Ocean acid: The effect of CO2 on life on the seabed
27 March 2014 Last updated at 12:05 GMT
BBC Newsnight has seen a UN report due out on Monday 31 March saying that there is conclusive proof that emissions of carbon dioxide (CO2) from modern society are turning the oceans more acidic.
It warns that a mass extinction of some species may be underway.
24 million tonnes of CO2 from industrial society is absorbed into the sea every day, turning whole oceans more acidic.
Off the remote eastern tip of Papua New Guinea naturally occurring CO2 offers a glimpse of what the future may be like for the world's oceans.
Roger Harrabin dived under the surface to see the effect.
Viewers in the UK can see more on this on Newsnight on Thursday 27 March at 2230 on BBC Two.