14 Nov 2013

Acidity levels soar in world's oceans - study

5:00 pm on 14 November 2013

A new report says the world's oceans are becoming more acidic at an unprecedented rate.

Scientists from the International Biosphere-Geosphere programme say they are confident that human emissions of carbon dioxide are to blame, and that acidification could increase by 170% by 2100.

They say that some 30% of ocean species are unlikely to survive in these conditions.

The researchers conclude that human emissions of CO2 are clearly to blame.

The study will be presented at global climate talks in Poland next week, and will state with that increasing acidification is caused by human activities which are adding 24 million tonnes of CO2 to oceans ever day, the BBC reports.

The addition of so much carbon has altered the chemistry of the waters.

Since the start of the industrial revolution, the waters have become 26% more acidic.

End of molluscs

Professor Jean-Pierre Gattuso, from CNRS, the French national research agency says that studies carried out at deep sea vents where the waters are naturally acidic indicate that around 30% of the ocean's biodiversity may be lost by the end of this century.

"You don't find a mollusc at the pH level expected for 2100, this is really quite a stunning fact."

The effect of acidity is currently being felt most profoundly felt in the cold Arctic and Antarctic oceans, which hold more carbon dioxide and are turning acidic more rapidly than the rest of the world.

"In the Southern Ocean, we already see corrosion of pteropods which are like sea snails, in the ocean we see corrosion of the shell.

"They are a key component in the food chain, they are eaten by fish, birds and whales, so if one element is going then there is a cascading impact on the whole food chain."

The authors warn that the economic impact of the losses from aquaculture could be huge - the global cost of the decline in molluscs could be $US130 billion by 2100 if emissions of carbon dioxide continue on their current pathway.