will know that their sea level data 100 years beforehand needs to be lowered by 1.2 inches (or whatever the precise figure then is) to be consistent with current measurement. They can either (a) adjust and republish all past data by lowering past sea levels retrospectively (wouldn’t that just produce howls of protest) or (b) adjust the current data by reference to a “standard basin size” datum to compensate for the basins becoming larger, which (as you have mentioned) seems to produce a higher current sea level readings – until everybody understands what is really going on.
CU also know that the (modest) rate at which sea levels are rising isn’t the important figure. The absolutely critical figure is any change (acceleration or deceleration) in the rate of rise – the 2nd order differential by time. This isn’t affected at all by the GIA adjustment, so CU obviously considered that the “standard basin” datum was the right way to go.
There isn’t a conspiracy here – only awkward principles and hard sums.

TimC says:
May 6, 2011 at 11:36 pm

@ P Solar: afraid you are seeing a conspiracy where there just isn’t one. It’s all about comparing like with like. Due to GIA the ocean basins are physically getting larger which – just by itself – is reducing apparent sea levels by about 1.2 inch/century (0.3 mm/year). It is entirely consistent with scientific principles that this effect is recognised for what it is and dealt with in the data.

If an ocean basin gets larger/deeper then the sea level will drop. This is “apparent” as in real, visible and measurable. Not “apparent” as in paradoxically wrong.
Any suggestion that it needs to be “corrected” comes from the idea that GMSL represents something other than sea levels. What could that something be, one asks.
Clearly GMSL is one candidate for the “other metrics” of climate change that are being called for. It does carry a signal that could be a primary input to calculating total ocean volume, mass or similar that could in turn be used as a climate metric. However, such a measurement or inference of climate cannot come from GMSL alone, there are (many) other factors like GIA that need to be accounted for.
The need to account for other factors does not mean that those other factors should be used to *corrupt* the GMSL data by being applied de facto as “corrections” or “adjustments”.
In that case we need to CALL it something else and stop calling it mean sea level data.
I’m not seeing a conspiracy, I’m seeing bullshit science and calling such.
If anyone wants to redefine sea level to be some intangible, notional datum that hovers somewhere above the physical sea level and gradually rises ever more above it, they need to come up front and say so very clear terms.

@Green Sand – “NOBODY expects the Glacial Isostatic Adjustment!
Thanks for the LOL 🙂
@Doug Proctor – Cheers Mate
Dave

@ ImranCan: the measurements are by internally calibrated satellite altimeters. I don’t think they are specifically referenced to the geoid but just presented as ΔMSL figures (changes in MSL as from a given reference date/time).
The GIA adjustment is to give a more accurate picture of the volume of water in the oceans (resulting from the hydrological cycle and melting land-based ice): if you want to go from levels to volume you have to adjust for any changes in the size of the bucket!

When the Sea level was higher! http://www.photographers-resource.co.uk/a_heritage/Castles/LG/Wales/Harlech_castle.htm

P. Solar & Others, When mucking around with models of a short series, discrepancies between models at high-leverage segments (such as segments containing sharp changes) are to be expected. It may be true that some modelers like the new model better for whatever reason, but that doesn’t mean they’ve carefully run diagnostics. While malicious intent cannot be excluded as a possibility for some players in the game, there is plenty of reason (even upon a mere preliminary glance) to suspect a strong role for ignorance & naivety.

Ray Boorman says:
Even though the actual sea level is what they purport to measure, they decide to add a small positive adjustment every year for the fact that some parts of the land are rising due to rebounding from the last ice age. Measurements are measurements where I come from, & if my local tide guage showed a rise of 2.7mm a year because the land is rising by 0.3mm, than that must be the true reading. Do they also adjust for the fact that any rising land areas are also increasing the sea-level rise in those areas which are not rising? I can’t see how this adjustement is anything other than an artifice to satisfy the CAGW believers.
Even where the land is rising it could be at less than 0.3mm a year. Also there’s plenty of places where land is subsiding. (In some cases considerably more than 0.3mm per year.)

You know, I find the stated error of 0.4 mm completely bogus. Look at the graph for any period. The latest data runs from 25-45 mm and is completely random. Which means the +/-10 mm range in data is PROBABLY the noise in the data. Gimme me a break. When did science lose its basic math skills.

P. Solar, have you considered that triangular filters based on harmonics of modes such as the day & year might provide slightly more sharply informative summaries? (Your Gaussian filter is actually not terribly different in shape, but technically (not practically) it does complicate interpretation. I acknowledge that this is a rather technical point.)

