Oh say can you see modern sea level rise from a geological perspective?

Guest post by David Middleton

Experts say the IPCC underestimated future sea level rise

A new study surveys 90 sea level rise experts, who say sea level rise this century will exceed IPCC projections

Wednesday 4 December 2013

John Abraham

It looks like past IPCC predictions of sea level rise were too conservative; things are worse than we thought. That is the takeaway message from a new study out in Quaternary Science Reviews and from updates to the IPCC report itself. The new study, which is also discussed in depth on RealClimate, tries to determine what our sea levels will be in the future. What they found isn’t pretty.


According to the best case scenario (humans take very aggressive action to reduce greenhouse gases), the experts think sea level rise will likely be about 0.4–0.6 meters (1.3–2.0 feet) by 2100 and 0.6–1.0 meters (2.0–3.3 feet) by 2300. According to the more likely higher emission scenario, the results are 0.7–1.2 meters (2.3–3.9 feet) by 2100 and 2.0–3.0 meters (6.5–9.8 feet) by 2300. These are significantly larger than the predictions set forth in the recently published IPCC AR5 report. They reflect what my colleagues, particularly scientists at NOAA, have been telling me for about three years.

The Guardian

Definition of climate “expert”: A parrot that can only say, “things are worse than we thought.”

The assertion of 0.7 to 1.2 meters (700-1200 mm) of sea level rise by 2100 is 100% unadulderated horse schist! This scenario would require an acceleration of sea level rise to a rate twice that of the Holocene Transgression and an average ice melt rate 24 times that of deglaciation. It is even highly unlikely that sea level will rise by as much as the ostensibly optimistic scenario (400-600 km). 

A Geological Perspective of Recent Sea Level Rise

All of the estimated sea level rise since 1700 is represented by the light blue blob and dark blue line inside the black oval. Sea level isn’t doing anything now that it wasn’t already doing before All Gore invented global warming. And Holocene sea level changes have been insignificant relative to the Holocene transgression…
Figure 1. Sea 1evel rise since the late Pleistocene from Tahitian corals, tide gauges and satellite altimetry.

Adaptation: “It’s déjà vu, all over again!”If mankind and our infrastructure adapted to this…

Figure 2. Northern Hemisphere temperature, atmospheric CO2 and sea level since 1700 AD.

We can adapt to this without breaking a sweat…

Figure 3. Projected sea level rise through 2100 AD.

Particularly since sea level rose just as fast from 1931-1960 as it has risen since 1985…

Figure 4. Paracyclical sea level rise since 1931.

Anyone threatened by 6-12 inches of sea level rise over the next 85 years is already being flooded by high tides and/or storm surges. The red areas on this EPA map would be threatened by 1.5 meters of sea level rise.

Figure 5. Coastal areas threatened by 1.5 meters of sea level rise along US Gulf Coast (US EPA).

Bear in mind the fact that it would take an average rate of sea level rise nearly twice that of the Holocene Transgression for sea level to rise more than 1.5 meters (~5 feet) over the remainder of this century. This caused sea level.to rise by ~10 mm/yr for about10,000 years…

Figure 6. Animatiion of Late Pleistocene to Early Holocene deglaciation (Illinois State Museum).

Approximately 52 million cubic kilometers of ice melted during that 10,000 year period.

52,000,000 km^3 ÷ 10,000 yr = 5,200 km^3/yr

The Antarctic and Greenland ice sheets were recently estimated to be losing ~213 gigatonnes of ice mass per year (Shepherd et al., 2012).. This is equivalent to 213 km^3/yr.

5,200 km^3/yr ÷ 213 km^3/yr = 24

Polar ice sheets are currently melting at about 1/24th the rate of the Holocene Transgression, if they are actually melting.

Isostacy, Eustacy, Cycles, Supercycles, Paracycles and Sequence Stratigraphy

Some have disagreed with the use of the words “cycle” and “oscillation” as they pertain to climate change and sea level. From a purely mathematical standpoint they are correct. Climate and sea level cycles and oscillations are technically quasi-periodic fluctuations. However, cycle and oscillation have become the accepted nomenclature for a wide range of quasi-periodic fluctuations and they are easier words to type.

Firstly, a couple of definitions:

Isostacy: 1. n. [Geology] The state of gravitational equilibrium between the lithosphere and the asthenosphere of the Earth such that lithospheric plates “float” at a given elevation depending on their thickness. The balance between the elevation of the lithospheric plates and the asthenosphere is achieved by the flowage of the denser asthenosphere. Various hypotheses about isostasy take into account density (Pratt hypothesis), thickness (Airy hypothesis), and pressure variations to explain topographic variations among lithospheric plates. The current model consists of several layers of different density. See: asthenosphere, eustasy, isostatic, isostatic correction, lithosphere, plate tectonics, topographic map

Eustacy: 1. n. [Geology] Global sea level variations. Changes in sea level can result from movement of tectonic plates altering the volume of ocean basins, or when changes in climate affect the volume of water stored in glaciers and in polar icecaps. Eustasy affects positions of shorelines and processes of sedimentation, so interpretation of eustasy is an important aspect of sequence stratigraphy. See: accommodation, basin, hiatus, isostasy, Milankovitch cycles, plate tectonics, regression, sequence stratigraphy, systems tract, transgression

Simply put… Isostasy is the land moving up and down; while eustasy is the water moving up and down. Sequence stratigraphy is the process of identifying depositional sequences as they relate to the cyclical rise and fall of sea level.

Figure 7. Cycles, paracyles and supercycles (AAPG).

For a detailed explanation of “relative changes of sea level from coastal onlap” see the following…

C.E. Clayton, ed., Seismic stratigraphy – applications to hydrocarbon exploration: Tulsa, Oklahoma, American Association of Petroleum Geologists Memoir 26, p. 49-212.

Or you can check out the University of Georgia’s online guide to sequence stratigraphy.

The Holocene Highstand

There are at least two schools of thought regarding Holocene sea level changes. The view favored by the IPCC and the so-called scientific consensus is that of a rapid rise in sea level during the early Holocene followed by a static quiescence from about 6,000 years ago up until the dawn of the “Anthropocene” (generally the Industrial Revolution). The second school of thought, favored by many (if not most) sedimentary geologists, is that of a dynamic Holocene sea level and a pronounced Holocene Highstand.

Figure 8. Sea level was 1-2 meters higher than it currently is during the Holocene Highstand.

Evidence for a Holocene Highstand is global in nature, consisting of stranded beaches and other facies associated with shorelines 1-2 meters higher than present day from 4-7 kya.

