The surprising news from scientists about rising sea levels!

By Larry Kummer. From the Fabius Maximus website.


Summary: Rising sea levels have become a core element — perhaps the core — of climate activists’ warnings. What do scientists say? Should we worry, panic, or despair? Here is a brief answer, plus much supporting evidence.

An example of Greenpeace informing the public.

As so many of the predicted effects of climate change have failed to appear on time (e.g., the end of winter, more and stronger hurricanes), rising sea levels have become the focus of climate activists. It creates easy (if unscientific, even daft) graphics of global flooding — hopefully panicking insurance companies and landowners. Unfortunately, as so often the case, the science has not supported their screams of “Wolf!”

Now a new cycle begins, with the first salvo being Jeff Tollefson’s “Satellite snafu masked true sea-level rise for decades” in Nature, 17 July 2017 — “Revised tallies confirm that the rate of sea-level rise is accelerating as the Earth warms and ice sheets thaw.” A mild tone, as such articles go. The mainstream news stories to follow, fed by activists, probably will be lurid — or even hysterical. People will be running for the hills if they take them seriously (but they don’t; even believers see them as entertainment).

Spoiler – Conclusions

Below you will find six charts and 2750 words from major institutional science websites plus eight works of cutting edge research. It describes the scientific basis for the terrifying news stories you have seen and will continue to see in the major news media. I’ll save you some time. Here are the four conclusions relevant to the public policy debate about climate change.

(a) The seas are slowly rising and will continue to do so. Europe is preparing many of its coastal cities for this. America is not. Unless we wake up, the results will not be pretty. Slow and stupid are the sins “Nature’s god” always punishes.

(b) There are some tentative signs that the rate of increase is already accelerating, rather than just fluctuating. But the data is noisy (lots of natural variation) and the (tentative) acceleration is small — near the resolving power of these systems (hence the significance of the frequent revisions).

(c) Graph E in paper (5) is the key. As the world continues to warm, the rate of sea level rise will accelerate (probably slowly). Understanding the four scenarios used in the IPCC’s AR5 is an essential first step to making sense of the stories in the news about rising seas (discussed below).

(d) Bottom line: activists are attempting to incite hysteria by exaggerating and misrepresenting what science tells us about rising sea levels.What do the scientists say about the rising seas?

We start, as always, with the Working Group I of the IPCC’s Fifth Assessment Report: Chapter 3 – Observations: Oceans. The oceans have been rising at varying rates for a long time.

“It is very likely that the mean rate of global averaged sea level rise was 1.7 [1.5 to 1.9] mm/yr between 1901 and 2010 and 3.2 [2.8 to 3.6] mm/yr between 1993 and 2010. Tide gauge and satellite altimeter data are consistent regarding the higher rate during the latter period. It is likely that similarly high rates occurred between 1920 and 1950.”

The chapter also discusses at length the high degree of “interannual-to-multi-decadal variability” due to climate modes (e.g., the North Atlantic oscillation, the Atlantic multi-decadal oscillation, the Pacific decadal oscillation, and the El Niño–Southern Oscillation) which obscure long-term trends.

Also see NASA’s website about sea level projections. The rise over the past 25 years is aprox. 3.2 mm/year (12.6″ per century). Red emphasis added

“High quality measurements of (near)-global sea level have been made since late 1992 by satellite altimeters …This data has shown a more-or-less steady increase in Global Mean Sea Level (GMSL) of around 3.2 ± 0.4 mm/year over that period. This is more than 50% larger than the average value over the 20th century. Whether or not this represents a further increase in the rate of sea level rise is not yet certain.”

Now let’s look at research since AR5’s WGI report was published in 2014.

What do the satellites say?

The major databases of global mean sea level show no acceleration in recent years. Here are two of them.

(a) AVISO – through 25 March 2017.

AVISO shows a 1993-2017 rise at a rate of 3.28mm/year (12.9″ per century) – and no acceleration. They are confident of their data. Aviso distributes satellite altimetry data from Topex/Poseidon, Jason-1, ERS-1 and ERS-2, EnviSat, and the Doris precise orbit determination and positioning products. It is a partnership of these major science institutions. They have not updated their graph since March 2017. See their interactive tool here. Click the graph to enlarge.

“Comparisons between these altimetry data and those obtained using independent techniques, such as the drifting buoys of the Argo network, the GRACE gravimetry satellite, or the network of tide gauges, can not only corroborate these results but also help us establish which of the possible sources of variation in mean sea level might explain the rise observed.”


(b) Colorado University Sea Level Research Group (SLMG).

The CU SLMG provides another graph showing rising sea levels — but no acceleration. They have not updated it since June 2016, probably waiting for recalculation of satellite data. The trend is 3.4 mm/year (11.8″ per century).

“Since 1993, measurements from the TOPEX and Jason series of satellite radar altimeters have allowed estimates of global mean sea level. These measurements are continuously monitored against a network of tide gauges. When seasonal variations are subtracted, they allow estimation of the global mean sea level rate. As new data, models and corrections become available, we continuously revise these estimates (about every two months) to improve their quality.”

Global Mean Sea Level. Seasonal signals removed (10mm = 0.4″.).

Where do activists get those scary scenarios?

When climate activists do not just make up stories, they use the worst-case scenario in the IPCC’s AR5: RCP8.5. Like a good worst case analysis, it assumes large changes in current trends in population (high) and technology (stagnant in the 21st century). The scenario is unlikely and becoming more so every day. RCP8.5 assumes that coal is the fuel of the late 21st century. Coal companies are going bankrupt now, replaced by natural gas and renewables. Electric cars are already commonplace in Europe, with mass production coming to America eventually as the technology matures (it’s in the early stages now). The potential solar and even fusion remains bright for coming generations.

Scientists are responding to this, with papers increasingly focused instead on the middle scenarios (RCP4.5 and RCP6.0). With continued technological progress, we might reach the RCP2.6 scenario in the mid 21st C – with negative greenhouse gas emissions. For details see Manufacturing climate nightmares: misusing science to create horrific predictions.

 Recent papers about new analysis of the data

Unlike what you read in the mainstream media about climate and economic data, collecting this data is not like counting apples. Hence the role of revisions and reanalysis of the data. The graphs of global sea level and atmosphere temperatures result from mind-blowingly complex calculations, whether based on instruments on satellites or Earth’s surface. See this presentation describing some of this complexity.

Improvements are an ongoing process, as seen in “Orbit related sea level errors for TOPEX altimetry at seasonal to decadal time scales” in Ocean Science, in press. The TOPEX mission ended in January 2006.

Scientists have attempted to understand the dynamics of rising sea levels, unlock their history, and detect the expected acceleration in the rate of rising sea levels. Here are samples of their recent work. Red emphasis added.

(1) Timescales for detecting a significant acceleration in sea level rise” by Ivan D. Haigh et al in Nature Communications, 14 April 2014.

“Our results imply that if/when the currently understood components of the variability in the records are removed, then accelerations significantly different from zero are likely to become detectable in individual tide gauge records later this decade or early next decade, using the methods considered here.”