@ Paul Vaughan: re your query I can only refer you to CU’s own quoted intro at the head of this article: “One important change in these releases is that we are now adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA), so you may notice that the rate of sea level rise is now 0.3 mm/year higher than earlier releases. This is a correction to account for the fact that the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land. Simply subtract 0.3 mm/year if you prefer to not include the GIA correction.”
My point was that any fixed, constant, rate adjustment of 0.3 mm/year will of course (a priori) show up as a rate change in the first order time differential, but will have no effect on the second order time differential figures (any changes to the rate of rise in MSL).
Other than that that I think you had better check the details from CU’s own website! For my money this is a sensible, practical change to let us see more clearly the data that is really important (the second order time differential figures) – but it seems to be causing a lot of angst around here!

Measuring sea-level that’s SEA LEVEL rise to an accuracy of .3mm…great and while we’re at it are there any Theologians out there who can tell me just exactly how many Angels can dance on the head of a pin?

@ Catcracking: if you look at the CU site explanation for the GIA adjustment (URL below) you will see reference to papers from Peltier in 2002 and 2009 which I think identified the effect. Although GIA is very gradual on a yearly basis it amounts to 3cm/century which can’t just be ignored – it is a real effect on MSLs, recently identified, which has to be taken into account:
URL: http://sealevel.colorado.edu/content/what-glacial-isostatic-adjustment-gia-and-why-do-you-correct-it
@ Mike Jonas: the NASA eclipse web pages (URL below) give estimates for ΔT (the difference between Terrestrial Dynamical Time – broadly time based on the earth’s position in its orbit round the sun – and Universal Time – based on the earth’s daily rotation about the NS polar axis) from 500 BCE to date, which I think can show the estimated changes in LOD and the standard error for the historical records.
URL: http://eclipse.gsfc.nasa.gov/SEcat5/deltat.html

On the Sea Level Reference Page, I suggest adding the following sub-heading to this graph:
NB! As of May 5th 2011, this graph no longer represents actual sea level rise.

“Correcting” for sea level rise is such a crock! It’s obvious they don’t want people to look at the chart an conclude there is not problem. If they present a chart that purports to depict sea level rise, it should be that and only that. If they want to then present a second chart corrected for what they think they know, fine, but don’t mess with the chart of the primary measurement. These people should be fired.

The “scientists” involved in this have zero integrity and we taxpayers should stop paying them for this crap.

@A G Foster says:
May 6, 2011 at 1:49 pm
Look, the problem is to figure out whether the mass of the ocean is changing. To know this you have to keep track of sea level, and you have to know if it’s warming and if the basins are changing.
We can’t measure all that stuff. The whole point of looking at sea level is get some idea of all that other stuff. Now, when sea level doesn’t do what the theory says it should do, the “scientists” are going about adjusting the data to fit the theory. No matter how you spin it, that is what they’re doing.
The bottom line is that if you live at a coastal area, there is no evidence that you have anything to worry about from climate change. It hasn’t made much difference to sea level rate of change.

@TimC
Indeed if you want to measure the volume of water then you need to take out such factors as the size of the bucket. But the volume of water is not what is of interest – it is the sea LEVEL ! Which is why the name of the academic group publishing this is : Sea Level Research Group, University of Colorado. So the size of the bucket is extremely important. There are many many factors which affect sea level – they could also take of such factors as sedimentation input, or basin subsidence. Why not throw out mid ocean ridge spreading as well ?? Or rock lost to subduction. The point is that its not correct to just throw out those factors which are inconvenient because they might be causing sea level to drop. If you want to be measuring global sea level then you need to be measuring global sea level – not some artificial number representing something else.
And referring to your other post : its not magma which is “flowing around” in the mantle. Magma is molten rock. The mantle is solid, not liquid.

@ ImranCan: This is just down to clear labelling. The CU graph doesn’t actually plot absolute sea levels: it plots ΔMSL (mm) on the Y axis against time. ΔMSL is change in sea level as from an arbitrary datum (the individual satellite’s altimeter reading at a given time/date) – I don’t think these are absolute figures, all referenced to a “standard” height on the geoid.
All that’s needed is clear labelling, so everyone understands precisely what is being plotted. The WUWT reference pages now make it crystal clear that CU’s graph includes this GIA adjustment; if you think the CU web page itself does not make this clear you will have to take it up with them!
And yes, the magma is indeed the molten rock under the mantle – but it very slowly flows according to relative pressures on the mantle such as from a mile’s depth of water or (lack of) a mile’s depth of ice.
@Paul Vaughan: I really think you should raise this with CU, if the papers mentioned in the GIA FAQ on their website don’t give you the answer.

Are we to believe it is sensible to assume GIA has no seasonal component? No interannual component? Whenever time & resources permit, this is going to be a very tedious audit to undertake.