Amazing GRACE

Greenland is alleged to have lost between 93 and 191 gigatonnes of ice per year from 1992 (ten years before GRACE was launched) and 2011. If we assume 1 Gt of ice = 1 km^3 of ice and that the current volume of the Greenland ice sheet is ~5 million km^3 and that Greenland continues to melt at a rate of 142 km^3/yr over the next 90 years… The Greenalnd ice sheet will lose a bit more than 0.3% of its ice volume. ~142 Gt of ice per year equates to about 0.003% of ice mass loss per year. At 142 Gt/yr, Greenland will be ice-free in 35,211 years.

GRACE (Gravity Recovery And Climate Experiment) consists of two satellites, launched in 2002, that measure subtle variations in Earth’s gravitational field. GRACE is the ideal tool for measuring changes in Earth’s polar ice caps.

Figure 9. GRACE Mission (Source University of Texas).

One of the most prolific authors on GRACE has been Dr. Isabella Velicogna, UC Irvine (one of Sheppard’s co-authors). Back in 2009 Dr. Velicogna published this paper in GRL:

Increasing rates of ice mass loss from the Greenland and Antarctic ice sheets revealed by GRACE.

Dr. Velicogna concluded that the ice mass-loss was “accelerating with time.” She found that “in Antarctica the mass loss increased from 104 Gt/yr in 2002–2006 to 246 Gt/yr in 2006–2009.”

Since the launch of GRACE, Dr. Velicogna has participated in several papers on GRACE and ice mass loss estimates for Antarctic and Greenland. Each paper has presented a more dire situation than the previous one, yet GRACE has not actually measured a significant ice mass loss in Antarctica. The actual GRACE measurements indicate a net mass gain (44 ±20 Gt/yr) from October 2003 through February 2007.

Figure 10. Total Mass Difference: TMD = Actual GRACE measurements. TMD – IJ05 and TMD – ICE5G = GRACE measurements adjusted for GIA (Riva et al., 2007).

Furthermore, the GIA-adjusted Total Mass Differences (TMD) from the TU Delft publication are significantly lower than those of Velicogna 2009. GIA is the abbreviation for “glacial isostatic adjustment,” sometimes referred to as post-glacial rebound (PGR). The areas of the Earth’s crust that were covered by thick ice sheets during the last glacial maximum were depressed by the ice mass. As the ice sheets have retreated over the last 15-20,000 years, the crust has rebounded (risen) in those areas. So, the GRACE measurements have to be adjusted for GIA. The problem is that no one really knows what the GIA rate actually is. This is particularly true for Antarctica. Riva et al., 2007 concluded that the ice mass-loss rate in Antarctica from 2002-2007 could have been anywhere from zero-point-zero Gt/yr up to 120 Gt/yr. Dr. Riva recently co-authored a paper in GRL (Thomas et al., 2011) which concluded that GPS observations suggest “that modeled or empirical GIA uplift signals are often over-estimated” and that “the spatial pattern of secular ice mass change derived from Gravity Recovery and Climate Experiment (GRACE) data and GIA models may be unreliable, and that several recent secular Antarctic ice mass loss estimates are systematically biased, mainly too high.”  So, there’s no evidence that the Antarctic ice sheets have experienced any significant ice mass-loss since GRACE has been flying.

The GIA has generally been as large or larger than the asserted ice mass-loss. In 2009, Velicogna asserted that Antarctic ice mass loss “increased from 104 Gt/yr in 2002–2006 to 246 Gt/yr in 2006-2009.” In the current paper, supposedly showing accelerated melting, they claim that Antarctica is lost an average of 71 Gt/yr from 1992-2011. Both of those estimates add up to about 1,400 Gt from 1992-2011. This would mean that Antartica didn’t lose any ice before 2002 or after 2009. The steepening of the trend occurred in mid-2006. So there were 5.5 years of +72 Gt/yr and 3.5 years of -70 Gt/yr measurements. Velicogna didn’t repeat the mistake she made in 2006, when she actually published the pre-GIA (PGR) measurements…

Figure 11. Antarctic ice mass from GRACE. The blue curve is prior to GIA/PGA adjustment (Velicogna and Wahr, 2006)

Before the GIA adjustment, GRACE indicated a gain in ice mass. This means that from 2002-2006, GRACE was measuring a mass gain of 72 ±76 Gt/yr. Note: the error bar of the GIA is larger than the measured anomaly. From 2006 to 2009, GRACE recorded a net loss of 70 ±76 Gt/yr. Now, there should be some PGR or GIA. However, prior to Thomas et al., 2011 PGR/GIA had been model-derived. Now it appears that PGR/GIA is actually much smaller than the models indicated and its distribution is highly variable.

But… Let’s assume that the Velicogna GIA/PGR adjustment is correct anid ice mass loss did accelerate from 2002-2009. Where did the water go? The rate of sea level rise has decelerated since 2002. Where did all that meltwater go?

Figure 12. Decelleration of sea level rise during global warming hiatus.

More fun with numbers… Let’s assume that Antarctica is losing 190 Gt of ice mass per year. 190 Gt sounds like a really big number, doesn’t it? 360 Gt of ice melt will yield 1 mm of sea level rise. 190 Gt is good for ~0.5 mm/yr of sea level rise. The volume of ice in the Antarctic ice cap is ~30,000,000 km3. 190 Gt is roughly 0.0006% of 30 million km3. GRACE is measuring no net change in the ice mass; yet a 0.0006% annual change is being calculated from the PGR adjustment. At 0.0006% per year, Antarctica will have lost 0.06% of its ice mass by the end of this century (99.94% of Antarctica will not have melted)! And sea level will have risen by… (drum roll)… 46 millimeters!!!…{ SARC} Almost 2 inches!!! Very extreme!!! {/SARC}

A recent geoid-corrected sea level estimate using GRACE measurements (Baur et al., 2013) indicates that the actual seal level rise is about half of what Jason/Topex indicate. The GRACE value agrees with another recent and equally unpublicized NOAA study of tide gauge data.

Is Sea Level Really Rising?

In light of Baur et al., 2013, this is a fair question. I think it probably is rising, barely rising. Two of the primary sub-tectonic components of sea level change are 1) thermal expansion of seawater and 2) glacial retreat (negative mass balance, ice ablating faster than accumulating). Thermal expansion only occurs when the climate is warming.