(2) Unabated global mean sea-level rise over the satellite altimeter era” by Christopher S. Watson et al in Nature Climate Change, June 2015. Gated. Abstract…

“The rate of global mean sea-level (GMSL) rise has been suggested to be lower for the past decade compared with the preceding decade as a result of natural variability, with an average rate of rise since 1993 of +3.2 ± 0.4 mm yr−1. However, satellite-based GMSL estimates do not include an allowance for potential instrumental drifts (bias drift). Here, we report improved bias drift estimates for individual altimeter missions from a refined estimation approach that incorporates new Global Positioning System (GPS) estimates of vertical land movement (VLM). …

“Applying the bias drift corrections has two implications. First, the GMSL rate (1993 to mid-2014) is systematically reduced to between +2.6 ± 0.4 mm yr−1 and +2.9 ± 0.4 mm yr−1, depending on the choice of VLM applied. These rates are in closer agreement with the rate derived from the sum of the observed contributions, GMSL estimated from a comprehensive network of tide gauges with GPS-based VLM applied and reprocessed ERS-2/Envisat altimetry.

“Second, in contrast to the previously reported slowing in the rate during the past two decades, our corrected GMSL data set indicates an acceleration in sea-level rise (independent of the VLM used), which is of opposite sign to previous estimates and comparable to the accelerated loss of ice from Greenland and to recent projections, and larger than the twentieth-century acceleration.”

(3) Refining satellite era estimates of global mean sea level rise” by Christopher S. Watson et al, slides presented at the International GNSS Service Annual Workshop in February 2016. This is an excellent introduction to the complexities of calculating sea levels from satellite data. A few of their conclusions.

  • “Our work suggests TOPEX is yet to be fully understood and is presently slightly overestimating the trend in GMSL. {The TOPEX mission ended in January 2006!}
  • “Our revised record seems more consistent with the sum of the observed contributions to GMSL. While not yet statistically significant, we see the emergence of an acceleration.
  • “Further reprocessing of TOPEX is currently underway by mission agencies, first results seem commensurate with our findings, but this remains in progress.”

(4) Revisiting the contemporary sea-level budget on global and regional scales” by Roelof Rietbroeka et al, PNAS, 9 February 2016 — “The simultaneous combination of sea-level anomalies from satellite altimetry and data from satellite gravimetry allows a partitioning of the sea-level rise into the different contributions.” Abstract…

“Dividing the sea-level budget into contributions from ice sheets and glaciers, the water cycle, steric expansion, and crustal movement is challenging, especially on regional scales. Here, Gravity Recovery And Climate Experiment (GRACE) gravity observations and sea-level anomalies from altimetry are used in a joint inversion, ensuring a consistent decomposition of the global and regional sea-level rise budget. …”

The thick grey line is the total change in sea level over the 2002–2014 period: 2.74 mm/year (10.8″/century).


(5) Temperature-driven global sea-level variability in the Common Era” by Robert E. Kopp et al in PNAS, 15 March 2016 —

“We present the first, to our knowledge, estimate of global sea-level (GSL) change over the last ∼3,000 years that is based upon statistical synthesis of a global database of regional sea-level reconstructions.

“GSL varied by ∼±8 cm over the pre-Industrial Common Era, with a notable decline over 1000–1400 CE coinciding with ∼0.2 °C of global cooling. The 20th century rise was extremely likely faster than during any of the 27 previous centuries. Semiempirical modeling indicates that, without global warming, GSL in the 20th century very likely would have risen by between −3 cm and +7 cm {1.2″ to 2.8″), rather than the ∼14 cm {5.5″} observed. Semiempirical 21st century projections largely reconcile differences between IPCC projections and semiempirical models.”

Graph A: Global sea level (GSL) under prior ML2,1. Note that the model is insensitive to small linear trends in GSL over the Common Era, so the relative heights of the 700–1000 CE and 20th century peaks are not comparable.” The sea level values are with respect to 1900 CE baseline. This graph is widely used, seldom with this important caveat. (1.0cm = 0.4″.)


Graph E: 21st century projections for RCPs 2.6, 4.5, and 8.5. Red lines show the fifth percentile of RCP 2.6 and 95th percentile of RCP 8.5. …Sea level values are with respect to 2000 CE baseline.” By roughly 2025 the rate of sea level rise accelerates substantially under all four RCPs. (10cm = 3.9″.) The acceleration is steep only under the unlikely worst-case RCP8.5 scenario.


(6) Is the detection of accelerated sea level rise imminent?” by J.T. Fasullo et al, Scientific Reports, 10 August 2016 — Abstract.

“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.

“A consequence of this finding is that barring another major volcanic eruption, a detectable acceleration is likely to emerge from the noise of internal climate variability in the coming decade.

Unpublished research, new fuel for scary stories.

Tollefson’s Nature article mentioned research presentations at the “Regional Sea Level Changes and Coastal Impacts” Conference in July 2017 (see the abstracts here). The eventual papers published from these might have a large impact on the public policy debate. Here are two. First, the one by Nerem that Tollefson mentions.

(7) “Understanding the Acceleration of Sea Level Rise During the Altimeter Era” by R. Steven Nerem et al. Nerem had given a presentation with the same title at a CMCC seminar in February. Tollefson says that “Nerem’s team calculated that the rate of sea-level rise increased from around 1.8 millimetres per year in 1993 to roughly 3.9 millimetres per year today as a result of global warming.” Oddly, this isn’t in the abstract. This will be important if this work leads to the revision of the sea level histories so that they show an acceleration in recent years.

“Over the last 25 years, data from TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3 have been used to observe changes in global mean sea level. A rate of rise of 3.4 ± 0.4 mm/year has been observed. However, observing a possible acceleration in the rate of sea level rise is more challenging and pushes the limits of the observing system accuracy. This presentation will examine the feasibility of detecting an acceleration in the altimeter sea level record.

“First, the available evidence for estimating how big of an acceleration might be expected in the altimeter record will be reviewed. Next, the errors in the altimetry will be discussed in the context of tide gauge validation of the altimeter record. The role of interannual variability in GMSL in measuring the acceleration will be addressed.

“We will also discuss the role of decadal variability and how it might influence the determination of acceleration, including the role that the 1991 eruption of Mount Pinatubo might have had on the altimeter sea level record.

“Finally, we will discuss progress towards understanding the acceleration of GMSL over the 25-year record, based on consideration of all of these issues, including the importance of using the tide gauge validation to understand the errors in the acceleration estimate.”

(8) “Sea Level Budget of the Altimetry Era Revisited” by Anny Cazenave el al. Gavin Schmidt tweeted a graph (below) which I believe is from this presentation, similar to but apparently better documented than in previous paper associated with Cazanave (#2 above). This shows a slight acceleration during the past two decades, and a small acceleration since 2014 (to 0.14″/year). But the former might be natural variation and the latter might be a temporary effect from the 2014-2016 El Nino period.

“We revisit the global mean sea level (GMSL) budget during the whole altimetry era (1993 – present) and show that using a large number of data sets to estimate the different components of the sea level equation improves the budget closure. Moreover, the budget approach allows to detect bias and drifts in the observations.

  • Six different altimetry-based sea level data sets have been considered over the period January 1993-December 2015. They include the Climate Change Initiative (CCI) sea level products from the European Space Agency (ESA).
  • The steric data include three data sets for January 1993-December 2004 and four Argo data sets afterwards.
  • Three glaciers time series are considered. For the ice sheets, the IMBIE data set is used until December 2003 and the CCI ice sheet products afterwards. Both IMBIE and CCI products combine a large number of individual data sets.
  • Changes in land water storage and atmospheric water vapour content are also accounted for.

