Do the Math

Roger Pielke Sr. claims that northern hemisphere sea ice has not declined as fast as computer models predicted. Yet we’ve often heard the opposite, that northern hemisphere sea ice is declining faster than predicted by computer models. How does Pielke arrive at the opposite conclusion?

Pielke compares sea ice data from Cryosphere Today to predictions from a 1999 paper, Vinnikov et al. 1999 (Global Warming and Northern Hemisphere Sea Ice Extent, Science, 286, 1934-1937,doi:10.1126/science.286.5446.1934). Vinnikov et al. said this:

Both models predict continued substantial sea ice extent and thickness decreases in the next century.

Pielke gets quantitative:

In their paper (in Table 1) they have model predictions (in units of linear trend in 10^6 square kilometers per decade) listed for the GFDL climate model from 1978-1998 of -0.34 (and -0.19 using a “smoothed model output”) and for the Hadley Centre climate model -0.18 (and -0.16 using a “smoothed model output”).

A value of -0.18 is the loss of sea ice area of 180000 square kilometers per decade, for example.

He then displays a graph of sea ice area anomaly (not extent such as in Vinnikov et al. but the difference isn’t really important):

Here’s where it gets weird. Pielke says this:

Until later in 2007, the sea ice areal extent continued to decrease in a manner which, at least visually, is consistent with the Vinnikov et al 1999 predictions (although the actual values of areal coverage differ substantially between the observations and the predictions, perhaps as a result of their formulation to compute areal coverage).

However, since 2006, the reduction has stopped and even reversed.

I refer the reader to our advice on “Defense Against the Dark Arts.” His misdirection is revealed by Step 3: look at more than they show you, and be especially wary of time spans that are too brief and areas that are too small. In this case the “time spans that are too short” alarm is flashing red — not only has Pielke cherry-picked his starting point, he’s comparing a predicted long-term trend to an observed time span of far less than a decade. That’s foolish of him, and misleading to his readers.

But what Pielke himself should pay attention to is Step 2: study the data yourself. In this particular case we can put it another way, which is an important lesson for Roger Pielke: Do the Math.

Suppose we ignore the fact that “since 2006″ is a ludicrous — some might suspect deliberately so — choice of time span. Let’s go ahead and estimate the trend in northern hemisphere sea ice area anomaly (Pielke’s own choice of data) since 2006 anyway, and compare it to the predictions from Vinnikov et al. 1999. In fact, let’s estimate the trend not just from 2006 to the present, but from every starting year since 1999 to the present:

We can do the same thing using actual extent data from the National Snow and Ice Data Center:

Note first that the estimated trend rate “since 2006″ is in between the two predictions — which certainly doesn’t contradict Vinnikov et al. 1999. Note also that even to get that close to the predictions, you really have to cherry-pick — because if you start from a year that gives us a decent estimate of the trend, it’s declining much faster than these computer models predicted.

Note also that when you start “since 2006″ or later, the error bars on the estimated rates are rather large. The trend for such short time spans is so uncertain, it really doesn’t give much information. Could it be that Roger Pielke is actually aware of that, but that he really doesn’t care about portraying sea ice changes correctly, he only cares about discrediting global warming science?


Roger Pielke has updated his post. He says I misrepresented him, and that

I do not disagree that the Arctic sea ice has been decreasing. My post was to compare the sea ice anomaly trends that were presented in the Vinnikov et al paper to real world observations updated to 2012. The figure in the Vinnikov et al 1999 paper shows a rather monotonic (but increasing over time) decrease in Arctic sea ice content with time. Tamino ignores what is obvious in even a visual comparison between the Vinnikov et al plot and the real world observations that the decline has stopped, at least for now.

So … first he says “However, since 2006, the reduction has stopped and even reversed.”

Then he says “I do not disagree that the Arctic sea ice has been decreasing.”

Then he says “the decline has stopped, at least for now.” His basis for this is “what is obvious in even a visual comparison.”

Hey Roger — what is obvious from numerical analysis is that the decline has not stopped. In fact even if you cherry-pick the starting time to get the lowest rate of decline, it’s still squarely in the range given by Vinnikov et al. DO THE MATH.

Roger seems to think I created a fantasy view of his post. The truth is, you can’t make this stuff up.

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91 responses to “Do the Math

  1. Alex the Seal

    To be fair – he does say “Perhaps this is a short term event and the reduction of sea ice extent will resume.”….. but then goes on to suggest that this rise might share an explanation with the level of Antarctic ice volume, implying that it is global in nature – and driven by temperatures.

    • He still claims the trend has reversed when it hasn’t, regardless of how short a period you use.

  2. This is someone who doesn’t realize that one can much more easily take a screen shot of a PDF than take and transfer a picture of a figure using a cell phone. He then instructs his readers to compare the fuzzy chart spanning 150 years to two charts spanning 34 years, which conveniently obscures the fact that 20 or 30 years of modeled decline happened in a decade (which seems to be a better place to start if you’re in the business of questioning the predictive power of climate models). I roughly scaled the 1999-now data and overlaid it on Pielke’s image so that everything was at the same scale –

  3. I’m somewhat humored by the failure of the 2008-present extent confidence interval to include zero. I’m curious, the size of the interval seems the same as the previous, though it should be larger due to its shorter span – is the similar size due to its very large deviation from zero?

  4. What is wrong with these people? OK, the rate of melt varies and projections made 15 years ago might not have got it exactly right: but this is like trying to predict the distance each wave will wash up the beach. Whether the next wave goes further than the last 5 waves, or not, doesn’t alter the fact that we know the longer term trend is that the tide is coming in.

  5. The man is dishonest, period. Even if he were obsessed with the denier case, he knows better. I suppose, in his mind, he’s “lying in a good cause,” but he’s still lying.

  6. So, his entire assessment is “visually, at least?”

    Sophisticated, that.

    • I myself am a card carrying eye baller. Mock increments in smidgins if you will, they’re darn near precise.

      • JCH, the human eyeball is one of the most sensitive instruments we have. It is guaranteed to detect patterns–whether they are really there or not.

      • Pedantically typing, it isn’t the eyeball that does the detection, it is the impage processing structures on the way into and in the brain.

