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New Science Scandal: ‘Fatally Flawed Hurricane Paper Should Be Retracted’

November 16, 2019

By Paul Homewood



Roger Pielke Jr has now weighed in on the flawed Grinsted hurricane paper:


Earlier this week a paper published by the Proceedings of the National Academy of Sciences (PNAS) by a team of authors led by Aslak Grinsted, a scientist who studies ice sheets at the University of Copenhagen, claimed that “the frequency of the very most damaging hurricanes has increased at a rate of 330% per century.”

The press release accompanying the paper announced that United States mainland “hurricanes are becoming bigger, stronger and more dangerous” and with the new study, “doubt has been eradicated.”

If true, the paper (which I’ll call G19, using its lead author’s initial and year of publication) would overturn decades of research and observations that have indicated over the past century or more, there are no upwards trends in U.S. hurricane landfalls and no upwards trends in the strongest storms at landfall. These conclusions has been reinforced by the assessments of the Intergovernmental Panel on Climate Change (IPCC), U.S. National Climate Assessment, and most recently of the World Meteorological Organization.

In fact, however, the new PNAS paper is fatally flawed. The conclusions of major scientific assessments remain solid. As I’ll show below, G19 contains several major errors and as a result it should be retracted.

The first big problem with G19 is that it purports to say something about climatological trends in hurricanes, but it uses no actual climate data on hurricanes. That’s right, it instead uses data on economic losses from hurricanes to arrive at conclusions about climate trends. The economic data that it uses is based on research that I and colleagues have conducted over more than two decades, which makes me uniquely situated to tell you about the mistakes in G19.

Compare the counts of hurricanes reported in G19 with those that can be found in climate data from the National Oceanic and Atmospheric Administration.

From 1900 to 1958, the first half of the period under study, NOAA reports that there were 117 total hurricanes that struck the mainland U.S.. But in contrast, G19 has only 92. They are missing 25 hurricanes. In the second half of the dataset, from 1959 to 2017, NOAA has 91 hurricanes that struck the U.S., and G19 has 155, that is 64 extra hurricanes.

The AP passed along the incorrect information when it reported that the new study looks at “247 hurricanes that hit the U.S. since 1900.” According to NOAA, from 1900 to 2017 there were in fact only 197 hurricanes that made 208 unique landfalls (9 storms had multiple landfalls).

Part of this difference can be explained by the fact that G19 focus on economic damage, not hurricanes. If a hurricane from early in the 20th century resulted in no reported damage, then according to G19 it did not exist. That’s one reason why we don’t use economic data to make conclusions about climate. A second reason for the mismatched counts is that G19 counts many non-hurricanes as hurricanes, and disproportionately so in the second half of the dataset.

The mismatch between hurricane counts in G19 versus those of NOAA by itself calls into question the entire paper. But it gets much worse.

The dataset on losses from hurricanes used by G19 to generate its top-line conclusions is based on my research. That dataset has been maintained by a company called ICAT located in Colorado. The ICAT dataset was initially created about a decade ago by a former student and collaborator of mine, Joel Gratz, based entirely on our 2008 hurricane loss dataset (which I’ll call P08).

In the years since, ICAT has made some significant changes to its dataset, most notably, by replacing P08 loss estimates with loss estimates from the “billion dollar disasters” tabulation kept by the NOAA National Centers for Environmental Information (NCEI). The replacement data begins in 1980, at the start of the NCEI dataset.

This process created a new hybrid dataset, from 1900 to 1980 the ICAT dataset is based on P08 and for 1980 to 2018 it is based on NCEI. This is hugely problematic for G18, which was apparently unaware that of the details of the dataset that they had found online.

In our comprehensive update of P08 published last year (Weinkle et al. 2018, or W18) we explained that the NCEI methodology for calculating losses included many factors that had historically not been included in tabulations of the U.S. National Hurricane Center, “for instance, to include federal disaster aid, federal flood insurance payouts, national and local agricultural commodity effects and other macro-economic impacts.”

That meant that one cannot, as ICAT has done, simply append the NCEI dataset from 1980 to the end of the P08 dataset starting in 1900. They are not apples to apples. Indeed, a big part of our work in the W18 update of P08 was to ensure that the data was apples to apples across the entire dataset, and we performed several statistical consistency checks to ensure that was the case.

The new PNAS paper, G19 unwittingly uses the ICAT dataset that staples together P08 and NCEI. I have shown with several graphs on Twitter why this matters: Before 1940, G19 and W18 loss estimates for individual are just about the same. After 1980, however, G19 loss estimates for individual storms are on average about 33% higher than those of W18. The result is a data incontinuity that introduces spurious trends to the dataset.

