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IPCC says “It is likely that the sea level rise has accelerated”. The evidence is flimsy, showing a larger problem.

21 December 2012

Summary:  Today we look at a weakness in the latest IPCC report, that illustrates a larger problem in the climate sciences.

Other posts in this series about second order draft (SOD) of the Fifth Assessment Report (AR5) by the Intergovernmental Panel on Climate Change (IPCC).

global-warming-2

Contents

  1. A weakness of the IPCC’s process
  2. This shows a far larger weakness in the climate sciences
  3. For More Information About Rising Sea Levels

(1)  A weakness of the IPCC’s process

The IPCC gets better” post lists some weaknesses of IPCC procedures, including this:

Mockton’s review also has long (very long) lists of peer-reviewed science overlooked by the IPCC (and ignored by the news media), because it ruins the narrative. This goes to the most serious criticisms of the IPCC: it’s narrow selection of sources, and blindness to many threads of research in the climate sciences.

… {this is} systematic misstating by IPCC authors of the climate science literature (eg, chapter lead authors often showcasing their own work and ignoring their critics). While just business as usual in academic science, the IPCC should not tolerable this when writing the foundation for high-stakes and high-cost public policy. It shows a lack of internal controls at the IPCC, and weakens their credibility — which is their greatest asset.

Let’s look at a high-profile example: rising sea levels — vivid, and so has become a widely used example of potential climate impacts (often hysterically so in the general media).  Judith Curry (chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology) examines rising sea levels as am example of the IPCC exaggerating the conclusions of current research.  This also illustrates a larger weakness in the climate change debate.

From Chapter 3 of the AR5 SOD (red emphasis added):

Two out of three reconstructions of GMSL (global mean sea level) from tide gauge data extending back to 1900 or earlier indicate non-zero acceleration. Estimates range from 0.000 to 0.013 [–0.002 to 0.019] mm yr–2, so it is likely that GMSL rise has accelerated since the early 1900s.

Prof Curry’s comment:

A fourth paper on this topic was recently published that was not referenced in Chapter 3 of the SOD {Gregory et al, below}.  So the addition of one more paper to the literature without an accelerating trend (2 out of 4) implies, according to the IPCC reasoning about uncertainty, that acceleration of sea level trend is ‘about as likely as not.’

Under this line of reasoning, the addition of one paper to the literature can change the assessment from ‘likely’ to ‘about as likely as not.’ And since the Gregory et al. paper seems to be superior from a methodological perspective, a more sophisticated assessment process would weight this paper more heavily. It looks to me like the IPCC needs to change this particular conclusion (especially the confidence level) in view of this new paper by Gregory et al.

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My problems with the IPCC’s characterization of and reasoning about uncertainty are described in my paper Reasoning about climate uncertainty, and this particular case is a good example of the flimsiness of many of the confidence assessments, especially for data sets that have a low maturity level.

The paper is “Twentieth century global mean sea level rise: is the whole greater than the sum of the parts?“, J M Gregory et al, Journal of Climate, in press. Abstract:

Confidence in projections of global-mean sea-level rise (GMSLR) depends on an ability to account for GMSLR during the 20th century. There are contributions from ocean thermal expansion, mass loss from glaciers and ice sheets, groundwater extraction and reservoir impoundment.

We have made progress towards solving the “enigma” of 20th-century GMSLR — that is, the observed GMSLR has been found to exceed the sum of estimated contributions, especially for the earlier decades. We propose that:

  • thermal expansion simulated by climate models may previously have been underestimated owing to 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 than in the second half of the century;
  • the Greenland ice-sheet could have made a positive contribution throughout the century; groundwater depletion and reservoir impoundment, which are of opposite sign, may have been approximately equal in magnitude.

We show that it is possible to reconstruct the times eries 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 approximate constancy of the rate of GMSLR during the 20th century, which shows small or no acceleration, despite the increasing anthropogenic forcing. Semi-empirical methods for projecting GMSLR depend on the existence of a relationship between global climate change and the rate of GMSLR, but the implication of our closure of the budget is that such a relationship is weak or absent during the 20th century.