“For each term of the sea level equation we use the mean of available data sets. The sum of components agree very well with the altimetry-based GMSL except at the beginning of the record (1993-1998). During the later period a single altimeter (Topex A) was operating. Moreover Topex A suffered significant instrumental drift. Previous studies attempted to estimate this drift by comparing with tide gauges and the experimental Poseidon altimeter data onboard the Topex/Poseidon mission.

“Here we use another approach and estimate the Topex A drift from the sum of components over January 1993-December 1998. Accounting for this correction leads to much improved agreement between observed sea level and sum of components. Using ensemble means for the GMSL and components rather than individual data sets leads to closure of the sea level budget.

“The trend of the residual time series is 0.0 +/- 0.2 mm/yr. The RMS is 2.4 mm/yr for the whole altimetry record. It decreases to 1.7 mm when the steric sea level is estimated with Argo (as of January 2005). We attribute the slightly larger RMS of the first decade to uncertainty of the steric component.

“For the whole altimetry period (January 1993-December 2015), the GMSL rate is now close to 3 mm/yr. However, significant GMSL rate difference is found between the 1st and 2nd decade of the altimetry era (2.7 mm/yr and 3.5 mm/yr respectively), suggesting sea level acceleration in the recent years.”


“We don’t even plan for the past.”
— Steven Mosher (member of Berkeley Earth; bio here), a comment posted at Climate Etc about our unpreparedness for the inevitable repeat of past weather.

For More Information

There is a serious problem with Earth’s seas: we’re killing them. See the ugly details here, and more here.

For more information see The keys to understanding climate change, all posts about computer models, and especially these about rising seas…


138 thoughts on “The surprising news from scientists about rising sea levels!

  1. I may be all wet, but I think we need to build huge space ships to carry excess water and blast it out to space!

    • Dig a channel to the dead sea, reflood it, Repeat for Death valley.
      That should compensate for the rising seas for a while, and is very cheap compared to other options.

      • Isn’t there a large, 200-foot “depression” in Libya where water would be evaporated so fast that the inflow could used to generate power? And the evaporated water might produce rain in deserts to its east.

      • Roger,

        I’ve seen proposals like that for depressions near the sea, where water could be pumped in a low cost — powered by the turbines at the bottom of the valley (probably wouldn’t work well for Death Valley — mountains and distance). For example, using the Dead Sea.

        As a side benefit, the big new lake would soften the local climate!

        There are probably reasons this wouldn’t work, but it’s a neat idea.

  2. When nautical charts, on which tens of thousands of lives and trillions of dollars in commerce depend, when they show a datum correction for sea level rise, then one can believe it is happening.

    But they don’t. Nautical chart have a GPS correction, but no sea level rise correction. Which tells us load and clear that sea level rise is ivory tower BS. It exists in theory, but not in practice, because no one will trust their life to it.

    • I live near the shore and moor my boat in a well-known antique, historic harbor. I have lived here all my life. At no time have the ordinary borders of this harbor changed, nor the water risen beyond historic levels, except in times like Hurricane Sandy when wind, tidal currents, and surge coincided to raise the levels beyond those of a normal high tide. There are some houses 200 years old sitting on the banks of this harbor. In the same place. 25 miles down the line, they’re building hi-rise condos as fast as they can right down to the water’s edge. When I see THAT deemed inadvisable (multi-million dollar investments), then I MIGHT start to believe in “sea level rise.” But I’m one of those oddballs who accepts personal observation of the obvious over the hair-splitting pontifications of “experts.”

      • Likewise, GR. But in my tectonically stable part of the earth they have actually fallen ~ 8 inches since 1946 based on accurate benchmarks.

        But that’s just my lyin’ eyes again.

        Meanwhile we must believe in measurements by circular orbit of a pear-shaped geoid using selectable algorithms of something that never stops rising and falling by the second.

    • Things to consider:
      Has anybody checked to see if there has been any sub-sea activity that could “raise” the level of the oceans with respect to satellites? (a new island has just been formed naturally off the cost of North Carolina)
      Has landfill been considered as a source of sea level rise? (China’s man made islands are only a small example of world-wide activity of this sort)
      considering that satellite orbits decay with time, has any consideration been give to the possibility of that being a “source” of apparent sea level rise?

  3. Satellite altimetry is very handy for the sea level alarmists, because it can apparently be tweaked to show almost anything.

    Considering that the longest single-instrument satellite altimetry record is only about a decade (compared to two centuries for tide gauges), and there’s apparently no time limit on going back and “fixing” the old satellite altimetry data, it is hard to imagine why anyone actually takes it seriously.

    This is the sort of thing they do to temperatures, all the time (h/t Steve Case):

    To the best of my knowledge, they’re still not doing that sort of nonsense to individual tide gauge measurement records, though some researchers have certainly been creative when calculating the “averages.”

    • Do satellites stop taking altitude measurements when over land? If not, then the “adjustments” to their sea-level measurements must also be applied to their altitude measurements of islands and continental features. What is the result of these adjustments? Did no one notice the satellites telling us the land was sinking, but the adjustments now make it stable? Or are the adjustments now telling us that the earth is expanding?

    • “Jason-2 flies in a low-Earth orbit at an altitude of 1336 km. With global coverage between 66°N and 66°S latitude and a 10-day repeat of the ground track, Jason maps 95% of the world’s ice-free oceans every ten days. Sea surface height accuracy is currently 3.4 centimetres, with 2.5 expected in the future.”

      How do they get the accuracy down to 4mm?

      • By doing a large number of measurements, the individual measurements are not accurate, but the distribution around the estimated average becomes accurate. The roughness of the sea level is much larger than the estimated sea level rise in decades. So individual measurements may not give a precise answer.

      • Hugs. How does that work? you seem to be confusing accuracy and precision. The reduction in the
        standard error of the mean can only done if bias is i.i.d.

      • Sorry Hugs, but that only applies to independent measurements of the same quantity. So unless it is known that the sea-surface does not rise or fall and the satellite orbit is known to be absolutely stable you can forget that.It is indeed a fairy-tale for the innumerate.

    • “Satellite altimetry is very handy for the sea level alarmists, because it can apparently be tweaked to show almost anything.”

      I find it slightly odd that satellite temperature measurments are considered “gold standard” here, whereas satellite sea level measurements are treated with suspicion. It is equally true that satelite temperature measuerments can in principle be “tweaked to show almost anything” as they are indirect measurments, unlike surface temperature measurements.

      Derivation of temperature from the satellite measurements is the output of a complicated model, unlike surface temperature data which is from direct measurement of temperture.

      • And if you truly believe that, you would probably buy into my business proposal for voodoo accupuncture. The surface temperature “records” are heavily influenced by UHI and infill from distant locations, as well as “corrected” sea surface temperatures. The satellite “records” are of short duration, and run contrary to tide gauges with a long record. Other than that, no problem.

      • In addition UHA satellite data is verfied by weather ballon data. However, tide gauges, a more certain metric, dispute the newly ajusted satellite data, and said tide guages only show about 1/2 of what the satellite gatekeepers claim.

  4. Watching climate alarmists create in real time fraudulent scenarios of a “climate crisis”, gain leadership buy in on these fraudulent scare mongering scenarios, and leverage that buy in into climate hype lucrative policies raises real questions about how religions and extreme political movements come from.

