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Two Feet Of Sea Level Rise By 2100 Claims Latest Paper

February 13, 2018

By Paul Homewood


h/t Cheshire Red


Today’s junk science comes from the Guardian (polar bear and all!):



Melting ice sheets in Greenland and Antarctica are speeding up the already fast pace of sea level rise, new satellite data shows.

At the current rate, the world’s oceans will be on average at least 60cm (2ft) higher by the end of the century, according to research published in Monday’s Proceedings of the National Academies of Sciences.

Based on 25 years of satellite data, however, the research shows that the pace has quickened. It confirms scientists’ computer simulations and is in line with predictions from the UN, which releases regular climate change reports.


This is the paper referred to:




Satellite altimetry has shown that global mean sea level has been rising at a rate of ∼3 ± 0.4 mm/y since 1993. Using the altimeter record coupled with careful consideration of interannual and decadal variability as well as potential instrument errors, we show that this rate is accelerating at 0.084 ± 0.025 mm/y2, which agrees well with climate model projections. If sea level continues to change at this rate and acceleration, sea-level rise by 2100 (∼65 cm) will be more than double the amount if the rate was constant at 3 mm/y.


Using a 25-y time series of precision satellite altimeter data from TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3, we estimate the climate-change–driven acceleration of global mean sea level over the last 25 y to be 0.084 ± 0.025 mm/y2. Coupled with the average climate-change–driven rate of sea level rise over these same 25 y of 2.9 mm/y, simple extrapolation of the quadratic implies global mean sea level could rise 65 ± 12 cm by 2100 compared with 2005, roughly in agreement with the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5) model projections.


GMSL from the adjusted processing of ref. 15 (blue) and after removing an estimate for the impacts of the eruption of Mount Pinatubo (12) (red), and after also removing the influence of ENSO (green), fit with a quadratic (black). The acceleration (0.084 mm/y2) is twice the quadratic coefficient.


Previous studies, such as this one from NOAA, had found that the rate of acceleration had actually decreased since the start of the satellite era in 1993.

What this new study has done is assume that Pinatubo had artificially slowed sea level rise prior to 1993, as this paper explained in 2016:

Global mean sea level rise estimated from satellite altimetry provides a strong constraint on climate variability and change and is expected to accelerate as the rates of both ocean warming and cryospheric mass loss increase over time. In stark contrast to this expectation however, current altimeter products show the rate of sea level rise to have decreased from the first to second decades of the altimeter era. Here, a combined analysis of altimeter data and specially designed climate model simulations shows the 1991 eruption of Mt Pinatubo to likely have masked the acceleration that would have otherwise occurred. This masking arose largely from a recovery in ocean heat content through the mid to late 1990 s subsequent to major heat content reductions in the years following the eruption.


In other words, the start of satellite measurements coincided with artificially low sea levels.

The new paper from Nerem at al makes adjustments to sea levels to allow for this effect, allowing them to claim that sea level rise would really have been less in the first decade if Pinatubo had not occurred.

But here’s the real point, one I have made in the past. Because of the Pinatubo effect, the claimed rate of rise since 1993 is artificially high.

It is claimed that sea levels have risen by 3.1mm/year since 1993, according to satellites.




Nerem’s paper reckons that if we take Pinatubo out of the equation, the rise would fall from 3.1mm to 2.9mm.



But both of these numbers include 0.3mm for glacial isostatic adjustment (GIA), a recognition of the fact that ocean bottoms have been sinking since the end of the ice age. This of course has nothing at all to do with sea level rise, as measured at coastal sites.

In other words, after taking out the effect of Pinatubo, the rate of sea level rise would only be 2.6mm/year.


Looking at the long term trend from tidal gauges, there is nothing remotely unusual about rate of rise.


Nerem et al claim that if sea level continues to change at this rate and acceleration, sea-level rise by 2100 (∼65 cm) will be more than double the amount if the rate was constant at 3 mm/y.

This is clearly nonsensical and unscientific. There is not the slightest evidence that a slight acceleration measured over the last two decades will continue. Indeed, all of the past data shows that the rate accelerates and subsides regularly.

For sea levels to rise by 65cm by 2100 would mean an average annual rise of 7.8mm, three times the current rate.

If you accelerate your car from 0 to 60mph in 10 seconds, and assume that such acceleration will continue, it would not be long before you were driving at light speed. (My calculator says about 8 hours!)

Yet this is essentially the same logic used by Nerem.

To call it junk science is being too generous.

