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Carbon emissions threaten sea life

Marine life such as coral is threatened by rising levels of acidity in seawater.


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Science and Technology
Global Change

(CNN) -- Excessive carbon in the atmosphere is already causing irreparable environmental damage to the Earth's oceans and drastic cuts in emissions are necessary to prevent further devastation, a panel of leading scientists has warned.

A report by the Royal Society, the UK's leading scientific academy, said that rising carbon levels caused by the burning of fossil fuels had dramatically increased the acidity of seawater, threatening the oceans' ecosystems.

Sea creatures such as coral, shell fish and star fish are likely to suffer because higher levels of acidity will make it harder for them to form shells and skeletons.

The report predicts that some types of plankton, a major food source for marine life, may be unable to make their calcium carbonate shells by the end of the 21st century.

Larger marine animals such as squid could face extinction as they find it harder to extract oxygen from sea water and their food supplies dwindle.

Combined with the effects of climate change, ocean acidification also poses a threat to tropical and subtropical reefs such as Australia's Great Barrier Reef and the hundreds of thousands of species that live off them, as well as to the human communities that depend on reefs for food and as natural coastal defenses.

"Along with climate change, the rising acidity of our oceans is yet another reason for us to be concerned about the carbon dioxide we are pumping into the atmosphere," said Professor John Raven, chair of the Royal Society working group on ocean acidification.

"World leaders ... must commit to taking decisive and significant action to cut carbon dioxide emissions. Failure to do so may mean that there is no place in the oceans of the future for many of the species and ecosystems that we know today."

Raven said that the burning of fossil fuels over the past two centuries had changed the chemistry of the oceans at a rate that was 100 times faster than had happened for millions of years.

Those changes could also contribute directly to global warming if the carbon-saturated oceans reach a point when they can no longer soak up any further emissions from the atmosphere.

In the past two centuries the oceans have absorbed around half of all carbon produced by humans, soaking up one ton for each person on the planet each year.

"The oceans play a vital role in the earth's climate and other natural systems which are all interconnected. By blindly meddling with one part of this complex mechanism, we run the risk of unwittingly triggering far reaching effects," said Raven.

While the report said that rising levels of ocean acidity are irreversible in current lifetimes, it warned that urgent action was needed to reduce levels of carbon in the atmosphere and called for further research into the consequences of ocean acidification.

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