Ocean life is "at high risk of entering a phase of extinction of marine species unprecedented in human history" according to a panel of scientists' new report .The ocean is in an extremely dangerous state and they say there is deadly combination of over-fishing, climate change and pollution that form a toxic cocktail that is and will further affect the human population.
And the impacts 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.
Alex Rogers, IPSO's scientific director and professor of conservation biology at Oxford University. says "the findings are shocking"
"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 the Greenland and Antarctic ice sheets, sea level rise, and release of methane trapped in the sea bed.
"The rate of change is vastly exceeding what we were expecting even a couple of years ago," said Ove Hoegh-Guldberg, a coral specialist from the University of Queensland in Australia.
"So if you look at almost everything, whether it's fisheries in temperate zones or coral reefs or Arctic sea ice, all of this is undergoing changes, but at a much faster rate than we had thought."
But more worrying than this, the team noted, are the ways in which different issues act synergistically to increase threats to marine life.
This increases the amounts of these pollutants that are consumed by bottom-feeding fish.
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.
The IPSO report concludes that it is too early to say definitively.
But the trends are such that it is likely to happen, they say - and far faster than any of the previous five.
Levels of CO2 being absorbed by the oceans are already far greater than during the great extinction of marine species 55 million years ago, it concludes.
IPSO's immediate recommendations include:
- stopping exploitative fishing now, with special emphasis on the high seas where currently there is little effective regulation
- mapping and then reducing the input of pollutants including plastics, agricultural fertilisers and human waste
- making sharp reductions in greenhouse gas emissions.
Carbon dioxide levels are now so high, it says, that ways of pulling the gas out of the atmosphere need to be researched urgently - but not using techniques, such as iron fertilisation, that lead to more CO2 entering the oceans.
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