Ocean acidification is set to cost us $1 trillion by 2100 as it eats away at our tropical coral reefs.
That’s the warning from a report released today by the United Nations Convention on Biological Diversity, which assesses the economic impacts the problem could have.
The ocean’s pH is now 8.0, down from 8.1 in the mid-18th century. Because the pH scale is logarithmic, this change means that, over the past 250 years, the world’s oceans have seen a 26 per cent increase in acidity – a result of the oceans absorbing about a quarter of our carbon dioxide emissions.
With ocean pH projected to dip to 7.9 by the end of the century, the oceans may soon be 170 per cent more acidic than they were before the industrial revolution – a change that is likely to affect not just our ecosystems, but our economies too.
Ocean acidification is a trend that went largely unnoticed until a decade ago, but the rapid pace of scientific investigation since means huge progress has been made in understanding its effects.
“It’s really challenging staying on top of the subject it’s growing so rapidly,” says Murray Roberts at Heriot-Watt University in Edinburgh, UK, who co-edited the report.
We know that acidification will be bad for marine organisms because past increases in acidity led to mass extinctions – particularly of those with hard calcium carbonate shells.
Coral reefs are particularly at risk. Acidification reduces the concentration of carbonate ions in the upper layers of the ocean, and when carbonate levels get too low, the calcium carbonate skeletons of the corals themselves will start to dissolve.
But simply pointing out that marine biodiversity will suffer may not be enough to encourage governments to take action, which is why some researchers have begun to put a price on the problem.
“If you’re coming at ocean acidification as someone in government and you need to decide between investing here or elsewhere, you need something compelling to help you understand why this is important,” says Roberts.
The report argues that the loss of tropical coral reefs to acidification could cost $1 trillion by 2100 in terms of lost shoreline protection and lost revenues for the tourism and food industries. Cold, deep-water reefs, meanwhile, are home to marine organisms that produce potent molecules that might inspire new anti-cancer therapies.
Such findings might be enough to encourage governments to continue to fund studies into the effects that lower ocean pH will bring – but no amount of research will reduce the problem. That can only come from efforts to reduce our carbon dioxide emissions, says Roberts.
“Ecosystems that have thrived and developed over millions of years are being smashed down by human activities in just a few decades,” says Caldeira. “It is a very sad state of affairs that hopefully we can turn around before it is too late.”
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