From an article on the sudden decline of fish in the world's oceans:
the trends are such that it is likely to happen, they say - and far faster than any of the previous five. "What we're seeing at the moment is unprecedented in the fossil record - the environmental changes are much more rapid," Professor Rogers told BBC News. "We've still got most of the world's biodiversity, but the actual rate of extinction is much higher [than in past events] - and what we face is certainly a globally significant extinction event.' The report also notes that previous mass extinction events have been associated with trends being observed now - disturbances of the carbon cycle, and acidification and hypoxia (depletion of oxygen) of seawater. Levels of CO2 being absorbed by the oceans are already far greater than during the great extinction of marine species 55 million years ago (during the Paleocene-Eocene Thermal Maximum), it concludes.
This is disconcerting to say the least. Much of the world relies on wild-caught fish from the ocean for protein.