    • Hunter,

      From another perspective, I’m amazed that climate-alarmists 3 decades-long bombardment of the US public — supported by academia, the news media, the big NGOs, the major science institutions and one of the two big political parties — has failed to achieve anything of note.

      It’s like a Sherman tank rolling over an apple, and the apple tossing the tank aside. It shows a stunning degree of incompetent execution.

      They would have better off copying their strategy from watching old natural disaster films — such as “When Worlds Collide” (1951) and “Gorath” (1962). Especially the latter, where scientists convince the world that it will soon be destroyed by a wandering star — and to build giant atomic rocket engines in Antarctica to move the Earth out of its path. The science is daft, but it’s inspirational.

      Get the scientists together. Present the evidence to the world. Answer questions. Open and honest. The path not taken.

      • ha…LOL……I was just going to say that same thing…….over 30 years…..actually over 100…and still no proof

      • The average person cannot read a graph or understand scientific discourse but they have run into used car salesmen and they aren’t stupid.

      • It is worth considering why the USA is very out of step with the rest of the world in accepting global warming.
        There seem to be two alterntives. Either the USA is the only place where citizen scientists are sufficiently developed to counteract the fraudulent attempts of word Governments to propagate lies for the purpose of world domination. Or the USA is a bit stupid.

        Unfortunately it is looking more and more like the latter.

        Carry on down the hole and the rest of the world will progress without you. It would have been better to have you along for the ride, but we will be OK as we watch US global influence slowly diminish.

        It may have escaped your notice, but Angela Merkel is now talked of as the leader of the free world. Until recently this was the title granted to the president of the USA. Maybe this does not matter to you.

      • seaice, the atmospheric carbon dioxide growth rate has been lock step with temperature since the inception of the MLO data set. If the future is anything like the past 60 years, the paris accord won’t make one iota of difference in CO2 levels. Who, then, is “a bit stupid” here?

  5. Has that picture of the Statue of Liberty from ‘The Day After Tomorrow’ been reversed, or did they actually have her holding up the wrong arm in the movie?


    • An example of Greenpeace informing the public.

      Serving suggestion. May contain image manipulation. We cannot be held responsible on damages caused by you believing what we say. May contain exaggerated depictions.

      Picturing the Statue Liberty in seawater is, in my opinion, pretty much like an H card; that is, cheap and worn-out. :)

  6. The worst possible thing imaginable about rising sea levels is that the current owners of sea-front are going to help drive up the property values of slightly-less-rich-people who own the buildings one block back.
    Then we we will really be in trouble, won’t we?

  7. It’s called an interglacial warming. It’s natural and there is nothing we can do about the warming. We can, obviously, prepare for the ocean rise where necessary and when necessary. But we cannot stop it. Better this than the dawn of a new glaciation. I grew up near the Great Lakes where mild verticle earthquakes were not uncommon due to the earth still “popping up” now and then in recovery from the thousands of feet of ice which were previously parked there. Was not that long ago that they melted, geologically speaking. And they will be back. All of this is fairly predictable in substance, it’s the when that is hard to figure.

    • Sea levels were higher 8000 ya. In all likelihood we are already descending in temperature toward the next major glaciation. That is what we should really be concerned about. We don’t really know how fast the onset might be, it is pretty much due and it would mean the planet could probably support fewer than half of the existing population.

    • Greenland is too far south to maintain glaciers in a long interglacial like this one will continue to be.

      The southern third of Greenland will melt out over the next 3,000 years and then the middle part will also melt out over the following 2,000 years.

      This interglacial will be the longest one ever at about 130,000 years yet to go. Not much will happen in Antarctica but Greeland’s glaciers will be gone and the water will go into the Oceans as well as leave central Greenland as an inland sea since it is below sea level.

      Of course, a time machine is required to prove these points are valid.

      • At least one recent paper argues that perhaps half of the Eemian sea level rise above today’s came from melting ice in West Antarctica, not just Greenland.
        I agree with your suggestion that the next full glaciation is a long way off.

  8. Satellite altimetry does not seem quite ready to give meaningful results. Given that the ocean surface is rough on centimeter to meter scales, it is easy to envision the reasons why averaging should be a problem. As the tide gauges in geologically stable areas show no acceleration, there just isn’t a reason for any alarm.

  9. Humans have been dealing with rising sea levels for a very long time. Probably, at least as far back as the Romans. You build a wall and optionally dump sand or similar behind the wall. Ask the Dutch how it’s done.

  10. Since it is a clear and present safety issue all beachfront homes shall be expropriated by eminent domain. I suggest we start with a pilot program in Malibu, Ca.

  11. There is more to the sea level change than rise in the global temperature and melting of glaciers.
    The map below shows North America tilting due to the Glacial Isostatic Adjustment (GIA) around the “hinge” line.

    (click on the map to enlarge)
    Notes: “(left) Vertical GPS site motions with respect to IGb00. Note large uplift rates around Hudson Bay, and subsidence to the south. Green line shows interpolated 0 mm/yr vertical “hinge line” separating uplift from subsidence. (right) Horizontal motion site residuals after subtracting best fit rigid plate rotation model defined by sites shown with black arrows. Red vectors represent sites primarily affected by GIA. Purple vectors represent sites that include effects of tectonics.”

    Important to note this is not a model but actual instrumental recorded data
    “Motions of three hundred and sixty Global Positioning System (GPS) sites in Canada and the United States yield a detailed image of the vertical and horizontal velocity fields within the nominally stable interior of the North American plate.
    North American plate is not limited to the US & Canada’s land but extends hundreds, even thousands of miles in the nearby Atlantic Ocean. Since there are no GPS data from the ocean floor it could be assumed that at least part of it (even if only the continental shelf) is subject to similar ‘rebalance’ as the adjacent land.

    If northern parts of the Atlantic Ocean’s floor are rising, some of the water would have to go elsewhere.
    Greatest uplift is in N.E. Canada Hudson Bay area has risen about 2m in the last hundred years.
    Another way of assessing what is happening within mantle is the change in local gravity currently measured by satellites. It is assumed that about 30% is directly due to the postglacial movement. The small decadal ‘vibrations’ in the mantle are propagating further down to the outer liquid core where the Earth’s magnetic field is generated. Consequently it may not be surprising that there is an apparent co-relation between data for the sea level rise and the changes (delta) in the magnetic field as measured in the N.E. Canada.

    Absurd… . may be or may be not.

      • GAAAAAAAAAA!!!! The PLATE is tilting–we’re all gonna DIE!!!!!!

        Let me fund a feasibility study of propping up the Continental Tilt via a new TILT TAX!!

        (Which still beats TILTING at WINDMILLS!)

      • Nope, the plate isnt tiltin it is deforming. The Laurentide ice squeezed up a bulge all around. That squeezed out rock is now slowly flowing back and filling out the depression. It takes a lot of time becaus rock is rather stiff and flows slowlyyyy.

    • V: that would put Hudson Bay rebound displacing 2,460 cubic km of water over the course of that century.

  12. “Coal companies are going bankrupt now, replaced by natural gas and renewables …”.
    Not Quite.
    “Over all, 1,600 coal plants are planned or under construction in 62 countries, according to Urgewald’s tally, which uses data from the Global Coal Plant Tracker portal. The new plants would expand the world’s coal-fired power capacity by 43 percent …” (NYT July 1).
    BTW concentrating on the IPCC Representative Concentration Pathways (RCPs) IMO is missing the point (or a red herring) because they all depend on assumed figures for climate sensitivity —
    being the main point of contention.