    • FWIW, if I remember my Psych 20, visual “interpretation” actually starts with the arrangement of retinal cells, much as aural “interpretation” starts with the arrangement of cochlear “hair cells.” But that was a long time ago…

  7. As I am doing my weekly round of AGW blogs I left comment on Martin Lack’s Lack of Environment concerning the trend in wild weather events, sparked by Mad March weather in both the US & UK. At the back of my mind such events confirm my [non-scientific] view of AGW but I am aware that without decades of data it could be just the weather. Forgiveable for me, perhaps to jump to conclusions but I don’t understand how someone like Pielke could jump to conclusions based on such little data. Living with a scientist I am aware her Phd students are prone to draw on too little data and jump to conclusions because they want to beef-up a fairly weak idea. Is R.Pielke so desperate to remain a leading voice in the debate that he is prepared to ‘big-up’ quite weak ideas?

  8. @Alex: worse, Pielke implies by saying there is a need for explanation that there is none.

    • Alex the Seal

      Indeed. There are many explanations/theories on Antarctic climate trends -which he apparently knows nothing about.

  9. Pielkes Sr. and Jr. are excellent examples of why scientific consensus is so important. Pielke the elder can never back down. He has invested too much of his career and reputation in denial of anthropogenic climate change. The sunk cost is simply too high, and now he will continue to double down rather than back down. Pielke the younger…well, he ain’t that bright. And in his mind, evidently filial piety trumps truth.

  10. At the end of his post, Pielke throws out “It has been claimed that most of the recent sea ice is thin and thus will melt quickly this spring. Perhaps so.” Ignoring the weasel-wording here*, the interesting bit is the following links to his 2000 and 2002 papers. This is interesting, not because he is linking to papers he wrote (if anything, it is surprising that he has linked to _only_ two of his own papers), but because I’d be really interested in seeing the methodology of his papers applied to the last 10 years of data. The papers showed insolation-weighted snow and sea-ice cover… Another way to think about it is that one interesting facet of snow and sea-ice retreat is the trend in albedo.

    Now, since the retreat of both sea-ice and snowcover in the northern hemisphere is strongest in the summer, I might expect that an albedo trend will be more significant than an area trend. However, I’d want to do the calculation… while the sun is higher in mid-summer, the snow extends further south in the spring, so one might expect that the key months for albedo would actually happen earlier than the summer solstice.

    And, in fact, this has been done by Flanner et al for data through 2008.: And lo and behold, Flanner et al. found “On the basis of these observations, we conclude that the albedo feedback from the Northern Hemisphere cryosphere falls between 0.3 and 1.1 W m−2 K−1, substantially larger than comparable estimates obtained from 18 climate models.”

    Funny that Pielke Sr. doesn’t cite that paper…


    *I say weasel wording, because he gets to imply that maybe the recent ice won’t melt quickly, even though IMHO it is highly likely it will based on looking at the pattern of the last half dozen years where occasional years briefly flirt with high spring ice cover – 2010 comes to mind – before melting away. I’d be interested in actually seeing a more sophisticated statistical analysis of this – I know that the correlation between April and September snow cover is very weak, which supports my contention, and visually, April looks like the noisiest month (, and looking at trends, it seems like March, April, and May have the weakest trends (2.6, 2.6, and 2.4 percent per decade)… actually, what I’d like to see is significance of trend by month: my guess is that April’s trend would be the least statistically significant (at maybe 99.0%, rather than 99.9% for a month like September).

  11. ps. I say “one interesting facet of snow and sea-ice retreat” because albedo feedback is only one impact… other sea-ice/snow retreat impacts on such things as arctic ecosystems (eg polar bears), coastal land loss from lack of ice protection from storms, large scale weather influences, permafrost melt and methane release, etc. etc. are all impacts that are not necessarily maximized in the summer months.

  12. What is their end game? Are they just confident that they’ll be dead before the bill comes due? Someone with Senior in his name will probably be dead, of course, but someone with Junior in it might not be. And most of our grand kids won’t be. How much cynicism and solipsism is exhibited here? Either they’re trying to assuage their intellectual vanity, or they’re simply taking bucks from carbon plutocrats and the rest of the world be damned.

    I’m often reminded — with climate denialists — of the scene in The Big Lebowski where Walter marvels that the kidnappers are self-proclaimed nihilists. (I love it that they pronounce it with a long i.) “F&&& me. I mean, say what you like about the tenets of National Socialism, Dude, at least it’s an ethos.” What ethos is appealed to with either vanity or creepy enrichment?

  13. I am shocked to find RPJr. so grievously misunderstood.
    It happens over, and over, and over, doesn’t it?

  14. Check out the UPDATE at the end of this post.

    • He’s still wrong even when he’s moving the goal posts. The models do not show a monotonic decrease in sea ice. They show swings of several hundred thousand square miles around a monotonically decreasing trend. Furthermore, the modeled noise around the trend is lower than the pre-1999 record (perhaps reduced noise is consistent with a lower total ice extent and not an area in which the model does not wholly reproduce reality). The phantom stall/reverse, 2006-2012 (if you even see it, my fit-by-eye results find a decreasing trend over any period that doesn’t start in 2007 or 2011) is totally precedented in the model predictions.

      In Pielke’s figure, the GFDL model shows a 1.2M sq mile increase in sea ice extent over three years from 2017 to 2020. The Hadley model shows a ~800k sq mile increase, 2008-2011. There are many similar events in both models over the 50-year modeled period. This is with data that looks to be a yearly average or moving average. Even if you think you see it, the current pause/increase is utterly consistent with the model — the only similar event is a fairly large (but less than 1M sq mi) increase, 2007-2008 that follows a similarly large decrease, 2006-2007.

    • Gavin's Pussycat

      Poor Pielke. Everybody gets him wrong

  15. Horatio Algeranon

    The Cycles on the Blog
    – Horatio Algeranon’s take on the popular child’s song
    (sung by “Cosmic Ray and the Deniers”)

    The cycles on the blog go round and round
    Round and round
    Round and round
    The cycles on the blog go round and round
    All around the Web

    The graphs on the blog go up and down
    Up and down
    Up and down
    The graphs on the blog go up and down
    All around the Web

    The temps on the blog go only down
    Only down
    Only down
    The temps on the blog go only down
    All around the Web.