(2)  This shows a far larger weakness in the climate sciences

We’re told that climate science research is the basis for public policy decisions necessary to save the world  But the climate science apparatus (data collection and analysis) are grossly underfunded. As in this example, where three studies provide the evidence for claims that the rate of sea level rise has accelerated.  Fixing one New York subway station after Sandy will cost $600 million.  How much is it worth spending to get reliable evidence on the rate at which the seas are rising?

Why are the people advocating massive public policy action to fight climate change not calling for massive research programs, beyond the garage-scale research of much climate science today — in which individuals or small groups tackle questions requiring large teams of multi-disciplinary experts? The most likely answer to that question tells us much about the debate.  The warmistas have their answers, and have little interest in more research.

What needs more funding

Some examples of research programs in need for more funds, stat.

(a)  The global climate surface measuring system is grossly inadequate. Even in the US, and the US has one of the best national networks.  At the other extreme, coverage in Antarctica is sparse — and coverage of the Arctic Ocean is almost non-existent.

(b)  We have few global sensors for less-familar problems.  For example, sensors watching solar activity — and scientists studying the results — are grossly underfunded.  As described in this article about space weather forecasting:  “Are We Ready for the Next Solar Maximum? No Way, Say Scientists“, Richard A. Kerr, Science 26 June 2009.

(c)  To understand the present and predict the future we need reliable data from paleoclimatology studies. The proxy data for reconstruction of historical climate data is absurdly poorly funded, considering the importance of the data.  Again multi-disciplinary teams are needed — with third party reviews of sampling techniques (to avoid cherry-picking of samples or proxies), interpretation (e.g., interpreting the underlying signal in terms of precipitation or temperature), and analysis (e.g., to avoid over-emphasis on certain geographical regions or samples).  Note:  these are only indirect measures of temperature.

(d)  These climate research programs should be coordinated, so that the gaps are filled and quality maintained through processes faster and more reliable than the routine academic mechanisms of peer-review.

(3)  For More Information about rising sea levels

  1. An example of important climate change research hidden, lest it spoil the media’s narrative, 22 May 2009 — About rising sea levels
  2. About that melting arctic ice cap, 17 April 2010
  3. Fear or Fail: about the melting Greenland ice sheet, 24 May 2010
  4. Today’s good news, about rising sea levels, 3 June 2010 — Esp note the links to articles and studies!
  5. More about the forecast for flooded cities in the late 21st century, 16 October 2010
  6. Looking into the past for guidance about warnings of future climate apocalypses, 17 October 2010 — Two of James Hanson’s past predictions
  7. About the coming sea ice Armageddon!, 19 June 2012
  8. Shaping your view of the world with well-constructed propaganda, 21 June 2012 — About rising sea levels.
  9. Run from the rising waves! (The latest climate catastrophe scare), 27 June 2012

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21 Comments leave one →
  1. guest permalink
    21 December 2012 12:32 pm

    So when the IPCC states that warming has paused, its assertions are reasonable and thoughtful, “they are getting better”; when they state that sea level is rising, its assertions are doubtful and they exhibit “weakness”. Looks like a kind of confirmation bias on the part of FM, though it is unclear what is the ultimate conviction (that there is no anthropogenic climate change? that the change induced by human activities is minimal compared to other factors? that its consequences are benign? that we are not experiencing any consequences yet? that the cost of business as usual is lower than strong mitigating actions? As far as I know, the overwhelming majority of qualified scientists who are looking into the matter answer “no” to all these questions).

    As for sea level: all 4 papers indicate they are rising, 2 that the rise is accelerating — however weakly. Knowing climate is a non-linear system, I would tend to be wary — minute initial effects can become prodigious after quite a while via positive feedbacks.

