Off the remote eastern tip of Papua New Guinea a natural phenomenon offers an alarming glimpse into the future of the oceans, as increasing concentrations of CO2 in the atmosphere make sea water more acidic. Streams of volcanic CO2 bubbles emerge from deep under the seabed here, like a giant jacuzzi. As the bubbles of carbon dioxide dissolve into the water, carbonic acid is formed.
The site hints at the possible fate of the world’s seas as 24 million tonnes of CO2 from industrial society is absorbed every day into the sea. Humans are turning whole oceans more acidic. We’re changing ocean chemistry faster than it’s changed for tens – maybe hundreds – of millions of years.
A draft UN report also warns that mass extinctions happened in the past, when CO2 levels changed more slowly than they are changing now. “The changes we’re making are irreversible for tens of thousands of years,” Fabricius tells me as the sun sets over the dugout canoes heading home after a day’s fishing. “We can protect reefs from over-fishing and local pollution if there’s a will. But with the atmosphere and oceans it’s completely different – there’s nothing to remove the effects of CO2 from the system. It’s terrible.”