    The noise on the blog goes only up
    Only up
    Only up
    The noise on the blog goes only up
    All around the Web.

    The cherries on the blog get picked and cooked
    Picked and cooked
    Picked and cooked
    The cherries on the blog get picked and cooked
    All around the web

    The science on the blog is non-existent
    The science on the blog is non-existent
    All around the web

    The sea-ice on the blog is in recovery
    In recovery
    In recovery
    The sea-ice on the blog is in recovery
    All around the web

    The driver of the blog is Cosmic Ray
    Cosmic Ray
    Cosmic Ray
    The driver of the blog is Cosmic Ray
    All around the Web.

    The blokes on the blog claim “It’s the sun”,
    “It’s the sun””
    “It’s the sun”
    The blokes on the blog claim “It’s the sun”
    All around the Web.

    The Stevies on the blog cry “wah wah wah
    Wah, wah, wah”
    Wah, wah, wah”.
    The Stevies on the blog cry “Wah, wah, wah”,
    All around the Web.

    The posts on the blog go round and round
    Round and round
    Round and round
    The posts on the blog go round and round
    All around the Web

    Feel free to add your own verses.

    • HA, I think you missed a trick a few posts ago: you could have had the uncertainty monster singing “L is for Linear, that’s good enough for me.” True, not much variation in the lyrics, but a bite-size mirthiness is ok.

  16. Mr Pielke’s blog post is basically about updating a figure from Vinnikov et al. (1999) with more recent observations. That figure shows observed and modeled annual mean sea ice extent (SIE) for the period 1900-2050.

    I understand that Mr Pielke does not want to do actual quantitative analysis of trends. He just wants to eyeball the recent sea ice data and compare them to the model predictions illustrated in Vinnikov 1999.

    The obvious way to do this comparison is to add recent observations of the same quantity (annual mean sea ice extent) shown in the Vinnikov figure to the original figure itself. It is very easy to do this. I don’t know why Mr Pielke has avoided doing this obvious direct comparison.

    Here is what I did. It took me very little time or effort:

    (1) Go to the NSIDC, and download actual northern hemisphere sea ice extent data.

    (2) Start Excel. Open the monthly SIE data files, and combine them into a single file. Compute annual averages (1979-2011). Note that there are one or two months with missing data that will have to be infilled (you can just average the same month from the preceding and following years).

    (3) Plot the results with date on the X axis and annual average SIE on the Y axis. Set the ranges for the axes as follows: X axis: 1900-2050; Y axis: 8 to 14 (million km2).

    The next steps are to show the original Vinnikov 1999 figure as a backdrop with the updated SIE data superimposed:

    (4) Go to Pielke’s blog post, right-click on the figure from Vinnikov et al. 1999 that he’s moaning and groaning about, and save it.

    (5) Open the figure in PhotoShop or another photo editing program, and crop it down to just the graph itself. Save the cropped version.

    (6) Back in Excel, use the cropped version of the figure as the backdrop in your XY scatterplot of observed annual mean SIE data through 2011.

    You should end up with something that looks like this:


    Since Mr Pielke wants to stick with visual, qualitative interpretation, here is my interpretation of this figure:

    Mr Pielke is correct that the GFDL model predictions shown in Vinnikov 1999 are not a perfectly accurate representation of annual mean sea ice extent. The model appears to have somewhat underestimated the rate of decline in sea ice extent.

  17. To be specific, the annual mean sea ice extent we have experienced in recent years is approximately what the GFDL model shown in Vinnikov 1999 predicted for the mid to late 2030s.

  18. Pielke senior has done this before, choose too short a timespan and trumpet meaningless result. See

    that was him distorting ocean heat content and sea level data a few years ago. Same technique.

    I used to hope he had gone emeritus and not charlatan; unfortunately every time he opens his mouth I tend further toward the latter designation. As a sometime scientist, he must be aware that he is lying, unless his faculties have degenerated immensely. But he seems coherent enough to make misleading graphs.


  19. As long as Pielke is responding to commenters from his site, what do these statements mean, mathematically:
    “The sea ice data had a significant change in its trend in 2006.”
    “2006 … is clearly a break-point in the sea ice data.”
    “This is obviously quite different from what is shown below from The Cryosphere Today below.” (I don’t have the data, but eyeballing the chart I’d guess there’s a declining trend; almost all of the “high” data is in the first year)
    “The figure in the Vinnikov et al 1999 paper shows a rather monotonic (but increasing over time) decrease in Arctic sea ice content with time.” (The polynomial fit or the actual models?)
    “…since 2006, the reduction has stopped and even reversed.”

    In some other cases (but not in these), you specify that this is your guess from visual inspection. Should these be taken in the same way. If not, what quantitative description should replace words such as “rather,” “clearly” and “significant?”

  20. I may be cynical, but it seems to me that deniers can only cherry pick to get the wrong result if they know what the correct result is. That is you have to start with a graph showing increases or decreases, recognise those trends, and then work out how to select an interval that appears to contradict the trend. In other words this is not random misuse of data in poor quality science but deliberate deception. Posterity will judge these people very harshly.

  21. Posterity?

    It can happen quite quickly. South Africa’s Mbeki and the AIDS tragedy is an example. Everyone outside South Africa was saying no, no, no, don’t go there! but he went with the garlic, herbs, african potato, veggies thing anyway. Millions of people are dead, orphaned or dying because of this wrong-headedness.

    His reputation in SA is not nearly as robust or shiny as it once was. He may not be reviled in quite the way Amin or Mugabe is, but he’ll not be far behind.

  22. In his second update, Pielke Sr write: “They have also chosen to ignore the inconvenient behavior of the Antarctic sea ice coverage.”

    Since Pielke Sr stated purpose of his post was to revisit Vinnikov 1999, a paper which was explicitly about declining sea ice in the Northern Hemisphere, his belated appeal to the Antarctic sea ice can only be seen as an attempt to move the goal post..

    Nice job, Ned. You nailed it.

    • Thanks, Ron.

