The oceans are in a worse state than previously suspected, according to an expert panel of scientists.
In a new report, they warn that ocean life is “at high risk of entering a phase of extinction of marine species unprecedented in human history”.
They conclude that issues such as over-fishing, pollution and climate change are acting together in ways that have not previously been recognised.
The impacts, they say, are already affecting humanity.
The panel was convened by the International Programme on the State of the Ocean (IPSO), and brought together experts from different disciplines, including coral reef ecologists, toxicologists, and fisheries scientists.
Its report will be formally released later this week.
“The findings are shocking,” said Alex Rogers, IPSO’s scientific director and professor of conservation biology at Oxford University.
“As we considered the cumulative effect of what humankind does to the oceans, the implications became far worse than we had individually realised”.
“We’ve sat in one forum and spoken to each other about what we’re seeing, and we’ve ended up with a picture showing that almost right across the board we’re seeing changes that are happening faster than we’d thought, or in ways that we didn’t expect to see for hundreds of years.”
These “accelerated” changes include melting of Arctic sea ice and the Greenland and Antarctic ice sheets, sea level rise, and release of methane trapped in the sea bed
But more worrying than this, the team noted, are the ways in which different issues act synergistically to increase threats to marine life.
Plastic particles also assist the transport of algae from place to place, increasing the occurrence of toxic algal blooms – which are also caused by the influx of nutrient-rich pollution from agricultural land.
In a wider sense, ocean acidification, warming, local pollution and overfishing are acting together to increase the threat to coral reefs – so much so that three-quarters of the world’s reefs are at risk of severe decline.
Life on Earth has gone through five “mass extinction events” caused by events such as asteroid impacts; and it is often said that humanity’s combined impact is causing a sixth such event.
And a third of the living creatures in the sea died, and a third of the ships were destroyed.