New sea level page from University of Colorado now up

As we surmised in earlier posts, the crozon.colorado.edu website was a test run. Here’s the newest graph from the revised http://sealevel.colorado.edu/

Updated: 2011-05-05

They write about the update:

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.

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.

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, though research on this is continuing. We will soon add a plot to the web site illustrating this effect.

Let us know if you spot any bugs in the new web pages. Thanks for your interest!

Comments welcome.

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216 Responses to New sea level page from University of Colorado now up

  1. Jason F says:

    they always correct upwards don’t they

  2. Ecotretas says:

    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

  3. Braddles says:

    The trend since early 2002, when the Jason satellites came into play, is only 2.3 mm/yr. Without all the convenient adjustments it is lower still.

  4. 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.

  5. Warren says:

    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.

    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, though research on this is continuing. We will soon add a plot to the web site illustrating this effect.

    Sorry, they lost me with adding then subtracting, then saying it didn’t matter and I could use the previous reading without the addition?

    And still researching La Nina?

    My head hurts.

  6. Hunter says:

    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.

  7. bushy says:

    So we are no longer measuring actual sea level but adjusted values bases on assumptions. The actual levels are what we want not ( well the sea is actually rising more than actually measured because of xyz so its worse than we thought).

    As far as La Nina causing a drop in sea level, surely this is spurious. An upwelling of cold water is not cooling the ocean overall. In fact because the surface is colder the ocean would be losing less energy overall in those cooler areas compared to energy absorbed from the sun. There would be a drop in sea level locally but this would be reflected by a rise elsewhere.

  8. Mac the Knife says:

    “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.

  9. Ray Boorman says:

    And do they also play off against each other the movements of the various tectonic plates? Eg India is pushing into Asia, which enlarges the Indian Ocean, but Africa is tearing itself apart, which diminishes the same ocean. They might also want to take into account the rise & fall of various plates as a result of earthquakes. The more you think about it, the more complicated a simple idea like sea level becomes.

  10. Brian H says:

    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.

  11. LabMunkey says:

    Huh, the new data’s knocked the average rate-rise down from 3.4 to 3.1 mm/year i see.

    I wish i could still find their data of the tidal gauge and satellitte data together. they used to have it all on one graph, it ws a great resource- but i haven’t been able to find it for ages.

  12. Mike Bromley the Kurd says:

    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?

  13. chris1958 says:

    Methinks putting in the GIA is a little naughty if the principal metric of practical significance is the actual rise in sea level compared to levels on land. Of course, if we’re interested in oceanic volume, then that’s another story.

  14. Andrew30 says:

    “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.

  15. Martin Brumby says:

    “the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land”

    OK, how does that work? (Honest question, not my usual sarcasm).

    “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”

    So La Nina has been hard at it, unsuspected, since 2008?
    (Sorry, sarcasm back on again…….must try harder…….)

  16. Mike McMillan says:

    So down from 3.2mm/yr to 2.9 if you don’t count their latest ‘adjustment.’ With any luck we may stay below even the adjusted line for a few decades if the apparent cycle in Tokyoboy’s Japan tide chart is real and worldwide.

  17. Dave A says:

    From http://sealevel.jpl.nasa.gov/technology/

    From its vantage point 1336 kilometers (830 miles) above the Earth, the US/European Jason-1 and OSTM/Jason-2 ocean altimeter satellites measure the height of the ocean surface directly underneath the satellite with an accuracy of 4-5 centimeters (better than 2 inches).

    n.b. centimetres not millimetres :-)

    throw in an unsubstantiated positive 5mm fiddle factor over the period of the graph. Cross calibrate with previous satellite to maintain the positive trend (c.f Mann, trees and real life) and admit that the surface of the earth moves as in the case of Japan’s 8 foot coastline shift earlier this year

    and then be amazed that your latest measurements show a decrease you cannot explain

    A 5 cm increase over 17 years measured by 3 different instruments accurate to 5cm from a height of 830 miles

    I’m scared we are all going to drown :-S

    :-))

    Dave

  18. Jantar says:

    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.”

  19. Bug shmug.
    So, if we don’t like the GIA correction, just remove it.
    How about they don’t include the GIA correction and tell people if
    they want to increase the rate of GMSL…
    wait, oh yeah, that would be double dippin…. my bad.
    /sarc

  20. John A says:

    They’ve dropped Envisat from the record. Without explanation.

  21. Mike Jonas says:

    Here’s their data which I saved from the old Colorado website:

    http://members.westnet.com.au/jonas1/ColoradoUniArchivedData.txt

    I have very quickly graphed the old and new data, and I have not checked it carefully!!!
    Graph of old data:

    Graph of new data:

    Graph of the differences:

    Interesting.

    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.

    In haste …..

  22. TimC says:

    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.

  23. Ecotretas says:

    Since I had last archived raw data (in 2010.6057) several new cycles appear in this data, that were not available before:

    2004.1173
    2006.8864
    2008.6782
    2008.7325
    2008.814
    2009.0311

    Ecotretas

  24. rbateman says:

    vaporware.

  25. Don Keiller says:

    So the rate over the last 19 years is 3.1mm/year. That comes out at 310mm/century.
    In old money that is 12.2 inches.
    OVER A FOOT! IT’S WORSE THAN WE THOUGHT!

  26. Jimbo says:

    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?

  27. Jimbo says:

    I forgot to bold

    “(new orbits, new tide model, new corrections) “

  28. 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 ?

  29. Edim says:

    This was to be expected. Hide everything that dilutes the message. Under the carpet!

    Long term it cannot work. The pile under the carpet is getting bigger and bigger…

  30. roger samson says:

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

  31. John Peter says:

    So to get to the IPCC predictions of sea level rise to 2100 we need some acceleration in the yearly rise. I see no such acceleration. In fact there is a recent deceleration. The next few years will be interesting.

  32. Ecotretas says:

    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

  33. sHx says:

    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.

    Hocus pocus!

  34. Mike Hebb says:

    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?

  35. Roger says:

    Is anyone positively, absolutely, no doubt about it, convinced they can even measure a 3 inch rise in sea level, over any given amount of time, for the entire world?

  36. Peter says:

    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.

  37. Buzz Belleville says:

    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.

  38. BarryW says:

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

  39. 4 eyes says:

    If the mid 2011 number comes in the same as the last bit of 2010 then I’d say that trying to fit a straight line to the data is folly. Then the plot would have more of the characteristics of a sine wave with a period of about 30 years rather than a straight line

  40. stephen richards says:

    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.

  41. Latitude says:

    So they are adding a constant to it…

    ..and it’s still going down

  42. stephen richards says:

    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!!

  43. zerored78 says:

    @Buzz Belleville

    It depends on the point of this measurement. Typically, people think about sea level rise being how much coastline on average is being reclaimed by the sea because that is what is most important to people on the coast. If that’s what this is supposed to be measuring, adjusting for changes to the volume of ocean space is not helpful.

    I have nothing against measuring volume. That would be interesting to track. I’m not sure we have the technology to really do it with any accuracy though.

  44. P. Solar says:

    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.

  45. 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.

    And the adjustment for GIA is based on peer-reviewed scientific literature, not some nefarious whim.

  46. Bill Illis says:

    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).

  47. “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, though research on this is continuing.”
    So, La Nina is affecting the heat content of the Pacific.
    I’ve been told that La Nina only causes redistribution of heat. Cold water coming up from the deep and warm water moving away to the west. Not a heat loss in the Pacific causing thermal contraction.
    I say look to the PDO!

  48. Green Sand says:

    “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

  49. TimC says:

    @ steven richards: it’s not a matter of right or wrong but of comparing like with like. The ocean basins are physically getting larger which – all by itself – is reducing sea levels by about 1.2 inch/century. This is before you can get an accurate picture of the important stuff such as the effect of thermal expansion and the rate land-based ice is melting.