@ Gary Pearse: thank you for that, but on your “hubris” remark I would be grateful if you would clarify where I have ever said in any comment under this Article – or at all – that “only a few commenters … understood the issue”. I’m not aware of ever having made such a comment.
There has been a very straightforward change in CU’s method. Instead of plotting ΔMSL, CU are now plotting ΔMSL + 0.3*y, where y is the number of years (or part years) elapsed to the time the data is taken. Anyone can easily reverse out this adjustment. I personally think this is a sensible and helpful step to adjust for GIA. CU obviously think so too, otherwise they wouldn’t have made the change. The change, and reasons for making it, are properly documented on CU’s website.
If you are uncomfortable with CU’s new method I can only suggest that you approach the CU people direct. It’s not in my power to change CU’s methods nor do I want to – as I said in my first comment under this Article I just can’t see what all the fuss is about.

@ Mike Jonas: (a) if you look at CU’s release notes, two paragraphs down from their “Raw data” hyperlink, you will see they already make adjustments to the data far more complex than just adding +0.3*y; (b) “Global Mean Sea Level Time Series (seasonal signals removed)” is (in my view anyway) still perfectly descriptive; (c) on an earlier point, governments of counties at risk of inundation (who can’t afford to employ sharp-eyed scientists to read release notes) actually have more time to play with before they are inundated than might first appear because of the adjustment; (d) the adjustment is anyway only 3cm per century – not exactly a huge figure and (e) it’s really no use banging on at me, you have to make your point to the CU people, or get over it.
@ ImranCan: Free dictionary definition for magma: “the molten rock material under the earth’s crust from which igneous rock is formed by cooling”. Isn’t it this that flows, because it’s molten?

@ ImranCan: what I actually said to another contributor (substituting the definition, for clarity): “the earth isn’t expanding: [the molten rock material under the earth’s crust] is just slowly flowing away from the ocean basins (which are therefore dropping) into the formerly glaciated land areas no longer bearing the weight of all that ice, which are rising. It’s rather like squeezing a toothpaste tube with the cap on – the total volume is unchanged.”
We don’t have to be PhDs to comment here, and I didn’t assume I was addressing one (I have a science masters from long ago but my actual career is in law). Without all the abstruse technical details, I think my comment above adequately described the processes at play.

@TimC
“Without all the abstruse technical details, I think my comment above adequately described the processes at play.”
Other than the fact that the mantle is NOT molten, you are spot on.

@ ImranCan: re your last, thank you – I am glad to agree.

TimC
I apologize for the collateral damage of my remark re impugning other commenters who have opposed the conversion of the sealevel series to a delta volume of ocean series – you are innocent of that.
AG Foster
I apologize for impugning your LOD specialty and I thank you for a very enlightening rundown on the significance of LOD and the factors that contribute to it. I suggest a full post on this interesting topic.
But you don’t get off scott-free! We shouldn’t have to extract a metric like msl from a halfway-to-ocean-volume-change metric especially when the name remains sealevel series. Also, knowing the MO of the alarmist, this new metric will ‘confirm’ that ocean levels are rising quicker than we thought. I would be happy to leave them with their delusions if they didn’t have the ear of our law makers and taxation pals. You are correct that a foot or so of water isn’t going to be catastrophic by 2100 but try googling agw or climate change and sea level rise and see what reasonable people are up against.

Catcracking: thanks, I take your point but isn’t it rather paranoid keep looking over our shoulders all the time, for fear of what others will say?
For me it’s more important to have data providing the most informative and useful insights into the natural world, wherever this takes us in the AGW debate. At some time all the controversy will be over – better sooner than later even if it turns out the sceptical position was more wrong than the warmist position (I think it will all be a matter of degree – pun partly intended!)

TimC says:
May 9, 2011 at 11:34 pm
For me it’s more important to have data providing the most informative and useful insights into the natural world, wherever this takes us in the AGW debate.

It’s equally important for the data to be given a name that ISN’T misleading.
Rename it!

This has to be the single most stupid thing I have read all day.
“This is a correction to account for the fact that the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land.”
Does that not suggest, and it stands to reason, that as result of the basin getting bigger, water levels would necessarily decrease. Further, the expansion of the sea floor results in mountain building and an increase in land elevation. While keeping my comments basic to the statements, where am I wrong?

As a geologist I don’t understand the statement “This is a correction to account for the fact that the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land.” Besides making my head hurt this statment doesn’t seem to make sense. If the ocean basins are getting bigger which is true because of plate spreading of the ocean ridges which produce mantle material, how does it move into previously glaciated regions on land. Somewhere there is an escalator that carries magma from the spreading ocean basins to the surface where previously glaciated areas once existed. Only in Boulder Colorado.