Recent reports that ocean acidification is proceeding at worrying pace, particularly in Arctic waters, have led some environmental optimists to question the severity of the problem.
Book author and blogger Matt Ridley, for example, argued in a 4 November opinion piece in the Times that ocean acidification may not be much of an issue.
“Study after study keeps finding that, far from depressing growth rates of marine organisms, higher but realistic levels of carbon dioxide either do not affect them or increase their growth,” he wrote, citing a recent meta-analysis of 372 relevant papers. Funds for ocean acidification research were better spent on efforts to counter what Ridley thinks are greater threats to marine ecosystems, namely overfishing and nutrient runoff.
Scientists with the UK Ocean Acidification Research Programme (UKOARP) have now released a detailed and well-balanced response. The briefing agrees that scientists should not overstate the threats of ocean acidification but makes clear that strong evidence does exist for severely negative impacts on a variety of marine species.
“Matt Ridley’s Opinion article is correct in identifying that there are uncertainties and some contradictory evidence regarding biological responses to future ocean acidification. However, for several aspects the article over-simplifies complex issues, or is inaccurate, or is potentially misleading,” UKOARP’s science coordinator Phil Williamson writes on behalf of the group.
“Ridley’s conclusion that ocean acidification will either be beneficial or have no overall biological effect is an invalid interpretation of the evidence. Whilst changes in ocean carbon dioxide, pH and carbonate chemistry will undoubtedly result in winners as well as losers, the calculation of an average response is scientifically flawed. That is because positive and negative impacts do not cancel out, but both contribute to ecosystem perturbation.”
The briefing than goes on to discuss point by point the arguments Ridley brought up to support his buoyant views. It concludes that while ocean acidification impacts may indeed not be quite as wide-spread as some dramatically pessimistic scenarios suggest, there are way too many uncertainties and unknowns to support any confidently optimistic scenarios either.
“It would seem premature to either attempt any ranking of relative threat (e.g. compared to over-fishing and nutrient runoff) or to dismiss ocean acidification as unimportant, based on what would seem to be an incomplete and possibly biased assessment of existing information.”