    Surely you are not suggesting this should just be ignored – good science means that it has to be recognised for what it is. To compare like with like I suggest it’s better that the figures are adjusted, otherwise we will all have to remember to make manual adjustments every time we look at the data.

    I also hope it will later be possible to make accurate adjustments for the effects of thermal expansion, so we can finally get an accurate handle on whether there is any change in the rate at which land-based ice is melting (ie. whether global surface temperatures have truly risen or not).

  50. Pamela Gray says:

    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.

  51. JohnH says:

    “the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land”

    So the Earth is expanding according to that statement, funny how there is a equal return of rock to the depths of the ocean caused by glacial erosion, which is not mentioned, which would cancel that out.

  52. OldOne says:

    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!

  53. Milwaukee Bob says:

    Buzz Belleville says:
    May 6, 2011 at 4:18 am
    ………. Transparency is neither a guarantor of correctness nor honesty, but often screens out the opposite of both.

  54. lizardbrain says:

    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.

  55. Claude Harvey says:

    What’s good for the goose is good for the gander. It seems to me according to the logic applied to the “adjustment”, when the process reverses (as it inevitably someday will) and sea levels begin to decline the “coolists” will be able to chirp, “It’s even worse than we thought! We must SUBTRACT 0.3 mm per year to account for ocean basins rising and land masses falling! Shut down the windmills and start burning something – quickly!”

  56. Neil Jones says:

    Response to bushy says:
    May 6, 2011 at 12:03 am

    Surely cold water welling up from the depths would be warming and expanding when it got to the surface.

  57. David Middleton says:

    Post Glacial Rebound (PGR) is highly variable. The continental crust in areas that were glaciated has been rising for the last 15,000 to 18,000 years. However, the continental crust in the fore-glacial bulge areas has been subsiding.

    Did they actually calculate the net 0.3mm/yr GIA? Or is than an assumption?

  58. Ron Cram says:

    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?

  59. Milwaukee Bob says:

    Buzz Belleville said at 5:32 am
    You do understand, ….. It’s adding o.3 mm to all plotted points. It has no effect on the rate of rise.
    What? Did you miss the part where he said:
    … so you may notice that the rate of sea level rise is now 0.3 mm/year higher than earlier releases

    AND “if” the 0.3mm is added to ALL data points – – why even bring it up? or add it? or why not 0.9mm? or -0.5mm? or 6.7mm?

  60. Ron Dean says:

    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.

  61. Bruce says:

    Ok. Only 3 measurements in 2011 so far. Lets look at measurement #3 over the last few years.

    2006.0720 25.011
    2007.0765 31.094
    2008.0810 34.438
    2009.0583 39.251
    2010.0628 31.337
    2011.0673 30.809

    5.7mm over 5 years = 1.14mm per year

    Acck. We are all gonna drown!

  62. BenfromMO says:

    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.

  63. Coalsoffire says:

    Buzz 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.

    ____

    Look at what they say themselves again:
    “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.”

    Who are we to believe? You say adding an annual adjustment every year does not affect the rate of rise, but they say it does. This may have only a one time effect on the slope of the graph, thus not showing an ever increasing acceleration trend, but it does have a constant, continuous, cumulative effect on the slope from what it actually should be (if we are actually measuring sea level). It’s “a trick to hide the decline” in plain sight all over again. “We explained it in the literature so it’s okay to produce a bogus graph” is the party line I believe.

  64. A G Foster says:

    Lots of misplaced skepticism around here. I see only 2 or 3 posters who understand the problems involved. There is no such thing as sea level per se–the sea isn’t level. Sea level at one Hawaiian island rises at a different rate from another–the younger islands sink faster as they settle down from their more recently added magma. Wind and the Coriolis effect can easily raise sea level a foot. The two coasts off Panama have different heights. The two sides of the causeway on the Great Salt Lake have different heights due to different salinity levels.

    And the planet constantly changes shape; they do well to quantify the effect of GIA on sea level rise–it’s very hard to measure, or calculate. And the paradox of sea level rise versus falling LOD remains. Munk wanted to use long range sonar to measure deep sea density (salinity/T) globally, but it was determined this would hurt lots of cetacean ears, so data are still sparse.

    On the other hand, population density increases due to natural growth about a thousand times as fast as due to current sea level rise, and if all the ice on the planet melted, it would still make less difference than current population growth rates. In the unlikely event that Greenland’s ice melted, natural population growth remains a far more serious problem. But we can handle it. –AGF

  65. P. Solar says:

    Also seems that the barometer adjustment is now obligatory.

    http://sealevel.colorado.edu/content/new-web-site-new-sea-level-release

    The inverted barometer correction (optional in previous releases) is now always applied for each mission.

  66. richcar that 1225 says:

    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.

  67. mike sphar says:

    Never mind, we found the adjustment knob, the NEW and IMPROVED adjustment hereinafter known as the GAIA adjustment will correct for all previously measured data points such that the current remains forever WORSE THAN WE THOUGHT!

    A little GAIA in your data will correct the info. Trust us for we know the truth.

  68. Theo Barker says:

    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.)

  69. Cirrius Man says:

    “the global ocean basins are getting slightly larger over time as mantle material moves from under the oceans into previously glaciated regions on land”

    Questions for the University of Colorado

    – Why are we no longer measuring actual sea level in the new graph, and what is the point of making a positive adjustment to highlight what the level would have been otherwise ? We only really want to know when our toes will get wet in the morning when we get out of bed !

    – If the mantle movement is a negative feedback to observed sea level rise then why is this not highlighted by the IPCC in their sea level prediction forcasts ? After all, this is a good news story !

    And finally
    – What was your measured isostatic rate of increase in 1980 ?
    – What is your predicted isostatic rate of increase in 2100 ?

    I’m guessing that the rate remains very constant, and if this is the case then how is it relevant to AGW ?

  70. Alcheson says:

    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.

  71. P. Solar says:

    David Middleton says:
    May 6, 2011 at 7:00 am

    Post Glacial Rebound (PGR) is highly variable. The continental crust in areas that were glaciated has been rising for the last 15,000 to 18,000 years. However, the continental crust in the fore-glacial bulge areas has been subsiding.

    Did they actually calculate the net 0.3mm/yr GIA? Or is than an assumption?

    My money is on “make a simple computer model and adjust the parameters until you get the desired result”.

    but I’m just old and cynical. I suggest you look at the link to the paper they give in release notes :

    http://sealevel.colorado.edu/content/release-notes

    Abstract:
    … the second may be estimated on the basis of mass balance measurements on existing ice-fields, and the latter on the basis of modern GRACE-based time dependent gravity field measurements, the inputs to the globally averaged rate of sea level rise may be directly constrained.

    But hang on, interpreting GRACE gravity data for ice sheets requires a model of mantle rebound.

    models upon models , wheels within wheels, and they claim +/-0.4 on 3.1 , that’s +/-13%. That probably does not even cover the uncertainly in the satellite data never mind the grossly simplistic, globally averaged rebound models.

  72. phlogiston says:

    A G Foster says:
    May 6, 2011 at 7:44 am

    Are you Tamino?

  73. TimC says:

    @ JonhH – no, the earth isn’t expanding: magma 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.

    @ Old One: I believe it’s a uniform adjustment of ~0.3mm for every year since the datum year 1980 – so the adjustment is ~0.3 * 30 = ~9mm total today. Yes this does uniformly affect the rate of sea level rise but only at the first differential by time: the all-important second differential (changes in the rate of rise) is not affected.

  74. 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.