    As for more funding — yes, indeed, it is necessary, and it is definitely better to fund all those scientists than the manufacturing of new, “improved” atomic bombs (as is unfortunately happening). However, I have a feeling that the underlying rationale is “we do not know with any certainty what is happening and how, so let us study things more in depth but let us just not do anything at all about the underlying causes yet”.

    “Why are the people advocating massive public policy action to fight climate change not calling for massive research programs”

    Because there is not one single, united, coherent position on climate change. Those vocal proponents of actions such as littering the landscape with wind farms, or sea-proofing cities represent sectors where money is to be made — so of course they are less interested in research than fat subsidies. Remember how bio-fuels were touted as the eco-friendly, low-carbon footprint (renewable! sun-grown!) substitute to gasoline?

    Like

    • 21 December 2012 2:40 pm

      Guest,

      (1) “So when the IPCC states that warming has paused, its assertions are reasonable and thoughtful, “they are getting better”; when they state that sea level is rising, its assertions are doubtful and they exhibit “weakness” … Looks like a kind of confirmation bias on the part of FM”

      (a) Nobody doubts that the seas are rising, as they have been doing for centuries (there is debate over the rate). The debate concerns the second derivative: is the rate of rise accelerating.

      (b) The accelleration of sea level rise has become a signature issue of warming alarmists, and the AR5 says its based on two papers. The “pause” has been the subject of a large body of peer-reviewed research, assessing its causes and significance. Here are a few of the sources, those for which I provided citations and links. Please acknowledge if you see the difference.

      The “pause” is acknowledged by a large number of climate scientists, including…

      • Phil Jones, director of the Climate Research Unit at UEA
      • James Hanson, NASA
      • David Whitehouse of the Global Warming Policy Foundation
      • Professor Judith Curry
      • The Berkeley Earth Surface Temperature project

      Here is a sliver of the literature:

      1. “Do global temperature trends over the last decade falsify climate predictions?”, J Knight et al. Part of “State of the Climate in 2008“, Editors T C Peterson and M O Baringer, Bulletin of the American Meteorological Society, August 2009
      2. Does the Global Warming Pause in the Last Decade: 1999-2008?“, Shaowu Wang et al, Advances in Climate Change Research, issue #1 2010
      3. Climate science: Decadal predictions in demand“, Mark A. Cane, Nature Geoscience, 21 March 2010 — Free copy here.
      4. Reconciling anthropogenic climate change with observed temperature 1998–2008“, Robert K. Kaufmann et at, Proceedings of the National Academy of Science, 19 July 2011
      5. Model-based evidence of deep-ocean heat uptake during surface-temperature hiatus periods“, Gerald A. Meehl et al, Nature Climate Change, 18 September 2011
      6. Global warming, human-induced carbon emissions, and their uncertainties“, JingYun Fang et al, Science China – Earth Science, October 2011 — Free copy here.
      7. Separating signal and noise in atmospheric temperature changes: The importance of timescale“, Ben Santer et al, Journal of Geophysical Research (Atmospheres), 18 November 2011
      8. Deducing Multi-decadal Anthropogenic Global Warming Trends Using Multiple Regression Analysis“, Jiansong Zhou and Ka-Kit Tung, Journal of the Atmospheric Sciences, in press

      It’s been discussed in the news media during the past 4 years (these articles cite a wide range of scientists):

      (2) “As for sea level: all 4 papers indicate they are rising, 2 that the rise is accelerating — however weakly. Knowing climate is a non-linear system, I would tend to be wary — minute initial effects can become prodigious after quite a while via positive feedbacks.”

      What does “I would tend to be wary” mean?

      (3) “that the change induced by human activities is minimal compared to other factors? … that we are not experiencing any consequences yet?”

      That is the conclusion of most research regarding attribution of past and current climate events; it’s a subject of research and debate. One or two degrees of warming since WWII. Perhaps some increased precipitation. Most of the news media stories blaming everything on global warming are without foundation in the climate science literature. The debate amogn scientists mostly concerns the future: the probability of large changes, their nature, magnitude, and timing.

