Sea level rise is normal, my friends

countries in sea level monitoring project

Accelerated sea level rise debunked

A new analysis finds evidence of a weak deceleration in mean sea level rise in the Australasian region from 1940 to 2000 in four very long-term tide gauge records.

It brings long-term confirmation to what the South Pacific Sea Level and Climate Monitoring Project (SPSLCMP) has been reporting for about 10 to 15 years — slow, non-alarming sea level rise.

schematic of sea level monitoring station

Stupendously good news

Although the research focuses on our trans-Tasman neighbours, it also includes an analysis of Auckland, giving another insight into our likely coastal future. However, failing to present a dramatic story, it probably will not get the same media attention as the Emerging Issues paper from the Royal Society of New Zealand in September, 2010, which looked at new research on sea level rise and tried to alarm us all.

Yet, stupendously, the new paper offers the best possible news for those at risk from rising sea levels, as it thoroughly refutes the nonsensical scare stories about “accelerating” sea level rise. Our newspapers and television stations must ignore good news like this precisely because it’s not alarming. Otherwise, why have they not told us the truth?

The Royal Society paper on sea level skilfully tells us to ‘be afraid, be very afraid,’ but avoids responsibility for saying so. For instance, it says that warmer climates have ‘always been linked’ with higher seas; there is ‘increasingly rapid melting’ of polar and glacial ice; and it persuades us that all the evidence points to rising, not falling, seas, by asserting that our uncertainty is ‘one-sided.’ A heading yells at us: “Projections of sea level rise have changed dramatically over the last four years.”

Who wouldn’t be left with an impression of dangerous rise, starting now?

Powerfully neutral

But it practically denies all it says — and leaves us completely undecided — by making the quite astonishing statement:

For the decades and centuries that are important for planning purposes, we cannot yet state the likelihood of a given rate of sea level rise.

What?! The paper gives us a powerful push in a neutral direction! So why on earth did they bother writing it?

Has the Royal Society said anything about the Australian paper cited below? Or has the Green Party? Or NIWA? NIWA must have heard about the sea level monitoring project, since they have such a cosy relationship with the BOM, who run it, so they must have noticed that this latest paper confirms the lack of accelerated rise reported by the monitoring. Why don’t they mention it? After all, it’s very good news.

Research Paper

The paper we’re referring to is P. J. Watson (2011) Is There Evidence Yet of Acceleration in Mean Sea Level Rise around Mainland Australia? Journal of Coastal Research: Volume 27, Issue 2: pp. 368 ­ 377. doi: 10.2112/JCOASTRES-D-10-00141.1

P. J. Watson is the Principal Coastal Specialist, NSW Department of Environment, Climate Change and Water, PO Box 2185, Dangar, NSW, Australia 2309.


As an island nation with some 85% of the population residing within 50 km of the coast, Australia faces significant threats into the future from sea level rise. Further, with over 710,000 addresses within 3 km of the coast and below 6-m elevation, the implication of a projected global rise in mean sea level of up to 100 cm over the 21st century will have profound economic, social, environmental, and planning consequences. In this context, it is becoming increasingly important to monitor trends emerging from local (regional) records to augment global average measurements and future projections. The Australasian region has four very long, continuous tide gauge records, at Fremantle (1897), Auckland (1903), Fort Denison (1914), and Newcastle (1925), which are invaluable for considering whether there is evidence that the rise in mean sea level is accelerating over the longer term at these locations in line with various global average sea level time-series reconstructions. These long records have been converted to relative 20-year moving average water level time series and fitted to second-order polynomial functions to consider trends of acceleration in mean sea level over time. The analysis reveals a consistent trend of weak deceleration at each of these gauge sites throughout Australasia over the period from 1940 to 2000. Short period trends of acceleration in mean sea level after 1990 are evident at each site, although these are not abnormal or higher than other short-term rates measured throughout the historical record.

Truth about Pacific sea level hysteria

Here, for some perspective, is the latest graph of sea level trends in the South Pacific — to the end of February, 2011.