  75. richcar that 1225 says:

    I think it is interesting that University of Colorado is taking on the glacial isostatic adjustment. This is real. As we know releative sea level at high latitudes appears to be declining as the coast rapidly rebounds.

    http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml

    Sea levels at lower latitudes appear to be rising faster especially when measured adjacent to subsiding coast lines. Relative SLR measured adjacent to the stable Australia craton have only shown about 1.2 mm/year. My bet is that they are applying this correction the wrong direction. The test would be to take a station with GPS data adjacent to it and see how it fits. In other words if an Alaska station shows -8mm/year releative sea level decline then the GPS station on the coast adjacent better show 8 mm/yr +3.1 mm/yr. This should be easy to check out.

  76. Gary Swift says:

    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?

  77. Jeff Carlson says:

    the only reason to measure “sea level” rise is to determine what it will effect on land … if the land is rising faster than the sea level then for then as far as humans are concerned the “sea level” they are concerned about has dropped …

  78. Ron Cram says:

    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.

  79. TomRude says:

    Amazing that before they were soooo good but OMG, forgot the ever so important mantle re-adjustement… What’s next? As a Canadian I certainly hope they’ll introduce a correction for political shift since the mantle has been now firmly over the shoulder of the PM… sarc/off

  80. TomRude says:

    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.

  81. Betapug says:

    Perhaps when reformulating “Data Product” there should be a mandated overlap period in which consumers can trial both to compare. New Coke anyone?

  82. Hank Hancock says:

    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

  83. A G Foster says:

    Re. Ron Cram at 8:42.

    But no one here has attacked the adjustment on any scientific basis whatever. Qualitatively, the need for the adjustment is obvious: rebound material has to come from somewhere–if the land rises the ocean bases must sink, and gravity measurements have advanced to the point that such movements can be detected. It is one thing to declare a qualitative BS and another to argue quantitatively. I have no idea how good the measurements are, and I suspect you don’t either, but if you deny the qualitative argument you’re really missing the boat. Just like the doubters when Richard Gross tried to measure the LOD change from the Japanese quake. –AGF

  84. wayne says:

    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.

  85. Bruce says:

    On Jan 24th I looked at the data:

    2006.7236 26.640
    2007.7280 25.493
    2008.7054 23.759
    2009.7370 31.748
    2010.7415 28.119

    As of today it is:
    2006.7236 28.870
    2007.7280 30.298
    2008.7054 29.811
    2009.7370 36.335
    2010.7415 31.270

    The trend changed from 1.479mm to 2.4mm over the same period.

    The trend should not have changed.

  86. Ron Cram says:

    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.

  87. richcar that 1225 says:

    Since there has been negligible thermal expansion since 2004 most of the sea level rise since then should be attributed to mass contribution (land ice melt). Yet with the new GIA I understand that they can account for only 60% of SLR or about 1.8 mm per year. This would match what most of us skeptics believe is closer to the truth and takes out the clear instrument bias that began with satellite altimetery since 1993.

  88. Gary Swift says:

    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.

  89. klem says:

    “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..”

    So an increase in sea level rise is caused by AGW but a decrease is caused by La Nina. No wonder the credibility of science in general has taken a beating recently.

  90. Lars P. says:

    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”

  91. Doug Proctor says:

    Dave A says:
    May 6, 2011 at 12:43 am
    From http://sealevel.jpl.nasa.gov/technology/

    Dave points out that in 17 years we have a 50 mm rise within observations accurate to 50 mm. Statistics, all statistics at 2011, 31 years after we were first supposed to be able to see the effects of global warming. All stats still (argued by warmists) within error bands of the CAGW models. As Treadgold keeps shouting, “There is no evidence!”. Perhaps he means unequivocal evidence, but along with Dave’s comments, a good point.

    In the three key points of CAGW, pCO2, global temperatures and sea-level rise, so far the deviations from “normal” pre-1980 trends are insufficient to falsify any of the models – within their claimed accuracy. The end-of-the-world scenario was and still is 2100, but 2050 could easily be taken as the end-of-the-world-is-upon-us date, if not before then. During the first 31 years of a 120 or 70 year timeline to doomsday, we still experience nothing available to the man in the street as hard evidence. How long must we go before the warmists accept they have a problem? Or will, like other millennial prophets, they simple postpone Judgement Day – and get away with it. At least twice.

    This could be a very long road we are on. Long enough that the Gore-Hansen-Suzuki-Schmidts are in their graves before their can be embarrassed.

  92. BenfromMO says:

    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.

  93. A G Foster says:

    Re. Ron Cram at 9:51:

    You may not be aware that GIA has been reasonably calculated to have contributed a decrease in LOD of .6ms/century for the last 25 centuries or so, via astronomical observation. This provides a reasonable framework from which to estimate the rate of change of the shape of the earth to less oblate, both quantitatively and qualitatively. That datum does not tell us whether the mantel sinks beneath the continents or the oceans, but the fact that the globe is mostly ocean gives us a high probability that volumetrically the majority of subsidence is oceanic.

    Silt deposition occurs at a rate comparable to continental uplift–one or two orders of magnitude less than GIA, hence, negligible until the GIA is better understood. The cryosphere is far more variable than the lithosphere, except as affected by the cryosphere. –AGF

  94. Philip Finck says:

    So when there are El Nino years they will have to say that the rate of sea level rise really isn’t as HIGH as measured because we believe that the El Nino years have artifically elevated the rate. FAT CHANCE of that!!

    And honestly, the statement about adding .3 mm/yr is so ambiguous that I have no idea what it means. They need to show say ten years of data with and without the adjustment. Is it a uniform adjustment up for each year. Or is it .3, then .6, .9 etc…? was this done to the entire data set?

    Uh Oh!! The mid-Atlantic ridge is a spreading center and thus thewidth of the Atlantic is increasing each year and as the mountain chain moves away from the spreading center it also subsides. So the volume of the Atlantic is increasing each year. Is this being cancelled some where by subduction, or is it being absorbed by mountain building…….. this gets rediculous after a while.

    Kind of like arguing with my wife. Somewhat satisfying at first but you know that the long term pain will make you shudder …like a hang over.

  95. sagi says:

    So even if the sea level does not change at all, it is made to rise anyway.

    Wonderful!

  96. George E. Smith says:

    Well I just made my own interpretation of that sea level rise graph. Id rew two; count them two, straight lines, throught the following four points:-

    #1 1993, -20 ; 2011, +50

    #2 1993, -03 ; 2011, +38

    They happen to cross at about 2003.5, +20, but you math geniuses can simply calculate the exact crossing point, at which time, the sea level stopped rising at its former rate.

    Of course as anyone can plainly see, the graph is actually logarithmic, that is the sea level is proportional to the logarithm of the date. Well theres about a +/- 50% uncertainty in the slope of that logarithmic curve or a 3:1 spread in the slope value if you prefer; but that is consistent with the theory, that it should be a logarithmic fit, and also consistent with the expected precision of predictions; excuse me; that’s projections of future sea level.

    For the purposes of this thesis, a “logarithmic curve” is defined as any graph that is not consistent with the archetypical form:-

    Y = m. x + c

  97. Geoff says:

    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.

  98. Ecotretas says:

    The impact on the rate of sea level rise is clear.
    Please out the two graphs I’ve put in my post at

    http://ecotretas.blogspot.com/2011/05/rate-of-sea-level-rise-going-down.html

    and check the differences between 2003 and 2007…
    Before, it was going slightly down, now it looks much stable.

    I maintain what I said before: These changes were made so that sea level rise stays above 3mm/year! But the rate is going down, and very fast, as you can see in my post.

    Ecotretas

  99. Laurie Bowen says:

    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 . . . .