      (4) “that its consequences are benign?”
      The climate has always varied strongly. The question concerns the nature, magnitude, and timing of anthropogenic effects — and the net impact on top of natural effects.

      (5) “that the cost of business as usual is lower than strong mitigating actions?”
      Quite so. Plus the desirability of alternative solutions: such as massive conversion to nuclear power plus electrification of transportation.

      (6) “As far as I know, the overwhelming majority of qualified scientists who are looking into the matter answer “no” to all these questions).”

      Based on this one comment, I don’t believe you know much about this debate. Unfortunately the news media has again let us down, providing more heat than light concerning these vital issues. So well-informed people can have an incorrect understanding of the state of the climate sciences.

      These posts attempt to correct that. But for many people the indoctrination runs too deep, so that even citing a large body of authorities doesn’t change their thinking even one jot.

      Like

    • 21 December 2012 3:14 pm

      M: “Why are the people advocating massive public policy action to fight climate change not calling for massive research programs”
      Guest: “Because there is not one single, united, coherent position on climate change.”

      Your answer implies that some activists advocate greatly increased spending, and some don’t. Please cite some of those advocating large increases in research funding. I haven’t found any (but might have overlooked them).

      Like

    • 21 December 2012 8:35 pm

      Guest,

      Your comment implies that you believe there has *not* been a pause (ie, no statistically significant global warming). Can you provide some supporting citations from climate scientists?

      Two notes based on previous similar conversations:

      (1). “Stop” and “pause” are different words, with different meanings. It’s not like “You say ‘potato,’ I say ‘patattah’.”

      (2). Scientists differ on the start date of the pause, by a few years. They use different confidence limits, different datasets of past global temperatures, and the datasets have been (& are frequently) revised.

      Like

    • 26 December 2012 12:02 am

      “As for sea level: all 4 papers indicate they are rising, 2 that the rise is accelerating — however weakly. ”

      Nope. The IPCC doesn’t claim anything like that, even at the low “likely” level of confidence. Read pages 3 and 31-32 for details.

      it’s fascinating that no matter how long the quotes given from IPCC reports and peer-reviewed literature, people stick to their beliefs. Warmistas know that scientists are authorities, except when they challenge warmista dogma — then they should be ignored.

      Like

  2. 21 December 2012 1:36 pm

    Fabius,

    You raise a very interesting issue here with regard to solar maximums. From the historical evidence it would appear that the likelihood of a major solar storm sufficient to cripple electronic systems approaches a near certainty in the current century. Without hardening of the grid and other systems the damage to the electronic infrastructure will likely be far more damaging to the information economy that the foreseeable effects of continued warming in the ranges predicted. Yet there is no political outrage or action. Where is the contingency planning?

    Like

    • 21 December 2012 2:57 pm

      Slater,

      (1) Regarding solar storms, is the response so far inadequate in speed or magnitude? The danger of the solar storm to the power grid was not well-appreciated until recently. These two reports summarized current knowledge and recommended action.

      (a) Severe Space Weather Events – Understanding Societal and Economic Impacts“, National Academy of Sciences, 2008. Esp see Section 7 – Future Solutions, Vulnerabilities, and Risks (pp 76-85). They describe mostly uncertainties about the probability of a severe solar event, and about the possible ways to mitigate its effects.

      (b) 2009 National Academy Report, funded by NASA and produced after a growing body of research indicated the need to marshal resources to prepare for this.

      Fixing something as large and complex as the power grid is not like children doing chalk drawings on your sidewalk. Especially when the grid itself needs major redesign for the new demands of the 21st century (ie, creating the “smart grid”). Thought, research, and planning for these multi-billion-dollar projects takes time. Something is being done. Probably not as fast as it should be, but then nothing is.

