A Geological Perspective on Sea Level Rise Acceleration

Guest geological perspective by David Middleton

There have been at least three recent peer-reviewed papers asserting an anthropogenic acceleration in the rate of sea level rise (SLR): Church & White, 2006 (CW06), Church & White, 2011 (CW11) and Nerem et al., 2018 (N18). N18 only covers the satellite era (since 1993) and might actually be correct, albeit irrelevant. The primary culprits in the SLR acceleration scam are CW06 and CW11. Two other recent peer-reviewed papers clearly shoot down the notion of a recent anthropogenic acceleration: Jevrejeva et al., 2008 (J08) and Jevrejeva et al., 2014 (J14). This post will focus on CW11 (updated through 2013) and J14.

J08 and J14 indicate that the acceleration, to the extent there is one, started 150-200 years ago, consistent with the end of neoglaciation and that a quasi-periodic fluctuation (~60-yr cycle) is present. CW06 and CW11 also note the 19th Century acceleration; but also assert a more recent acceleration, presumably due to anthropogenic global warming. This SLR acceleration is, at worst, innocuous.

If this acceleration was maintained through the 21st century, sea level in 2100 would be 310 ± 30 mm higher than in 1990, overlapping with the central range of projections in the Intergovernmental Panel on Climate Change Third Assessment Report (IPCC TAR) [Church et al., 2001].

CW06

310 mm from 1990-2100 is less than 3 mm/yr… Not much of an acceleration.

Figure 1. Jevrejeva et al., 2014 (red) and Church & White, 2011 (green).

CW11 is about 100 mm lower than J14. For direct comparison I plotted CW11 on the secondary y-axis with a 100 mm offset.

Figure 2. J14 vs CW11. 310 mm is less than the length of an Estwing rock pick. The green curve is CW11’s pentadal (5-yr) average. The red curve is J14’s pentadal average. The CW11 y-axis is shifted up 100 mm to tie J14.

J14 starts 60 years earlier than CW11, capturing the falling sea level at the end of neoglaciation and the Little Ice Age. We can see that J14 and CW11 match up pretty well from 1880-1930 and then again from about 1993 onward; but they are very different from 1930-1993. J14 exhibits an acceleration to 3.2 mm/yr from 1929-1963 and then a decceleration to less than 1 mm/yr from 1963-1993, after which it accelrates back to about 3.2 mm/yr.

Figure 3. J14 vs CW11. Which one is the geologist’s pick? Black curve = J14. Green curve = CW11.

CW11 totally misses this quasi-periodic fluctuation.

Which is right?

Three factors generally control the rate of sea level rise and fall:

  1. Water temperature and salinity changes (steric).
  2. Cryosphere changes (glacio-eustatic).
  3. Changes in the configurations of the continents and ocean basins (isostatic).

Isostatic processes are only relevant to globally averaged sea level changes taking place over thousands to millions of years and can be ignored for the purposes of this exercise.

Water temperature and sea level

When water is heated, it expands. When t cools, it contracts. Earth’s average sea surface temperature has generally been rising since the coldest part of the Little Ice Age, the 1600’s. While the sea surface can warm and cool fairly quickly, it takes more time for that heating and cooling to affect deeper waters. A lag between warming and sea level rise should be expected.

J14 matches up very well with sea surface temperature if a 20-year lag is applied to J14.

Figure 4. J14 vs HadSST3 (Wood For Trees). The HadSST x-axis is shifted 20 years to the left.

According to J14, SLR accelerated from 1.8 mm/yr (1882-1915) to 3.2 mm/yr (1929-1963) about 20 years after the onset of the early 20th Century warming period. It then decelerated to less than 1 mm/yr after the onset of the mid 20th Century cooling period.

Vermeer & Rahmstorff, 2009, concluded that a lag of more than 10 years should be expected in the response of sea level to temperature changes. CW06 also noted a ~20-yr lag between temperature change and SLR rate changes.

Between 1930 and 1960, GMSL rises faster than the quadratic curve at a rate of about 2.5 mm yr−1 (Figure 2c), following (with about a 20 year lag) the 1910 to 1940 period of more rapid global temperature rise [Folland et al., 2001]. 

CW06

J14 exhibits a lagged response to the ~60 year temperature cycle (quasi-periodic fluctuation), CW11 does not. CW11 totally misses the mid-20th century cooling (“The Ice Age Cometh“) effect on SLR. This cooling was so significant that it even halted the rise in atmospheric CO2.

Figure 5. Despite rising emissions, atmospheric CO2 stabilized, possibly even falling, from 1940-1955. (MacFarling-Meure et al., 2006, NOAA ESRL and CDIAC)

According to MacFarling-Meure:

The stabilization of atmospheric CO2 concentration during the 1940s and 1950s is a notable feature in the ice core record. The new high density measurements confirm this result and show that CO2 concentrations stabilized at 310–312 ppm from ~1940–1955. The CH4 and N2O growth rates also decreased during this period, although the N2O variation is comparable to the measurement uncertainty. Smoothing due to enclosure of air in the ice (about 10 years at DE08) removes high frequency variations from the record, so the true atmospheric variation may have been larger than represented in the ice core air record. Even a decrease in the atmospheric CO2 concentration during the mid-1940s is consistent with the Law Dome record and the air enclosure smoothing, suggesting a large additional sink of ~3.0 PgC yr-1 [Trudinger et al., 2002a]. The d13CO2 record during this time suggests that this additional sink was mostly oceanic and not caused by lower fossil emissions or the terrestrial biosphere [Etheridge et al., 1996; Trudinger et al., 2002a]. The processes that could cause this response are still unknown.

[…]

[11] The CO2 stabilization occurred during a shift from persistent El Niño to La Niña conditions [Allan and D’Arrigo, 1999]. This coincided with a warm-cool phase change of the Pacific Decadal Oscillation [Mantua et al., 1997], cooling temperatures [Moberg et al., 2005] and progressively weakening North Atlantic thermohaline circulation [Latif et al., 2004]. The combined effect of these factors on the trace gas budgets is not presently well understood. They may be significant for the atmospheric CO2 concentration if fluxes in areas of carbon uptake, such as the North Pacific Ocean, are enhanced, or if efflux from the tropics is suppressed.

MacFarling-Meure et al., 2006

J14’s quasi-periodic fluctuations are clearly consistent with ocean temperatures.

Cryosphere and sea level

There are places on Earth that are so cold that water is frozen solid. These areas of snow or ice, which are subject to temperatures below 32°F for at least part of the year, compose the cryosphere. The term “cryosphere” comes from the Greek word, “krios,” which means cold.

Ice and snow on land are one part of the cryosphere. This includes the largest parts of the cryosphere, the continental ice sheets found in Greenland and Antarctica, as well as ice caps, glaciers, and areas of snow and permafrost. When continental ice flows out from land and to the sea surface, we get shelf ice.