South Pacific sea levels to Feb 2011

12 Thoughts on “Sea level rise is normal, my friends

  1. Australis on April 16, 2011 at 6:17 pm said:

    BoM: “The analysis reveals a consistent trend of weak deceleration at each of these gauge sites throughout Australasia over the period from 1940 to 2000”.

    I assume this means that actual Australasian coastal sea levels (as opposed to eustatic or notional ‘global’ levels) have risen throughout the course of the 20th century, but the speed of that rise became lower and lower as time went by.

    If this is the case, it would seem to prove that coastal sea levels are poorly correlated with global warming. Or not correlated at all, actually, if the rise was decelerating while atmospheric warmth was accelerating during 1978-98.

    Rather, it is consistent with the hypothesis that sea levels have risen continuously since the end of the LIA, but that rise is slowly losing momentum.

  2. Yes, and if it’s true that sea levels are poorly correlated with temperature, it means they are rising in “recovery” from the LIA because ice is melting or there’s another source of water, but neither is triggered by an increase in atmospheric temperature. Curious! Has insolation increased or cloud cover decreased?

  3. Richard C (NZ) on April 17, 2011 at 1:41 am said:

    I find the title of this paper and the use of the word “yet” fascinating:-

    “Is There Evidence Yet of Acceleration in Mean Sea Level Rise around Mainland Australia? ”

    That the answer is no, in spite of “a projected global rise in mean sea level of up to 100 cm over the 21st century” seems to be very difficult to admit and the author may even be disappointed that one of the “multiple lines of evidence” is just not meeting expectations. It’s as if accelerating sea level rise is a fait accompli and it’s just a matter of time before it kicks in (but not “yet”).

    There are now less than 90 years left of the 21st century for the projected rise to occur but if the deceleration of 0.02-0.04 mm/year/year continues then the 2100 rate can be calculated using the average initial velocity (Vi) of the 1920-2000 rise which was 120/80 = 1.5mm/year (current global satellite 3.1mm/year). by substituting in a = (Vf – Vi)/t.

    After 50 years (2060)

    -0.03 = (Vf – 1.5)/50

    Vf = 0mm/year

    After 90 years (2100)

    -0.03 = (Vf -1.5)/90

    Vf = -1.2mm/year

    So now Barbara Dreaver can breathlessly announce that by 2060 sea levels in the vicinity of Australia and New Zealand will have stopped rising and by 2100 will be falling at -1.2mm per year – a good news scoop for TV1.

    Bryan Walker at Hot Topic can stop writing 3 hanky weepies about the poor folks of the Pacific low-lying islands that were sure to be inundated and instead break the joyful news to his loyal readers that the latest science indicates a wonderful reprieve.

    The Royal Society of New Zealand will rush these findings post haste to the PM’s climate change adviser Sir Peter Gluckman who will immediately brief the PM and the Minister of Climate Change so that govt departments and the people of NZ are informed of this amazing turnaround from predictions and we can all celebrate the let-off from catastrophe .

    It’s just a warm fuzzy feel good story all around.


  4. Richard C (NZ) on April 17, 2011 at 2:37 am said:

    “Has insolation increased or cloud cover decreased?”


    The paper describes “Short period trends of acceleration in mean sea level after 1990”. During the first half of the 90s, cloud cover (mainly low-level) did decrease (low-level cloud is not modeled) allowing an insolation increase at the sea surface, the result being increased ocean heat and thermal expansion which shows up as the short periods of sea level rise acceleration. Svensmark explains the cloud cover change as the solar wind modulated cosmic ray effect..

    This is a hugely important phenomenon and one in which the IPCC has been negligent. See:-

    Reflected Sunlight Shines on IPCC Deceptions and Inadequacies

    Figure 3: Global Albedo change 1984 – 2004 shows the effect of cloud cover change and solar energy flux.