      (2) Perhaps the American public has been over-propagandized by too many warnings of shockwaves — high impact, low probablilty events. We could go broke preparing for them all! For a discussion of shockwaves — what they are and how we should prepare — see this post from January 2009. For more see the Shockwave section of the Science Reference Page.

      (3) What I find most fascinating about this is America’s gross underinvestment in its public infrastructure, so that even normal storms (like Sandy) cause devestation. Reports over several decades warned about NYC’s vulnerability to flooding, but they did nothing. Not the slightest preparations. Ditto for New Orleans, where the local government proved unable to even implement its emergency plan — which was grossly inadequate (again, despite decades of warnings). Perhaps we’re just not very bright.

      Like

    • 22 December 2012 5:45 am

      Slater,

      Part of my reply was cut-and-pasted from another thread. The remark about “yelling that nothing is being done” was not directed at you, as your comments have always been measured and well-expressed. I have deleted that clause.

      Note to self: read more carefully before cut-pasting.

      Like

  3. 21 December 2012 4:10 pm

    “That is what the IPCC says. I assume that they have a adequate basis in research for statements about the past. I very much doubt you and I are going to develop better analysis with the resources at our use.”
    - Fabius Maximus, 12/18/12

    Now they’ve said something you don’t like, and you’ve changed your story to say they don’t know what they’re talking about. You’ve called other casual commenters “climate alarmists”. Do you think it’s possible that you’re guilty of the same armchair science that you complain so often about?

    Like

    • 21 December 2012 4:22 pm

      Guthrie,

      I don’t see any correspondence between what I said and your intrepreation.

      (1) “a adequate basis in research for statements about the past”
      This is a discussion about the present (recent accelleration of sea level rise), not the past. That’s more difficult to determine. Forecasts about the future are more problematic still.

      (2) “you and I are going to develop better analysis with the resources at our use”

      Prof Curry is contrasting the IPCC’s probability estimate with the current research literature. There is no mention of you or I developing our own estimates, or even evaluation of the literature.

      This goes to one of the most frequent — and most daft — rebuttals to these posts. To show some areas of debate in the climate scientists (vs belief that “the science is settled”), I cite a wide range of statements by scientists and scientific organizations — plus citations of the peer-reviewed literature. I don’t say who is correct (I almost always say the opposite, that time will resolve these issues). People say “you’re not a climate scientist, so why should your opinion matter”.

      I no longer believe this is a good-faith rebuttal, but a deliberate misstatement. It’s been used by too many people who are too intelligent and educated. That’s a guess on my part; there are other interpretations possible.

      Like

    • 21 December 2012 4:31 pm

      Guthrie,

      One more response to your commment, specifically to “Now they’ve said something you don’t like, and you’ve changed your story to say they don’t know what they’re talking about.” That’s a bizarre intrepretation of this post.

      • I am quoting a prominent climate scientists, the basis of whose opinion can be understood even by laypeople. It’s not just “me”; see my previous response to your commment.
      • Curry is saying that the IPCC is not appropriately assessing probability of their assessments, relying on too-few studies in immature datasets.
      • This also shows the small base in the science literature on which base we’re asked to take large-scale and expensive measures. In this specific case, two studies (our of 4 on the subject).

      To summarize this as “{I} say that they {the IPCC} don’t know what they’re talking about” is daft. Really daft.

      The IPCC work is on the whole sound, by most assessments. But it’s not gospel. Especially concerning the great question about the standard of proof required for major public policy action (as opposed to the academic standards the peer-reviewed literature is designed for). Which is the point here.

      Like

  4. 21 December 2012 8:55 pm

    Having a look at the measurements and potentials offsets is good science. But to get lost in the weeds and imply that the rise of sea level might not be a real problem is myopic to the extreme. To summarize the analysis in my recent book, High Tide On Main Street, it helps to look at the larger cycles of sea level. It goes up and down almost four hundred feet (120m) with each ice age cycle. For the last few million years, they have occurred every 95 – 125 thousand years, per the Milankovitch Cycle forcing. The last peak ice was 20,000 years ago. We would now be due to start the 80,000 year cooling phase.