The other part of the cryosphere is ice that is found in water. This includes frozen parts of the ocean, such as waters surrounding Antarctica and the Arctic. It also includes frozen rivers and lakes, which mainly occur in polar areas.

The components of the cryosphere play an important role in the Earth’s climate. Snow and ice reflect heat from the sun, helping to regulate our planet’s temperature. Because polar regions are some of the most sensitive to climate shifts, the cryosphere may be one of the first places where scientists are able to identify global changes in climate.

NOAA

Glacier mass balance is a way to measure changes in the cryosphere. A glacier with a negative mass balance is losing more ice than it gains annually. A glacier with a positive mas balance is gaining more ice than it loses annually.

Global glacier mass balance has been negative since the end of neoglaciation in the mid-1800’s. When glaciers and ice sheets have negative mass balances, much of the meltwater eventually finds its way to the ocean and sea level rises. Over most of the past 150 years, more glaciers have been retreating (negative mass balance) than advancing (positive mass balance).

Another way to measure glacial advance and retreat is by changes in glacier length. Oerlemans, 2005 climate reconstruction was devised from changes in global stacked glacier length. The following graph overlays atmospheric CO2 and northern hemisphere temperatures on Oerlemans’ stacked glacier length plot.

Figure 6. 45% of the ice loss occurred before 1900, when atmospheric was still below 300 ppm. By 1950, 75% of the ice loss had occurred. Only 25% of the ice loss has occurred since humans allegedly became the primary drivers of climate change. At the time of “The Ice Age Cometh” (1975), 90% of the ice loss had already occurred.

In the extremely unlikely event that the climate models are right, 90% of the ice loss occurred before an anthropogenic fingerprint could be discerned.

Figure 7. Modified after IPCC AR4 and the March 1, 1975 cover of Science News.

We can see that the 20th Century quasi-periodic fluctuation is also present in Oerlemans’ stacked records of glacial length.

Figure 8. Can you say “consilience“?

CW11, on the other hand, is not even close…

Figure 9. CW11 at same scale as figure 6

J14’s quasi-periodic fluctuations are clearly consistent with changes in the rates of glacier retreat CW11 is not.

A bizarre claim in Church & White 2006

The quadratic implies that the rate of rise was zero in about 1820 when GMSL was about 200 mm below present day values. This level is consistent with estimates from bench marks carved in rock in Tasmania in 1840 [Hunter et al., 2003] and the height of ancient Roman fish tanks [Lambeck et al., 2004], which implies virtually no long‐term average change in GMSL from the first century AD to 1800 AD.

CW06

That’s simply wrong.

Figure 10. Global last 7,000 years, error bars omitted (Brock et al, 2008 after Sidall et al., 2003). J14 is overlaid in red at the same scale. Ljungqvist, 2010 nothern hemisphere climate reconstruction is also overlaid. The relatively large swings in SLR over the past 2,000 years are clearly consistent with the millennial scale Holocene climate cycle.

Conclusion

It is plainly obvious that Jevrejeva et al., 2014 is more consistent with climate and cryosphere changes than Church & White, 2011 and, therefore, more likely to be accurate.

I apologize for the total lack of sarcasm in this post and for not finding a clever way to insert horst schist and other geological euphemisms into at least one fracking sentence.

References

Brock, J.C.,  M. Palaseanu-Lovejoy, C.W. Wright, & A. Nayegandhi. (2008). “Patch-reef morphology as a proxy for Holocene sea-level variability, Northern Florida Keys, USA”. Coral Reefs. 27. 555-568. 10.1007/s00338-008-0370-y. 

Church, J. A., and White, N. J. ( 2006). “A 20th century acceleration in global sea‐level rise”. Geophys. Res. Lett., 33, L01602, doi:10.1029/2005GL024826.

Church, J.A., White, N.J., 2011. “Sea-level rise from the late 19th to the early 21st Century”. Surv. Geophys. http://dx.doi.org/10.1007/s10712-011-9119-1.

Jevrejeva, S., J. C. Moore, A. Grinsted, and P. L. Woodworth (2008). “Recent global sea level acceleration started over 200 years ago?”. Geophys. Res. Lett., 35, L08715, doi:10.1029/2008GL033611.

Jevrejeva, S. , J.C. Moore, A. Grinsted, A.P. Matthews, G. Spada. 2014.  “Trends and acceleration in global and regional sea levels since 1807”.  Global and Planetary Change. %vol 113, 10.1016/j.gloplacha.2013.12.004 https://www.psmsl.org/products/reconstructions/jevrejevaetal2014.php

Ljungqvist, F.C. 2010. “A new reconstruction of temperature variability in the extra-tropical Northern Hemisphere during the last two millennia”. Geografiska Annaler: Physical Geography, Vol. 92 A(3), pp. 339-351, September 2010. DOI: 10.1111/j.1468-459.2010.00399.x

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.

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.,  B. D. Beckley, J. T. Fasullo, B. D. Hamlington, D. Masters, G. T. Mitchum. “Climate-change–driven accelerated sea-level rise”. Proceedings of the National Academy of Sciences. Feb 2018, 115 (9) 2022-2025; DOI: 10.1073/pnas.1717312115

Oerlemans, J. “Extracting a climate signal from 169 glacier records”. Science (80-. ). 2005, 308, 675–677, doi:10.1126/science.1107046.

Siddall M, Rohling EJ, Almogi-Labin A, Hemleben C, Meischner D, Scmelzer I, Smeed DA (2003). “Sea-level fluctuations during the last glacial cycle”. Nature 423:853–858 LINK

120 thoughts on “A Geological Perspective on Sea Level Rise Acceleration

  1. MSL was higher than now for most of the past 8000 years. It has been rising at about the same secular trend rate since the depths of the Little Ice Age during the Maunder Minimum, c. AD 1695.

    But its long-term trend has been down since the end of the Holocene Climate Optimum over 5000 years ago, or at the latest the Minoan Warm Period more than 3 Ka, headed for the next Big Ice Age in some 3000 years or so.

    • Starting points are so important when contributing to a narrative. Never believe conclusions from climate data that covers short geological periods. The resolution of the data can also be used to justify erroneous conclusions. Without believable error ranges any data should simply be ignored.

      • Spot on, Rick. It’s the big picture that counts. It is quite likely that levels will rise a bit faster now. After all temperatures are still rising. So what? We are well into one of the cyclical, geological, hot periods of the late Holocene. The last one (1000 years ago) lasted about 400 years, didn’t it? So can’t we expect that this one will be another couple of hundred years? Relax and enjoy it. Warm weather is so much nicer than cold. And it is quite likely that all the extra CO2 will even make it slightly warmer. Lovely.

    • Harlech castle sea gate is 4 m. ABOVE present sea level. Stable ground.
      Traitors gate is STILL above sea level DESPITE London sinking 2 m in the last 1000 years.
      WAIS instability anyone?