  100. Laurie Bowen says:

    Let me clarify . . . I didn’t write the book . . . I just ran across it . . . U of C may care to comment . . . on it’s relevence . . . .

  101. P. Solar says:

    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?

  102. Ecotretas says:

    P. Solar,

    Google is your friend. Just click the Cache entry…

    Ecotretas

  103. F. Ross says:


    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?

  104. SteveSadlov says:

    If you ever see this doctored chart flattening, or God forbid, sloping downward, then prepare yourself for new types of “phenomena” that would make even the darkest Sci Fi lit look like a cake walk. 6 billion starving people are not a pretty sight.

  105. P. Solar says:

    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.

  106. Brian D says:

    I understand the crust of the earth moving up and down. But they also need to take into consideration the displacement of water due to the silt/debris entering the oceans from land, underwater volcanoes, etc.

  107. Neil says:

    <B?An Alarmist View of "Glacial Isostatic Adjustment"

    The ocean bed’s bigger? I revel!
    It means I can say that sea level
    Is rising much faster
    Than ever! Disaster!
    Cry hell, and high water, and devil!

    </limerick>

  108. A G Foster says:

    Attacking the question from the other side of the coin, so as to avoid the geoid argument, suppose you set a pan on a sponge next to a table of the same height, and you fill the pan with some water, measuring the water level from the table. You pour in more water and measure the level from the table. But then you realize the pan has sunk in the sponge, and your former measurements did not take into account the sinking pan. So you try to figure out how far the pan sunk, and you add that to your measurement. That’s the “adjustment,” and it’s very reasonable. And you can always distinguish between adjusted and non adjusted measurements. In fact you always have to. –AGF

  109. Gary Pearse says:

    The GIA adjustment came out of those round table discussions about the travesty that sea levels are NOT going up faster than we thought. Since the whole deal about rising sea levels is that Vanadu and the Ganges delta are going to be inundated, we should stick to the real altimetry of the sea. At least they should state that the low-lying areas are now clearly safe. Hell the Maldives may become under a meter of adjusted water even though they remain high and dry.

  110. k winterkorn says:

    During La Nina, global atmosphere temps decrease compared to during El Nino phases of ENSO. This suggests that there is decreased transfer of heat from the oceans to the air during La Nina. Assuming that Solar input to the oceans is unchanged (may not be true depending on secondary cloud cover effects of La Nina/El Nino), then net ocean heat content should rise during La Nina, even though the surface waters are in general cooler in the East Pacific. If net ocean heat content rises during La Nina, then thermal heat expansion should be positive during La Nina.

    It would require substantial increase in polar and glacial ice volume to overcome the the thermal expansion effect. It becomes an empirical question whether the thermal expansion or increased ice volumes are greater in their effect on net sea level. It is unthoughtful to simply state that a decreased sea level in recent years is due to La Nina in absence of good data.

  111. P Gosselin says:

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

  112. Gendeau says:

    Why would a graph of “Mean Sea Level” be corrected apart from to give a stable reference level?

    If you want to produce a graph of “delta Mean Sea Level corrected for non-vertical sea-shores” (or anything else) – fine!

    But it is NOT a graph of “Mean Sea Level” anymore. This stinks of incompetent science allowed by political interests. Sack incompetent scientists, and keep doing it until we end up with competent scientists with morality.

  113. tty says:

    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.

  114. John Blake says:

    Publish your base-data aligned with new-and-improved (sic) model adjustments/reconstructions, and disinterested observers will readily determine just what these terminally mendacious hoaxers have cooked up.

    But yes, we have no bananas today.

  115. Bulldust says:

    Wonderful … another statistic rendered unusable due to human tampering. You people pay tax dollars for this? I know, I know … glass houses … stones … Aussie governments are just as bad :)

  116. Theo Goodwin says:

    1776 No taxation without representation.

    2001 No adjustment without scientific justification.

  117. Hu McCulloch says:

    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).

  118. Scott Covert says:

    Post a graph of GSML, not some hybrid Delta Sea Volume Level.

    If you want to plot Sea Volume change, get all the factors, sea floor contour, sedimentation, irrigation runoff, land ice melt rates, barometric profiles, sea water expansion, gravimetric profiles from satellite data, etc…

    Adjusting seal level biasing on only one factor does not depict sea surface level relative to ground level. If you want to prove AGW by how much ice is melting and thermal expansion, you need to track sea volume, not sea level. Leave the sea level data alone and get a grant to calculate sea volume.

  119. Mike Jonas says:

    P. Solar says:”Could anyone with a pre-adjustment copy pastebin it somewhere and post a link?

    http://wattsupwiththat.com/2011/05/05/new-sea-level-page-from-university-of-colorado-now-up/#comment-654150

  120. Matt G says:

    “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.”

    This makes little sense because GIA correction is balanced in different areas of the world. When one side sinks the other rises, it doesn’t affect global sea level, only the areas where this occurs. Fair enough this is not actually mentioned as the reason, but how about the change form natural volcanism? Sea levels change over thousands of years also due to changing lands masses under the ocean when igneous rock displaces water from oceanic volcanoes. This easily dwarfs any material moved by flow of the ocean currents, so how can this material lost be larger than material put into the oceans from volcanoes? Where is the evidence which outweighs which? I currently see this as unfounded and not supported by evidence used to alter results to follow predictions.

  121. Mike Jonas says:

    Buzz Belleville says: “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.

    You are quite right, but give people a bit of a break. After Climategate etc, there is a huge amount of scepticism about all data. If Colorado Uni are above-board – and I see no reason to suppose otherwise – then I’m sure that will come through here in due course.

    Hank Hancock – A quick read suggests that Dr. Peter Bromirski is referring to local sea level, not global.

  122. A G Foster says:

    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. –AGF

  123. 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.

  124. George E. Smith says:

    “”””” Matt G says:
    May 6, 2011 at 1:37 pm
    “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.”

    This makes little sense because GIA correction is balanced in different areas of the world. “””””

    Well it doesn’t make any sense at all. The purported negative effect of sea level rise, is how far underwater New York gets.

    So who cares that the rise isn’t as much as it should be, because Joe is filling his swimming pool. All that matters is how much the sea level rises; not what all the gory details are. Where would we be if everybody was making adjustment to come up with a figure that would be correct only if what is happening, is not happening ? Totally asinine to make corrections for anything that is happening, so that the sea level then would not rise at all if those things didn’t happen.

  125. Gendeau says:

    “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

  126. KD says:

    To GIA or not to GIA that is the question!

    Perhaps a good place to start would be with WHY we care about global sea level in the first place, no? As several have pointed out, in a nut shell, we care because we want to know when to move our house away from the beach (deliberately simplistic and flip).

    That being the case, the only thing one should care about is the sea level relative to the land, and the rate of change of said relative sea level. In this case, the GIA is a “good guy”, helping prevent disaster, so adding back an increased rate of rise is an ALARMIST action, ie one undertaken to artificially increase the apparent rate of seal level rise which will certainly be misunderstood by the masses, especially the mass media.

    I would say this is typical of the CRY WOLF climate “science” community..

  127. Jerry from Boston says:

    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?

  128. Maxbert says:

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

  129. Betapug says:

    Some useful information and illuminating diagrams on Mean Sea Level and its significance for surveying in Canada : http://www.geod.nrcan.gc.ca/hm/msl_e.php

    I note MSL levels referenced to satellite defined datum vary +or – 2metres over the globe. Does the ocean surface topography meander around in the short and long term?
    I feel quite queasy!