  1. manicbeancounter permalink
    February 13, 2018 6:45 pm

    “Projections are actually coming into line with linear trends.
    The IPCC’s median estimate is 2 feet 7 inches, and a NOAA estimate is nearly 7 feet, or over 2 metres of rise.

    These estimates by climate activists are having serious consequences for public policy, such as in Miami-Dade.

    The graphic below is from a 2016 report by the “Sea Level Rise Task Force”.

  2. manicbeancounter permalink
    February 13, 2018 7:32 pm

    Using Jereveja et al 2014 graphic, sea levels rose by around 110mm between 1930 and 1965, or 3.14mm per year. This is consistent with the rate from the satellite data since 1995.
    The early twentieth-century warming was roughly from 1910 to 1944, so there was about a 20-year lag between surface temperature rise and sea-level rise acceleration. The current spurt in global warming was from 1976, whereas the current acceleration in sea level rise was from 1995. Given that in HADCRUT4 the linear rate of temperature rise was zero from 2002 to 2014, there is an obvious forecast here.

    More importantly, HADCRUT3 used to show the late C20th warming was about the same magnitude as the early C20th warming, but now temperature data sets show up to twice the warming due to “improvements”. It suggests we are need of climate models to “improve” the obvious defects in Jereveja et al 2014. To paraphrase a Kevin Trenberth email to Michael Mann (cc Gavin Schmidt of NASA GISS, Thomas Karl of NOAA, Phil Jones of Hadley Centre)on Mon, 12 Oct 2009.

    The fact is that we can’t account for the lack of sea-level rise at the moment and it is a travesty that we can’t. The climate models shows there should be even more sea level rise: but the data are surely wrong. Our observing system is inadequate.

  3. jim permalink
    February 13, 2018 7:46 pm

    Paul, Not only is this paper ‘jumk science’, but the whole idea that you can measure sea level rises to 1mm from a satellite is worse than ‘junk’.
    Shame that tidal gauges don’t give the ‘right answers’ for our warmist chums.

  4. February 13, 2018 8:26 pm

    We are into dial a disaster for sea level rise. 2 feet, 2 meters, or whole ice sheets melt. We’ve been getting these disaster predictions for years and have the same sea level rise.

    The article measures a short period and gets 2 feet projecting 23 years out an additional 82 years. Right.

    If it’s linear then the 2-3 mm/yr SLR has to start NOW and go to 7.5 mm/year. No one has shown it is doing that. Sounds like BS to me.

  5. Broadlands permalink
    February 13, 2018 8:32 pm

    Once again.. scary reports but no suggestions as to what humans could do about it, even if they could. Keep the research funds coming in because we need to study it carefully? The science isn’t settled???

    • John Palmer permalink
      February 13, 2018 8:52 pm

      Oh, c’mon….do you know how much it costs to own a Tesla, let alone to fund ever-more-irrevelant climate/sea level/ ice-melting research?
      Give ‘em a break, won’t ya!
      Research which sets out deliberately to “prove” an unfounded hypotheses is not scientific research, it’s quasi-religious zealotry.

      • Broadlands permalink
        February 14, 2018 4:39 pm

        Indeed John… Have you read about the “adjustments” and the hiding the data, tuning the models described in SCIENCE magazine? October 2016, vol 354, pages 401-402. A real eye-opener.

  6. Coeur de Lion permalink
    February 13, 2018 8:33 pm

    Both the unreliable Shukman (BBC) and the over-the-hill Attenborough have gleefully cited Miami as an indicator of ‘global warming’ with associated ‘stock’ pictures, failing to mention that much of Miami has been built below Mean High Water Springs and the East Florida coast is tectonically falling (tho’ not by much). Liars. A civil engineering problem, not a climate one.

    • John Palmer permalink
      February 13, 2018 8:55 pm

      Quite so.

    • February 14, 2018 2:11 pm

      Likely the tectonic adjustment in Florida is the result of isostatic rebound as a result of the interglacial ice melt. The land is still adjusting from that event. As the northern reaches rise it is not “flat” but has dips and tilts. Florida might be tilting down a bit due the northern isostatic rebounds.

  7. J Martin permalink
    February 13, 2018 9:51 pm

    I wonder if aquifer depletion is an appreciable component of sea level rise.

  8. Hivemind permalink
    February 13, 2018 11:01 pm

    “To call it junk science is being too generous.”

    Try “propaganda”.

  9. Phoenix44 permalink
    February 14, 2018 9:01 am

    When did simple extrapolation of short term become science?