    • What would happen, if the US passed a law, that everyone living on all coasts will need to relocate their homes to higher ground, including Pres Obama’s new home?

  2. I apologize for the total lack of sarcasm in this post and for not finding a clever way to insert horst schist and other geological euphemisms into at least one fracking sentence.

    You’re forgiven. This time. Don’t let it happen again. 😉

  3. David Middleton

    “Global glacier masS balance has been negative since the end of neoglaciation ”

    Great post, as always….

    (You should see this in about 5 hours ! ) lol

  4. Wolfgang Cramer is presenting a paper in Barcelona on Thursday that states the Mediterranean will rise one meter by 2100. Dire consequences to follow.

  5. In the past people here have mentioned the effect of humans draining the aquifers into the ocean via pumped irrigation as a factor in sea level rise. Is there any compelling evidence of that?

    • That aquifers are being drained is not in doubt.
      That adding water to the oceans would lead to raising the level of the oceans is not in doubt.
      What remains is to calculate how large the increase is. The answer is, not much. I don’t remember the exact numbers, but it works out to a couple of millimeters over the last 100 years.

  6. “That’s simply wrong” No. He’s not “wrong”.

    He has arrived at a totally invalid and misleading conclusion based on insufficient data – but he is most definitely not wrong.

    If I was around for two thousand years and faithfully took the outside temp at 1.00pm on 1 January each year, then I could reach the conclusion that the average temp where I live was about 5c and had been for two thousand years. That record would ignore summer, autumn and spring temperatures and would have produced a misleading and worthless conclusion based on data that was inadequate to say the least. But I would not be “wrong”.

    This is why WUWT exists – to highlight the errors that form those “conclusions” that really weren’t worth the effort that was spent on reaching them.

  7. The CO2 ‘thing’ interests me. The alarmist CO2 budgets pretend that they precisely balance. Reality seems to be that the books don’t actually balance that well. It’s good to see evidence that atmospheric CO2 levels are influenced by ocean temperatures.

  8. It is so confusing. To make it a real science, you need to inject a healthy dose of consensus. You can extract any information from sufficiently noisy data, ask Michael E. Mann, distinguished.

  9. “I apologize for the total lack of sarcasm in this post and for not finding a clever way to insert horst schist and other geological euphemisms into at least one fracking sentence.”

    The abject lying by the climate alarmism scammers is indeed getting less and less humorous. Sure, we can mock them, but the amount and volume of their climate alarmism lies is reaching a point where even modest “warmists” will have to soon decide where they take their stand — Either on the side of abject lying of the alarmists or on the side of objective science and get the “denier” from the alarmist crowd.
    Any middle ground on climate change based on the evidence that they’ve tried to hold for so long, like Roger Pielke, Jr, is going to quickly become a No-Man’s Land. They are becoming road-k1ll run over by a alarmism bus, like the dead armadillo in the center of the road. Not because of anything the skeptics have done, but because of a politically-motivated bent toward alarmism, deception, and propaganda now being put out in the name of “Science.” This bent towards rapid ramp-up of alarmism was of course a reaction by the climate scammers to the decades of public apathy towards their original claims; claims that always became falsified with the passing of time.

    This bent toward’s ever more untenable climate alarmisim clearly tracks the same Leftward tack of the moderate Left politics towards extremism here in the US (I can’t speak for other countries). And what is clear right now is the US Democrats have an internal civil war on their hands. The media is trying to to ignore it.

    Witness the late entries of “moderate” Democrats into that clown car disaster that has become their original field of Presidential nominee hopefuls. Little Tommy Steyer’s entry in July. Bully Bloomberg’s November entry, a billionaire former-Republican turned Democrat who was always just a Statist-Nanny RINO. Both billionaires are using their money to buy air-time and media coverage without any attempt at first building a grass-roots organization or support, something very foreign to the Democrats. Deval Patrick’s entry in late November, a “moderate” Democrat with no fund raising organization with the Iowa caucus and New Hampsire primary so close is certainly a too-late losing cause. Clearly, these “Carpet Bagging late enters” have a strategy that requires a no-clear winner status by the end of the primaries, so that a contested Democratic Convention votes with their party’s SuperVoters to carry the day. Their hope would be to see one of the moderates “Rise out of the ashes” as a consensus nominee at their convention that will leave the SJW socialists supporting Bernie, Pocahontas and Buttigieg howling mad, and likely walk away.
    And even more incredible, there still remains rumors that Crooked Hillary will soon enter the fray. The Democrat’s internal Civil War would then become too obvious to ignore by the main stream press.

    My point here bringing up the Democrat’s ever further Leftward-running politics is that I can see this same sort of Climate Change Civil War taking shape in climate science, with some lag time of a year or so. My hypothesis is essentially that the pseudo-science of climate alarmism volume is tracking the political tack to the Democrat’s race to the left. More and more scientists who’ve kept quiet and kept out of the fray are going to be forced to take sides with this current level alarmism acceleration driving a widening gap between observable facts and the evermore wild projections.

    We saw the first hints of it in the reaction to the Mark Jacobsen renewable energy lies PNAS paper that got a quick rebuttal from engineers who would have to try and deal with his lies, and then Jacobsen’s ugly lawsuit attempt to get a retraction on that rebuttal that utterly failed.
    Can’t wait for Crooked Hillary to jump in and see what happens.

    Interesting times indeed.
    MAGA.

      • Sommer,
        The climate scam has always been about the money.
        Whether its insurance, buying hungry politicians, the renewable energy scam on the middle class electricity bills, government subsidies for solar and wind, or Climate Aid billions to the UN… it’s all about the money.
        The money buys the politicians. The money drives the GreenSlime to fund eco-nutter GreenBlobbers like Tides Foundation, NRDC, 350.org, the Sierra Club, etc. The climate money animates the UN bureaucrats becasue money and power are coupled for them. Climate money animates the Vatican, becasue Catholic Charity NGO’s stand to gain with %-age overhead payments to Rome

    • Bloomberg was a Democrat before he was a Republican, after which he was an Independent, then a Democrat. But always a gun-grabbing nanny-statist.

      • I’d love to see him run as an independent after he fails to get the Democrat’s nomination in June.

        But I also believe the Bloomberg and Steyer are principally running to be able to funnel many hundreds of millions of dollars in campaign money to the Demo-rats. That will be amounts far, far beyond the measly $35,500/yr allowed by federal campaign law and the legally-binding FEC guidelines that come from it. That’s the real reason these billionaires are running IMO. To basically buy the office of President and the US Senate elections for Democrats so they are then beholden to these GreenSlime billionaires.

    • “Clearly, these “Carpet Bagging late enters” have a strategy that requires a no-clear winner status by the end of the primaries, so that a contested Democratic Convention votes with their party’s SuperVoters to carry the day.”