  130. A G Foster says:

    Re. Climateforall at 1:49: So do you think this is a permanent decline? It’s done this before and it always goes back up. I’d laugh as much as anyone if sea level went down, but I sure don’t expect it, and if it happens it might mean the deep freeze is upon us. You probably don’t understand anything about the LOD problem, so I’d advise you to look it up. LOD sets constraints on possible sea level rise; repeated claims of recent tripling not only fly in the face of the sea level data, but they fly in the face of LOD. The earth can’t be speeding up while ice is melting at catastrophic rates.

    Pass the binky? –AGF

  131. Geir Aaslid says:

    What do real sea-level-rise scientists have to say about this computer model showing a trend of rising sea level?
    Nils Axel Mörner is a geologist who goes out to measure actual sea level rise , or the lack of it, instead of peddling “snake oil” computer models.
    As can be seen from this link, already in 2007 Mörner stated there was no sea level rise whatsoever. He has also pointed out the the computer models used by IPCC and fellow travelers are operating with “adjusted data”, justifying this by saying “otherwise we cannot get a trend of rising sea level”. A quick Google search shows that Mörner today confirms there is still no trend of sea level rise.

    So why should we take this computer model from the Uni of Colorady seriously at all?

  132. Dan in California says:

    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.

  133. David Burton already beat me to determining MSL, using existing tide gauges.

    Thank goodness. It would have taken me months to do the calculations.
    0.61 mm/year.

    Though before we get our hopes up, RealClimate already “debunked” him, saying that his calculations are not peer-reviewed and doesn’t take into account GIA.

    In regards to tide gauge mean sea level averages, what purpose does it serve to include an adjustment for GIA?(rhetorical)

    Tide gauges are one dimensional readings though. Simply height.

    GIA is about 3D volumetric displacement of land mass, due to uplift from ice sheet loss, and giving a value to correct a means for that displacement of land mass.

    So while we’re at it, lets adjust for subduction, sinkage, sea wave erosion, lava buildup, island construction(my favorite), and any other phenomena that adjusts the height of any given tide gauge.

    We can’t though, because each tide gauge is not affected by one or more phenomena that another tide gauge might be affected by.

    That is why the GIA correction can only be applied to satellite altimetry data.
    This only allows the alarmist community to confuse the issue, using convoluted models to support their propagandization.

    The actual, physical observance of existing tide gauges the world over show only a 0.61 mm/year rise in the historical registry.

    Which leads me to wonder where all that rise is hiding at.

    If we don’t see any physical evidence at known tide gauge sites, then all the rise must be happening wherever man is not present.

    Those 50 mile long, remote, uninhabitable beach fronts must be 10 feet under water right now.

  134. P. Solar says:

    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.

  135. P. Solar says:

    The rate of change plot shows the differences in the new data that are not obvious in the straight difference Mike Jonas provided here : http://members.westnet.com.au/jonas1/ColoradoUniDiff.jpg

  136. P. Solar says:

    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!

  137. P. Solar says:

    Another revealing view of what has been sneaked in with the data revision. Looking a plot of second differential we see some significant difference in behaviour around 1998. There is more to this than meets the eye and the other “tidal” adjustments are more subtle than a fix slope you can subtract “if you don’t want it”.

    The old data showed what may be an expected response to the globally hot year of 1998, a sudden acceleration in GMSL that has been receding since (Hansen would probably call this rebound).

    What the new massaging has done is to even out this feature so as to produce a steady rise in place of the expected step rise and subsequent fall.

    This looks dangerously like P. Jones’ attempt to rewrite climate history and rub out the post war cooling with his bucket cooling hypothesis.

    Did someone already call this “hide the decline 2″ ?

  138. Phil R says:

    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.

    Maybe I don’t understand, but my question is then why add anything if it has “no effect on the rate of rise.” It’s not the rate, it’s the alarmism. Why not just add 3 mm, or 3 cm (or 3 m), “to all plotted points.” That would still have “no effect on the rate of rise,” but would sure scare a lot of people if they could be convinced that sea level rise was worse than we thought.

  139. peter_ga says:

    I was wondering how this trend in sea-level was correlated with other parameters such as oceanic heat content and variation in length of day from terrestrial conservation of angular momentum.

  140. P. Solar says:

    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.

  141. Paul Vaughan says:

    P. Solar, They probably don’t even realize. You should write to them.

  142. Paul Vaughan says:

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

  143. P. Solar says:

    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.

    No, you have not even read what they say then have done. They added 0.3mm per year. EVERY YEAR.

    This can be seen in the rate of change I posted.

    This does not affect the rate of change of rate of change or second differential of sea level. That gets frigged by the “adjustments” made to the tidal models and anything else they have forgotten to declare and smooths 1998 effects into a steady rise.

    We smelt a rat, now we can see it.

  144. P. Solar says:

    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?

  145. Just The Facts says:

    I didn’t find this particularly reassuring:

    “Calibration Updated: 2011-05-05

    Ideally, one would want to include all of the available tide gauges in the calibration. A number of gauges, however, have a significant lag in reporting of records and are not available for the Jason calibration. On the other hand, some others do not extend backward through most of the T/P mission. We have restricted the ~100 available gauges to a set of 64 near real-time stations that span the majority of both the T/P and Jason missions, and will therefore provide a relatively consistent calibration for both.”

    http://sealevel.colorado.edu/content/calibration

    Considering the “relatively consistent calibration” and large variations seen in the calibration data, i.e. 1 – 2 mm/year swings:

    “adding a correction of 0.3 mm/year due to Glacial Isostatic Adjustment (GIA),” seems suspect. The method for measuring sea level changes appears quite antiquated;

    http://sealevel.colorado.edu/content/tide-gauge-sea-level

    and I am curious about the ~36 tide gauges that aren’t “near real-time stations” and aren’t included “in the calibration”.

    Perhaps the University of Colorado should spend more time improving their measurement and calibration techniques and less time trying to explain away the failure of sea levels to follow the Catastrophic Anthropogenic Global Warming Narrative…

  146. savethesharks says:

    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

  147. savethesharks says:

    P. Solar says:

    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.

    =========================

    Bravo and agreed. Keep up the good work.

    And yes…the smell of a rat…is getting rather strong.

    Chris
    Norfolk, VA, USA

  148. wayne says:

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

  149. savethesharks says:

    Just The Facts says:
    May 6, 2011 at 10:02 pm

    Perhaps the University of Colorado should spend more time improving their measurement and calibration techniques and less time trying to explain away the failure of sea levels to follow the Catastrophic Anthropogenic Global Warming Narrative…

    ===================

    Extremely well said.

  150. TimC says:

    @ 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.

  151. TimC says:

    @ P Solar: I’m afraid you are reading more into the GIA adjustment than it deserves. It’s all about comparing like with like. Due to GIA the ocean basins are physically getting larger which – 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 actually 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 size” datum was the right way to go.

  152. P. Solar says:

    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.

  153. ImranCan says:

    Completely bizarre correction. Either the sea level is going up or it s going down presumably its measured against some geodetic surface …. and there are many factors that might make it go up or go down …. why suddenly not include one that makes it go down ???? Lets just take that logic to an end member state … lets just assume that this GIA was a much larger effect .. say -5mm/year. So even though sea level was actually going down, they would state that it was going up …. bizarre.
    The truth is they couldn’t show an updated graph with sea level rise now only being 2.8mm/yr. That just wouldn’t fit the story that this problem is accelerating – its worse than we thought.

  154. Dave A says:

    @Green Sand – “NOBODY expects the Glacial Isostatic Adjustment!

    Thanks for the LOL :-)

    @Doug Proctor – Cheers Mate

    Dave

  155. TimC says:

    @ P Solar: thanks for that. Let’s take a worked example: suppose (to keep it simple) at 2000.0 the ΔMSL figure was 8.0 mm (no GIA adjustment) and the GIA adjustment was 6.0 mm. In 2100.0 suppose the figures are then ΔMSL 318.0 mm (no GIA adjustment) with GIA of 36.0 mm.