    • Chris,

      Re: “As Beijing Joins Climate Fight, Chinese Companies Build Coal Plants”, NYT, 1 July 2017.

      That article has gotten big press. it is also quite misleading. A large fraction of the proposed plants are trial balloons, which never get built. Many are replacements for old or dirty plants. And the effects of the shift to natural gas — and to a lesser extent, renewables — are just beginning to be felt.

      80% of the new plants are in China, part of China’s mad and unsustainable debt-fueled infrastructure construction boom. Extrapolating that out gives fun numbers — clickbait headlines — but is unlikely to happen. China’s leaders are frantically trying to leash the boom before it explodes. one or the other will happen, eventually.

      Here’s a look at the numbers. All of these reports are thinly sourced, since data from China ranges from somewhat believable to fiction.


      • So in other words yes China are building new coal fired power stations ! What is misleading about that ? Their commitment to burn coal for power both now and into the future is obvious , stop splitting straws .

      • I read the referenced document from Greenpeace. Apparently there is nothing to worry about, since coal is getting sidelined at a fast enough pace that we will meet any of those bogus targets in climate agreements. Paris, Cancun etc.

        But this statement was jarring:

        “With thousands of deaths from five serious typhoons since 2006, including unprecedented
        destruction caused by Typhoon Yolanda, the Philippines has already witnessed some of the
        dire implications of climate change.”

        What a disgraceful and dishonest statement ! Anytime we point out lack of warming, its “climate is not weather”, and here you have events that have happened naturally for eons, now labelled ‘implications of climate change’. What kind of sick mind does it take to spread that kind of misrepresentation?!? oh, that’s right eco-extremist minds.

  13. Remember when it rained so much in Queensland that it lowered sea levels….
    How come Greenland has put on more water ice in the past three years and it didn’t?
    BTW the area affected in Greenland is about the same as the area was in Australia

      • There’s no world record low temp in Greenland. But if the melt continues like it has this year, we’re doomed. With a glaciation.

      • “There’s no world record low temp in Greenland.”

        No, just a northern hemisphere cold record for July with -33 C. The previous record, -30,7 C, was set last year.

      • This is the 3rd winter in a row where an ever increasing SMB gain has occurred on the Greenland ice sheet. That is the main point. The Big Question is what happens next on the Greenland ice sheet? Are we g0ing to see 300 or 400 Gt above average with this next winter season? Note how the current trend of melting ice has come close to a halt over the last 6 days. I had thought that the melt season may end early this year, but not this early.

  14. Could the sea level rise be caused by draining aquifers?
    When working in KSA they drilled deeper every year sometimes 300m (1000ft) per year. Perhaps the water cycle needs revising.

    • Yes — apparent sea level rise can be caused by pumping fluids — water or petroleum — out from under a tide gauge. In some cases, “they” have had to resort to pumping fluids e.g. waste water into oilfields in order to discourage further subsidence. For the most part the problem is thought to be limited to a fairly small number of sites. It won’t affect satellite measurements, but the transfer of water from aquifers to the ocean does contribute a bit to slr. That’s thought to be largely offset by increased amounts of water being impounded on land behind hydro/irrigation dams.

  15. I grew up in Newcastle, NSW, Australia in the 60’s. I went back to live there for a couple of years in 2011 to 2013. Newcastle Beach hasn’t changed in 50 years so I call sea level rise or fall fake news. :)

    Just a quick back of the envelope observation.

    • Steve,

      (1) Look at the satellite maps. There is massive local variation in sea level changes. Looking at one spot and declaring that is the world is weak logic.

      (2) If sea level rose at Newcastle at the global average rate for 50 years ending in 2013, that would be a little over 5″. Are your memories of the coast in 1963 that precise?

      Eyewitness testimony isn’t reliable about details in events from last week.

      • More straw splitting , if the convict made median tide gauge in Sydney and Tasmania are pretty much exactly where they were when made in the mid 1850s does this mean that by your logic all the oceans are sending water to the northern hemisphere .

      • Very precise. 5″ would mean that the World Pool on the left hand side of the beach would be now under water at every high tide. :)

  16. “(d) Bottom line: activists are attempting to incite hysteria by exaggerating and misrepresenting what science tells us about rising sea levels.” Do you think this thing about “sea levels” has any thing to do with Big Al’s up coming climate change movie?

    • I don’t know anything about what Al’s movie but I wouldn’t be surprised.
      But the CAGW meme also has a history of changing the focus from one (failed) projection to another.
      Classic example: “CAGW” was all the rage. No pre-boiled lobsters being caught in Maine so now that’s because of “Climate Change”.
      No recent Katrinas in the the US so “The sea level is RISING!!!”.

  17. Median tide gauge from Tasmania that was made over 150+ years ago is still clearly visible and I believe there is one in Sydney that also doesn’t seem to show anything alarming .
    Flannel and Suzuki and quite a few other warmistas own sea front property and aren’t selling up , but the MSM won’t give us the truth just the ideology to which they’ve become indoctrinated too .

    • Robert,

      (1) “that also doesn’t seem to show anything alarming ”

      Can you point to anything in the data shown in this post that is “alarming” about the past rate of sea level rise? The concerns are about when and what rate will accelerate.

      (2) What does the tide gauge at Port Arthur, Tasmania tell us?

      See “The Sea Level at Port Arthur, Tasmania, from 1841 to the Present” by J. Hunter, R. Coleman, and D. Pugh in Geophysical Research Letters, April 2003. Abstract:

      “Observations of sea level at Port Arthur, Tasmania,southeastern Australia, based on a two-year record made in 1841 – 1842, a three-year record made in 1999 – 2002, and intermediate observations made in 1875 – 1905, 1888 and 1972, indicate an average rate of sea level rise, relative to the land, of 0.8 ± 0.2 mm/year over the period 1841 to 2002. When combined with estimates of land uplift, this yields an estimate of average sea level rise due to an increase in the volume of the oceans of 1.0 ± 0.3 mm/year, over the same period.

      “These results are at the lower end of the recent estimate by the Intergovernmental Panel on Climate Change
      of global average rise for the 20th century. …”

      • Sea levels have been rising since the last ice age Receded , how much of any rise nowadays is natural and how much is from coal burning and how is it possible for anyone to work it out .

      • Sincere apologies for the troll comment but rereading your post and comments I’m no wiser to where your at .
        Climate change seems to be your interest and how to mitigate for changes caused by it but all the info I see seems to indicate nothing to see here just good ol Mother Nature doing the thing she’s done for ever .
        When did man first realise that the ocean and sea levels constantly change and sometimes in big swings up and then down again .
        Anyone with ocean front property could possibly be in for a dunking but then again they might end up two blocks from from the ocean , is the world warming ? I hope so it’s very cold here .

      • Robert,

        “I’’m no wiser to where your at .”

        It’s journalism. Reporting the news, drawing simple conclusions.

        “all the info I see seems to indicate nothing to see here just good ol Mother Nature doing the thing she’s done for ever .”

        If you are not concerned about the possibility of a large acceleration in sea level rise, well that’s odd — but everyone is entitled to their opinion.