      That would set the stage for Hillary to step in. The only problem for me is I believe Hillary has really lost her leadership role and some Democrats are not very enthusiastic about a political comback from Hllary. Plus, Hillary may still have legal issues with obstructing justice and her involvement in the effort to use the U.S. government’s power to try to undermine Trump and unseat him after he was elected.

      What we end up with is the Democrats are in crisis which is causing them to make huge political mistakes which will detrimentlly impact their political power in the future. Which is very good news for the U.S. because the Democrats seem to be living in a false reality that makes it impossible for them to govern the United States properly. Democrat rule is the road to ruin, and that is becoming obvious to more and more people every day.

    • Joel,

      I just finished an “Arrogant Bastard Ale” in celebration of having paid our real estate tax bill on time yet again. The brewery ran afoul of some British sensors it seems (1). I thought you’d get a kick out of their response.

      Dr. Jacobson dropped his legal suit a while ago. He commented earlier this year to a retraction watch post on the subject (2).

      1) https://www.stonebrewing.com/blog/philosophy/2019/response-portman-group#ageGatePassed

      2) https://retractionwatch.com/2018/02/23/prof-who-just-dropped-10m-suit-against-pnas-i-was-expecting-them-to-settle/#comment-1669099

    • The speculation regarding Hilary becoming the candidate via a brokered convention, or such, has ticked up over the last few days. Thing is, there seem to be Many rumours that her walking abilities have decreased further since her last filmed falling episodes, and these may be given weight by the fact that she always appears these days sitting on a comfy couch. I saw a purportedly recent picture of her recently that was not good, big swollen ankles etc, so I’d have to conclude that her health is not good ? It may even be in rapid decline ?

      So just wondering, and agreeing with your Clown Car observation regarding the current runners, could it be that the chimera of another Hillary run is really just a frightener that will make the acceptance of another late entry all the more palatable ?

      Viewed from another aspect, the re election of The Donald seems so certain that any politician of worth will not be sticking their heads above the parapet for 2020, leaving the geriatric leadership of the Democrats with huge problems, having stifled political talent to protect their own positions for so long. Yet another resemblance to the Marxist regimes of old, sclerotic leadership that leads to implosion. 🙂

  10. Question quasi related to sea level:

    We consider the Moon to be ‘tidal locked’ in its orbit about Earth since the same side always faces Earth. If the Moon had seas of liquid water similar to Earth, would there be a ‘high tide’ on the Moon on the side facing away from the Earth?

  11. Possible questions to pose to a climate alarmist who is worried about sea level rise. Your feedback is appreciated:

    Suppose you are right, and CO2 is the major, if not the only, driver of the Earth’s temperature. If you want to stop sea level rise, you would have to drop the global temperature to a point where there is an equilibrium between land based ice melting and ice accumulating: Basically, this temperature would be at the cusp of the next glacial period of an ice age. How many degrees colder do you envision this being? What is the CO2 level that is needed to accomplish this? Do you have any idea what lower temperatures and lower CO2 levels would do to global food production? Do you want to starve millions of people just to prevent the sea level from rising?

    • Your question, “Do you want to starve millions of people just to prevent the sea level from rising?”

      The Left says, “Starve millions? No”. They actually want billions to starve. They want Ehrlich’s and Holdren’s nightmare to come to fruition by design, to “Save the Planet.” They are the very manifestation of Agent Smith’s monologue in the Matrix, a manifesto that sees humanity as a virus, a plague on the Earth to be eradicated.

      • Paul Ehrlich, in 1967, proposed mass, involuntary sterilization in the US to avert a global famine beginning in 1975. The catastophe’s cause? Global cooling due to industrial activity. Still he was optimistic, LOL. “We must assume,” he said, “that man will get a another chance, no matter how little he deserves one.”

        Ehrlich certainly got a second chance: to sing the same Malthusian death song, lyrics slightly revised.

    • To answer the question, just look at figure 1 or figure 2. You can see that the last time sea level was not changing was 1850. But with time lag etc, you would need a temperature from a little earlier. If you take some sort of average of 1800 – 1850, you will get a fairly good look at the temperature required to stop sea level rise.

    • “Basically, this temperature would be at the cusp of the next glacial period of an ice age. How many degrees colder do you envision this being? What is the CO2 level that is needed to accomplish this? Do you have any idea what lower temperatures and lower CO2 levels would do to global food production?”

      Basically “climate” is a local, distributed phenomenon.

      On the risk of repeating myself:

      “Climate” is like a land rain, a Torrential steady rain, a country rain.

      You drive the dry, dusty highway; taking a bend your inmidst a Torrential Country rain. The left embarkment is dry, to the right the fields swim in water.

      The next bend returns to a dry, dusty highway.

      Impossible to foresee, like the weather, what comes up: unless observing the real world hopefully learning to read it.

  12. Church & White 2006 actually found a statistically insignificant deceleration in sea-level rise after 1925. They didn’t report it in their paper, but I did, here:
    http://dx.doi.org/10.1007/s11069-012-0159-8

    That’s paywalled, but here’s a preprint:
    http://sealevel.info/climate/jnathaz1/

    Excerpt:

    The IPCC’s Third Assessment Report noted the “observational finding of no acceleration in sea level rise during the 20th century.” But there is still a lot of confusion about sea level rise. Much of it results from misunderstanding the findings of a key paper, Church, J. A., and White, N. J., 2006, “A 20th Century Acceleration in Global Sea-Level Rise.” Geophysical Research Letters, Vol. 33, L01602, 4 PP. DOI: 10.1029/2005GL024826

    Church & White fit a quadratic to averaged and adjusted tide gauge data, and detected a small acceleration in rate of sea level rise for the 20th century as a whole. But it turns out that all of that acceleration occurred in the first quarter of the 20th century (and the late 19th century). After 1925, their data showed a small deceleration in rate of sea level rise, rather than acceleration.

    Since nearly all of the anthropogenic contribution to CO2 levels occurred after 1925, that means Church & White detected no acceleration in rate of sea level rise in response to anthropogenic CO2.

    In 2009, Church and White released a new data set, based on a different set of tide gauges. I applied their 2006 analysis method to the new data. I found that it not only showed deceleration in sea level rise after 1925, all of the acceleration in sea level rise for the full 20th century was also gone. I shared my results with Drs. Church & White, and on June 18, 2010, Dr. Church replied, confirming my analysis: “For the 1901 to 2007 period, again we agree with your result and get a non-significant and small deceleration.”

    In 2011, Church and White released a third data set. This one shows a very slight acceleration in sea level rise after 1925, though much smaller in magnitude than the deceleration seen in their other data sets. The post-1925 acceleration in this data set, if it continued to 2080, would add just 0.8 inches of sea level rise, compared to a linear projection.