    These figures are enough to say it all, whichever way round you wish to give out the data.

    Your way: “In 2100.0 we know that a century beforehand sea levels were actually at 8.0 mm. Due to GIA effects that figure has now become -22.0 mm, against the current actual figure of 318.0 mm, a MSL rise of 340.0 mm”.

    My (and I think CU’s) way: “In 2000.0 the GIA adjusted MSL figure was 14.0 mm. The adjusted figure today is now 354.0 mm, a MSL rise of 340.0 mm. The current GIA adjustment is 36.0 mm”.

    I really don’t think much turns on it, either way!

  156. TimC says:

    @ 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!

  157. Gilles says:

    so to summarize they now publish a virtual sea level that would have existed without GIA ?

    looks very much like the virtual astrological signs that would be correct without the precession of the equinoxes, doesn’t it ?

  158. Paul Vaughan says:

    TimC May 6, 2011 at 11:36 pm
    “[...] the 2nd order differential by time. This isn’t affected at all by the GIA adjustment [...]“

    What is the academic mainstream rationale for assuming constant GIA?

  159. Paul Vaughan says:

    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.

  160. batheswithwhales says:

    I don’t get it.

    If mantle material is moving from under the oceans to compensate for land rise because of glacier melt, it means that the sea basin gets deeper, thereby hiding the increase in sea water.

    But what is Colorado actually measuring? Changes in sea level or changes in the total amount of sea water?

    It seems to me they overnight changed interest from one to the other

  161. Mark says:

    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.)

  162. Mark says:

    Dave A says:

    From http://sealevel.jpl.nasa.gov/technology/

    From its vantage point 1336 kilometers (830 miles) above the Earth, the US/European Jason-1 and OSTM/Jason-2 ocean altimeter satellites measure the height of the ocean surface directly underneath the satellite with an accuracy of 4-5 centimeters (better than 2 inches).

    n.b. centimetres not millimetres :-)

    So where does the 0.4mm accuracy claim on the graph come from? If the original data is only accurate to 40-50mm. Any data processing tends to increase the level of inaccuracy, in certainly isn’t going to reduce it by two orders of magnitude.

  163. AJStrata says:

    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.

  164. See the two very interesting graphs on the bottom of this page:

    http://climate4you.com/SeaTemperatures.htm

    Agust

  165. Paul Vaughan says:

    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.)

  166. Lars P. says:

    The “Colorado correction” – I fear the name will stick.
    GIA adjustment is only part of the story. The trend resulted from data is different to the one before, the relative values of the last years to each other have changed significantly.
    How can historical data change? It reminds me of the temperature record where 1934 keeps on getting colder with the time, same with 1998 (but not so fast).
    Look at 2002-2010 in the new and old graph. It is totally different giving a different trend, more then GIA adjustment would give.
    This cannot be with real data.
    Btw, if the GIA effect would be real it would mean the oceans should be now 60 cm lower then at roman optimum.

  167. TimC says:

    @ 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!

  168. Just The Facts says:

    Agust Bjarnason says: May 7, 2011 at 10:05 am

    See the two very interesting graphs on the bottom of this page:

    http://climate4you.com/SeaTemperatures.htm

    Thank you. I’ve added climate4you’s Global Mean Sea Level Change graph;

    to WUWT’s Global Climatic History Reference Page;

    http://wattsupwiththat.com/reference-pages/global-climatic-history/

    Ocean Reference Page;

    http://wattsupwiththat.com/reference-pages/ocean/

    and ENSO Page:

    http://wattsupwiththat.com/reference-pages/enso/

    In addition, I’ve changed the title of the University of Colorado graph on all pages to Global Mean Sea Level Change with a “Correction” of 0.3 mm/year added May, 5th 2011, due to a “Glacial Isostatic Adjustment (GIA)” and added links to their Calibration and Release Notes pages in the Source Guides at the bottom of each Reference Page.

    The Release Notes;

    http://sealevel.colorado.edu/content/release-notes

    deserve scrutiny, as the most recent release has many more changes than any of the previous releases noted. Why?

  169. charles nelson says:

    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?

  170. Ian says:

    Yes, they always have to UPdate the new data and DOWNgrade the old data to get a nice spike in measurements that can only be attributed to CO2 forcing. It’s the new science, if the data doesn’t fit your hypothesis than the data is obviously wrong.

  171. Mike Jonas says:

    A G Foster says: “The earth can’t be speeding up while ice is melting at catastrophic rates.

    The argument here, as I understand it, is that a rising sea level increases the Earth’s diameter and hence LOD must increase. Someone please say if I’ve got it back to front, because it seems to me there’s a factor going the other way, and it’s this : sea level is affected mainly by melting land-based ice rather than by melting sea ice. But the land-based ice starts off above sea level, in some cases a long way above sea level, so by melting it moves in towards the Earth’s centre, not away. Hence its effect is to shorten LOD, not lengthen.

    P. Solar says: “The rate of change plot shows the differences in the new data that are not obvious in the straight difference Mike Jonas provided here : http://members.westnet.com.au/jonas1/ColoradoUniDiff.jpg

    The linear trend in the straight differences (MS Excel Trend() function) is actually 0.24mm p.a. (4.3mm over 17.8 years). Maybe the wild changes up to 2002 (the TOPEX period) make it hard to see.

    I have done another couple of graphs, using the new data, which I think are illuminating: I did a least squares linear fit for two line segments, where the ‘flex point’ was itself optimised not pre-chosen:

    It clearly shows how the rate of sea level increase has slowed (from ~3.53mm p.a. to ~1.94mm p.a).
    The second graph has the first trend line extended:

    It shows that the 2010 El Nino was insufficient to bring the sea level back to the original trend. To my mind, that indicates that the cause of the lower recent rate is not the La Ninas, as Colorado Uni suggest (they don’t claim it, only suggest it), but could be the PDO phase. The reasoning behind this is that El Ninos in the past appear to have caused at most temporary increases, not a change in trend. There is presumably no reason why La Ninas should behave differently.

    I have emailed the graphs and this suggestion to Colorado Uni for their comment.

  172. Catcracking says:

    Consider me skeptical
    Anyone else suspicious as to the timing of these adjustments?
    Surely they didn’t just now learn that there is a GIA effect (although I doubt they really understand quantitativly how to calculate the effect).

    It seems they did not like the story the raw data was now indicating and they needed to muddy the water to keep the CAGW agenda alive by suddenly introducing a new factor. At least they did not hide the fact that new adjustments were added, but the CAGW folks have a story to ignore the decline that will never reach the MSM propaganda.

    As I recall the same thing happened with the ARGO sea buoy data. The raw data had to be adjusted before it could be released since the facts did not support the claim that the heat is accumulating in the ocean.

    I’m an engineer, show me the raw data, adjusted data is always subject to intense scrutiny.

  173. A G Foster says:

    Paul Vaughan says:
    May 6, 2011 at 9:11 pm
    A G Foster, What’s the academic mainstream rationale for assuming constant GIA?

    It’s based on the fact that the ice load from the Last Glacial Maximum has been gone for 8,000 years. Over the long haul it’s not constant, but asymptotic. Moreover the LIA could be complicating things–much melting, warming, and rebound could be due to the LIA, a lot smaller but more recent than the LGM. LOD history since Galileo strongly suggests a response to the LIA. The current static LOD could very well be due to LIA GIA. –AGF

  174. A G Foster says:

    Mike Jonas says:
    May 7, 2011 at 3:35 pm
    A G Foster says: “The earth can’t be speeding up while ice is melting at catastrophic rates.”