So what does this all mean?

It means that G19 has identified trends in hurricane losses that are the result of two datasets being improperly combined. This is why G19 results in trends that are inconsistent with the climatological record of U.S. hurricanes while W18 results in trends that are fully consistent with the climatological record of U.S. hurricanes.

When an analysis of economic loss trends from hurricanes in inconsistent with the climate record, the response should not be to claim that the climate record is flawed, but instead, to have a closer look at what biases and errors may have crept into the economic analysis.

Anyone wanting to understand trends in U.S. mainland hurricanes should look at data on U.S. mainland hurricanes, not economic data on losses. Below in the historical record of U.S. hurricanes. So far, 2019 has had two landfalls (the season ends November 30).

The figure blow shows landfalls of the strongest storms (major hurricanes, Category 3+), and 2019 has had none.

The bottom line here is that a fatally flawed paper on climate science passed peer review at a significant journal. It used a dataset found online that had not undergone peer review, much less any quality control. The flawed conclusions of G19 have been loudly promoted by activist scientists and uncritical media.

The result has been a polluting of our discussions of climate science and policy. I have no doubt that good science will win out in the long run, but if we do not enforce basic standards of research quality along the way, we will make that battle much more difficult than it need be.

Full post


As my analysis a few days ago showed, there are many other concerns about Grinsted’s paper.

Roger’s new findings are utterly damning, and it is hard to see how PNAS can do anything other than withdraw the paper.

  1. It doesn't add up... permalink
    November 16, 2019 11:30 am

    It means that G19 has identified trends in hurricane losses that are the result of two datasets being improperly combined.

    In other words it uses a hockey stick procedure. They are evidently disciples of Mann.

  2. john cooknell permalink
    November 16, 2019 11:33 am

    They seemed to have missed the obvious, but they got the answer they so dearly wanted, so nobody bothered to check the facts. Not for the first time!

    Accounting is not an exact science, at its best it is an art-form, gives you a flavour of what happened or is happening at a given point in time. As I was told many years ago “it much depends on how you look at things”, and “what do you want to say?”

    It is the fraudsters friend! The world has been fooled by accounting, several world banking crises are a testament to its veracity. Professor Stern never noticed either, and you thought he would, as he is renowned world leading economist.

    • john cooknell permalink
      November 16, 2019 12:11 pm

      Because I could never find out from anyone, I used to end my budgetary statements with the phrase “VAT will be accounted for in accordance with Group Accounting Policy and Requirements”

      Never got a single question in 30 years!.

    • November 16, 2019 12:29 pm

      …and climate expert:

      “One of the world’s leading experts on climate change has been telling Commonwealth finance ministers that much more money needs to be pumped into tackling the problem. Professor Lord Stern, co-chair of the new Climate Economy report, said that investments of US$90 trillion were needed and that the time for action was now.”
      “Climate expert emphasizes the fierce urgency of now. In MIT talk, Lord Nicholas Stern calls the next 20 years “absolutely defining” for society.”

      and a “scientist”:
      On Thursday 16 May 2019, rector Rik Van de Walle will be presenting an institutional honorary doctorate to Lord Nicholas Stern in the Aula at 17:30, in the name of Ghent University

      and speaker for hire:

    • November 16, 2019 3:08 pm

      Of course the natural suspicion is that had things gone the “wrong” way, the authors would have dug deeper into the dataset/methods to find out why. But because it went the “right” way, they just drew a line under it and submitted.

      And because it went the “right” way, the credulous editor sent it to some reviewers who gave it a cursory glance because it did not challenge their preconceptions.

      And it takes outsiders to spot it all, after the mainstream media have trumpeted it to the world.

      Will the bbc retract their article, I wonder?

    • Bertie permalink
      November 16, 2019 8:32 pm

      I’ve always understood than for an accountant the best answer to the question “what is 2 + 2”
      is “what do you want it to be?”.

  3. November 16, 2019 12:05 pm

    I note the PNAS paper was edited by Kerry A. Emanuel, Massachusetts Institute of Technology. He jumped aboard the AGW bandwagon a few years ago, with interests in the insurance industry:

    “In the Eye of the $torm – Kerry Emmanuel – The Non Political Scientist”

    “Dr Kerry Emanuel of MIT caused a storm recently, [2012] when he said in a Mother Jones video that, as a Republican scientist, he is almost ashamed to be an American, because not all Republican candidates have embraced Global Warming. An LA Times Op-Ed from January 5th 2012, portrayed him as the conservative scientist out to save the world.