    Since the rate of sea level rise has not increased significantly in response to the last 3/4 century of CO2 emissions, there is no reason to expect that it will do so in response to the next 3/4 century of CO2 emissions. The best prediction for sea level in the future is simply a linear projection of the history of sea level at the same location in the past…

    • To me, the most striking thing about Church & White is the lack of a significant deceleration in response to the mid-20th century cooling.

      • Don’t bring inconvenient facts into this. And don’t make logical conclusions. You’re just a geologist – what would you know. You do know you’re dealing with climate scientists here, probably leading climate scientists?

      • In the eyes of the alarmists, any evidence that agrees with their theory proves their theory.
        Any evidence that is disagreement with their theory is disproven by the evidence that agrees with the theory.

        Therefore they ignore the lack of SLR deceleration. In their minds the lack of deceleration merely proves that there was no mid-20th century cooling.

      • Sorry about the botched </a> tag.

        Here’s a quote from Church & White 2006, to ponder:

        “An additional spatially uniform field is included in the reconstruction to represent changes in GMSL. Omitting this field results in a much smaller rate of GMSL rise…”

        The lack of effect from mid-20th century cooling doesn’t really surprise me.

        The sea-level rise from thermal expansion of the upper layer of the ocean, if it warms, or the sea-level fall from thermal contraction of the upper layer of the ocean, if it cools, have strictly local effects. Such changes do not cause water to “run downhill” and raise sea-levels elsewhere, because gravity balances mass, not volume. They just cause a slight “bump” or “dent” in the ocean surface. (If water at the bottom of the ocean were to thermally expand or contract, that would affect sea-level everywhere. But most ocean temperature changes are confined to the top layer.)

        So if, for example, you get a warm spot out in the middle of the Indian Ocean, the thermal expansion will affect satellite altimetry, but you should not expect it to show up in coastal (tide gauge) measurements.

        Of course, temperatures also affect ice mass balance for ice sheets and glaciers, but not necessarily in the way you might expect. Some of the effects increase sea-level, but some decrease it.

        Warmer air temperatures:

        ● can cause melting of glacial ice, increasing sea-level, if the the temperatures rise above 0°C

        ● can increase rates of sublimation, if the temperatures remain below 0°C

        ● can increase the moisture content of air, and thus increase snowfall on ice sheets and glaciers, if temperatures remain below 0°C

        ● can cause reduced sea ice coverage, and thereby greatly increase evaporation from the ocean, and “lake/ocean-effect snowfall” on downwind ice sheets and glaciers

        Some of those things increase sea-level, and some of them decrease it. Since coastal sea-level trends have not shown any significant, sustained, detectable change in trend in the last ninety years, even as temperatures increased, there’s good reason to believe that the factors which increase sea-level and the factors which decrease sea-level are similar in magnitude, and are approximately cancelling each other out.

        https://sealevel.info/150-061_Maassluis_Netherlands_1848-2016_smooth4_vs_CO2_annot1.png

  13. With the alarmists becoming ever more doctrinaire and the likes of John Cook ‘immunising’ children against sceptical arguments it is clear that logic is not an effective tactic. What I propose is ridicule. If the north pole melting will cause sea levels to rise 4 metres, why don’t sea levels rise every summer? Can we create some memes with Al Gore – eg “Gore said the ice cap would be gone by the year 2000” – “How inconvenient”. Other suggestions?

    • David, I think that you can reassure your children and even grandchildren that the sealevels will not rise 4m in their lifetimes, if this (2013) paper on the consequences of the melting of Greenland ice mass is correct:
      https://iopscience.iop.org/article/10.1088/1748-9326/8/2/025005
      The future sea-level rise contribution of Greenland’s glaciers and ice caps
      (open access)
      From the abstract :
      Abstract

      -“We calculate the future sea-level rise contribution from the surface mass balance of all of Greenland’s glaciers and ice caps (GICs, ~90 000 km2) using a simplified energy balance model which is driven by three future climate scenarios from the regional climate models HIRHAM5, RACMO2 and MAR. Glacier extent and surface elevation are modified during the mass balance model runs according to a glacier retreat parameterization. Mass balance and glacier surface change are both calculated on a 250 m resolution digital elevation model yielding a high level of detail and ensuring that important feedback mechanisms are considered. The mass loss of all GICs by 2098 is calculated to be 2016 ± 129 Gt (HIRHAM5 forcing), 2584 ± 109 Gt (RACMO2) and 3907 ± 108 Gt (MAR). This corresponds to a total contribution to sea-level rise of 5.8 ± 0.4, 7.4 ± 0.3 and 11.2 ± 0.3 mm, respectively …..”
      I have not yet checked on the citing papers to see whether any corrections are added in following years
      but there would have to be really major faults in the paper to convert contributions in sealevel rise, in 80 years, from 10 mm to several metres.

      • I’m comfortable with the knowledge that 1 meter over the next 100 years is essentially physically impossible. Beyond that, I’ll be long-dead… And all of our children have 4 legs and are spayed or neutered… Grandchildren are less likely than 1 meter of SLR… 😉

        • Laissez-faire, David Middleton:

          In 2050 Angela ‘angie’ Merkel will be 94+

          She’s got no kids, let alone great-grandchildren; but insists Germany has to be the avant-garde of non-nuclear renewable “decarbonising” because in the former DDR she learned to keep the thrown aka chancellors cabin Luft Oberhoheit.

          Biting away the untrustworthy common sensers without geostrategic plans, intentions.

          NG – like in NoGood / Angie.

          Beware of Laissez-faire!

    • Point taken, but the “north pole” melting won’t cause sea levels to rise at all because the ice at the north pole is floating sea ice. It’s already displacing the same amount of ocean that it would completely melted. Even the doomers know this; well, the ones who know some rudimentary science. It’s glacial melt in Greenland and Antarctica that has everyone in a bother, even though their contribution to global sea level rise is minuscule.

  14. It’s called the National Evolution Climate Lies And Atheists Mag.
    Make Satan proud
    1john 5:19

    1006 languages JW.org

  15. Three factors generally control the rate of sea level rise and fall:
    1.Water temperature and salinity changes (steric).
    2.Cryosphere changes (glacio-eustatic).
    3.Changes in the configurations of the continents and ocean basins (isostatic).

