The Snailgate Papers

The story of the snail Rhachistia aldabrae miraculously coming back to life after being declared an extinction victim of climate change has been getting a fair amount of attention, following a WUWT post, a Delingpole piece, and an article in the Times by Ben Webster (paywalled, but excerpts available via GWPF or Bjorn Lomborg). Now, inevitably, referred to as “Snailgate”, the incident looks bad for the Royal Society, who rejected a paper questioning the alleged extinction, and has still not taken any action (such as a note on the original incorrect paper, or retracting it) after proof of the snail’s resurrection.

An article in Forbes helpfully gives links to the papers concerned.

The original paper was Gerlach (2007) Short-term climate change and the extinction of the snail Rhachistia aldabrae, in a Royal Society journal called Biology Letters. That paper was submitted on June 18 and accepted July 11, an unusually fast turn-round. The methods used by Gerlach to claim extinction seem rather flimsy, based on examination of collections containing specimens.

The rebuttal paper, written by Clive Hambler and others, was rejected and does not seem to be available [Update 20th Oct: it is now, see comment below]. We know from the Webster article that it pointed out that most of the habitat was inaccessible and has never been visited, and correctly predicted rediscovery of the “extinct” snail. It appears that the Hambler script was sent to the same reviewers who had accepted the Gerlach paper, which Delingpole rightly describes as a conflict of interest.

Papers that have cited Gerlach (2007) can be found with Google Scholar, which says there are 12 – not many for such a prolific field. The most high-profile of these is Cahill et al (2013), How does climate change cause extinction?, published in Proc Roy Soc B, which itself already has 79 citations.
According to Webster’s article, Cahill et al “suggested that this was the clearest example of man-made climate change causing an extinction.” The wording used by Cahill et al is in fact a bit more oblique than Webster implies: “In almost all cases, the links between extinction and anthropogenic climate change are speculative (but see [82]), which is why these cases were not included previously in our review.” [82] is the Gerlach paper.

The Cahill et al paper was much cited by IPCC AR5 WG2, see Chapter 4 here (IPCC did not cite Gerlach). This chapter presents mixed messages – on the one hand we have “only 20 have been tenuously linked to recent climate change (Cahill et al., 2013)” but then there is the worrying suggestion that climate scientists just have to look harder for evidence to confirm their hypothesis: “This does not mean that climate has not played an important contributing role; indeed it has been argued that the low level of confidence in attribution is due to the lack of studies looking for climate signals in extinctions (Cahill et al. 2013).” There are some outright alarmist statements, such as this one quoted in the media: “These considerations lead to the assessment that future species extinctions are a high risk because the consequences of climate change are potentially severe, widespread and irreversible since extinctions constitute the permanent loss of unique life forms” (not linked to Cahill et al).

So what should happen now? Justin Gerlach should have the integrity to ask the Royal Society to withdraw his incorrect paper. He has written an article on his website acknowledging the rediscovery of the snail, but makes no mention of any retraction of his paper.

As long as he and the Royal Society take no action, snailgate will continue to provide fodder for the sceptics.

5 thoughts on “The Snailgate Papers

  1. Don’t look for them and we don’t find them.
    Then we do what we always do. We convince ourselves that the evidence that destroys our agenda does not exist.
    Then we go on our delusional fund grabbing greedy way viciously attacking each PERSON who disagrees with us not the accurate science they bring to the debate.

  2. In the Executive Summary of our Chapter 4 we wrote:

    there is generally very low confidence that observed species extinctions can be attributed to recent climate

    So Gerlach’s mistake about the snail didn’t affect the overall IPCC conclusion over past extinctions and whether they can or can’t be attributed to climate change

  3. There’s now an article on the snailgate story at Retraction Watch, appropriately called “At a snail’s pace”.
    This notes that the editor of the journal, Richard Battarbee, has made a half-hearted attempt to address the problem by writing an Editorial article about the case. But there is no retraction, and no warning flag on the original paper.

  4. Via Bishop Hill, the rebuttal paper by Hambler has now been made public. It is in fact a short comment on the original Gerlach paper, only just over a page in length.

    It ends with
    “It is unwise to declare this species extinct after a gap in (known) records of ten years. Declarations of extinction should be cautious (Butchart et al. 2006; Roberts & Kitchener 2006). We predict “rediscovery” when resources permit.”

    So in summary, a paper falsely claiming that the snail had gone extinct due to climate change, based on flimsy evidence, was published, but a response pointing out the error and correctly predicting the rediscovery was rejected.

    The Royal Society has published a list of the most-read articles from Biology Letters in September 2014. The Gerlach snailgate paper is number 3.

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