    In February last year, [2011] Dr Emanuel was playing the same “Republican scientist who believes in global warming” message in a radio interview for NPR. He brought in the usual mantras about the tobacco industry and a campaign of disinformation funded by vested interests, but failed to mention his own vested interest in the disaster insurance business.”

    • November 16, 2019 12:29 pm

      He dubs himself as “The Non Political Scientist” and then proceeds to be political. The fact that he gives this to “Mother Jones” and they accept it, validates that he is a highly political leftist whose scientific views are governed by that rather than facts.

  4. November 16, 2019 12:56 pm

    “Fatally Flawed Hurricane Paper Should Be Retracted”

    In the singular?
    You mean there is just one of those?

  5. mjr permalink
    November 16, 2019 1:37 pm

    as Mart Twain should have popularised … “there are three kinds of lies: lies, damned lies and climate change statistics “

  6. November 16, 2019 6:19 pm

    Reblogged this on Tallbloke's Talkshop and commented:
    Looks like Pielke Jr. opened the trapdoor on that one. Who’s next for the slaughter of climate alarmist claptrap masquerading as science?

  7. November 16, 2019 7:02 pm

    Meanwhile it will be all out there for the kids to wet their beds about.

  8. john cooknell permalink
    November 16, 2019 8:55 pm

    I will be surprised if the authors withdraw the paper quickly, my guess is PNAS will take its time and wait for formal comments, then review with the authors, then fiiddle around for a bit for no particular reason.

    Then procrastinate, for some time, to allow boredom to set in.

    Then pretend it never happened, and carry on to the next load of garbage (sorry, scientific endeavour), such is the nature of science.

    • November 16, 2019 10:32 pm

      If PNAS is happy to have a discredited paper on its books, so much for its own reputation.

      • November 17, 2019 12:05 am

        The strategy is to use PNAS as a vehicle with sufficient scientific imprimature to impress the media.
        “Academy membership is one the most prestigious honours for a scientist, and it comes with a tangible perk: members can submit up to four papers per year to the body’s high-profile journal, the venerable Proceedings of the National Academy of Sciences (PNAS), through the ‘contributed’ publication track. This unusual process allows authors to choose who will review their paper and how to respond to those reviewers’ comments.”

        “This article is a PNAS Direct Submission.”

        Click to access iforc.pdf

        “More than 50% of Direct Submissions are declined by the Editorial Board without additional review, within 2 weeks on average. For papers that are sent on to an editor and reviewers, the average time to receive a decision is 41 days. If accepted, authors have their articles published online as soon as 4–5 weeks after acceptance.

        Authors must recommend three appropriate Editorial Board members, three NAS members who are expert in the paper’s scientific area, and five qualified reviewers. The Board may choose someone who is or is not on that list or may reject the paper without further review.

        Authors are encouraged to indicate in their cover letter why their suggested editors are qualified to handle the paper. The editor may obtain reviews of the paper from at least two qualified reviewers, each from a different institution and not from the authors’ institutions.

        PNAS will invite the reviewers, secure the reviews, forward them to the editor, and secure any revisions and subsequent reviews. The name of the editor must remain anonymous to the author until the paper is accepted. Direct Submissions are published as “Edited by” the responsible editor and have an identifying footnote.”

        Hurricane alarmist Kerry Emanuel is stated as editor of this paper. He is also a PNAS member editor, so gets to decide what gets through:

        He has been an editor for Aslak Grinsted previously:

        Schellnhuber is also a member editor. The late Stephen Schneider used this process for years.

  9. It doesn't add up... permalink
    November 17, 2019 3:03 am

    Improving the statistics.

    If we look at the data on the numbers of landfalling hurricanes per year and construct a frequency histogram for 0,1,2…7 per year it does look like a reasonable fit for a Poisson distribution, at least as a first guess: this is a typical expectation for modestly rare random events. Poisson distributions are entirely characterised by the average expected value. The mean number of hurricanes per year is 1.8. However, if we construct a 50 year moving average of the number of hurricanes it is immediately apparent that the average has been in decline from just over 2.0 to just over 1.5 in recent years, with the decline setting in once years post 1970 are included in the average. The moving average is a much better descriptor of the trend in hurricane numbers than a least squares fit line.

  10. Charlie permalink
    November 17, 2019 12:55 pm

    Why does the University of Copenhagen not jump all other this junk “science”. This ultimately reflects on the University

  11. November 17, 2019 11:43 pm

    Reblogged this on Climate Collections.


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