An ecological catastrophe in acidified seas

Carbon emissions are acidifying oceans at a faster rate than at any time in the past 300 million years, raising the prospect of ecological catastrophe in decades to come, say scientists.

When seawater becomes too acid, corals and shrimp-like plankton at the bottom of the food chain cannot survive. The knock-on effects can lead to widespread mass extinction of marine species – and is believed to have done in the past.

In the last 100 years atmospheric carbon dioxide has risen to about 30 per cent above pre-industrial levels. At the same time, oceans have becoming increasingly acidic – and the Intergovernmental Panel on Climate Change is predicting this trend will continue.

Writing in the journal Science, researchers said the last time ocean acidity increased in a similar fashion 56 million years ago, it dramatically changed the ecological landscape.

Today, the oceans are acidifying at a rate at least 10 times faster than occurred then, but it may take decades before the effects on marine life show themselves.