      I don’t routinely follow Mr Pielke’s blog, so I don’t know whether this kind of behavior is normal for him, or just a temporary aberration. But let’s be very clear about what’s going on. In his original blog post, Mr Pielke says this:

      “In [Vinnikov et al. 1999], there is a presentation of the model predictions of sea ice extent along with observations up to 1998. This weblog introduces the subject of how well have the model predictions done.”

      That is a very clear and specific goal: testing the post-1998 model predictions by comparing them to observations.

      The caption for the figure in question (Figure 2 in Vinnikov 1999) says “Observed and modeled variations of annual averages of NH sea ice extent” [my emphasis] So the obvious and most straightforward way to do what Mr Pielke claims he wants to do — test the accuracy of the model predictions from Vinnikov 1999 — is to compare those predictions to later observations of annual averages of NH sea ice extent.

      That is exactly what I did. That is an apples-to-apples comparison.

      Mr Pielke, instead, apparently wants to compare Vinnikov’s predictions of annual averages of NH sea ice extent with daily estimates of NH and SH sea ice area anomaly. He wants to do the comparison visually instead of quantitatively, and he wants to focus on very short-term trends (five years).

      Here is another version of the apples-to-apples comparison that Mr Pielke is studiously avoiding. This is the same figure I posted yesterday, but focusing on the 1970-2020 period (the period of the observations). I’ve also added a polynomial fit to the observations, for comparison with the polynomial fit to the model:


      The obvious conclusion is still exactly the opposite of the one Mr Pielke is struggling to draw. The GFDL model output in Vinnikov 1999 appears to have underpredicted the rapid decline in sea ice extent.

      • Let’s also consider Mr Pielke’s focus on trends starting in 2006. The observed trend in annual NH sea ice extent from 2006 onwards is -0.024 million km2/year. Looking at the entire record, similar five-year trends range from +0.032 to -0.18 million km2/year.

        Since the start of the observational record in 1979, there have been eight five-year intervals (some of them overlapping) when the trend in SIE was less steeply decreasing than Mr Pielke’s post-2006 trend. Yet despite these frequent flat or even upward-sloping blips, the long-term trend is consistently downward, and last year’s annual mean extent was the lowest on record.

        Mr Pielke is focusing on a very short time scale during which the observed variation is primarily noise, not signal. He apparently missed this sentence from the Vinnikov 1999 paper that he linked to:

        “To reveal a long-term systematic climate trend, we need observations from a period long enough so that the influences of natural interannual and interdecadal climate variability, as well as random errors of observation, do not create pseudotrends that are as large as the true climate trend.”

        He also appears to have missed Vinnikov’s Figure 3 and the related discussion, which examines the frequency at which trends of varying magnitude occur in the modeled data, as a function of trend length.

        I have taken the liberty of updating Vinnikov’s Figure 3 with several observed trends from different time intervals:


        Note, first, that the orange diamond for the 1979-1998 period falls pretty much exactly on the square from Vinnikov’s Figure 3 — that’s a nice confirmation that my representation of the observations matches Vinnikov’s. Vinnikov states that the probability of this trend occurring naturally, based on the statistics of the model run, is less than 2%.

        The orange diamond labeled “1979-2011″ represents the observed (linear) trend over the whole period of record. As we’ve seen, the decline has accelerated over time, so it’s not really a linear trend. Nonetheless, even the linear version of this trend is highly unlikely to have been observed based on purely natural variability alone (probability much less than 0.1%, according to Vinnikov’s Figure 3).

        What about just the observations from after the publication of Vinnikov 1999? The orange diamond labeled 1998-2011 shows the trend over this twelve-year period. The rate of decline was so high that it actually is positioned above the top of the graph from Vinnikov’s paper. Extrapolating the curves suggests that the probability of observing this particular trend is around 0.1%.

        Finally, what about Mr Pielke’s 2006-2011 interval? Note that Vinnikov’s Figure 3 doesn’t even bother to show statistics for trends shorter than 10 years. Nonetheless, I’ve added that point to the figure, too.

  23. Indeed. And if Pielke Sr was interested in testing the skill of the prediction, he could have followed up on that fact to cast the skill of GFDL R15 circa 1999 in doubt. That he didn’t, but chose instead to double-down on his ‘NH sea ice rate of decline is less than predicted’ is telling, as his ‘but, but, but, the SH’

    As I read it there are 3 balls that Pielke Sr swings at in that post:
    1) NH SIE is not declining as fast as predicted by GFDL R15 1999.
    (ssssttttrrrrriiiiikkkkeeeee: see Ned above)
    2) SH SIE is not declining very fast
    (see Curry 2010)
    3) The NH SIE trend since 2006 is anomalous
    (ssssttttrrrrriiiiikkkkeeeee: see Tamino OP)

    If he really wants to understand what is “eyeball anomalous” about 2006+ NH SIE, I suggest he look in Arzel 2005: “We show that the amplitude of the seasonal cycle of sea ice extent increases in both hemispheres in a warming climate, with a larger magnitude in the Northern Hemisphere”. I haven’t done the math yet to verify that is what is going on, but then again, neither has Pielke Sr.

    • “If he really wants to understand what is “eyeball anomalous” about 2006+ NH SIE, I suggest he look in Arzel 2005: “We show that the amplitude of the seasonal cycle of sea ice extent increases in both hemispheres in a warming climate, with a larger magnitude in the Northern Hemisphere”.”

      Hey, thanks for the tip. That looks like a very interesting paper. And it was written before the notable increase in amplitude occurred.

      Plus, I like the fact that one of the authors’ addresses is apparently located on “Chemin du cyclotron”…

      • “Plus, I like the fact that one of the authors’ addresses is apparently located on “Chemin du cyclotron”…”

        Yes, it’s a real address, not unrelated to the fact that there are two cyclotrons in the building… it’s also the workplace of some fine climate scientists, like André Berger, of insolation fame, or Jean-Pascal van Ypersele, vice-chair of the IPCC.

    • Did some (naive) math. If I did it right, the last five years of annual variation of monthly extent and area (ie … meanMar – meanSep) does not appear to significantly deviate (< 2s.d) from the 1979-2011 R 'lm' (OLS) linear trend for annual melt. Increasing trend in annual variation is apparent. Extent is more variable than area. Data is here I’ll post a graph in the evening.