    George Smith could sympathize with you. Elevation has nothing to do with it–the inertial arm is measured as the cosine of the latitude: near zero at the poles and near unity near the equator. Of course the ocean isn’t sitting on the equator–its effective average is 63 degrees as I recall. So any land based ice beyond that latitude (north or south–sea ice doesn’t do anything) will slow the earth down when it melts–until it’s done and inelastic rebound kicks in. Then the earth speeds back up.

    This stuff got kicked around a few weeks back in a discussion on LOD stat analysis–forgot the author’s name. Mulholland posted a reference. –AGF

  175. TimC says:

    @ 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

  176. DirkH says:

    Sea level scientists don’t want to leave all the cheating, adjusting and lying to climatologists. Scientific race to the bottom. Fire them all.

  177. batheswithwhales says:

    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.

  178. Mike Jonas says:

    A G Foster and TimC – thanks for your replies. I should have done more thinking and reading first!

    About GIA : Have I got this one stuffed up too? The Colorado Uni web page says “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.“. So the GIA adjustment doesn’t relate to actual sea level at all – it is explicitly a sea level increase which has not happened. So there are no circumstances in which adding in the GIA adjustment is meaningful for sea level. All uses of the Colorado Uni sea level data should always therefore first deduct 0.3mm p.a.

  179. Jim says:

    “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.

  180. Jim says:

    @TimC : What is it about the definition of sea level RISE that you don’t understand???

  181. mike g says:

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

  182. mike g says:

    Something fishy about the LOD stuff, too. If ice melts from high elevation and flows into the sea, raising the sea level, how can anybody say lengthens the day? That water is getting closer to the center of mass, which would speed the rotation, not slow it. And, if magma flows under formerly glacier covered land, raising the land level, didn’t it have to flow from somewhere else, lowering the level where it came from? Maybe liquid rock is a lot more compressible than I’m giving it credit for being? Why does every imaginable natural phenomenon trend in the favor of warmists or else the data has to be massaged until it does?

  183. mike g says:

    @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.

  184. TimC says:

    @Jim: excuse me?

    Sea levels are rising according to all the satellite altimetry measurements, compared with measurements as at past dates.

    The ocean basins are also getting bigger according to the recent GIA analysis. This has the effect of slightly reducing the sea levels.

    If you would rather take actual rises, net of the GIA reductions, just reduce the figures by 0.3 mm/year as CU suggest.

    If you would rather focus on interesting data such as the total volume of water in the oceans (to get a handle on whether the net amount of water running off icesheets and glaciers is increasing due to higher global temperatures, or staying pretty much constant) you have to add the GIA adjustment, as CU are now doing, to get the true level of rise due (principally) to increases in the volume of water in the basins – ie. the water run-off from land-based ice.

    Clear now?

  185. ImranCan says:

    @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.

  186. Paul Vaughan says:

    Not satisfied with the responses to my Qs:

    “What is the academic mainstream rationale for assuming constant GIA?”
    “What’s the academic mainstream rationale for assuming constant GIA?”

    Anyone able to succinctly answer the Q as posed?

  187. TimC says:

    @ 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.

  188. Paul Vaughan says:

    P. Solar, I’ve just taken a look at interannual GMSL’ & GMSL”. You’ve got a serious leverage problem in your trend lines because of seasonal components. For each difference you take, you need to integrate over dominant modes. Bear in mind that the further y-outliers are from the x-mean, the worse the leverage problem. Your seasonal components are introducing a leverage problem in the worst possible place – i.e. at the extremes. I recommend trading your gaussian filters for repeat 1 year moving averages for starters. (The dominant temporal mode of terrestrial variations is KNOWN, so gaussian isn’t the best option.) You’ll need 1 application on the raw (non-anomaly) data and then n additional applications for the nth derivative. See Maraun & Kurths (2005) section 3 for more. Sometimes repeat 6 month smoothing is also needed; it depends on the nature of the series (i.e. on whether there’s a semi-annual component).

  189. Paul Vaughan says:

    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.

  190. Gary Pearse says:

    TimC & Foster

    Your view of this matter is clear – it is useful to know what the changes in ocean vol are and you are happy to learn that the bucket changes +0.3*A of ocean in mm^2. Surely you are aware, though that the issue of d msl has been entirely about inundation of low-lying countries and regions and the catastrophe to be wrought.

    To cripple real and useful data to morph it into some completely different and less useful metric has got to be viewed with great scepticism, especially when the higher numbers obtained will then be illegitimately used for the same purpose (watch and see if I am wrong). How are you going to handle the Maldives being under a metre of virtual seawater and yet remain high and dry – why should a country, harbour engineer or navigator have to subtract a factor added on to the sea level series to find out how much actual water they’re dealing with. You had the hubris to say that only a few commenters showed that they understood the issue. Indeed, you showed yoirself to be acquainted with the smaller egghead issue that allowed you to add value to your smaller specialty of LOD. The commenters you impugn rightly understand the larger issue here.

  191. TimC says:

    @ 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.

  192. A G Foster says:

    Re. Gary Pearse at 1:23:

    No rational person can ever make a catastrophe out of a sea level rise of 30cm/century. The only way Hansen could make any case at all was by claiming a tipping point for Greenland–if melting hits a certain point the ice basin could collapse, leading to melting unprecedented in the last 100,000 years. But posters here have aptly pointed out on other 0ccasions that during much warmer periods that never happened. I’ve spend some effort in other arenas showing what a farce the Bangladeshi sea threat is: land subsidence due to millions of tube wells is orders of magnitude greater than sea level rise. Sedimentation due to supposedly increased Himalayan melting is also on the rise, and seemingly quite able to keep up with current and future sea level rise. Beach formation continues to be reported on the Ganges Delta. Yes, the threat of sea level is a complete farce–none of us said otherwise. I’ve countered anthropologists who claimed Eskimo villages were being inundated, noting that low lying Pacific islands are usually the more recently populated–they are periodically annihilated, and it has always been like that. They couldn’t care less between 10 meter waves whether the sea has gone up or down a foot in the last century.

    But that doesn’t mean that every effort should not be made to accurately gauge the true ice/water balance on the planet, and I applaud CU for its efforts to do just that. So here’s the skinny on LOD and GIA. Over a century ago Assyrian tablets were deciphered which showed eclipses occurring two hours off what would be expected, so astronomers compiled data from these, Chinese and Greek sources to determine the rate of the earth’s rotational deceleration. George Darwin, son of Charles, calculated that the earth and moon separated two and a half billion years ago. This deceleration was attributed to tidal friction: a constant tidal bulge lags and drags 2 hours behind the maximum tidal pull.

    With the first primitive satellite telemetry it was discovered that the earth is shaped like a pear, and the flat top was attributed to the fact that the globe was still recovering from the last ice age. Then mirrors were put on the moon and laser ranging produced the rate of lunar recession. The comparative contributions of lunar and solar tides are easily calculated, and the loss of terrestrial angular momentum to the moon could be determined by the lunar laser ranging (LLR).

    Atomic clocks were put into action back in the 50’s, when LOD was determined mainly by stars crossing a telescopic view, and LOD could be studied with new precision, and compared with what LLR showed showed was due to tides (2.3ms/century). LOD increase calculated from ancient eclipses was only 1.7ms/century. The difference was attributed to GIA, .6ms/century.

    But since the invention of atomic clocks no such deceleration has been detected–rotation has been up and down but stable on average (google “leap second” in Wikipedia). This presents a considerable problem for proponents of dangerous melting, since after all, melting is what sets the globe up for the following rebound. Just as the globe speeds up due to rebound, it slows down due to melting, and all this happens because the mantel is part elastic and part plastic. That is, there is instanteous GIA due to loading and there is slow, inelastic GIA, still going on 7000 years after the ice disappeared. The .6ms/century is a fairly reliable estimate of LOD change due to GIA. But the current acceleration is possibly due to GIA from the LIA, or heavy snow in Antarctica, or both.

