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Comment and Earth

My dive into the blighted future of acidified oceans

Under the waves of Papua New Guinea, a vent of pure carbon dioxide showed a BBC environment analyst what an ocean choked by CO2 looks like

By Roger Harrabin

11 June 2014

I HAVE gazed into the future of the tropical oceans, and it’s not a reassuring sight.

In Papua New Guinea, the Ring of Fire has bestowed a unique gift on science – an underwater vent of pure carbon dioxide.

Normally researchers projecting the effect of rising CO2 must rely on computer models. But here they can observe it for real as the CO2 bubbles dissolve to form carbonic acid, creating on a small scale the conditions expected globally by the end of the century.

At first it is a beguiling sight through a diver’s mask. The parcels of CO2 are silvered by the sunlight as they wobble towards the surface. But then the eye wanders to the background. The reef is miserably depleted. Tough boulder corals survive, but the most spectacular branching corals and table corals that provide breeding grounds for fish are missing. Research suggests more than a third of coral species will ultimately be wiped out.

Just a few hundred metres away, an unpolluted reef acts as a scientific control. Adorned by more than 500 species of coral, it is a carnival of life and colour.

This tale of two reefs enables researchers to draw conclusions about which creatures will thrive with the shift in ocean chemistry and which will perish.

Beyond this natural laboratory the full effects of rising CO2 are still hard to predict. But we do know that the current rate of change in sea chemistry is 10 times faster than the last great acidification event caused by volcanic activity 56 million years ago – an event that appears to have contributed to serious ecological disruption.

“The current rate of change in ocean chemistry is 10 times faster than the last great acidification event”

Some major politicians are waking up to “the other CO2 problem“. US Secretary of State John Kerry will make ocean acidification a key theme of his Our Ocean conference in Washington DC next week. He is likely to offer funds for a monitoring network to track the rate of acidification.

But the proposed carbon cuts from power stations announced by President Obama won’t be enough to prevent severe acidification, even if China and other nations play their part.

The future lies beneath the waves in Papua New Guinea, if anyone cares to look.

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