    This might happen, it might not. It’s not science.

  10. February 14, 2018 10:06 am

    Isn’t Manhattan supposed to be underwater by the end of this year?

    • dave permalink
      February 14, 2018 1:38 pm

      Yes; but people will just believe harder.

  11. gallopingcamel permalink
    February 14, 2018 2:04 pm

    At the present rate of melting it will take 10,000 years to melt the entire 30 million giga-tonne “Ice Inventory”.

    It has happened before without the aid of humanity burning fossil fuels.

  12. February 14, 2018 2:22 pm

    The rise and fall of sea levels, usually measured as “tides” are caused by the combined effects of the gravitational forces exerted by the moon, the sun and the rotation of earth. You can throw the earth’s elliptical orbit fluctuations, tilt variations on the axis and wobble into the mix. Not only do they effect our temperatures due to our relationship to the sun, but effect the gravitational pull. They are all cyclical.

    Then toss in the isostatic rebound from the last glacial episode in for good measure. As pointed out elsewhere, the rebound is not a disc rising, but involves dipping and tilting. One shore might be higher and another dipped lower. It is not as simple as putting your ruler in the water or a satellite fly-over.

    I agree that calling this article “junk science” is generous.

  13. February 15, 2018 12:38 pm

    The sea level gauge at Newlyn Harbour has been there for a hundred years, anchored in granite, and now tied in to GPS. The rise in sea level is around 1 mm per year, once subsidence of the station is accounted for. There is zero acceleration. Newlyn is like the sea level CET.

  14. Broadlands permalink
    February 16, 2018 2:31 pm

    Did anyone actually read the paper? “With careful attention to each of these issues, however, a preliminary satellite-based estimate of the climate-change–driven acceleration of sea-level rise can be obtained.”

    “However, detecting acceleration is difficult because of (i) interannual variability in GMSL largely driven by changes in terrestrial water storage (ii) decadal variability in TWS , thermosteric sea level, and ice sheet mass loss that might masquerade as a long-term acceleration over a 25-y record, (iii) episodic variability driven by large volcanic eruptions and (iv) errors in the altimeter data, in particular, potential drifts in the instruments over time….”

    Other than all that??? Who referreed that stuff?

    Edited by Anny Cazenave, Centre National d’Etudes Spatiales, Toulouse, France

  15. February 16, 2018 6:06 pm

    Here’s a chart showing the adjustments Nerem et al made to the satellite data:

    The astute observer of that little graph will note that the time line since 1998 has not changed. Claiming that adjusting the first 6 years of the satellite data will influence what the data will do 82 years from now amounts to scientific chutzpah.

  16. February 16, 2018 9:34 pm

    First of all the article is misleading. It does not take in consideration tectonic movement of the continental plates, assuming that the plates stand still which is not the case. Second, the polls ice is ticker than ever and showing a polar bear on the ice is just a manipulation. I do not know who is paying for theses studies but I have a feeling that american people are paying to be lied to. I would better find one other job than to lie to the people with loony theories like global warming.

  17. February 17, 2018 10:10 pm

    @Paul Homewood,
    “If you accelerate your car from 0 to 60mph in 10 seconds, and assume that such acceleration will continue, it would not be long before you were driving at light speed. (My calculator says about 8 hours!)”

    Your calculator needs adjustment! One “g” is 9.81 m/sec/sec and that is the same as the speed of light in 1.03 years.

    At a steady acceleration of one “g” it would take 354 days to reach the speed of light assuming that we live in a Newtonian universe. It seems more likely that we live in an (approximately) Einsteinian universe which means one can never achieve light speed. Here is Ethan’s take on the issue:

    • dave permalink
      February 18, 2018 8:43 am

      This Nerem claims the data proves an increasing rate of acceleration. I think Paul meant to write something along the lines of:

      “If you accelerate from 0 to 60 mph in 10 seconds, and then from 60 to 120 mph in the next 9 seconds, and then from 120 to 180 mph in the next 8 seconds,and then…pretty soon you will be using 1.21 gigawatts of power.”

      • dave permalink
        February 18, 2018 9:11 am

        “…an increasing rate of acceleration…”

        That should be “an increasing rate – i.e. an acceleration.” An increasing rate OF acceleration would be the third (positive in the case) derivative with respect to time.

      • February 18, 2018 10:37 am

        I took the easy route!

        0 to 60 mph in 10 seconds, 61 to 120 mph in another 10 secs, 121 to 180 mph in another 10 secs, etc

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