  18. This is simple. Do some real research on King Tides and the effect on coastal cities. During hundreds of years of coastal build-up people didn’t build where the tide would flood. Positively they were well aware of where that measurement had remained for centuries. Today, Florida is willing to spend $1B to protect the city of Miami by raising streets and building pump stations in case the raised sea wall fail. I would agree with one point you make. Science has not forecasted well. However, they have become much better in the last year or so. The entire world supports climate science except for a minescual number of [snip]. Other than world war, can you recall anything that can get the world to agree? Sorry, the mean ole Globalist are going to win this one, and they should.

    • We had an El Nino the last year or so. Are you trying to say this is evidence that the climate models were correct?

      Forty years of failed predictions and this is somehow vindication that climate science got it right.

      Do you know the Scientific Method is? Science is not about “belief”.

      • Reg,

        Sidenote – Your comment about the recent El Nino reminded me about an important lesson from that. Alarmists went hysterical in their warnings about the “super” “monster” “Godzilla” El Nino that was going to wreck the world. NOAA predicted it would be one of the three most powerful since (from memory) the 1950s.

        NOAA was right. The alarmists were wrong. Again.

        Oddly, after it ended journalists developed immediate amnesia about their stories of the looming El Nino horror. I never saw the stories congratulating the scientists at NOAA. Nor those with journalists’ mea culpa — pledging never again to feature almarists in the news.

    • Billy, not a chance. When and if a CAGW becomes actually “statistically probable” (even at p<0.10) then ok.. You don't mind taking one up the ole turd splicer (sorry bout that).

  19. Every place the media have presented where inundation is increasing during King Tides and Storm Surges is incurring subsidence, either due to tectonics, mining (including mining H20), compaction/settling or some combo of these.

    • Meanwhile in my non subsiding favorite area of water front, the levees I used to ride my bike on (and later party on) 35 – 40+ years ago have never been raised, in fact, they have eroded and otherwise degraded due to the holes the squirrels dig. These are dirt levees with no hard covering, with a bit of rip rap where the waves are higher than ankle slappers. And this is super crazy expensive real estate – including some big, big name tech firms and residential “Gold Coast” types of developments. So if here in the “Green” and “Climate Aware” Bay Area we are not raising levees, this is not the top risk or close to it.

    • James,

      You are missing the point, like so many of the people in this thread. Scientists are worried about how well we are prepared for an acceleration in the rate of sea level rise, not the 20th century’s slow rate of rise.

      For an example of how sea level rise compares with subsidence, see this paper about New York City. The destruction from Storm Sandy is a warning which the City has not heeded (as the subway crisis shows, NYC can barely maintain its existing infrastructure).

      “Impacts of sea level rise in the New York City metropolitan area” by Vivien Gornitz et al, Global and Planetary Change, 2002.

      • What’s the worst thing that can happen if we get global warming? Global warming in itself is a good thing for several reasons as most people know. The scare thing that is most used is the prospect of sea level rise and the flooding of coastal cities. I submit that this problem was solved several hundred years ago in Holland by constructing several thousand miles of dikes and pumping water out with windmills. With modern technology – backhoes, earth moving equipment, concrete seawalls, and diesel-powered pumps it would seem that for us this would be a trivial problem, especially given that we have ~ 100 years to get it done.

      • Jim,

        “What’s the worst thing that can happen if we get global warming?”

        That’s not a useful question, although 3 decades of alarmist propaganda have people thinking of this in binary terms. Don’t buy into their framing.

        The debates (among scientists and for public policy) are about the rate, timing, and eventual magnitude of warming. The worst case in AR5 is RCP8.5, which is horrific (all the research showing how is pouring water on a wet rock).

        The best case given is RCP2.6 (with eventual negative GHG emissions). Seeing the net impacts of that is more difficult, because it means weighing poorly understood good and bad effects.

      • Scientists are worried about how well we are prepared for an acceleration in the rate of sea level rise, not the 20th century’s slow rate of rise.

        Scientists should then do better communication, because alarmist advocates always mention “sea level rise”, not some “possibility of future acceleration of sea level rise”. Also, they talk about feet and metres, i.e. absolute theoretical rise, not the amount of detected acceleration. They also talk about not sea level as measure at the gauge, but always as a satellite-measured number which is better described as an average sea depth.

        The problem with left wing is that they’re actually very good with words. They are good in making things look like the story supports their values. So people who are engineers and taxi-drivers may be as right-wing they want. They will not be heard! Who is heard, is the journalists, who are, as a rule, almost all left-wing ideologues.

  20. Unfortunately, as so often the case, the science has not supported their screams of “Wolf!”

    Well, I don’t find it unfortunate.

      • With “adjustments”, and the “adjustments” appear to make up the lion’s share of change.

      • Bartemis makes a good point. If the instrument reading for an industrial process, and the adjusted results entered into the logbook showed the same graphical features, a good instrument engineer would immediately question the validity of the adjustment methodology, and investigate its validity for the specific situation in great depth. I think most of the isostatic adjustment when developed, actually used tide gauge readings in supposed geologically stable areas as a basis, so very easy to get a “double wrong” instead of “two wrongs cancel” situation.

  21. Larry, the rahmstorf graph pretty much says it all. If temps rise we’re in trouble and if they fall we are not. It still remains to be seen where temperatures will go from here. My thinking is that with more and more heat sinking into the oceans at a faster rate (note thermal expansion in your graphs) surface temps won’t keep up, hence we could reasonably expect to see the rate of sea level rise begin to fall. (the heat sinking capacity of the oceans becoming a negative feedback for surface temps)…

    • afonzarelli,

      There are lots of possibilities in the future! As I mentioned in the post, my guess is that the march of technology will put us on track for RCP2.6 sometime before 2050 — with its negative GHG emissions.

      We are, I believe, starting a new industrial revolution. Like the ones before it, this will have effects on a scale we can’t imagine today. Oddly, Leftists simultaneously believe in the rapid adoption of solar and electric cars — and the likelihood of RCP8.5 in which technology stagnates.


        Larry, at the risk of making you groan, i would ask you to look at this derivative plot of co2 vs temps. The similarity with the smoothed sea level derivative plot is striking. For whatever reason the carbon growthrate is likewise tied to a temperature above an equilibrium state temp. Because of this, consider the possibility that RCP8.5 won’t produce any greater atmospheric carbon growth than RCP2.6. i’m not trying to make a case for a natural rise in co2 here. Just a case that this temperature/ co2 growthrate relationship bears watching as we head into the future. (you’re free to groan now… ☺)

      • afonzarelli,

        I write about the public policy aspects of climate change. So posts like this about the science are inputs to the policy debate, reporting what the major institutions and peer-review literature say.

        I try not to enter the debate about the science. Although I have occasionally given in to the temptation when the target is too tempting.

      • Sorry, Larry, i spelt derivative wrong. (where’s cunningham when you need him?)…

        Sure, i understand. That’s why i put the ‘groan’ caveat in there. As a reader, i think it’s important to challenge all aspects of whatever i see written. At the very least, i always want to broaden people’s horizons. In this case i thought the comparison with the rahmstorf graph was apt (and perhaps something that you may or may not have seen before). That’s the neat thing about these comment pages. Hopefully, we’ll all move forward together…

  22. There is something of interest here that was only pointed out to me today, and I haven’t had time to fully digest, but I will toss it out for others to look into as they see fit.

