The Blue Planet movie: RIGHT ON PLASTICS AND PCBS, WRONG ON ACIDIFICATION

Matt Ridley

The climate change obsession is still sometimes getting in the way of telling the truth. The most dishonest sequence in the series was when Attenborough watched shells dissolving in a tank of acid, to a soundtrack of fizzing noises, and was told by Professor Chris Langdon that although this was “more dramatic than what’s happening in the oceans”, nonetheless “the shells and the reefs are really truly dissolving”.

This is highly misleading in several different ways. Was it carbonic acid, or another acid? The reduction in alkalinity will get nowhere near neutral, let alone actual acidity, even by the end of the 22nd century, so “dissolving” is false, let alone happening now. The changes in ocean pH expected even by the end of this century are minuscule compared with what was shown in that tank, and by comparison with the daily and seasonal changes that an average reef experiences. (Coral bleaching, a different issue, is more serious, but more temporary.)

A 2010 analysis of 372 studies of 44 different marine species found that the world’s marine fauna is “more resistant to ocean acidification than suggested by pessimistic predictions” and that it “may not be the widespread problem conjured into the 21st century”:

"Ocean acidification has been proposed to pose a major threat for marine organisms, particularly shell-forming and calcifying organisms. Here we show, on the basis of meta-analysis of available experimental assessments, differences in organism responses to elevated pCO2 and propose that marine biota may be more resistant to ocean acidification than expected.

Calcification is most sensitive to ocean acidification while it is questionable if marine functional diversity is impacted significantly along the ranges of acidification predicted for the 21st century. Active biological processes and small-scale temporal and spatial variability in ocean pH may render marine biota far more resistant to ocean acidification than hitherto believed."

And recent work has established that corals’ ability to make skeletons is “largely independent of changes in seawater carbonate chemistry, and hence ocean acidification...the relevance of their commonly reported finding of reduced coral calcification with reduced seawater pH must now be questioned”. Indeed, one study found that calcifying plankton “respond positively to acidification with CO2enrichment”,

"As a result, cell growth and cellular calcification of E. huxleyi were strongly damaged by acidification by HCl, but not by acidification by CO2 enrichment...The present study clearly showed that the coccolithophore, E. huxleyi, has an ability to respond positively to acidification with CO2 enrichment, but not just acidification."

another that the growth rate of corals also increases with higher carbon dioxide up to 600 parts per mllion and concluded:

"Furthermore, the warming projected by the Intergovernmental Panel on Climate Change for the end of the twenty-first century caused a fivefold decrease in the rate of coral calcification, while the acidification projected for the same interval had no statistically significant impact on the calcification rate—suggesting that ocean warming poses a more immediate threat than acidification for this important coral species."

The producers of Blue Planet II claim every word of the commentary was based on solid scientific evidence. Not in this case. In a magnificent series, they got that one wrong.

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