There has been little to no net thermal expansion since the most recent phase of warming stopped. Glacial retreat will generally occur whenever the climate isn’t significantly cooling. The most recent period of significant glacial advance (positive mass balance, ice accumulating faster than melting/ablating) was during the Little Ice Age. Most alpine/valley glaciers, like Glacier National Park, reached their maximum Holocene extent during this period. Most glaciers will remain in a state of negative mass balance until the climate begins to cool on a similar scale as the Little Ice Age. This is why the average rate of sea level rise dropped from 3.6 mm/yr to ~2.7 mm/yr since 2003. However, many other factors affect sea level, it’s not rising everywhere and the rate is extremely variable locally and regionally.

However, Mörner, 2003 makes a very strong case that the adjustments applied to the raw TOPEX/POSEIDEN data actually account for all of the apparent sea level rise from October 1992 through April 2000.

Global mean sea level may be eustatically rising at a rate of ~3 mm/yr… It might be rising at half that rate or not at all. It’s definitively not rising at an alarming rate.

Oh Say Can You See… Modern Sea Level Fluctuations From a Geological Perspective?

The short answer is no.

Figure 13. Sea level rise since Middle Jurassic Period.


Bard, E., B. Hamelin, M. Arnold, L. Montaggioni, G. Cabioch, G. Faure & F. Rougerie. Deglacial sea-level record from Tahiti corals and the timing of global meltwater discharge.Nature 382, 241 – 244 (18 July 1996); doi:10.1038/382241a0

Baur, O., Kuhn, M. and Featherstone, W.E. 2013. Continental mass change from GRACE over 2002-2011 and its impact on sea level. Journal of Geodesy 87: 117-125.

Blum, M.D., A.E. Carter,T. Zayac, and R. Goble. Middle Holocene Sea-Level and Evolution of The Gulf of Mexico Coast (USA). Journal of Coastal Research, Special Issue 36, 2002.

Jameson, J., C. Strohmenger. Late Pleistocene to Holocene Sea-Level History of Qatar: Implications for Eustasy and Tectonics. AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California.

MacFarling Meure, C., D. Etheridge, C. Trudinger, P. Steele, R. Langenfelds, T. van Ommen, A. Smith, and J. Elkins (2006), Law Dome CO2, CH4 and N2O ice core records extended to 2000 years BP, Geophys. Res. Lett., 33, L14810, doi:10.1029/2006GL026152.

Miller, K.G., et al. (2005) The Phanerozoic Record of Global Sea-Level Change. Science. Vol. 310 no. 5752 pp. 1293-1298 DOI: 10.1126/science.1116412

Moberg, A., D.M. Sonechkin, K. Holmgren, N.M. Datsenko and W. Karlén. 2005. Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data. Nature, Vol. 433, No. 7026, pp. 613-617, 10 February 2005.

Nerem, R.S., D.P. Chambers, C. Choe & G.T. Mitchum. Estimating Mean Sea Level Change from the TOPEX and Jason Altimeter Missions. Marine Geodesy. Volume 33, Issue S1, 2010, pages 435- 446 Available online: 09 Aug 2010 DOI: 10.1080/01490419.2010.491031.

Riva R., B. Gunter, B. Vermeersen, R. Lindenbergh & H. Schotman. The effect of GIA models on mass-balance estimates in Antarctica. Department of Earth Observation. and Space Systems, Delft University of Technology. GRACE Science Team Meeting, Potsdam. Oct 17, 2007.

Shepherd and a long list of co-authors. A Reconciled Estimate of Ice-Sheet Mass Balance. Science, 30 November 2012: Vol. 338 no. 6111 pp. 1183-1189

DOI: 10.1126/science.1228102

Thomas, I. D., et al. (2011), Widespread low rates of Antarctic glacial isostatic adjustment revealed by GPS observations, Geophys. Res. Lett., 38, L22302, doi:10.1029/2011GL049277.

Vail, P.R., R.M. Mitchum, and S. Thompson, 1977, Seismic stratigraphy and global changes of sea level, part 3: Relative changes of sea level from coastal onlap, in C.E. Clayton, ed., Seismic stratigraphy – applications to hydrocarbon exploration: Tulsa, Oklahoma, American Association of Petroleum Geologists Memoir 26, p. 63-81.

Velicogna, I. and J.Wahr (2006),Measurements of time‐variable gravity show mass loss in Antarctica, Science, 311(5768),1754–1756, doi:10.1126/science.1123785

Velicogna, I. (2009), Increasing rates of ice mass loss from the Greenland and Antarctic ice sheets revealed by GRACE, Geophys. Res. Lett., 36, L19503, doi:10.1029/2009GL040222.

101 thoughts on “Oh say can you see modern sea level rise from a geological perspective?

    • @ Ed,
      I hate Droid. I actually wrote this post on my “smart” phone. It auto “corrects” mm to km… I actually had to change mm back to mm from km every time I typed it.

  1. Sorry, I thought the IPCC used the findings of the worlds top experts? So who are these guys to contradict them?

  2. Never mind the old climate. This is the new, manmade climate. All bets are off, and the sky’s the limit as far as what could happen. You need to get with the times, man.

    • @ Bruce,
      Geologists spend their careers in an effort to “get with the times.” We just view time a bit differently than most people.

  3. When did Science devolve into a reliance on Argumentum Ad Verecundiam instead of analysis of data? I’m disturbed that using a Delphi technique is regarded as ‘ hard science’ and overrides analysis of observational data.

  4. In the real world, an ‘expert’ has verifiable predictive skill.
    In the academic world an ‘expert’ has published many ‘papers’.
    …….And ne’er the twain shall meet!

  5. Very nice analysis.
    The only thing not covered is the “slide off” rather than “melt” alarmism. Not possible for Greenland due to geology. Theoretically possible for WAIS. But no local sedimentary evidence (e.g. from ANDRILL) that WAIS ever has in the Pleistocene. The 2 papers claiming otherwise (rapid rise near end of Eemian) are both deeply flawed. The most recent West Australia paper is so flawed it probably constitutes scientific misconduct and should be withdrawn. I posted on it at Climate Etc, titled Ice Sheet Collapse?

  6. [i]The Antarctic and Greenland ice sheets were recently estimated to be losing ~213 gigatonnes of ice mass per year (Shepherd et al., 2012).. This is equivalent to 213 km^3/yr.[/i]
    This was the average for 1992-2011. In 2012 the Greenland ice sheet alone lost 570 GT (see [url=http://neven1.typepad.com/.a/6a0133f03a1e37970b017c347585d0970b-pi]here[/url]).

