Ocean heading for mass extinction, scientists warn

Impending doom: the report says without swift action the fight to save species could be lost.
(Supplied : Linda Cash )

By Sarah Dingle

Scientists are warning of a potential marine massacre with a mass extinction of sea life akin to the death of the dinosaurs.

A new report says the seas are battling pollutants, overfishing and warming, and warns that without swift action the fight to save species could be lost.
The International Program on the State of the Oceans report brought together coral reef ecologists, toxicologists and fisheries scientists.
And when they compared notes, the result was grim.
Co-author Professor Ove Hoegh Guldberg, who specialises in reef ecosystems, says scientists found "unprecedented warming".
"We're seeing acidification in the ocean and now we're starting to see a drop in oxygen concentration throughout the major part of the ocean," he said.
"Now it's impacting directly on sea life, but the other is that it is a potential early step towards conditions which are associated with so-called mass extinction events."
Professor Guldberg does not want to be alarmist, but says a growing human population is to blame for many of the changes.
He warns the pressure will only increase, with the world's population set to grow by another 3 billion people in the next 30 to 50 years.
"As human populations have expanded in coastal areas - and it's really boomed throughout the world - you've had the modification of coastlines by the very fact that by destabilising vegetation you get nutrients and sediments going out in those coastal waters," he said.
"That's had a tremendously damaging effect in our neighbourhood. In South-East Asia for example, the entire loss of marine ecosystems that used to be there and used to support people."
Dr Alex Rogers is the scientific director of the International Program on the State of the Oceans and a professor of conservation biology at Oxford University.
He says when he got together with his colleagues they realised changes in ocean temperatures were occurring much faster than they had expected.
"The changes that people had been predicting would happen in the lifetime of our children, or our children's children, are happening really now before our eyes," he said.

Dead zones

Professor Guldberg says concerns about marine environments often take a back seat both in public debate and scientific research.
"They did a study last year where I counted the number of peer-reviewed papers on climate change on the land versus the sea and there were 20 more papers, 20 times as many papers, associated with problems on land versus the sea," he said.
He says the sea provides up to a quarter of the world's protein and is concerned about the proliferation of dead zones if nothing is done.
Dead zones are areas where oxygen levels in the water drop to zero, a condition known as anoxia.
He says in these conditions only certain species survive.
"It won't be fish that we like to eat. There are animals and plants - well in fact I shouldn't say animals but more plants and bacteria, green slime, that will prosper in the anoxic environment," he said.
Professor Guldberg says the ocean is the life support system for the planet's atmosphere and if uncontrolled degradation continues, the threat of mass extinction is real and does not just apply to the sea.
"If we barrel along as we are right now, there's an increasing risk that we will be entering into one of these mass extinction events," he said.
"This is where you essentially get a runaway set of conditions which will be very unsustainable as far as human or any other life that we have on the planet today."
"This comes back to the fact that the ocean is central to the climate and conditions across the entire planet."
Professor Guldberg says to control the pace of change the world must move to zero emissions within the next 40 years.
The report's findings will be presented at the United Nations headquarters in New York this week.