    You missed the Fourth major factor
    Three Four factors generally control the rate of sea level rise and fall:
    1.Water temperature and salinity changes (steric).
    2.Cryosphere changes (glacio-eustatic).
    3.Changes in the configurations of the continents and ocean basins (isostatic).
    4.Because we’re climate scientists and we say so (esoteric)

  16. Good posting, David. I have done quite a few detailed strat columns in the Neuquen Basin of Argentina, trying to construct a migrating environment for carbon-rich metal traps for mining exploration. I have been greatly surprised often by how variable the stratigraphy is when you are neither in the middle of continental facies or deep marine facies. That is, when you are looking at a coastal paleoenvironment it is common to see cyclic repetitions of shallow marine water (patch reefs with beautifully preserved ornamentation on Trigonia, for example), mixed or intratidal (with a mixture of marine and continental fossilized material), and coastal continental beds (with fossilized dinosaur bones and trees). The colors of these beds tend to reflect the oxidation state of iron and other repeated factors, with shallow marine medium gray, mixed green, and continental red. One transect displayed about 100 cycles in a vertical exposure of about 300 meters. What was sea level doing to produce these cycles? No way the land was yoyoing up and down, this was sea level changing. What, then, is normal? What’s the noisy background we are trying to extractan anthropogenic signal from? I would throw in a gratuitous fracking schist comment but I am too gneiss for that. Press On.

  17. “310 mm from 1990-2100 is less than 3 mm/yr… Not much of an acceleration.”

    My understanding is that “3mm/yr” is a velocity, not an acceleration.
    Given my (mis)understanding, this article is TLDR. What am I missing?

    • The average rate since 1993 has been about 3 mm/yr. If the average rate from 1990-2100 turns out to be less than 3 mm/yr, it won’t have been much of an acceleration.

    • NeedleFactory
      The precise definition of the “acceleration” would be the first derivative of the curve. If the ‘curve’ is essentially a straight line, then the acceleration is the slope of the line. A horizontal line is zero acceleration.

      • Rate/speed is first derivative of position/height/depth.

        Acceleration is second derivative of position/height/depth = first derivative of rate/speed.

        In a graph of sea-level (vertical axis) vs. date (horizontal axis):

        A straight line is zero acceleration, regardless of whether it is horizontal or diagonal.

        A concave-up trace shows positive acceleration.

        A concave down trace shows negative acceleration, a/k/a deceleration.

        I’ve learn that many people get confused by this, so I made a little primer:

        https://sealevel.info/acceleration_primer.html

  18. David

    Among the remarkable things shown on the sea level curve for the past two hundred years or so is the abrupt change that occurs after about 1850. Before that, sea level was up and down with no discernable pattern. Then about 1850, it changes suddenly to a more-or-less linear trend from ~1850 to present. Why the abrupt change in pattern? Is this a matter of change in data recording or is it a real phenomenon?

    Don

    • Don,
      I think it’s a combination of sparse data points and the transition from neoglaciation to the current period of generally retreating glaciers. If look at the pre-1850 error range, it’s pretty large.

  19. Looked at from a geological (versus an anthropological) time-scale, the recent rate of change in sea level is quite modest, and may even have a long-term downward trend:

    https://ourchangingclimate.files.wordpress.com/2011/01/post-glacial_sea_level-incl-3-mm-yr-1-trend.png

    The plotted data reflect the influences of both the average prevailing temperatures and the availability of ice to melt. With the bulk of the northern-hemisphere ice from the last major glaciation gone, the thermosteric rise in sea level has come to dominate the change. (Look at the graph for the change in the last 8,000 years.)

    I don’t have the feeling that extant models properly account for the complexity of thermosteric volume increase because the density-change with temperature is not constant; it is not even linear. Unloaded land, resulting from melted ice, rises (isostatic rebound), decreasing the volume of the local ocean basins. On the other hand, deepening oceans increase the load on the floor of the oceans, causing subsidence, which increases the global volume. The local sea level, as measured by tide gauges, is controlled by both actual eustatic sea level rise and local land elevation changes. The density of sampling from tide gauges probably isn’t sufficient to speak to more than what is happening at the particular port that is being monitored. It is, after all, the changes at shorelines, where people live, that is the important metric, not theoretical mid-ocean eustatic changes that have practical significance.

    Those who prepare tide prediction tables are aware of ~20-year lunar cycles that are of little concern for next year’s tide tables, but need to be accounted for when claiming that there is a recent ‘acceleration’ in sea level increase. Longer periods are known; however, those making tide predictions have little incentive to discern the cause.

    Just as with global (and regional) temperatures, there are also short-term sea level variations that are essentially noise resulting from unknown processes. Basing predictions of sea level 80 years in the future, from changes in the last 5, or even 10 years, is irresponsible.

  20. My apologies if I am wandering off topic here, but I was interested in Figs 1 and 2 in the presentation because the J14 curves for the 13 -mo av seem to show the effect of the AMO which I increasingly notice in other data series , eg the HADSST3. HADCRUT4 and CET (Central England Temperature ).
    My assumptions were that a positive AMO meant a warmer period for us in NW Europe, but a paper just published gives rise to doubt that and has left me somewhat confused:
    https://doi.org/10.1016/j.quascirev.2019.106004
    -Atmospheric response to mid-Holocene warming in the northeasternAtlantic: Implications for future storminess in the Ireland/UK region-

    The section in the paper that seems contrary to my (layman’s) assumptions says:

    -“Spatial observations of SST in the North Atlantic Basin(1870se2000s) demonstrate that on multidecadal timescales atripole pattern, referred to as the Atlantic Multidecadal Oscillation(AMO), dominates SST variability on ~50e70 year timescales(Cunningham et al., 2013;Hall et al., 2015;Knight et al., 2005;Pintoand Raible, 2012). During positive phases (AMOþ) anomalouslywarm SST dominate, while during negative phases (AMO -)anomalously cool SST occupy the subpolar North Atlantic Basin(Knight et al., 2005). Typically, AMOþ(AMO -) phases coincidewith a weakened (strengthened) subpolar gyre (SPG) circulation(Holliday, 2003), and reduced (enhanced) heat exchange with theatmosphere, which results in cooler (warmer) climates in NWEurope”-

    That seems the opposite of what I thought as the influence not only on surface temperatures , but also , for reasons of sealevel rise, on sea temperatures.
    (However about 5 years ago Euarn Mearns’s site had a discussion about whether unjustified assumptions about air temperatures were being drawn from SST by, presumably, the Hadley Centre.
    http://euanmearns.com/hadcrut4-strikes-out/)

  21. Based on physical science I respect, it appears the oceans are warming thus raising global temperatures as the oceans discharge their heat into the atmosphere while simultaneously the warmer oceans cause an increase in volume reflected in nominal sea level rises. All to be expected since the end of LIA.

    Just my two cents.

  22. David Middleton

    Some remarks

    0. I’m not interested in any discussion concerning CO2’s influence, let alone about how much of the amount of sea level rise is of anthropic character. We all here don’t know anything about that.

    *
    1. You omit a very important paper:

    Reassessment of 20th century global mean sea level rise
    Sönke Dangendorf, Marta Marcos, Guy Wöppelmann, Clinton P. Conrad, Thomas Frederikse, and Riccardo Riva
    May 22, 2017

    https://www.pnas.org/content/114/23/5946

    Their data is here:
    https://static-content.springer.com/esm/art%3A10.1038%2Fs41558-019-0531-8/MediaObjects/41558_2019_531_MOESM2_ESM.txt

    *
    2. You write: “CW11 is about 100 mm lower than J14. For direct comparison I plotted CW11 on the secondary y-axis with a 100 mm offset.”