    “The moon’s albedo is 7, which means 93 units of 100 are absorbed and 7 units reflected. Earth’s albedo is 30 on average for the entire globe. The amount varies from a high of 75 to 95 percent for fresh snow down to 8 or 9 percent for coniferous forest. Seasonal variation in snow and ice cover is important as it affects global energy and therefore the weather from year to year. However, the major factor is variability in the type and amount of cloud cover. Thick cloud varies from 60 to 90 and thin cloud from 30 to 50. This variability explains most of the change in albedo shown in Figure 3. The right side scale shows changes in energy with a range of about 9 watts per square meter. Compare this with the 2.5 watts per square meter change estimated to be due to human activities.”

    The next section deals with IPCC inadequacy in regard to natural forcings. AR4 Figure 4 Table of Radiative Forcings has only one forcing in the Natural Category – TSI (Total Solar Irradiance). As Tim Ball writes:-

    “IPCC reject irradiance as a cause of temperature change since 1950, but they also reject variations in sun/earth relationships, known as the Milankovitch Effect and the relationship between sunspots and temperature hypothesized by the Svensmark Cosmic Theory. The latter shows a relationship between changes in solar magnetism evidenced by sunspots. As the magnetism varies it determines the amount of galactic cosmic radiation reaching the Earth, which creates low cloud. As low cloud varies albedo varies.

    The Earthshine project of the California Institute of Technology that produced Figure 3 concluded in 2004. “Earth’s average albedo is not constant from one year to the next; it also changes over decadal timescales. The computer models currently used to study the climate system do not show such large decadal-scale variability of the albedo.” Sadly, there are many factors affecting climate change that the IPCC ignore or underplay to achieve the political result that human CO2 is the sole cause.”

  5. Nice analysis. Lots of warm fuzzies, little looking at facts.
    I like ‘3-hanky weepies’! It’s exactly what he does.

  6. Hemi Mck on April 19, 2011 at 4:34 pm said:

    In 1836 in his travels on the HMS Beagle Darwin observed that in the Western Pacific the sea level must be slowly rising as compared to the bits of land showing. He came to this conclusion from observing that there were no old coral reefs exposed on the land, rather the islands were either ringed by coral or there were simply coral rings. He knew that reef coral only survived to 10 fathoms (60 feet) and that below that it was merely dead coral stacked on top of dead coral. He therefore deduced that atolls where the remains of subsided islands. Darwin even had an idea of the rate of rise of the sea level. He concluded nearly 200 years ago from simple observation and logic that the rate of rise of sea levels had to be less than the rate of growth of reef coral.

    If Tuvalu looks after its coral it should be OK.

    Hemi McK

  7. Try this for a picture of Christchurch “climate refugees”

    Bad news for the Pleasant Point Yacht club. The building is stuffed and sinking into the swamp.

  8. Richard C (NZ) on July 24, 2011 at 12:51 am said:

    Tamino has a post on Watson 2011 (picked up the link at HT):-

    How Not to Analyze Tide Gauge Data

    I’m inclined to agree that the Watson analysis is very poor. Tamino dissects Fremantle and finds acceleration from (approx) 1897 – 1927, deceleration 1927 – 1975 and acceleration 1975 – 2009. I doubt that a Loess smoothing for Auckland would return a similar acceleration to Fremantle due to falling levels 2000 -2009 (Fremantle rising over that period) but might still be a recent acceleration. I haven’t got a link to the Auckland data source but Hannah 2010 is referred to by Hannah, Bell, Paulik 2010.

    The Tamino method for identifying acceleration by time derivative of a quartic model is very interesting:-

    a = 2 \beta_2 + 6 \beta_3 t + 12 \beta_4 t^2. (see the blog post for this).

    Fremantle data here:-

    It comes as absolute values above a datum, Tamino has plotted an anomaly but doesn’t give the baseline but I assume it’s the entire series. Then he computes a second anomaly to remove the annual cycle then smooths with Loess. which is surely better (?) than Watson’s moving average.

    Auckland (Hannah, Bell, Paulik 2011) here:-

    What’s has got my attention is Tamino’s method of deriving instantaneous acceleration which is different to looking for a departure from a long-term trend that I’ve been looking for. I haven’t looked at the local tide guage data in this light, I’ve mainly been looking at the global satellite trend using a 3rd order polynomial (Loess might be better) which seems a good fit to my unskilled eye. It’s easy then to eyeball approximate instantaneous rates.

