BBC: 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...