    I disagree.

    CW11 is not “about 100 mm lower than J14”: the two time series are departures (anomalies) from different means. That is the reason why you see them differing by such a lot.

    If you want to correctly compare them, you must shift these anomalies such that they refer to the same baseline (reference period). They may then still differ but for other reasons.

    Since Jevrejeva & al. stops at the end of 2009 and satellite altimetry starts with 1993, the best is to compute, for all other time series of interest, the offset of each time series wrt the mean of a reference period all series have in common, e.g. 1993-2009.

    Here is a graph whose plots all are based on that common reference period, allowing for a more correct comparison of
    – C&W (the CSIRO version including data till 2013)
    – Jevrejeva & al.
    – Dangendorf & al
    – NOAA sat altimetry
    and, as an unprofessional outsider:
    – my little layman job (considering only raw raw PMSL data, without any VLM or other adjustments):

    https://drive.google.com/file/d/11XCSd7YE9QwNFLOrp5a86TVGkf8E6oud/view

    Now we have a fair comparison (I deliberately omitted in the graph the period before 1880 because of the increasing backward paucity of PMSL data).

    *
    3. You pretend that Jevrejeva & al. “clearly shoot down the notion of a recent anthropogenic acceleration”.

    How can you write that? We just need to read what they themselves write in the conclusion of their most recent paper:

    Global sea level reconstruction based on 1277 tide gauges records has been used to determine global and regional sea level changes from 1807 to 2010.
    .
    There is an excellent agreement between the linear trends from GSL12 and satellite altimetry sea level since 1993, with rates of 3.1 ± 0.6 mm·yr^-1
    and of 3.2 ± 0.4 mm·yr^-1 respectively.

    and

    GSL12 shows a linear trend of 1.9 ± 0.3 mm·yr^-1 during the 20th century
    and 1.8 ± 0.5 mm·yr^-1 for the period 1970-2008.

    The trends in mm/yr for 1970-2008, computed by Excel out of C&W, Dangendorf and my outsider evaluation:
    – C&W: 1.97
    – Dangendorf: 1.87
    – Bin: 1.71

    The fact that the acceleration is, in Jevrejeva’s data, less visible over the whole XXth century than in the other data sets is simply due to the fact that it shows a much higher trend at the beginning of the century than all others.

    Let us compare, for the different PMSL tide gauge data evaluations, the sequences of trends for the same, here 5-year distant periods (1883-2009, 1888-2009, …, 1993-2009):

    https://drive.google.com/file/d/1OPGBfY2jXeEFJZVIlPEZ_qHxLx68dLyU/view

    If there was ‘no acceleration’, the trend of all these consecutive trends would in all cases be equal to… zero, and would be represented by a flat line.

    Again: how much man-made has to be integrated in SLR acceleration is – here – not primordial for me.
    Fact is that the acceleration exists. That we don’t view it as dramatic is no reason to ignore it.

    *
    For me as a layman, the best approach is that of Dangendorf & al. Not because it shows lower trends than others. But because their work has shown the highest strength.

    • Adjusting to a common baseline is the same thing as a static shift. It doesn’t alter fact that J14 matches the cyclical changes SST and glacial length. CW11 doesn’t.

  23. sea level in 2100 would be 310 ± 30 mm higher than in 1990, overlapping with the central range of projections in the Intergovernmental Panel on Climate Change Third Assessment Report

    And according to the most recent Fifth Assessment Report, it overlaps with the lowest range, the RCP2.6 scenario. Here’s the list from AR5:

    RCP2.6 – 260 to 550mm
    RCP4.5 – 320 to 630mm
    RCP6.0 – 330 to 630mm
    RCP8.5 – 450 to 820mm

  24. From the article: “According to J14, SLR accelerated from 1.8 mm/yr (1882-1915) to 3.2 mm/yr (1929-1963) about 20 years after the onset of the early 20th Century warming period. It then decelerated to less than 1 mm/yr after the onset of the mid 20th Century cooling period. . .

    Figure 6. 45% of the ice loss occurred before 1900, when atmospheric was still below 300 ppm. By 1950, 75% of the ice loss had occurred. Only 25% of the ice loss has occurred since humans allegedly became the primary drivers of climate change. At the time of “The Ice Age Cometh” (1975), 90% of the ice loss had already occurred.”

    Thanks for this article, David.

    This is more evidence for the 20th Century warming that the fraudulent Hockey Stick chartsters try to erase. That history they don’t like says the climate warmed up from about 1910 to 1940, then cooled from 1940 to 1980, then warmed from 1980 to present. And, lo and behold, CO2 concentrations increase when it is warming (with a lag) and concentrations decrease when it cools, and we have the record in the ice.

    Speaking of the “Ice Age Cometh” graphic on the chart: Notice that the fraudulent Hockey Stick chart shows the time of the “Ice Age Cometh” as not particularly cold. Not any colder than recent preceding years. Folks looking at that chart would say, “What Ice Age”?

    The Climategate Data Manipulators, in order to erase the look of the warmth of the 1930’s (just as warm as today) they not only had to cool the past but that resulted in the more recent past showing more warming, and that’s why the 1970’s on a Hockey Stick chart doesn’t stand out as particularly cool.

    Fraudulent Hockey Stick chart:

    https://bobtisdale.files.wordpress.com/2018/12/Reference-Figure-1.png

    And this (below) is the profile the global chart should really have, the one they changed:

    Hansen 1999

    https://climateaudit.files.wordpress.com/2007/02/uhcnh2.gif

    Notice how the warm 1930’s and the cool 1970’s are clearly shown. And from this, it should be clear just how much they have bastardized the Hockey Stick chart in an effort to fool people into believing we are living in a world that is warmer than any time in human history.

    But all you have to do is look at an unmodified chart (from any part of the world) to see that is not true, that it was just as warm less than one hundred years ago, and that’s what the Alarmists don’t want you to see, and that’s why they changed the temperature chart into the Lie we see today, the bastardized Hockey Stick chart.

    The only “evidence” the Alarmists have is a Big Lie.

  25. In addition to Water temperature and salinity changes, Cryosphere changes ), and changes in the configurations of the continents and ocean basins, seawater level is affected by position and alignment of major planets, varying distance to Sun and Moon, and the rise and fall of the mid-ocean ridges.
    When I hear alarm over sea rise, I check the data from the tide gauge at Fort Denison at Sydney harbour, near the Pacific Ocean, which is now 50-mm above the reading in 1850 A.D. I then go back to sleep.