    Andy, you’re the mathematician. Bob, Gary, You guys have stats knowledge that I haven’t – any comments on the Tamino post?

  9. Richard C (NZ) on July 25, 2011 at 8:51 pm said:

    Watson 2011 is the subject of the latest JoNova post (CCG was on to it in April).

    My contribution (after consultation with a couple of helpful CCG guys):-

    Richard C (NZ):
    July 25th, 2011 at 6:29 pm

    Thanks Ross # 25 for the Axel Morner article, it’s been a while since I’ve looked at the issues in it but revisiting them in the light of what I’ve learned since makes it all the more relevant.

    The TOPEX/Jason satellite data also has a deceleration, it’s very easy to pull down the data and fit a 3rd order polynomial to show it. The problem is the difference in linear trends between globally averaged tide guage data and the satellite trend of TOPEX/Jason (Envisat is less). The “adjustments” to satellite data documented by Axel Morner are incriminating, without which the satellite era data would show no rise. Axel Morner explains:-

    As reported above regarding such adjustments, an IPCC member told me that “We had to do so, otherwise it would not be any trend,”

    Re Tamino. A curve fitting exercise like his will show both recent acceleration and deceleration in individual tide guage data but they are very small and so what? It’s the global aggregate that matters. The required rates of global acceleration for any levels above normal (18mm/decade tide guage, 31mm/decade satellite) are just not evident recently. Houston and Dean refute Rahmsdorf and Vermmeer saying they “are curve fitting, not modeling physics, so the approach cannot be used to predict future sea level”. Even the IPCC has discounted the R & V proposition for the lack of physical relationships.

    The other problem I see is that once a model has been fitted e.g. Tamino’s, the apparently “better” correlation is then projected into the future with alarming connotations e.g. Tamino. This ignores the bigger picture (OHC stalled since 2003/04, clouds, grand solar minimum prediction etc) where there isn’t the drivers to continue the projection.

    The important point I think is the H & D conclusion:-

    “The important conclusion of our study is not that the data sets we analyze display small sea-level decelerations, but that accelerations, whether negative or positive (we reference studies that found small positive accelerations), are quite small. To reach the multimeter levels projected for 2100 by RV requires large positive accelerations that are one to two orders of magnitude greater than those yet observed in sea-level data.”

    Reply to: Rahmstorf, S. and Vermeer, M., 2011. Discussion of: Houston, J.R. and Dean, R.G., 2011.

    Re the Auckland tide guage series. Folks here may be interested in this paper:-

    Auckland: A Case Study in the Regional Assessment of Long-Term Sea Level Change
    John HANNAH, Rob BELL and Ryan PAULIK, 2011

    It puts Auckland in broad perspective including millennial and global, also cites Watson 2011.

  10. Richard C (NZ) on July 25, 2011 at 9:06 pm said:

    Nils-Axel Mörner article here:-

    There Is No Alarming Sea Level Rise!

    The pdf at nzclimatescience wouldn’t save to disk for some reason.

  11. Richard C (NZ) on July 26, 2011 at 6:01 pm said:

    Wrong link – should be:-

    Auckland: A Case Study in the Regional Assessment of Long-Term Sea Level Change

    John HANNAH, Rob BELL and Ryan PAULIK, 2011

  12. Richard C (NZ) on July 26, 2011 at 6:09 pm said:

    While I’m at it, let’s bring up this file:-

    by Vincent R. Gray | August 16, 2010
    The SEAFRAME sea-level study on 12 Pacific islands is the most comprehensive study of sea level and local climate ever carried out there. The sea level records obtained have all been assessed by the anonymous authors of the official reports as indicating positive trends in sea level over all 12 Pacific Islands involved since the study began in 1993 until the latest report in June 2010. In almost all cases the positive upward trends depend almost exclusively on the depression of the ocean in 1997 and 1998 caused by two tropical cyclones. If these and other similar disturbances are ignored, almost all of the islands have shown negligible change in sea level from 1993 to 2010, particularly after the installation of GPS levelling equipment in 2000.

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