In my book The God Species I take science writer Matt Ridley to task for downplaying the dangers of ocean acidification. He responded via email, and I to him. Here is the exchange. Matt’s final short responses are also included, indented as ‘Ridley2′. Square brackets are mine, for clarification.
Ridley: You say [in The God Species]: “Why not just admit candidly that whilst the human advance has been amazing and hugely beneficial, it has also had serious environmental impacts?” Answer: I do. Human beings have serious environmental impacts. I say so and I do not deny them. For example: ”Take coral reefs, which are suffering horribly from pollution, silt, nutrient runoff and fishing – especially the harvesting of herbivorous fishes that otherwise keep reefs clean of algae.” From megafaunal extinction to alteration of the composition of the atmosphere, I detail lots of changes wrought by humans. On both climate change and ocean acidification, I accept a human alteration of the environment as real. What I argue with is whether the negative impacts are always as great as claimed or the positive ones always as small as claimed. That’s quite different from not admitting that there are impacts, serious and otherwise.
Lynas: Fair enough. Everyone is of course entitled to draw their own conclusions – hopefully based on a reasonably non-selective reading of the available scientific evidence – about the relative seriousness of the different environmental challenges we face. That is actually sort of the point of the ‘planetary boundaries’ exercise: to quanfify numerically the possible limits to human alteration of different Earth system processes, and in so doing highlight their urgency or otherwise. From the ‘planetary boundaries 1.0′ exercise which I profile in the God Species book, the conclusion is pretty firmly that biodiversity and climate change are top-level urgent concerns, closely followed by the disruption of the nitrogen cycle, ocean acidification and others. I hope you can see the value in this as a way to ground our discussions and prioritisation efforts somewhat.
In addition, the boundaries all interact, and not always in bad ways – for example, our accidental spreading of large quantities of nitrogen in terrestrial and marine ecosystems, whilst causing problems like biodiversity loss and eutrophication, also has the benefit of increasing carbon uptake and thereby slightly reducing global warming. My strong contention is that we need to consider the boundaries together (assuming they are widely accepted in current or amended form) in any meaningful analysis of how to manage the planet sensibly.
Ridley: Next, to your discussion of ocean acidification. I resent the implication that I am a “denier”. What precisely am I denying? I don’t deny that oceans are being made lower in pH by human emissions. I don’t deny that man-made emissions are affecting climate; (I question the evidence for any large effects through net positive feedbacks). And why use a word deliberately intended to draw a parallel with the offensive lie of holocaust denial? I don’t call people like you “climate change liars” when I think you exaggerate the probability of severe harm.
Lynas: Again, fair enough, and although I have used the term in the book elsewhere, I accept that the term ‘denier’ is problematic. In principle a person could call anyone he or she disagrees with a ‘denier’. In fact, due to my stance on nuclear power, I have been called a ‘Chernobyl death denier’. So the charge cuts both ways. Were I writing the book now I would perhaps be more careful about any use this term. However, although you are free to “resent the implication” in that I discuss your position in the context of “denialist” websites and the like, I do not actually call you a ‘denier’. In fact I talk about the “criticism levelled by Ridley and other ocean acidification sceptics”, which is hopefully less objectionable. But please note that I wrote this section of the book in response to your charge in The Rational Optimist that “ocean acidification looks suspiciously like a back-up plan by the environmental pressure groups in case the climate fails to warm”. Do you still think this is a reasonable statement scientifically, with its implication that the undeniable lowering of oceanic pH was dreamt up by Greenpeace?
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Mark Lynas web site, 13 July 2011. Full article.