  26. David,
    Cannot follow your talk of rise being lagged after temperature change for reasons related to water depth. View the sea as being like the alcohol or Mercury in a thermometer. No significant late there. Lags require a storage/memory mechanism while the lag happens. What mechanism do you have in mind? Geoff S

  27. “I apologize for the total lack of sarcasm in this post and for not finding a clever way to insert horst schist and other geological euphemisms into at least one fracking sentence.”

    David, I award you no points, and may God have mercy on your soul.

    0.0

    🙂

    • If I had just taken a swig of Diet Coke, it would now be splattered all over my monitor… ROTFLMFAO!!!

  28. Interesting that the step-down in global glacier length coincides with Australia’s actual “hottest-evah” period, the ‘Federation-Drought’. Saw-tooth decade-scale steps-up when cooling, decade steps-up plus down when peaked, and similar steps-down when cooling. A pity this graph doesn’t come up to present-day as it looks more interesting. Decade-scale steps-up and down when bottoming-out too?

    Either way the ‘now’ end is visually out of step with cAGW’s narrative-o’-doom, but is consistent with natural-variability.

    https://debunkhouse.files.wordpress.com/2019/12/oerlemans_3.png?w=700

    • WXcycles

      It’s a bit too easy tho show out of context a graph fitting to your personal narrative.

      You give here the wrong impression that Johannes Oerlemanns’s meaning would exclusively reduce sea level rise to natural variability.

      The best is to cite him:

      The pressure, both scientific and political, to make estimates of future sea-level change has led to the use of so-called semi-empirical approaches in which a simple relation between past sea-level rate and temperature or radiative forcing is determined, and then extrapolated through the twenty-first century (e.g. Rahmstorf 2007; Grinsted et al. 2009; Vermeer and Rahmstorf 2009).
      .
      The uncertainties in such an approach are large and the resulting potential errors in projections enormous.

      The paragraph above is in an article written by Oerlemans together with two other scientists:

      Estimating the Glacier Contribution to Sea-Level Rise for the Period 1800–2005
      P. W. Leclercq, J. Oerlemans & J. G. Cogley

      https://link.springer.com/article/10.1007/s10712-011-9121-7

      Debunkhouse? Hmmmh 🙂

      • The abrupt step-down in global glacier length in that graph between 1890 and 1900 does coincide with Australia’s ‘Federation-Drought’. That’s an observation which you fail to counterpoint with anything factually relevant.

        Your quote refers to sea level change, whereas my reference was specifically to the abrupt global change in glacier lengths, that coincided with the logged hottest known period within Australia’s colonial history (hotter than now and almost 130 years ago and well prior to the significant CO2 rise).

        I fail to see how that has anything to do with your slight of a “personal narrative”, given I’ve never mentioned the ‘Federation-Drought’ here before, at any time.

        And this is from your ink:

        “… 2.1 Glacier Length Variations
        The dataset on glacier length used in this study is an extension of the one used in Oerlemans et al. (2007). A number of records has been updated, and 152 records were added, mostly from remote areas like Greenland, Alaska, Central Asia and the southern Andes. The total number of records is 349. Although there is a reasonable coverage of the land masses (Fig. 1), there are relatively few records from regions where much ice is found (Alaska, islands of the Arctic Ocean, Antarctica). … … The backbone of the data set is formed by Fluctuations of Glaciers data of the World Glacier Monitoring Service (WGMS 2008 and earlier volumes). Other sources are regular scientific publications, expedition reports, websites of glacier monitoring programs, and data supplied as personal communication. … ”
        https://link.springer.com/article/10.1007/s10712-011-9121-7

        So the global glacial retreat trend shown is accepted valid thoroughly assessed data. The abrupt step-down in glacier length depicted does coincide with the hottest period observed in Australia, so far observed in records.

        You seem to be arguing that data and such clear associations should just be ignored. If you can’t even counterpoint without mucking it up perhaps you should try a different hobby?

        • WXcycles

          “If you can’t even counterpoint without mucking it up perhaps you should try a different hobby?”

          Thx for your personal attack. No reply at that low level intended.

  29. David, interesting post. Since long-term sea level rise in the middle of the ocean has little or no effect on human interests and activities, I decided to take a look at long-term sea level rise at coastal locations where there are recent continuous GPS monitors. I only found one long term measurement site with a collocated CGPS that showed little recent vertical land motion and it was at Honolulu HI where the measured sea level rise since 1905 has been 1.49 +/- 0.21 with no sign of acceleration in recent years. Data from this site suggest a global coastal absolute sea level rise rate of about 15 centimeters (6 inches) over 100 years, which is hardly alarming. More info and graphs here:
    https://oz4caster.wordpress.com/2019/11/28/sea-level-rise-catastrophe/

    • Bryan – oz4caster

      I follow your professional comments on Nick’s blog since long a time with much interest. But what you write here I really can’t understand.

      Why do you select so few data? There are over 1,500 tide gauges worldwide, thousands of GPS sites…
      Is it so complicated to search for a combination of them?

      You bring one and only one isolated example? So do I.

      At the end of the Bothnian Gulf on the Swedish side, there is a PMSL tide gauge in Furuögrund:
      203; 64.915833; 21.230556; FURUOGRUND

      This corner is known to be at the centre of a glacial isostatic rebound area.

      Quite in the near (about 10 km) you find a pretty GPS site in Ostvik: 64.8792 N, 21.0483E

      Please don’t tell me it’s too far away for a suitable GIA correction: the local VLM uncertainty at the tide gauges is estimated at 4.10^-3 mm/yr per kilometer of distance between the gauge and the GPS station.

      And using that data you easily understand that the raw PMSL data of the tide gauge with a trend of -7.9 mm/yr for 1916-2017 becomes something quite different when the VLM correction (10.4 mm/yr) is applied to the gauge’s time series.

      Rgds
      J.-P. D.

  30. To those who think that multidecadal oscillations in regional sea levels would request for a minimum of 50-60 years of sea level data to establish a robust  long term trend, I propose the following test:

    – (1) generate an anomaly time series out of all gauge data out of the well known PSMSL data, wrt a given period (I use to choose 1993-2013 for comparisons), by excluding all gauges having failed in providing sufficient data for anomaly construction;

    – (2) select, out of the accepted stations, those having at least 100 years of activity;

    – (3) generate a corresponding time series like in (1) but out of the stations selected in (2).

    Result: the comparison of 679 PSMSL stations with 81 out of them having at least 100 years of activity, for the period 1880-2018

    https://drive.google.com/file/d/1UsJgaymQYMGiR1Vxc6cghgzBI5baeor0/view

    Trends in mm/yr

    1880-2018:
    – all: 0.161 ± 0.02
    – 100+ yr: 1.58 ± 0.03

    1993-2018 (sat era):
    – all: 3.07 ± 0.08
    – 100+ yr: 2.88 ± 0.20

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