    For astronomical calculations, we need transformations between the Earth fixed frame of reference and the frame of the “fixed” stars. Depending upon the precision needed, we sometimes make use of the “length of day” or LOD value which determines how fast the Earth is rotating about its axis.

    Angular momentum is always conserved so, all things being equal, a shift of water mass from the poles to the equator, or a general thermal expansion, should result in an increase in spin inertia, and a corresponding slow down in spin rate, manifesting in an increasing length of day.

    This is the LOD data from the IERS:

    There is a definite general increase in LOD since temperatures began rising after the LIA. But, it is not monotonic. Oddly enough, in the past century, it appears to decrease most in the 1910-1940 era of global temperature acceleration, and increase most in the 1940-1970 era of deceleration. Since 1970 or so to 2000, it has been on a general decline, another era of accelerated warming very similar to the 1910-1940 era according to the surface temperature sets.

    As I say, I haven’t sorted out for myself what all this means yet. There is a paper about the “enigma” here for any interested:

    • This is what Prof Humlum has to say at his excellent climate data site climate4you: “… periods with relatively high planetary rotation velocity (and low LOD) tend to be associated with relatively warm periods, and vice versa …”.

      • LOD might be affected by some of the Pacific’s factors. California’s precipitations data have spectral components distribution closely ‘associated’ with LOD.

      • It could be a lagging indicator. Temperatures rise, ice starts melting, LOD increases, temperatures fall, ice continues melting and LOD increasing until temperature returns to break even point, ice starts reforming with LOD decreasing, temperature bottoms out then starts rising again, ice starts melting again, LOD increases, and so on.

        So, not so much LOD increasing while temperatures decrease and vice versa, but LOD increasing after temperatures increased in the past, and decreasing after temperatures decreased in the past.

      • I suspected the ENSO, change in direction of trade winds and piling up of water in W. Pacific slowing/speeding the rotation rate.
        Spectral distribution of the ENSO data leaves no room for any doubt.

      • A reasonable guess is that the East Antarctic Ice Sheet grows in mass during warm periods and decreases in cold periods. This is a reasonable guess since it is essentially completely controlled by the precipitation, and glaciological studies shows that the ice sheet was much thicker during past warmer intervals.

        Yes, I know that the Antarctic Ice Sheet is supposed to be shrinking, but actually raw GRACE data are not significantly different from zero. The “decrease” is pure adjustment.

      • Sounds somewhat plausible, but we have a situation where long term LOD is increasing with temperature. It’s just the short term variations that seem out of phase. That is why I suspect it is more likely the system phase response producing a frequency dependent lag.

      • LOD never decreases. Atomic clocks are so accurate, we need to insert “leap seconds” into the time base because of tidal drag from the Moon.

        If you disagree, please tell me when was the last time a “leap second” was removed.

      • You have a mistaken understanding of LOD. LOD is basically the rate of change of the difference between atomic time and UT1 that gets quantized to produce leap seconds. As such, the monotonicity of the latter (since inception in 1961) does not imply monotonicity of the former.

        As you can see in the plot above, the LOD goes up and down. It peaked in the early 1900’s at about 4 msec/day, which means you would get a leapsecond in about 250 days. Currently, it is on the order of about 1 msec/day, so we should be getting leap seconds every 1000 or so days, or about 2.7 years, plus or minus. We’ve had three of them in the last 6-7 years, so that’s about right.

    • Monsoons are moving huge amount of water from the equatorial Indian ocean and Pacific have the opposite effect.

  23. According to a book I am reading named, “13 Facts That Prove Humans Don’t Cause Global Warming”, twelve thousand years ago the oceans were 400 feet lower than they are today. In comparison, an inch or two in todays world is nothing. It probably comes from all the water pumped out of the deep wells in California that will take a hundred years to refill.

  24. Willis, ignoring any/all data prior to 1950 makes your analysis worthless.
    Ignoring satellite data makes you look stupid.

    Isn’t “satellite data” the gold standard?

    • @ Steve Heins –

      Try harder to be more polite, I’m sure you can.

      Serious question: do you think the satellite data shows an acceleration signal?

  25. Perhaps the author(s) are unaware of the Gregory et al. assessment from a few years ago:

    Confidence in projections of global-mean sea level rise (GMSLR) depends on an ability to account for GMSLR during the twentieth century. There are contributions from ocean thermal expansion, mass loss from glaciers and ice sheets, groundwater extraction, and reservoir impoundment. Progress has been made toward solving the “enigma” of twentieth-century GMSLR, which is that the observed GMSLR has previously been found to exceed the sum of estimated contributions, especially for the earlier decades. The authors propose the following: thermal expansion simulated by climate models may previously have been underestimated because of their not including volcanic forcing in their control state; the rate of glacier mass loss was larger than previously estimated and was not smaller in the first half than in the second half of the century; the Greenland ice sheet could have made a positive contribution throughout the century; and groundwater depletion and reservoir impoundment, which are of opposite sign, may have been approximately equal in magnitude. It is possible to reconstruct the time series of GMSLR from the quantified contributions, apart from a constant residual term, which is small enough to be explained as a long-term contribution from the Antarctic ice sheet. The reconstructions account for the observation that the rate of GMSLR was not much larger during the last 50 years than during the twentieth century as a whole, despite the increasing anthropogenic forcing. Semiempirical methods for projecting GMSLR depend on the existence of a relationship between global climate change and the rate of GMSLR, but the implication of the authors’ closure of the budget is that such a relationship is weak or absent during the twentieth century.

    Notice the final sentence. Such honesty is rare these days.

    • Kurt,

      “Perhaps the author(s) are unaware of the Gregory et al. assessment from a few years ago:”

      As the post says, the papers cited were from after AR5. Gregory was received in 2012 and published two months before AR5. But that’s a trivial point.

      More important, Gregory 2013 is one of a long series of papers attempting to “close the budget” so that the components of sea level rise add up to the observed sea level rise. The papers cited here show that during the past five years that has been done (as always, more can be done to better understand this).

      This is a common problem in these threads — people cite old papers (in climate science 4 years is often old — as representing the current state of knowledge. Lots of money and many scientists are working on these problems, and the frontier of knowledge is moving.

      • Larry,

        Thank you for your feedback. I take your point, … but…:

        co-authors to the Gregory paper were both Church and White, whose earlier papers have been quoted as much as anyones that their IS a separate and detectable man-made sea-level rise signal. The Gregory paper (from 2012, published in 2013) says the OPPOSITE. Apparently the experts at the IPCC WG1 chose to ignore this inconvenient bit of information.

        You can’t have it both ways: either the sea level rise rate is accelerating (ostensibly to increased human CO2 emissions) or it is not. Claiming a doubling in sea level rise rate late 20th Century vs entire 20th Century (as the IPCC does) is duplicitous at best, fear-mongering at worst.

        Until a more recent paper demonstrates that Gregory, White, Church, … was in error, I will continue to doubt any claims that there exists a man-made signal.

        Any “acceleration” signal is purely due to short-term noise and/or natural fluctuations. Most of the problems with the satellite record (showing about 3 mm/y) are probably due to drift, since the satellite signal shows no acceleration, either (same for the tide gauges), but the difference of 1-2 mm/y between the two needs to be reconciled eventually.

        There does not exist a long-term anthropogenic sea-level rise contribution, not in the data at least.

      • Kurt,

        “Claiming a doubling in sea level rise rate late 20th Century vs entire 20th Century (as the IPCC does) is duplicitous at best, fear-mongering at worst.”

