Ocean acidity has reached critical levels and the impacts could be far worse than we thought
Ocean acidity is one of the key markers of Earth’s health, because if it tips too far towards acidic then the results can be catastrophic – and a new study suggests the world’s waters are now entering this danger zone.
A team of scientists from the US and UK looked at what’s known as the planetary boundary for ocean acidification, defined as a 20 percent drop in average surface aragonite saturation – that’s the calcium carbonate material that many marine organisms use for shells and skeletons.
Combining computer models with the latest field measurements, the researchers found that globally, the oceans were either very close to or beyond the boundary. Around 60 percent of deeper waters have gone beyond it, and 40 percent of surface waters.
Given the damage already recorded, the team suggests the boundary should actually be set at a 10 percent drop in aragonite saturation – a level the ocean as a whole went past at the turn of the millennium. [Continue reading…]