    • @Les,
      That would be right after the 8.2 kya cooling event and prior to the Holocene Climatic Optimum… I’m not seeing the relevance.

  7. Excellent run down on sea level and ice loss with paleo sea level changes for backdrop. Even the promoters know that a few hundred Gt is not large and we were regaled with olympic sized swimming pools as a metric for awhile. It’s frightful when you consider all this new seawater being heated up at a rate of 4 Hiroshima bombs a second. You know that all pretense at science is being abandoned in desperation when they have to use these new scary “units” to get their shivers across. Small thing, please spell the terms isostasy and eustasy with s.

  8. David: Just offered as more information. At the least, the rate is still twice current rate.
    I just like confimring data, when I can.

  9. It is data & perspective like this the causes most all geologists to be in the skeptics camp.
    Understanding climate variations & sea level variations over geologic time scales (long before evil CO2 emitting people came along / sarc) is essential , especially in regard to anything related to sedimentation. We have seen changes in the geologic record that dwarf anything that has been experienced in modern times & thus feel very comfortable that any changes we have seen could easily be generated by purely natural cycles – as variations of this size & larger have been seen in the past. And of course there is no hard evidence that any observed change is caused by mankind – only correlation, and as we know correlation is not causation.
    Thanks providing this post & educating the readership with a geologic perspective on sea level changes & climate changes,

  10. “The Holocene Highstand” is one of those inconvenient fluctuations, like the MWP, that tends to to be avoided by people who need to walk on eggs to keep their funding. Even if no one ever said, “We need to erase Holocene Highstand,” they might as well have said it.

  11. Nautical charts have a WGS84 datum correction for latitude and longitude, to bring them into alignment with GPS. Yet nowhere do we see a datum correction for “global sea level rise”.
    If sea level rise was actually happening then the nautical charts would be the first place one would expect to see it noted. Tens of thousands of lives and trillions of dollars in commerce depend on the accuracy of these charts. A difference of just one foot in ocean depth can add thousands of miles to the route a ship must take, with significant cost implications.
    So, when the cartographers of the world add “global sea level rise” to their chart datum, then and only then can you believe it is happening. Because if the cartographers haven’t see fit to add it to their charts, then it quite simply is not significant.

  12. Brilliant.
    It takes a geologist (private sector, of course), to calmly and logically destroy one of the great pillars of the global warming cult. That great pillar is, of course, runaway rises in sea level.
    I really enjoyed the use of data from the Holocene Transgression here. I had never seen the numbers interpreted like this before.
    As the great gorebot would say, “this is an embarrassing fact” for the purveyors of alarmist scare stories.
    Private sector geologists, like you (and I),are the bane of the alarmists. We tell it like it is and use the geological record, plus real data analysis, as the tools to unravel the fantasies of what passes for so much of climate science today.

  13. The whole kaboodle smells of greenbacks!
    Many regular readers and commenters will, politely, suggest “Was it ever different?”
    Happy Christmas to ALL reading here – on both sides . . . . .

  14. Sea levels not rising fast, Arctic ice come in profusely, hiatus extending, snow in Jerusalem and finally Financial Post declares:
    For global warming believers, 2013 was the year from hell. Almost everything that could go wrong did go wrong for the cause of global warming.
    The 13th year of the third millennium Anno Domini was an unlucky one for our AGWarmista friend.
    I thought it may be good opportunity to use this 1845 prologue translation as
    the 2013 ode dedicated to our unfortunate AGWarmista friend
    Asleep under a heavy dream
    profuse of horrific visions
    hardly of a choice accessible.
    With a fleeting contemplation
    of this nightmare he’s freed,
    but alas, deceived of any hope
    sunk in an even darker realm.

  15. Surely thermal expansion of the top few metres of ocean would add more to sea level rise than land ice melt.
    Or am I missing something – I’m not a scientist.

  16. David
    Nice post thanks.
    Some of the typos my spell checker found:-
    Animatiion Animation
    Greenalnd Greenland
    Antartica Antarctica
    anid and
    Decelleration Deceleration
    You missed the source for Mörner 2003 from your list of references.
    Like you, I wonder where all the extra water is going to come from, but 400 – 600 km puts us into the realm of the outer planets 😉

  17. Experts? Ha! Ha! Ha! Don’t make me laugh! They don’t even know a fundamental property of water….. Anybody else notice it?

  18. Great graphs. Thanks. The IPCC Working Group I draft report stated the following:
    “Between 1993 and 2010, the rate was very likely higher at 3.2 [2.8 to 3.6] mm yr–1; similarly high rates likely occurred between 1930 and 1950.” I wondered why they didnt state what those high rates were in the 30s and 40s. Now I know. Only one tenth of a mm difference with 3.2 vs 3.1, which means they were virtually the same which means nothing new or unprecedented. The warmists can stop hyperventilating now.

  19. Bill Marsh says: “When did Science devolve into a reliance on Argumentum Ad Verecundiam instead of analysis of data?”
    About the same time politicians found some scientists could be bought with other people’s money..

  20. If I was a warmist I’d try to find a way to prevent Anthony of accessing the internet and raw data… It would be a whole lot easier than trying to lie/explain why all assumptions, models, theories and even tomorrow’s weather forecast, are completely off.
    Nice article.
    I’ve done a whole bunch of searching and have yet to find any IPCC explanations on the increase of ice (mass not only extension) in the poles. Can’t figure out, yet, where all that water will come from if there’s more ice every time… of course, ice is less dense than water, so if it all takes to sail then it’d displace more water than the one used at freezing.

  21. A few things to consider in the predictions, the solar sunspot minimum we are in will put a new historic change on all predictions. Two, A cooler solar sunspot minimum in the 1700s and 1800s created a weaker century of sunspot cycles and, thus, cooler temperatures and less sea rise.
    Thus, the the numbers for the minimum will retard the numbers in the predictions. What ice is regained in the minimum will have to melt again and then start the numbers again.
    These people who made these predictions are going nuts in about 10 years.
    Now, the period 6000 years when everything tapered off was the refill period of the Mediterranean Sea, Persian Gulf, Red Sea, and all the water cavities that go with them. The same will hold true as the sea rises which will probably happen over the centuries to come but at a slower rate than predicted.
    I like the charts though. This is a keeper.
    One final thing is the movement of Topography. This will absorb water and CO2 as well. Those who predict need the whole picture, not just models and charts.
    Most Sincerely,
    Paul Pierett

  22. Your reference to “unpublicized NOAA study of tide gauge data” has been discussed in several blogs. The original paper is linked inside the hockeyshtick blog.
    Basically the NOAA 2012 paper combines all current data on sea level. Actual sea level rise is estimated at one point one millimeters per year with a relatively large uncertainty.
    paleoclimatology reviews show the amount of work on past sea levels is enormous.
    Almost all of the observed sea level proxies show about the same results, that the current sea levels are of little practical concern.
    Roman era fishing ports are at about the same level as today, or show a drop in levels.
    The industrial era has photographic evidence that sea levels are about the same as the 19th century. For example the construction of the Statue of Liberty in NY harbor.

