Ocean Ecosystems Face 'Ticking Bomb' as Seawater Acidity Passes Critical Level

The world's oceans are in worse health than previously realised, scientists have warned, with a key measurement showing that we are "running out of time" to protect marine ecosystems.

- Lisa Bachelor

Ocean acidification occurs when carbon dioxide is rapidly absorbed by the ocean, where it reacts with seawater to make it more acidic. The phenomenon damages coral reefs and other ocean habitats and, in extreme cases, can dissolve the shells of marine creatures.

Until now, ocean acidification has not been deemed to have crossed its "planetary boundary" beyond which the ability to maintain a healthy planet is in danger of failing.

The planetary boundaries are the natural limits of global systems such as climate, water and wildlife diversity; six of the nine had been crossed already, scientists said last year.

However, a new study by the UK's Plymouth Marine Laboratory (PML), the Washington-based National Oceanic and Atmospheric Administration, and Oregon State University's Co-operative Institute for Marine Resources Studies found that ocean acidification's "boundary" was also reached about five years ago.