    But the oceans are 0.8 degrees C (1.5 F) warmer than at any time in the last 10 million years. That correlates rather well with the sea level record, the ice sheet extent, and global CO2. The warming ocean is why the cycle is now changed.

    As shown by looking at the 40 million year geologic record (Alley 2005; Archer 2008) sea level moves by 65 feet (20m) for each degree C, in the same direction. That relationship is clear from millions of years and multiple data points, and simply makes sense. Warmer planet, melting ice sheets, rising ocean, coastlines moving inland. It just takes a while for the adjustment, due to thermal inertia, like trying to stop the Titanic from hitting the iceberg.

    Denial and disbelief are understandable as this is the first time in 6,000 years that this has occurred. During that period — pretty much all of human civilization — sea level and the coastline have been stable. That was an anomaly. We need to wake up and adapt.

    Arguing about the esoteric aspects of measuring sea level rise and allowing it to distract us from the larger truths does not seem like a good use of our intelligence.

    Like

    • 22 December 2012 12:18 am

      Englander,

      “But to get lost in the weeds and imply that the rise of sea level might not be a real problem is myopic to the extreme”

      Can you point to something on this website saying such a daft thing!

      Can you point to a climate scientist saying such a daft thing? Even those few who dispute the consensus estimates of increase don’t say that, based on what I’ve read.

      The IPCC section cited concerns a different question than your comment: the current rate of increase in sea levels. Is it accelerating, or continuing at the rate of the past few centuries? As the abstract states, there are many factors at work — some offsetting. Resolution of the current datasets does not appear to give a clear answer.

      As for your certainty that sea levels will rise — over what time horizon? — I’ll just say that my (limited) understanding of the literature suggests that certainty might not accurately represent the current state of our knowledge.

      All that being said, thank you for posting your views!

      Like

    • 22 December 2012 1:11 pm

      Based on the historical record where are we in relation to historical max/min sea level elevations? Are current coastlines near historical peaks, at median levels or are they relatively low? I would assume that this becomes impossible to measure over long time horizons due to plate shifting, but what about the last thousand millenia or so?

      Like

    • 22 December 2012 3:29 pm

      Slater,

      That’s a great question.

      The FM website staff anticipates your requests even before you make them! Scroll down and you will see three graphs of sea levels, over different time horizons. With, of course, links for more info.

      These are from next Monday’s post.

      Like

  5. 22 December 2012 4:38 am

    Maximus,

    As I read the thrust of your post, it points to the discrepancies in the measurement of sea level height, which questions whether it is accelerating. The implication of non-acceleration is that it is slowing, further implying that perhaps it is not such a problem.

    I was putting the inevitable rise in perspective based on the historical record. Your candor about your understanding is welcome.

    If you are interest a short post of mine with the relevant graph is at “Why Sea Level will Rise for Centuries; ultimately 100 feet +“. See the bottom (4th) graph in the post to illustrate that 40 million years of temperature – sea level records show a very straight line correlation of 65 feet of rise per degree C.

    While it is absolutely correct that we cannot accurately say how soon the ice sheets will adjust (melt, raising sea level) it seems rather clear that they will, regardless of our micro ability to reconcile measurements over a period of a few years. That was the point I tried to make.

    Thank you for your time, fairness, and space to respond.

    Like

    • 22 December 2012 5:00 am

      Englander,

      “it points to the discrepancies in the measurement of sea level height, which questions whether it is accelerating. The implication of non-acceleration is that it is slowing, further implying that perhaps it is not such a problem.”

      An article about rising sea levels, a discussion about a possible acceleration of the rise — and you conclude that the inference is that not accelerating means slowing. That’s quite a logic FAIL. But it’s the sort of casual error we all make on occasion in comments.