  23. Mr Middleton. An excellent post and as another David, Mr Schofield, noted – with the list of experts and their studies cited/referenced, where does the IPPC find theirs?
    David Middleton on December 21, 2013 at 11:46 am
    Note to self: Try not to use the word “actually” so often.
    I actually thought it was actually only me that actually did that! 🙂

  24. The least controversial plot of all should be the worldwide average of tide gauges which are indeed historically global rather than just northern hemisphere, unlike thermometer records. And finally Church & White in their latest update in 2011 actually included this simple plot, extracted here from their original misleading spaghetti graph of various “adjusted” values that amount to virtual sea level as far as anybody on the beach is concerned. I added a trend line too:
    Reference: http://www.springerlink.com/content/h2575k28311g5146/fulltext.pdf
    This is now the most important plot in the whole debate since both claimed ice loss and deep ocean heating would have shown up by now in tide gauge data, but utterly no trend change exists in it, as is seen in the pencil straightness of the vast majority of long running single site plots in the first place.

  25. The figure labled “Global Mean Sea Level (1993 – 2013)” has a box box that says, “From 1993 to 2003, sea level rose at a rate of 3.6 mm/yr
    Since 2003, sea level has risen at a rate of 2.7 mm/yr, not rising at all from 2009 through 2011”
    Hmmmm, depends on the age of the data set. True enough, the current data says 1993 – 2003 is 3.6 mm/yr, (I get 3.5 mm/yr) but if you look at that same data reported at the time, thanks to the Interne Archive Way Back Machine, it’s only 2.6 mm/yr.
    Historical data has been rewritten.

  26. Can’t see nor measure the “Anthropocene” either! Sort of like a Dick Chaney “un-observable non-measurable” like those pesky WMDs.

  27. Scientific evidence does not support this so called experts claim, but the main issue is how can this happen even if it was the case when the planet is not warming?

  28. However, many other factors affect sea level, it’s not rising everywhere and the rate is extremely variable locally and regionally.

    Does that include water for irrigation?
    Groundwater abstraction is about “one fourth of the current rate of sea level rise of 3.3 mm per year.”
    Here is the paper’s abstract.
    It’s always worse than we thought IN THE FUTURE. Sheesh. Can we adapt? I duno.

    Half a world away in the tropical Pacific Ocean a similar saga unfolded. During the Greco-Roman climatic optimum, the Polynesians migrated across the Pacific from island to island, with the last outpost of Easter Island being settled around A.D. 400 (35).

  29. You say that the Greenland ice sheet would take 35000 years to disappear completely.
    That’ll pass sooner than we think….
    So act yesterday…….

  30. It seems to me that isostatic changes can induce eustatic changes in a way not mentioned.
    Let’s pretend the Earth is a toy balloon, filled with water to make it non-compressible. Glue a poker chip on the bottom and call it Antarctica. Glue three more poker chips around the top and call those chips North America, Europe, and Asia. Press on the chips to simulate the extra weight in glaciated conditions. You will notice the diameter of the balloon increases proportional to the amount of water displaced. The reverse happens when pressure is released. With continental rebound, as the ice melts, the ocean basins shrink raising sea level. This eustatic change would be opposite in sign and probably equal to the isostatic adjustment.

  31. Great stuff! I don’t know many geologists, but as an engineer I know many others. We are all skeptics as far as I can tell. Geologists and engineers have to be right, whereas climate “scientists” only need to be famous, in their own little field

  32. Here in Holyhead there is no discernible rise. Discernible being important. If you can’t discern it then what’s the problem?
    A lot of the infrastructure here is quite old. The breakwater and the fish dock date back 200 years and show no signs of sea level rise.
    Satellites cannot detect year on year millimetric differences in sea level. It is impossible. It took them about a year to determine that the Welsh mountain Glyder Fawr was 1000m rather than 999m. So don’t lie to me you climate scientists. Your petticoats are showing..

  33. “before All Gore invented global warming.”
    It was James Hansen and Margaret Thatcher who got the ball rolling. Gore was a late-comer.

  34. You might wish to look at this paper:
    “Ice-sheet collapse and sea-level rise at the Bølling warming 14,600 years ago”
    Past sea-level records provide invaluable information about the response of ice sheets to climate forcing. Some such records suggest that the last deglaciation was punctuated by a dramatic period of sea-level rise, of about 20 metres, in less than 500 years. Controversy about the amplitude and timing of this meltwater pulse (MWP-1A) has, however, led to uncertainty about the source of the melt water and its temporal and causal relationships with the abrupt climate changes of the deglaciation. Here we show that MWP-1A started no earlier than 14,650 years ago and ended before 14,310 years ago, making it coeval with the Bølling warming. Our results, based on corals drilled offshore from Tahiti during Integrated Ocean Drilling Project Expedition 310, reveal that the increase in sea level at Tahiti was between 12 and 22 metres, with a most probable value between 14 and 18 metres, establishing a significant meltwater contribution from the Southern Hemisphere. This implies that the rate of eustatic sea-level rise exceeded 40 millimetres per year during MWP-1A.
    Note the estimated 40 mm/a sea level rise…

  35. Have you noticed that in the absence of good evidence Warmists have now resorted to surveys of scientists? Why not just present the evidence of catastrophe sooooooon?
    I live bang on sea level and just 200 metres to the beach. If I can sleep well at night then I urge Alarmistas to take it easy. Have a break, have a Kit Kat.