  24. Last thing: Why did Pielke choose to investigate this in June 2009 and April 2012 — months during two of the three highest sea ice anomaly peaks in the past several years? Perhaps the stop/reverse thing wasn’t so obvious in, say, August-October 2011 when the sea-ice anomaly was at its second lowest point in recorded history.

    • Interesting question, Zach. The sample size is small, but there appears to be a consistent pattern of Pielke posts occurring at the end of a sudden rise in his preferred metric (sea ice area anomaly):


      In both cases, the Pielke blog post appeared when the LOESS smoothed anomaly curve had (temporarily) risen about 0.5 million km2 above its previous low point.

      If history repeats itself, there will be another multi-year decline in sea ice area, starting right around now.

  25. Hi Ned,

    You say “I don’t routinely follow Mr Pielke’s blog, so I don’t know whether this kind of behavior is normal for him, or just a temporary aberration”.

    Unfortunately, this kind of behviour appears to be becoming the norm for Pielke since circa 2006.

    He could not refute your argument, so I see that he is now arguing strawmen in his “update 2″ post. He says,

    ” I disagree that this is the proper metric to show, and that anomalies provide the more appropriate comparison as this avoids the confusion as to which value is actually plotted in the Vinnikov et al paper with respect to the models.”

    This is incorrect and suggests that he has not read the paper properly. It is incorrect because he is comparing apples with oranges. There is no reason to be confused what Vinnikov et al. are plotting. The caption to their Figure 2 clearly stipulates that Vinnikov et al. are plotting the annual average sea ice extent. Yet Pielke insists that it is acceptable to evaluate those annual data using monthly anomalies. Ridiculous, Pielke’s pseudo analysis gets an F.

    He then goes on to lament that,
    ” Tamino and his commenters appear unable or uninterested in actually constructively discussing this issue. They have also chosen to ignore the inconvenient behavior of the Antarctic sea ice coverage.”

    Its appears odd that Pielke seems to believe that anyone who disagrees with him is not being constructive, or incapable of discussing the science– he has made that false allegation against RC, SkepticalScience and now Tamino (there are probably several others). Does he make the same juvenile allegations against reviewers of his papers who take issue with some aspect of his research? I sincerely hope not.

    He is also wrong that the Antarctic sea ice data are inconvenient. First, this response of Antarctic sea ice to the warming southern oceans was predicted by Manabe et al. back in 1992 (Pielke ignores that). Second, the increase in Antarctic sea ice is not statistically significant, nor is it accelerating (Pielke ignores that). Third, the increase in Antarctic sea ice is not sufficient to offset the loss of Arctic sea ice (Pielke ignores that). Forth, the west Antarctic ice sheet is losing mass at an accelerating rate, and so is Antarctica as a whole (Pielke ignores that). Fifth, Tamino et al. are not ignoring trends in Antarctic sea ice– here is one of several posts by Tamino on Antarctic sea ice when he was refuting untenable claims made by another fake skeptic (Pielke ignores that too).

    Frankly, Pielke’s original post and subsequent attempts to save face are offensive to anyone who knows something about sea ice. Moreover, it is unfortunate that he is hoping to try and mislead people who are not in the know, with his faux analyses and cherry picking.

    Pielke’s original position on this is untenable, yet he will never admit it.

    [Response: Just one disagreement — the increase of Antarctic sea ice since 1979 (using data from NSIDC) actually is statistically significant.}

  26. Hi Tamino,

    Thanks. Mea culpa. I was looking at the monthly data and found that only one month had a stat. sig. linear trend (IIRC). But I should have looked at the annual data to compare apples with apples.

    Am I correct in assuming that you found the trend in annual Antarctic sea ice since 1979 to be statistically significant?

    [Response: I used monthly data, and even correcting for autocorrelation the trend is still significant. Using annual averages the trend is still significant.]

  27. It is clear from the updates to the original post that Pielke the Elder’s goal os to be “not even wrong”. He will shift goalposts when his squibbs come up short. He will obfuscate when his arguments are domonstrated fallacious. He doesn’t even care if he’s right, just as long as no one can prove him wrong.

  28. “It appears odd that Pielke seems to believe that anyone who disagrees with him is not being constructive…”

    Well, that would depend upon just what is being ‘constructed,’ wouldn’t it?


  29. Hi Tamino,

    My apologies, I am not being clear. By “monthly” I was referring to trends for individual months (e.g., all Januaries etc.). But perhaps I got that wrong too ;)

    • Yes, when you do this you will lose statistical significance, because you’ve effectively divided the data into 12 smaller sets. I rather imagine that the “skeptics” will like this technique. “If we look at the temperature on 3rd of May for the last hundred years we find no statistically significant increase”.

  30. Good gracious me. Pielke Senior just won’t admit error. He now has a third update up in which he continues to make subjective and qualitative statements, with yet more obfuscation and whining.

    He also trots out the predictable excuses for not directly engaging his critics and for not admitting error,

    “Finally, reading the comments on Tamino illustrates the lack of professional courtesy that is the benchmark of science. I am not presenting my comments on Tamino for that reason. Most of the commenters also hide behind anonymity to insult rather than actually debate a scientific issue. The Tamino weblog approach illustrates the unfortunate state of scientific debate with respect to climate state.”

    IIRC, Ned has been nothing but polite. Peers who review Pielke’s papers are anonymous and not always polite either (in fact, reviewers can be downright rude), so I guess Pielke feels that reviewers are “hiding behind anonymity” and thus feels free to ignore them too. But wait, he has publushed many papers, so I find it hard to believe that someone who is so familiar with the trials of rigorous peer review can have such a thin skin. No, it is much more likely that this is just an excuse on Pielke’s part to run away from rigorous scientific debate.

    Readers here should not that Pielke’s lamentations about the lack of “professional curtosy” ring very hollow. In fact they show Pielke to be duplicious. Pielke is in the unfortunate habit of chastizing, denegrading, insulting and mocking those peers and groups who do not share his opinions and world view/ideology. Just a few examples of incredibly unprofessional and juvenile behaviour by Pielke in this regard can be seen at SkepticalScience. So he can save us all the hypocrisy and duplicity.