    At any rate, far from advancing the cause of the alarmists, LOD is a serious problem that most alarmists don’t know anything about. Just like they don’t know anything about Capt. Cook’s hundred foot pack ice. We skeptics like to think we are smarter than the warmists, so it’s somewhat dismaying to see legitimate science condemned as warmist propaganda–it hardly helps our cause. –AGF

  193. Mike Jonas says:

    TimC – Colorado Uni are supposedly giving us sea level data. The data is called “Global Mean Sea Level Time Series”, “Raw Data”. If I want the sea level, I now have to take 0.3mm p.a. off their data, because the data is not raw, it has been adjusted by something which is explicitly not part of the actual sea level. There are no circumstances in which I can obtain a sea level without taking 0.3mm p.a. off their data. How stupid is that?

  194. ImranCan says:

    @TimC
    I am not sure how to say this more clearly.

    1) If they are removing factors like ‘basin size’ then they are no longer reporting sea level (whether it is a delta or an absolute). They are reporting something else. I have taken it up directly with CU.

    2)The mantle is not molten. There is NO magma flowing around and making basins bigger. What is ‘flowing’ is mantle rock – at that temerature and pressure it behaves like a plastic and has rheological properties that allow it to flow. At surface the rocks name is peridotite and it is mostly composed of magnesium and iron minerals like olivine and pyroxene. Magma (which you keep referring to) is what comes out of volcanoes or mid ocean ridges is created via different processes such as mantle upwelling which causes decompression resulting in partial melts – that is liquid magma.

    You can’t just ‘wing’ these terms and bandy thenm around without displaying ignorance. Sea level is sea level (and not volume) and the mantle is the mantle (and not magma).

  195. TimC says:

    @ 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?

  196. ImranCan says:

    @Tim C
    There is always a danger when one uses Websters as a basis for proclaiming scientific knowledge.

    The mantle is not liquid. It is a viscous solid. And there is not a pool of magma which is flowing around down there. Magma is a very specific product of partial melt of mantle material caused under specific circumstances upwelling at eg. mid ocean ridges and/ or mantle plumes (like under Hawaii). It is true that magma originates from mantle rock, but it is not present generally.

  197. TimC says:

    @ 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.

  198. ImranCan says:

    @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.

  199. wobble says:

    TimC says:
    May 8, 2011 at 6:52 am

    If you would rather take actual rises, net of the GIA reductions, just reduce the figures by 0.3 mm/year as CU suggest.

    If you would rather focus on interesting data such as the total volume of water in the oceans (to get a handle on whether the net amount of water running off icesheets and glaciers is increasing due to higher global temperatures, or staying pretty much constant) you have to add the GIA adjustment, as CU are now doing, to get the true level of rise due (principally) to increases in the volume of water in the basins – ie. the water run-off from land-based ice.

    No, if CU is claiming to report “Sea Level” then they shouldn’t be adding a 0.3mm/year correction to their sea level graph.

    It would be much more credible for CU to have another graph titled “Sea Volume” which adds the 0.3mm/year correction.

    Interestingly, CU is now claiming that:

    Sea Volume Rate of Increase = Sea Level Rate of Increase + 0.3mm/year.

    Yet they are keeping the misleading title of “MSL” on this graph.

    My question is, if Sea Volume stops increasing at all, does that still mean that Sea Level will be DECREASING by 0.3mm/year?

  200. TimC says:

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

  201. I think the “GIA Corrected note” under the upper left legend to be wholly inadequate. For instance, what GIA correction? Today it is 0.3 mm/yr for the past 15 years, Last month it was nothing. What will it be next year? So it is inexcusable not to be specific here about the amount and direction of the GIA correction.

    CU should put the “With +0.3 mm/yr GIA Correction” immediately below the “Seasonal signals removed.” Note in the lower right.

    What could be the objection to this extra bit of documentation? … Unless you prefer to hide the decline of the the rate.

  202. Gary Pearse says:

    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.

  203. Catcracking says:

    TimC says:
    May 7, 2011 at 6:48 pm
    @ 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

    Tim,
    Obviously you miss my point that it is not a coincidence that they suddenly now incorporated a new correction factor to mislead people by to “hide the decline”. Why did they not apply it earlier?

    As you point out they did not just learn about it yesterday, since the date of your referenced referenced papers on the subject is 2003 and 2007.

    The MSM will conviently report the “corrected” numbers rather than the raw data to keep the fear of rising sea level on the table.

  204. TimC says:

    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!)

  205. A G Foster says:

    Re: Gary Pearse says:
    May 9, 2011 at 11:45 am

    I assure you I am no expert on the subject. For genuine expertise see Richard S. Gross in “Treatise on Geophysics,” vol. 3, 239-294: “Earth Rotation Variations–Long Period.” If you are affiliated with an institution this can be requested online at

    http://www.elsevier.com/locate/permissionusematerial

    And I have to agree with TimC–we’re making a mountain out of a molehill here. We certainly would insist on corrections for shoreline subsidence, so why not basin subsidence? But then I would have to agree, it could no longer be called “sea level data” –sea depth data, yes. But it never was “raw” data. As for timing, I don’t think they expect it to keep going down. It’s been rising for 7000 years, fairly steadily. This 10% correction is not in the same ballpark with claims of “tripling.” It is a step forward, however clumsy.

    We need to be able to step back and forth across the divide between paranormal alarmist science and normal science, and to distinguish between the two. If the pseudoscience didn’t exist nobody would be complaining here, and the alarmists are not to be taken seriously in a discussion between serious scientists. –AGF

  206. wobble says:

    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!

  207. wobble says:

    A G Foster says:
    May 10, 2011 at 7:24 am

    As for timing, I don’t think they expect it to keep going down.

    I agree that they don’t expect it to keep going down.

    But the idiots that made silly claims about future sea level rise probably didn’t take the increasing size of the basin into consideration. Those silly claims need some support in order to prevent embarrassment.

    Utilizing this adjustment and continuing to call it sea “level” provides a bit of support.

  208. A G Foster says:

    It would be not only interesting but useful to compile a list of those who have made the unsubstantiated claims of sharp sea level rise. Time to google. –AGF

  209. EM says:

    sealevel.colorado.edu does not respond this morning.

  210. Matt says:

    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?

  211. Lars P. says:

    They are doing it the wrong way.
    If the continents are rising the sea level rise is the satellite measurement minus(!) continental rise.
    So the value that makes sense is to subtract the GIA from measured sea level, resulting in a 2.6 mm/year sea level rise which comes closer to the tide gauge sea level estimates.

  212. Geo Jack says:

    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.

  213. P. Solar says:

    Including the GIA correction has the effect of increasing previous estimates of the global mean sea level rate by 0.3 mm/yr.

    my bold. Note this is not just the sea level but the rate of change of sea level. Assuming what they have written is correct that is not a linear but a quadratic increase (an accelerating increase) in GMSL.

    … we would like our GMSL time series to be a proxy for ocean water volume changes. This is what is needed for comparisons to global climate models, for example, and other oceanographic datasets.

    Well that would explain it. A quadratic increase in GMSL (volume proxy) would give a quadratic increase in total heat energy. This is exactly what would be the result of an exponential increase in CO2 ( ln(exp(CO2)) = linear forcing = quadratic rise in Temp ).

    It’s hard to see how the mantle rebound could be acceleration 11000 years down the line. They have just written themselves a “CO2 fingerprint” into the data with this change.

    It’s a small adjustment but every little helps. As the temp record starts to diverge from the CO2 trend , this will ease it back into line.

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