  36. Jeff L says:
    December 21, 2013 at 12:42 pm
    … We have seen changes in the geologic record that dwarf anything that has been experienced in modern times & thus feel very comfortable that any changes we have seen could easily be generated by purely natural cycles – as variations of this size & larger have been seen in the past. …
    So true, you put that very neatly. I’m a geo also, just not for the “evil oil and gas industry”. One of the things that always surprised me over the past 20 years was that not only are the self-proclaimed environmental hyper-concerned so incredibly ignorant of Earth’s actual environment, over the broader swath of time available to science, it seems they didn’t even want to know about Earth, the place they self-nominated to ‘protect’. Nor do they want to know how routinely it’s assaulted via natural process and prosaic variability that makes present conditions look like a comparative perfect stasis.
    I can understand that they don’t know much about earth, though time, of course, as how could they? They don’t study the earth itself, as that’s the sole domain of geology, and they aren’t geologists. An geology literally translated from Latin root means, “The study of Earth”.
    They instead study pet topics of ‘concern’, and very selectively at that, while they poking fun at the one science that is wholly and solely dedicated to the study of the earth, in unimaginable detail and scope, and to convey the findings to all other human beings, so that we can actually lift the veil of ignorance about earth, that the enviro-saints exploit for their assorted tawdry propaganda fabrications.
    But they assert we have it all wrong, even though we present easily verifiable and repeatable evidence, recorded in great detail, fully accessible. Yet they do so using repeatedly falsified computer models, highly disputed theories that don’t comport with the observed data, and asserted projected suppositions, that will not be tested or confirmed in any of our life-times.
    But what I don’t understand and don’t forgive in the merely ignorant among them, is why they also don’t want to know about Earth, almost at all, and actually hate talking about it, and respond with … DENIAL OF THE SCIENCE … I can’t get over the cheek of them.
    Black is the new white, down is the new up. But it’s good to finally see people are waking up to the genuine science-denial-ism at work here. And frankly, where are all the other sciences in this? Why are they not also pointing out to the environmentalists that the only formal science discipline dedicated to study of the Earth is in fact Geology?
    And why is it the lame-brain Media don’t seen to grasp that simple scientific reality? Or that just maybe our views are a wee bit more scientifically valid, substantive and measured than any of the self-appointed enviro-expert wannabes, when it comes to expounding the way Earth really behaves, environmentally, through time?
    Heck, what could we possibly know about any of that stuff, eh?

  37. An interesting read David. Thanks
    Do we have the names of these 90 experts? It would be interesting to know their backgrounds, history and career affiliations.
    You can fix your android issue by shutting off the auto correct. I primarily use voice to text myself.

  38. The figure labled “Global Mean Sea Level (1993 – 2013)” has a box box that says, “From 1993 to 2003, sea level rose at a rate of 3.6 mm/yr
    Since 2003, sea level has risen at a rate of 2.7 mm/yr, not rising at all from 2009 through 2011″
    Hmmmm, depends on the age of the data set. True enough, the current data says 1993 – 2003 is 3.6 mm/yr, (I get 3.5 mm/yr) but if you look at that same data reported at the time, thanks to the Interne Archive Way Back Machine, it’s only 2.6 mm/yr.
    Historical data has been rewritten.

    Good find, saved as a reminder. And as usual. Pretty much all the CAGW narrative depends on rewriting history (temperature and more as well as sea level), leaving only lousy, when any, explaining within their narrative of events like the LIA, the 1960s-1970s global cooling scare (which didn’t happen ex nihilo without significant reason), and the current “pause” in global warming. Without that, the history of climate is elegantly, beautifully consistent as common for real science in nature (as in http://img250.imagevenue.com/img.php?image=45311_expanded_overview2_122_15lo.jpg ).

    • @Henry Clark,
      Yeah… if you start unwinding all of the “adjustments,” sea level isn’t doing much of anything.

  39. Mushroom George,
    You are right! I never thought of that. There is an opposite to the isostatic adjustment that they seem to ignore.

  40. I remember Steve F at Lucia’s blog put together a reasonably convincing model a while back. Even for a pretty high warming rate of .3 degrees per decade, in the final version of the model, he got was only just slightly higher than the high end of what the IPCC had at the time. For more realistic rates it was somewhere in the middle of their projections. This thing that happens were people actually try to argue that sea level rise will really be huge, continue to amaze me. Why would anyone actually believe such nonsense?
    Anyway, here was his last post on it:

  41. The Ol’ Seadog. says:
    December 21, 2013 at 1:23 pm
    They don’t even know a fundamental property of water….. Anybody else notice it?
    OH ! OH! OH!
    Water is wet?

  42. But… Let’s assume that the Velicogna GIA/PGR adjustment is correct anid ice mass loss did accelerate from 2002-2009. Where did the water go? The rate of sea level rise has decelerated since 2002. Where did all that meltwater go?
    = = = = = = = = = =
    The discrepancy was explained by CO2 resting the weight of its forcing-field on the global hydrological accelerator resulting in a regionally constrained flooding effect in Australia…actually and ridiculously:

  43. A good link to a YouTube video was posted here by some-one(Many Thanks) about the difficulty of measuring Sea Level.
    At the end of the video they say that they can only measure to about 1 metre,If this Is true why do Climastrologists preach about millimetres?
    The video Is here—

    Is this short video presentation correct?

  44. I’ve read all the data. It looks like the average sea level rise is 200 mm/century which is 7.874 inches/century.
    My prediction is based on this average increase. So based on this, with + or – 10%, my prediction for 2113 is a 7.874 inch rise in sea level. + or – 10% gives a range of 7.087 inches to 8.661 inches. Check back with me in 2113 to see if I am correct. I will be 170 years old by then.

  45. It seems that climatology has forgotten that there’s an extensive network of tide gauges that provide a fairly decent global representation today. You would think the tide gauge network would agree with satellite measurements. It doesn’t.
    According to the tide gauge network, the rate of sea level rise (SLR) from 1950 to 1979 was ~2.06 mm per year based on my analysis. From 1980 to 2010 the rate dropped to ~1.39 mm per year. Beenstalk et. al’s. recent paper found numbers closer to 1 mm per year, controlling for population density (tide gauges tend to be located in areas of larger population and greater rates of subsidence).
    The tide gauge network lends support to David’s conclusion that today’s rate of SLR is about the same as the 1930’s through the 1950’s, although the error margin is significantly larger for that period due to overrepresentation of the Northern Hemisphere and some population density bias.

  46. Scott Scarborough says:
    December 21, 2013 at 4:24 pm
    Mushroom George,
    You are right! I never thought of that. There is an opposite to the isostatic adjustment that they seem to ignore.
    ….. and if they’re going to add on isostatic rebound, shouldn’t they be consistent and subtract out glacial ice melt ??
    Or better still, shouldn’t they just f— off and die.

  47. @ jimbo,
    Have a break, have a Kit Kat.
    That would just over excite them again with all the caffeine etc. and who needs that during the festive season from those guys?