    It is no wonder that his peers and colleagues have grown tired of his ongoing vendetta against some of his peers. One wonders when the AGU and AMS will grow tired too…

    But to stick to the science, his argument that looking at the daily data are more useful shows that he is either ignorant about the importance of signal-to-noise ratio or choosing to ignore it to advance his misinformation. There is of course a lot of detail in the noise (focusing noise is a good way of obfuscating and distracting people from the big picture too as it happens), but that detail is not necessarily terribly useful or insightful.

    • The ad hom accusation regarding Ned is pretty feeble to begin with, as noted below, but it does have some basis in fact. Ned’s first link in this thread:

      But Pielke is referring to comments in general here, not just Ned. I don’t think I’d be interested in taking up a discussion in a place where I’d severally been called mentally decrepit (‘emeritus’) and a liar. I wish the frustration could be set aside and these sorts of comments avoided. Aside from the obvious reasons, it just gives critics amo (to distribute amongst themselves), and the target an escuse not to engage. Comments like this do no good whatsoever – except to vent well-justified frustration.

      • A monicker I used temporarily has been infilled to this blog. ‘Priest’ = ‘barry’. I like to at least keep my pseudonym consistent.

      • Well, I for one wasn’t particularly polite. My only defense is that when one ‘calls it as one sees it,’ politesse may need to take a back seat. I don’t think the evidence available–ie., the comments and ‘analysis’ in the public record–suggests that Dr. Pielke is operating in good faith. I’d be delighted to see evidence to the contrary.

  31. It seems to me that Pielke always cries foul and accuses his critics of rudeness, whenever his mistakes are pointed out. It’s his version of “ad hominem.”

    In this case it’s all he can revert to, because he is so astoundingly, demonstrably wrong. Even though I advised him to DO THE MATH, he still hasn’t done so. He even urges me to “do the math” because one of my results seems, so he claims, impossible — but not only did I do the math, it looks like more than one reader here did so too, and confirmed my result.

    Also laughable is the fact that he tries to take refuge in appealing to daily data. I urge all interested readers to download the daily data and DO THE MATH. Pielke is wrong, whatever data set you choose.

    If he had the guts and the integrity to say “OK I goofed,” then I might have answered my own question “Could it be that Roger Pielke is actually aware of that, but that he really doesn’t care about portraying sea ice changes correctly, he only cares about discrediting global warming science?” in the negative — it would have shown that he at least cares about getting the right answer. But his obstinate refusal to admit his mistake, and his obstinate refusal to DO THE MATH, strongly suggest that indeed he does not care about the right answer, he only cares about discrediting global warming science.

    Or maybe … could it be that after my post he actually did do the math, but still refuses to admit the truth?

  32. Good lord. That third (?) update from Pielke is a real doozy. Read this paragraph:

    The absolute values on the left side of the Vinnikov et al plots are also misleading, as clearly the real world annual average of sea ice extent shown in the above figure from The Cryosphere Today is not even close to the values plotted for the GFDL model or what are reported in their paper to be the Chapman and Walsh, or Parkinson et al observed data. The reason for the disagreement is likely due to different definitions of sea ice extent. Showing anomalies from the current data on The Cryosphere Today is a way to focus just on the anomalies and their trend over time, and to avoid dealing with the absolute values themselves.

    No, no, no!

    Vinnikov et al. plotted the annual mean of sea ice EXTENT. The Cryosphere Today data that Pielke shows are sea ice AREA. They are different metrics, Mr Pielke!

    The Vinnikov 1999 paper specifically discusses all the sources of sea ice EXTENT data that they analyzed, and notes minor differences among the definitions (e.g., using a 15% concentration cutoff vs not).

    This is one of the reasons why I gave Mr Pielke a hard time for not comparing apples to apples. I’m actually rather mind-boggled that Mr Pielke would be unaware of the difference between ice AREA and ice EXTENT. I suppose this explains why he referred obliquely to some “confusion” about the ice extent data in Vinnikov. There’s actually nothing “confusing” about the data they use; he just didn’t realize he was comparing it to the wrong thing.

    • May have to start calling Pielke “Roger the dodger”.

      • Dodger-Man, Dodger-Man
        Spins the lies on warming spans
        Line goes up or now around
        If called out just double down
        Look out!
        Ever constant Dodger-Man

        All day long:
        With the crud,
        Can’t stop gish-gallop floods.
        How he swings through forum threads
        Ever confounding human heads;
        Hey there–
        Ever constant Dodger-Man

        For a ray of sun,
        Rates of change are a bore.
        Urban heat on the run
        No trends to answer for

        Dodger-Man, Dodger-Man
        Friendly naysayin’ Dodger-Man
        Wealth and fame
        His reward
        Inaction has us floored

        Life got your droughts up?
        Need to make a graph up?
        Quick, find the Dodger-Man!

        (Next Up: “Man of Constant Dodging” by the Statistical Bottom Brothers)

  33. Pielke just added a paragraph to the bottom of his third update. The paragraph in question does not even make sense.

    My advice would to be to not bite Tamino, he is asking questions to try and deflect attention from his errors.

    • Two comments on the last para in Pielke Update #3:

      1) I think he is shifting away from defending his claim that ‘obs demonstrate less decline than the model’ towards a position ‘maybe the obs demonstrate the lack of skill in GFDL R15 1999′ as I suggested he do in the first para of this comment.

      2) “The best defense is a good offense.” Having realized his initial claims are unfounded, he is not only moving the goal post, he just passed the ball to Tamino, asking him what would constitute a good test of the skill of GFDL R15 1999.

      The last is an interesting question, to be sure, but hopefully Dr Pielke won’t abandon his position entirely before he answers the question below as to how he would quantitatively support his claim that SIE/SIA trends show a breakpoint in 2006.

      [Response: If he showed the guts and integrity to admit that he goofed and he was just plain wrong -- then we might be able to discuss the science. In which case I'd be happy to answer his question.]

    • Maple: My advice would to be to not bite Tamino, he is asking questions to try and deflect attention from his errors.

      BPL: And his errors are what, exactly? I’m always glad to hear professionals criticized by asinine partisan dilettantes.

      • Barton, I think you may have misunderstood Mapleleaf. That might be due to the missing comma before “Tamino”.

      • Hello Barton

        I’m a little confused by you saying “I’m always glad to hear professionals criticized by asinine partisan dilettantes”.

