Reply to Ridley’s article (The Times)

The Times has published today a reply to Ridley’s article of 4 November.


Matt Ridley (Opinion, Nov 4) should brush up on his basic chemistry and biology before he critices scientists who worry about ocean acidification.

First, any shift of acidity is still important even if it is (just) within natural ranges; and in the future it will be much larger than that. Second, it has been known for some time that some organisms may make shells starting from bicarbonate ions. But there is abundant evidence that dissolution of their shells is controlled by the carbonate ion concentration, so decreases in carbonate means a problem for retention of shells.

Third, his claim of “no significant mean effect” of predicted future CO2 levels is only true because that is an average over several processes and many species, among which there will certainly be winners and losers.

Overall, decrease in calcification rate means a change in the ecosystem structure, and probably its function too, with unpredictable consequences. We entirely agree that the jury is out on how damaging acidification will be, but the scientific community is right to be concerned to research this “other CO2 problem”.

Professor John Shepherd, FRS, University of Southampton
Professor John Raven, FRS, University of Dundee
Professor Andrew Watson, FRS, University of East Anglia

The Times, 8 November 2010. Article (subscription required).

3 Responses to “Reply to Ridley’s article (The Times)”

  1. 1 John 9 November 2010 at 00:24

    It is refreshing that the respose says this:

    “We entirely agree that the jury is out on how damaging acidification will be, but the scientific community is right to be concerned to research this “other CO2 problem”.

    Ridley’s column was refreshing and realistic, it seems to me, and the response recognizes that the jury is still out — well done!

  2. 2 Matt Ridley 9 November 2010 at 20:54

    This is what I wrote to the writers:

    Dear Professors Shepherd, Raven and Watson,
    Thank you for your letter in today’s Times.
    You concede my point that the shift of acidity will be within natural ranges.
    You concede my point that some organisms make shells from bicarbonate.
    You concede that it is `true’ that there is no net effect of carbon dioxide on marine organisms.
    All this is very, very different from the exaggerated claims that I was attacking.
    I’m delighted. Many thanks.
    Yours sincerely
    Matt Ridley

    • 3 Jean-Pierre Gattuso 10 November 2010 at 09:51

      Points 1 and 3 of Matt Ridley’s comment above are not supported by the scientific evidence. Links to related primary literature are available on this blog.

      I also paste below a comment that I made a few days ago on another thread.


      The conclusions of Hendriks et al. (2010) have been thoroughly discussed (Dupont et al., 2010; Hendriks & Duarte, 2010). However, Hendriks and colleagues conclude “Calcification is most sensitive to ocean acidification…” This is is complete disagreement with the conclusion of Ridley that “… study after study keeps finding that, far from depressing growth rates of marine organisms, higher … levels of carbon dioxide either do not affect them or increase their growth rate”.

      Furthermore, the meta-analysis of Duarte et al. (2010) was followed by two other meta-analyses which showed that ocean acidification has a significant effect on some organisms and processes (Kroeker et al., 2010; Liu et al., 2010). For example, Kroeker et al. (2010) conclude “We … found negative effects on survival, calcification, growth and reproduction”.


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