        It would be helpful to quote sources when you make claims about them. Let’s replay the tape to see the money quote from AR5 Chapter 3 (italics added):

        ““It is very likely that the mean rate of global averaged sea level rise was 1.7 [1.5 to 1.9] mm/yr between 1901 and 2010 and 3.2 [2.8 to 3.6] mm/yr between 1993 and 2010. …It is likely that similarly high rates occurred between 1920 and 1950. {my note – before AGW become dominant} …

        “It is likely that the rate of sea level rise increased from the early 19th century to the early 20th century, and increased further over the 20th century. The inference of 19th century change is based on a small number of very long tide gauge records from northern Europe and North America. Multiple long tide gauge records and reconstructions of global mean sea level confirm a higher rate of rise from the late 19th century.

        “It is likely that the average acceleration over the 20th century is [–0.002 to 0.019] mm yr–2, as two of three reconstructions extending back to at least 1900 show an acceleration during the 20th century. (3.7.4)”

        Likely is AR5’s lowest level of confidence.

        “Any “acceleration” signal is purely due to short-term noise and/or natural fluctuations. ”

        Yes, AR5 says that might be so. But they respect the data and express conclusions in terms of uncertainty. I am astonished at how often in this thread people give conclusions as if God just whispered in their ear.

        “is duplicitous at best, fear-mongering at worst.”

        I suspect if deuling was still in style, comment threads would have more careful accusations. Remarks like that in 1880 Dodge City might have you on the street looking an IPCC lead author in the eyes. Given the state in 1880 of pistols, holsters, and medical tech — making outcomes somewhat random — I suspect you would be wondering it “duplicitous” was really the best word to use.

      • Larry,

        You’re missing the forest for the trees.

        Re-read the following:

        You can’t have it both ways: either the sea level rise rate is accelerating (ostensibly to increased human CO2 emissions) or it is not.

        Decide which position you’re attempting to defend, then provide data to support it.

        Gregory, White and Church are all believers in human-caused catastrophic global warming. Yet they wrote a paper five years ago saying they found no (or extremely weak) evidence of the same in the sea level record, even though one must certainly manifest itself… eventually.

        The much-expected and hoped-for increase in sea level rise rate (acceleration) has been curiously absent from the data until now. Much like Trenberth’s “travesty”… What could one possibly conclude from such a record?

      • Kurt,

        “You can’t have it both ways: either the sea level rise rate is accelerating (ostensibly to increased human CO2 emissions) or it is not.”

        You appear unclear about how the real world works. While the reality is either X or not X, today’s available observations are often unable to determine which is true. Today’s research is clear — there are only tentative signs that sea level rise is accelerating. For those who rely on science, not revealed wisdom, observations are often in the grey zone of uncertainty. AR5 honestly and professionally reflects that uncertainty.

        You have given not the slightest basis for your claims of “duplicitous”, nor for your misrepresentation of what AR5 said.

        “Decide which position you’re attempting to defend, then provide data to support it.”

        This is science, not a baseball game.

        “What could one possibly conclude from such a record?”

        It means that the acceleration might have become detectable. Further observations will give answers. But continued warming — and the evidence is overwhelming that the world will continue to warm for the foreseeable future — means that the rate of sea level rise will eventually accelerate.

        Observations and research will tells us about magnitudes and timing. How much and when. Those provide the basis for effective public policy action.

        All of these seems clear. Your comments appear to show some objection to this, but do not convey what that is.

      • Larry,

        At this stage it is perhaps best to agree to disagree and move on.

        You seem wedded to the meme that human CO2 emissions will {eventually} manifest themselves in an increase in sea level rise rate, despite the utter lack of evidence to support that claim.

        But I wish you well in your efforts to “effectively seek the truth.” Sometimes that includes seriously questioning one’s most deeply held beliefs.

        [duplicitous – ADJECTIVE FORMAL: behaving dishonestly in order to trick someone]

        Since Gregory, Church and White were Lead Author, Coordinating Lead Author and Contributing Author, respectively, to AR5 WG1, Ch. 13 “Sea Level Rise”, one would expect that these individuals would have argued for accurate representations of the scientific conclusions from their own paper(s) — could we at least agree on that?

        Gregory, White, Church et al., published 2013, stated (final sentence of Abstract): “Semiempirical methods for projecting GMSLR depend on the existence of a relationship between global climate change and the rate of GMSLR, but the implication of the authors’ closure of the budget is that such a relationship is weak or absent during the twentieth century.”

        In IPCC AR5 (2013) WG1, Ch. 13, Sea Level Rise – Executive Summary, Church (as Coordinating Lead Author) stated the following: “It is very likely that the global mean rate was 1.7 [1.5 to 1.9] mm yr–1 between 1901 and 2010 for a total sea level rise of 0.19 [0.17 to 0.21] m. Between 1993 and 2010, the rate was very likely higher at 3.2 [2.8 to 3.6] mm yr–1.”

        Taken together, these two statements are incongruent. The claim of a rise from 1.7 to 3.2 mm/y can only be made if one grafts satellite readings (which show no acceleration) onto tide gauge readings (which show no acceleration either). This is duplicity. Once again, you can’t have it both ways. This isn’t quantum physics, where Schrödinger’s Cat can be both dead and alive simultaneously.

        BTW, the range of acceleration rates listed also include deceleration (negative values). Rather humorous. And the range given for the would-be acceleration signal (-0.002 to +0.019 mm y -2) is itself less than the tolerance in the actual sea level rise rate, even after a century of said “acceleration”.

        Your comment, “You appear unclear about how the real world works” is particularly entertaining. Is this anything other than your personal effort to insult or falsely condescend to one who disagrees with you, since you apparently don’t seem willing or able to detect the logical fallacy in your own position?

        Respectfully, I believe you are the one lacking in scientific acumen (and/or common sense) here. In the real world (as well as in “real” science), a claim must be backed up by data in order to have credibility. Perhaps an illustration from the banking world would help clarify.

        Let’s say you were a bank executive. A branch office manager had instituted a scheme to improve profits at his local office some ten years ago. He was confident it was working. He even reported that his analysis, over the ten year period to date, showed that the profit margin was increasing year-on-year, on average (with 66%+ likelihood). Surely you would continue to support his scheme, for over the coming ten years, the signal of increased profits would certainly manifest itself in the statistics. So you wait another ten years. And your branch manager says it is now very likely (90%+ likelihood) that there had been an increase in profits, maybe in another ten years or so it would really take off. But it WAS somehow possible, but statistically unlikely, that profits were not increasing at all, or even in fact decreasing. Hmmm.

        Perhaps you fail to realize just how important the detection of a human-signal in sea level rise is to the entire premise (that CO2 emissions need to be curbed as soon as possible). How can you even begin to discuss ‘effective public policy action’ if you can’t even detect a climate signal associated with inaction?

  26. I live about 5 miles west of Lake Michigan. My house sits on top of a massive, ancient hill left behind by the last glacial retreat.

    I will only be concerned about this if I see a cargo ship sailing along in the spot where the train tracks are now over by the harbor. The beach would be about 50-some feet higher than the current beach.

  27. I wonder how much the total amount of moisture in the atmosphere above the earh’s and sea level surfaces fluctuates in all reasonable time scales and if this has any impact on sea level.

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