        You appear to be referring to me when you say that. If so, I can assure you that I am not a dilettante when it comes to climate issues. In fact, you and I have corresponded by email, albeit briefly in Granger causality a while back.

        As for Dr. Roger Pielke Senior’s errors, they have been well documented in the main post and by other posters here, inlcuding moi. But I am happy to draw up a list if you wish.

      • Whoa there, Barton, down boy!
        Besides the missing comma, substitute the proper noun Pielke for the pronoun he and I think you’ll better understand what Maple Leaf said.

  34. A digression, but the NH annual melt (aka seasonal cycle) aka Arzel 2005 is displayed here

    Dr Pielke, two questions.

    You seem to be insisting that NH SIE/SIA trends are non-linear.

    1) Are you aware the non-linearity is due to accelerating decline?

    2) Are you able to move your claim of that the NH SIE/SIA trends experienced a shift in 2006 away from the qualitative (eyeballing charts) to the quantative (unit root, breakpoints)?

  35. Urmm … drought stopped … started raining. Oops … rain stopped … drought again. Oops rain started … no drought … No rain … drought again.

    – From “Diary from a Sawtooth World,” by R. Pielke.

  36. Yeah, Doug, it’s called “weather.”

  37. Well, Roger Senior is now quadrupling down. Still will not do the math (although he assures us he is now finally working on some) and still will not admit error. Instead we get this,

    “In the latest comment in the Tamino post Do the Math, I am critizied for using sea ice area and not sea ice extent (along with the now to be expected personal insults by a number of commenters on Tamino). However, in my view since it is area, not extent that better maps with radiative feedback, the Cryosphere Today presentation is preferred.”

    This is a strawmen here that Pielke Senior needs to be called on. First, the issue here is not whether or not ice area is superior to ice extent, or vice versa. The point is that Vinnikov et al used annual sea ice extent in their paper, so to validate that forecast one should use the same metric averaged over the same time scale. In fact, Tamino and Ned did exactly that.

    Pielke Senior then agoes on to rehash the disparity between the two model simulations. This has already been addressed in the paper and here and as such is a red herring.

    Pielke Senior then makes another strawman argument,
    “Tamino would have to show that the anomalies for the extent and are coverage were distinctly different, and then I would agree that the two should not be interpreted as having the same anomalies.”

    Here Pielke Senior is attributing an argument to Tamino when Tamino is not the one making that argument. It was Ned and Ned simply pointed out that Pielke Senior was inocrrect to talk about sea-ice area when Vinnikov et al. used sea-ice extent. So Tamino has to demonstrate nothing because he made no such claim. The only person who has to demonstrate something is Roger Pielke Senior. Specifically, to do the math.

    Pielke Senior then finsihes with, yes, another strawman:
    “However, until and unless that happens, Tamino (and a number of the commenters) are not, in my view, following the scientific method which is to seek to refute hypothses (i.e. in this case the Vinnikov et al or other model preditions) rather than defending the models.”

    This if both wrong and offensive, and hypocritical to boot. In fact, I would argue that Pielke’s original post is the very antithesis of good science and the scientific method. Additionally, I do not recall Tamino defending the simulations made by Vinnikov et al. In the very first line of the main post Tamino specifies what the issue is “Roger Pielke Sr. claims that northern hemisphere sea ice has not declined as fast as computer models predicted.”
    In other words, Pielke is insinuating that the models are alarmist and useless– at least that is what I suspect how wishes his audience to interpret his post.

    Either way, in the very next line Tamino notes that the models are wrong, but in the opposite direction to what Pielke is claiming. So Tamino is not “defending the models” as Pielke Senior is falsely claiming. In fact, several readers here have also noted that they have been too conservative in their estimates of Arctic sea ice loss.

    After having torn down his strawmen, Pielke Senior then accuses Tamino of being dishonest. I suspect saying that is probably projection on Pielke’s part.

  38. Regarding Pielke’s new goal to test the question, “Is the break-point visible in 2006 statistically significant?” This must be carefully done so as not introduce bias by focusing on a particular year (which should go without saying) or defining “breakpoint” or otherwise devising his hypothesis in a way that’s influenced by first looking at the data. Lastly, the same analysis needs to be applied in an apples-to-apples manner to the pre-1999 record and the models’ outputs.

  39. Skeptical Science on Vinnikov and Pielke – the 2006 cherry pick is bad, but not the only problem with Pielke’s analysis. The Arctic sea ice decline is 27 years ahead of the Vinnikov prediction, and there’s less than a 0.1% probability the decline is due solely to natural variability.

  40. Four updates (and counting). It would simplify things if Roger would just open his blog for comments, or alternatively if he’d engage in the discussion here. On the other hand, if his goal is to maximize the obfuscation and avoid dealing with his missteps, then he’s probably going about it the right way.

    Roger, if you just want to explore the satellite record of Arctic sea ice, then nobody here cares whether you look at extent vs. area, or daily anomaly vs annual mean. Any combination of those is fine.

    The problem is that you set out to evaluate the success of the GFDL model shown in Vinnikov 1999′s Figure 2. But you did it all wrong, and you can’t bring yourself to just say “sorry, I screwed up.”

  41. Oh this is getting really silly. Pielke Senior now has a fifth update, with no hint of admitting error on his part. Pielke is clearly getting very, very desperate, and has stooped so low now as to post some of Tamino’s personal info. Is Pielke Senior turning into Marc Morano or Poptech? I hope not.

    Pielke claims,
    “The failure to identify yourself when discussing a scientific issue shows a lack of professional courtesy.”

    Well, using his logic, Pielke is accusing scientists who review his papers and funding proposals of being rude and unprofessional by remaining anonymous. Got it.

    It is very odd (yet terribly convenient) that Pielke is so affronted by the tone of some here and elsewhere, while turning a blind eye to the caustic tone of his friend Anthony Watts and his followers. What is even more odd is Pielke lecturing others on their “tone” when he openly and repeatedly mocks his peers. Now that is unprofessional Dr.Pielke. Do you really not see the double standard that you are applying here Roger?

