PARIS: Ocean acidification has risen by a quarter since pre-industrial times as a result of rising carbon emissions, casting a shadow over the seas as a future source of food, scientists warned on Wednesday.

In the past two centuries, the sea's acidity level has risen 26 percent, mirroring the proportion of carbon dioxide it absorbs from the air, they said in a report to the UN Convention on Biological Diversity (CBD) meeting in South Korea.