  48. Great post that took me ages to read and absorb, then I realised that it was all for not as the alarmists are already moving on to the new Alchemy.
    I noted two stories on the World News today: Methane is the new CO2 “and it is worse than we thought”. As I was reaching for the razor blades the second news item was even better (in an “it’s worse than we thought” sort of way). Apparently, we have passed “Peak Food Production” (moving right along from “Peak Oil” and the Club of Rome’s “End of Oil” {due in 2000}) and it is now inevitably all downhill to extinction from here as we lack water, fertilisers have ‘polluted’ the soils, climate change has devastated agriculture (they omitted to mention record harvests in 2013) and we can expect to see mass starvation from 2015 – if we do not act now on radically implementing World Government under the UN and Agenda-21 (as it is worse than we thought).
    Debunking them is fun, but it will not win the argument as this is all about politics, not scientific reality.
    Enjoy your last Xmas Dinner while you can as _______ (fill in the blank) is worse than we thought and we is doomed.

  49. To piggie back 》
    This is good stuff.
    How much energy do we get from the moon?
    Does the moon matter with respect to Sea level?
    What would happen if some crazy comet came by and changed its orbit by a mm……?.

  50. NevenA says:
    December 21, 2013 at 12:19 pm
    [i]The Antarctic and Greenland ice sheets were recently estimated to be losing ~213 gigatonnes of ice mass per year (Shepherd et al., 2012)..
    Yeh, they said that. But, then there’s Zwally 2012 at NASA with ICESat …..

    During 2003 to 2008, the mass gain of the Antarctic ice sheet from snow accumulation exceeded the mass loss from ice discharge by 49 Gtlyr (2.5% of input), as derived from ICESat laser measurements of elevation change.

    So, there’s that.

  51. I’m sorry. Whomever! You need to up your game, and not just your basic average substantially up your game!
    If you are intending to scare me with anything less than at least +6.0 meters of sea level rise at the end Holocene………..then whomsoever you are I wish thee the best of luck!
    The last interglacial went TU with anywhere from +6 to +45 meters amsl:
    and call…………………..
    My hole-card would be +52 meters amsl:
    If the most obvious result of anthropogenic global warming (AGW) is sea level rise then the very least you need achieve is +6M amsl. If your AGW proposes to be anomalous it may need to also exceed +52M amsl.
    Otherwise you are disposing of liquid organic waste product in juxtaposition to the wind/noise etc………….(or P’ing in the proverbial wind etc. et al)
    Not even the Goracle has prognosticated sea level rises that come any closer by 2100 than the low-end of the estimate of sea level rise at the end of the last interglacial’s second thermal peak. At the very best the Goracle’s estimates come in slightly better than 10% of what might have actually occurred without anthropogenic GHG emissions.
    And I am supposed to be scared by a “signal” just barely over 10% of what most recently was likely to have occurred? Anyway? Or would slightly over just 1% do?
    Would you like fries with that? Or some more Kool-Aid?
    That is literally (meaning, in this case, from the literature) how absurd the claims of AGW are at what is obviously the half-precession old Holocene with respect to the end of the last interglacial.
    Thanks, David, for such an informative post.
    – William

  52. Thanks David Middleton for a wonderful informative article. There is a tremendous amount of information there, and those are great charts and illustrations.

  53. To add to the Holocene Sea Level Highstand you have the fact the glaciers (Long term) are growing not receding.

    Temperature and precipitation history of the Arctic 2010
    Miller et al
    Institute of Arctic and Alpine Research and Department of Geological Sciences, University of Colorado, USA et al
    …. Solar energy reached a summer maximum (9% higher than at present) ~11 ka ago and has been decreasing since then, primarily in response to the precession of the equinoxes. The extra energy elevated early Holocene summer temperatures throughout the Arctic 1-3°C above 20th century averages, enough to completely melt many small glaciers throughout the Arctic, although the Greenland Ice Sheet was only slightly smaller than at present. Early Holocene summer sea ice limits were substantially smaller than their 20th century average, and the flow of Atlantic water into the Arctic Ocean was substantially greater. As summer solar energy decreased in the second half of the Holocene, glaciers re-established or advanced, sea ice expanded

    A more recent paper looking at glaciers in Norway.

    A new approach for reconstructing glacier variability based on lake sediments recording input from more than one glacier January 2012
    Kristian Vasskoga Øyvind Paaschec, Atle Nesjea, John F. Boyled, H.J.B. Birks
    …. A multi-proxy numerical analysis demonstrates that it is possible to distinguish a glacier component in the ~ 8000-yr-long record, based on distinct changes in grain size, geochemistry, and magnetic composition…. This signal is …independently tested through a mineral magnetic provenance analysis of catchment samples. Minimum glacier input is indicated between 6700–5700 cal yr BP, probably reflecting a situation when most glaciers in the catchment had melted away, whereas the highest glacier activity is observed around 600 and 200 cal yr BP. During the local Neoglacial interval (~ 4200 cal yr BP until present), five individual periods of significantly reduced glacier extent are identified at ~ 3400, 3000–2700, 2100–2000, 1700–1500, and ~ 900 cal yr BP….

    The authors of BOTH papers simply state that most glaciers likely didn’t exist 6,000 years ago, but the highest period of the glacial activity has been in the past 600 years. This is hardly surprising with ~9% less solar energy.

    • @ Gail Combs,
      That is correct. Maximum glacial retreat occurred during the Holocene Climatic Optimum (~4-7 kya). The long-term secular trend has been one of glacial advance. This period is known as the Neo-glaciation. Many if not most alpine/valley glaciers, like Glacier National Park, formed during the Neo-glaciation, reaching their maximum extent during the Little Ice Age. There are multiple higher frequency, lower amplitude cycles superimposes on the Neo-glaciation, the two most notable have periods of ~60 and ~1,000 years. While the secular Holocene trend is one of glacial advance, we are currently nearing the end of a ~500-yr warming leg of the ~1,000-yr cycle. The general glacial retreat since the end of the Little Ice Age is a cyclical phenomenon.

  54. ferdberple
    A difference of just one foot in ocean depth can add thousands of miles to the route a ship must take
    You didn’t calculate that for yourself, did you? Two feet increase of the diameter of any circle will increase it’s circumfence by about two meters.

  55. With today’s cooling we will have to live with falling sea levels, though some coral reefs will die if sea level falls over 1m. The last ice age saw a fall of over 130m, it rose as the ice receeded to a level 8m over today’s, the proof is in the geology as David could confirm.
    All the above is based on the GHG theory being correct. It is not.