      Thanks for explaining!

      Like

  6. 22 December 2012 5:41 am

    For anyone not familar with the debate about sea levels, I recommend reading the articles listed at the end, which review some aspects of the climate science debate. To see the context, look at these graphs. Remember, the world has been warming for the past two centuries — and the consensus of climate scientists is that anthropogenic CO2 has become the largest forcing since aprox 1950.

    Click to enlarge these graphs.

    (1) Long-term sea levels based on proxy data

    From “Sea-level fluctuations during the last glacial cycle“, M. Siddall et al, Nature, 19 June 2003 — Gated.

    .

    Nature, 19 June 2003

    Nature, 19 June 2003

    .

    (2) The past century (direct measurements, moderately reliable)

    From the EPA’s Climate Change Indicators page.

    .

    From the EPA "Climate Change Indicators" page

    From the EPA “Climate Change Indicators” page

    .

    (3) Recent (reliable direct measurement)

    From the University of Colorado Sea Level Research Group:

    .

    U CO Sea Level Research Group

    U CO Sea Level Research Group

    Like

  7. 22 December 2012 6:32 pm

    There’s been a vast amount of discussion on this topic in blogs; there’ve been many papers published over the last decade, all but a few people have failed to spot that there may not, in fact, be any actual discrepancy between tide gauges and satellite data. The satellite maps show that most of the rise is in the western central Pacific and eastern Indian Ocean; tide gauges there almost uniformly reflect the indicated rate of rise since 1993. The simple fact is that most tide gauges worldwide are along coastlines where the satellites show lower than average rates of rise. they show clearly that the US west coast has seen no rise or a small fall since 1993. Tide gauges along that coast confirm that.

    Also many fail to spot (perhaps some choose to ignore) that gauges measure sea level relative to the land. Local subsidence or rise confuses the issue. Satellites measure absolute sea level. any attempt to correlate the latter with gauges is bound to fail, even if gauge data is corrected because sea level rise around the globe is far from uniform and as I mentioned, most gauges aren’t in areas where most rise has occurred.

    I’m not relying on other’s opinions or papers – I do my own plotting of gauge data, about 200 stations to date. There are many discrepancies between gauge rates and satellite rates even when land elevation changes are take into account (GPS data is sparse), but I believe from the evidence there is reasonable correlation, though far from 100%.

    Like

    • 22 December 2012 7:04 pm

      Mostlyharmless,

      “Also many fail to spot (perhaps some choose to ignore) that gauges measure sea level relative to the land. ”

      That’s a powerful point. It touches on a larger point of great importance! Often climate changes seem simple, such as rising temperature and rising oceans. In fact these are usually subtle and complex dynamics. Urban heat island complicates the temperature record. Computing the global temperature record requires measurements from the majority of the Earth’s surface which has few or no reliable measurements before WWII (eg, sea surface, polar, much of the 3rd world). And sea surface measures are distorted by changes in geography. Some natural, such as isostasy. Some anthropogenic — such as the massive changes in conditions around cities (which distorts tidal gauge records) and the extractions of the fresh water lens under Pacific Atolls.

      The combination of “hidden” complexity and passionate advocacy has distorted the “grey literature”, IMO beyond use. The IPCC’s reliance on non-professional sources (ie, peer-reviewed literature) has repeatedly caused embarrassment, and diminished their credibility. As a result I see people relying more on the professional literature. It’s seen, I believe, in AR5. Close readers of the FM website will have seen that here over the past four years.

      It’s a good thing, IMO, for those of us who are reporting developments in the climate sciences for wider audiences. This is a different playing field than that of people engaging in the debate. As usual in western history, those debates include professionals, credentialed experts, and talented amateurs. New insights will eventually emerge from them. But for us by-standers, whether reporting or just watching, my recommendation is to rely on the literature — especially when considering the need for large-scale and expensive public policy matters.

      Everyone will, of course, make their own decisions on these matters.

      Like

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