    Roger, a suggestion, instead of obsessing over tone and monikers and using them as a crutch or excuse to not engage in a scientific discussion and in the process showing yourself to be hypocritical, please do try and do some actual quantitative and rigorous analysis before posting. You have again jumped before thinking in your latest post on the TOA imbalance and the OHC data from Levitus et al. (2012) and in the process mangled the physics– but that is a story for another time.

    A question to you Roger, are you going to demonstrate the integrity and professionalism that you expect of others and admit fault when it is pointed out to you? The ball is in your court.

  42. Dr. Pielke – Re: your most recent update: Personally, I choose to use a pseudonym, a tag, while posting on these topics. That’s because I subscribe to the notion that “I’ll let my words speak for themselves.” Science isn’t about names, or reputations, or authorities, it’s about the data, observations, and good evidence. Ad Hominem attacks of this nature are a fallacy, an admission of a lack of evidence on your part.

    Your current tactic of “outing” folks who decide to present their ideas rather than their home addresses can only be considered cyberbullying – and at this point makes me rather happy that you refuse to let people comment on your blog site, as I now cannot consider you trustworthy with personal data.


    Regarding the current topic – You have (mis)compared area to extent (different numbers entirely). You have (mis)compared annual averages to monthly averages. You have once again (as per the multiple discussions of short term time frames on SkS) asserted notions without any statistical significance, making great claims from what is essentially noise. You have thrown a bunch of strawmen and nonsense at the Vinnikov study.

    And you will not consider that you may have been mistaken.

    If you wish to discuss unprofessional behavior, I would suggest considering your refusal to face the errors that have been pointed out to you. I find (IMO) your behavior appalling, and ill-becoming of an established scientist.

  43. KR,


    IMHO, this kind of behaviour by Pielke Senior is completely unbecoming of an AGU fellow– Pielke Senior’s abominable behaviour makes one wonder if AGU have grounds to rescind Pielke Senior’s fellowship….

    Yes, Pielke Senior will probably play the martyr card, but AGU is selling itself (and science) short if it decides to be affiliated with such despicable behaviour by one of its own.

  44. Update #5: Provide a benchmark criteria to assess for the coming seasons. From my perspective, I view that the models are not refuted if the anomalies in sea ice areal coverage fall at close to or greater than the rate of, say, the order of 100,000 square kilometers per decade in the next few years.


    Dr Pielke, do you seriously propose to test the skill of “models” with absolutely no reference to the behavior of the model itself?

    Your proposed test is rubbish.

    Let us say that Model A projects a ~100,000 sq km increase in sea ice area for 2011-2020. Let us say that Model B projects a ~100,000 sq km decrease in sea ice area for 2011-2020. Let us say that Model C projects no increase or decrease.

    Now if the obs from 2011-2020 show a ~100,000 decrease in sea ice coverage for the decade, you will find all three models ‘not refuted’?

    Surely you cannot have meant what you wrote and posted. I look forward to your clarification.

  45. > Remind me again why we give a damn what Pielke thinks?

    More important — watch who picks up what he says.

    You know about whitewashing and greenwashing.
    This smells like gaswashing.

    Morano feeds his talking points to scientists who repeat them.

    Then the talking point can be cited to “A Real Scientist”

    Lobbyists get their senators and congressmen to put their language into the record.

    Our legislators don’t need science. They need ‘arguable’ claims they can consider as sufficiently reliable opinion to do what they’re asked to do.

    And they get them, in large commercial quantities, especially in this election year.

    “This is the year when author Robert Heinlein forecast that the U.S. would tumble into a vicious theocracy led by a fundamentalist, rabble-rousing preacher.”

  46. In response to update #6: “I did make an error in my post by assuming that anomalies in sea ice extent and sea ice area would be the same.” I assumed that they were similar enough in my first post above, scaled the Cryosphere Today image to match the original model image and came to the same conclusion as folks using more apples-to-apples comparisons: (e.g. a 20-30 modeled drop in a decade). Even assuming that it’s reasonable to compare the CT plot to the Vinnikov 99 plot, I don’t see that Pielke would’ve come to the same conclusion had he plotted them on the same scale. The monthly variations (and possibly apparent plateau) in the CT plot are totally unremarkable given noise in both the instrumental record and model results.

  47. Philippe Chantreau

    Pileke Sr has shown everything one needs to know on SkS. The thread is linked higher in this discussion and can be found easily, along with related threads, through the search engine at SkS.

    It was initially motivated by his throwing of some rather heavy handed ad-hom arguments on his own site. When called on it, he tried to deflect the taking apart of these arguments to “discussion of science” as it became obvious the arguments could not be defended. His double standards about ad-homs were also made glaringly obvious by SkS and he tried once again to talk about something else, although he had lengthy attacks on other people’s motives, integrity and what not on his own blog, where those who are attacked can not address it.

    Pielke Sr asserted on SkS that WUWT had the “highest standards of scientific robustness” (his own words) but when challenged to explain some of the more egregious nonsense spewed there, he of course talked about something else. He was almost cornered by Dikran Marsupial into admitting that he did not care about statistical significance but, as I recall, abandoned the discussion before things could be completely spelled out, even though they were abundantly clear already.

    It was overall a sad display from one who has some vociferous pretentions concerning the scientific method. By his actions and words, Dr. Pielke Sr has demonstrated that he is to be treated no different than people like Monckton or even Morano, who is close to scientifically illiterate and specializes in politically motivated mind-manipulation. Pielke is not scientifically illiterate, but the results of his actions goes exactly the same direction as Morano and the like of him.

    How much “sincerity” underlines Pileke’s actions is known only to him. However, his preference for eyebaling over true statistical analysis, his systematic choice of insufficient time periods and the ridiculous double standards he cultivates speak for themselves.

  48. In his latest update, Pielke asks:

    “I am requesting that, since they appear to have the statistical analysis program and data readily available that Grant Foster and/or dana1981

    i) perform the same analysis for sea ice area that they have done for sea ice extent”

    I suggest that Dr. Pileke actually read the Vinnikov paper (it’s linked in the SkS post). The title of the paper is “Global Warming and Northern Hemisphere Sea Ice Extent”. The paper only looks at the predicted change in Arctic sea ice extent, not area. Thus there is not a modeled area prediction to compare to (not that there is any reason to think the result would be any different for predicted vs. observed area as it is for extent).