  56. The tide gauges are only showing between 1.0 mm/year to 1.5 mm/year of sea level rise.
    I downloaded the Permanent Mean Sea Level Service (PMSL) database and the arithmetic average of all tide gauges was only 1.4 mms/year since 1980.
    A new paper looked at all the tide gauges and came up with 1.0 mm/year. (note that some sea level reconstructions from tide gauges did not use all the data available).
    Keep in mind that the land is rising by an estimated 0.3 mm/year due to continuing glacial isostatic adjustment. The average of 323 GPS stations which have been active for more than three years is 0.44 mm/year.

    • @ Bill,
      ~1.7 mm/yr is what the geoid corrected GRACE data indicate.
      If 3 mm/yr is innocuous, 0.5 to 2 mm/yr is irrelevant, particularly in light of the natural variability due to atmospheric and oceanic circulation patterns.

  57. This sea level rise comes up periodically and periodically I try to straighten it out. Sea level rise will be 24.6 centimeters (a little under ten inches) by 2100. How do I know this? Thanks to Chao, Yu, and Li (Science April 11th 2008). They corrected all published sea level data for water held in storage by all dams built since 1900. The sea level rise, so corrected, turned out to be linear for the previous eighty years. It had a slope of 2.46 millimeters per year. Anything that has been linear that long is not about to change anytime soon. Somebody tell that to these “experts” who from time to time pop up, knowing nothing of the history of sea level, and pretending they know the future. 2.46 millimeter per year works out to 24.6 centimeters per century and that is the most likely sea level rise by 2000.

  58. Thanks David. Great post.
    Living on an island, it has been fun to watch as climate scientists come to warn us of near-future flooding and offering to buy our properties cheap. These good fellows are from the marine and atmospheric science institute in the next island, and they recently finished a new building to expand their premises.

  59. Nice one as usual David. I always enjoy your essays.
    Apropos overusing “actually”, worse is even greater overuse of “absolutely” during a radio interview. My ears burned when I read the transcript on the Internet.

  60. Arno Arrak says:
    December 22, 2013 at 8:45 am
    This sea level rise comes up periodically and periodically I try to straighten it out. Sea level rise will be 24.6 centimeters (a little under ten inches) by 2100. How do I know this? Thanks to Chao, Yu, and Li (Science April 11th 2008). They corrected all published sea level data for water held in storage by all dams built since 1900…..
    All a dam does is cause a short term interruption of the flow of the water from the sky to the oceans.
    The area of the lakes formed by the dams is a spit in the bucket.
    Doesn’t anyone take decent geology courses anymore???
    The life of a lake is Lake ===> shallow pond ====> to swamp ====> spring meadow
    The life of a river is similar. As it erodes its bed the slope becomes less so you get meanders and oxbow lakes so the river actually becomes longer. Also the sediment it carries gets dumped into the sea and the delta area growsalso lengthing the river and the slowing down of the flow means the river is carrying more water.
    I doubt if any of these geologic phenomenon or the filling in of swamps/ponds by mankind was taken into account in these calculations.

  61. The Permanent Mean Sea Level tide gauge record has been referred to several times. HankH said “It seems that climatology has forgotten that there’s an extensive network of tide gauges that provide a fairly decent global representation today. You would think the tide gauge network would agree with satellite measurements” The examples he cites are all fairly short term. If you deal only with the lower numbered stations you tend to get longer records, and the longer records come far closer to the satellite estimates – try New York, for example. You also see some marvellous examples of isostatic effects in Stockholm and other Scandinavian ports, while places like Galveston are sinking rapidly into the sea.
    The one thing you can’t see is the post 1930’s acceleration that the IPCC loves, but when you go into the basis, you discover it is all the fault of Principal Component Analysis and we know what wonderful hockey sticks that can produce, don’t we!

  62. the ostensibly optimistic scenario (400-600 km).

    That would replace the troposphere, stratosphere, mesosphere, exosphere, …

  63. @nvw,
    I’m familiar with the MWP-1a hypotheses. Estimates of sea level rise rates over that period are quite variable. It entirely depends on the time period over which it occurred.
    The Bølling warming was very pronounced, rapidly bringing the Greenland ice cap from glacial maximum temperatures nearly to those of the Little Ice Age. It’s quite possible that short-term meltwater pulses could have well exceeded 10 mm/yr. However, the baseline was glacial stage temperatures and there were nearly 50 million km^3 of continental glacial ice below 60° latitude at the onset of the Bølling warming.

  64. See page 10, Figure 7 in this USGS publication… http://pubs.usgs.gov/pp/1760/b/pp1760b.pdf
    MWP 1-A is consistent with a very slow crustal rebound, which failed to keep pace with the initial melting of the Laurentide and Fennoscandian ice sheets during the Bølling-Allerød interstadial.
    Even if the Antarctic ice sheet played a major role in MWP-1A (a real possibility), there’s no reason to think that it could have yielded the freshwater flux to the ocean that is that is the main evidence for MWP-1A without a lot of ice melting.

  65. bullocky says:
    December 21, 2013 at 12:10 pm
    In the real world, an ‘expert’ has verifiable predictive skill.
    In the academic world an ‘expert’ has published many ‘papers’
    When I was a very junior doctor at the Hammersmith Hospital, London a long time ago an “Expert” was “A man from another hospital with slides”

    • @Bullock,
      Today’s expert has a PowerPoint… 😉
      Of course, Excel and PowerPoint are my “brushes & canvas”…. LOL!!!

  66. The slowing down of sea level rise in the last decade is one of the most important pieces of evidence for a current change in climate regime in the direction of cooling.

  67. But we can and have quantified secular rebound: it contributes 0.6ms/century to LOD: http://articles.adsabs.harvard.edu//full/2003A%26G….44b..22S/B000027.000.html
    In the last 40 years LOD has decreased by 2ms: http://upload.wikimedia.org/wikipedia/commons/2/28/Deviation_of_day_length_from_SI_day_.svg
    which, barring interference due to core/mantle coupling, suggests that polar ice accumulation has overwhelmed GIA as far as the planet’s moment of inertia is concerned. –AGF

  68. It is even highly unlikely that sea level will rise by as much as the ostensibly optimistic scenario (400-600 km).
    I sure as hell hope so!

  69. Reviewing my last post, short as it is I see it needs correcting. That’s -0.6ms/century, and since rebound and ice accumulation both contribute to acceleration of earth rotation that should say ice accumulation has overwhelmed deceleration due to tidal friction, not due to GIA. –AGF

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