The world's coral reefs are in danger of dying in the next 20 years unless the world drastically cuts carbon emissions, a coalition of scientists led by Sir David Attenborough has warned.
Louise Gray, The Telegraph 7 Jul 09;
The delicate eco systems, known as the "rainforests of the sea", support huge amounts of marine life.
But as oceans absorb carbon dioxide, they become more acidic, making it impossible for coral reefs like the Great Barrier Reef in Australia to survive. Reefs are also at greater danger of bleaching as sea temperatures warm.
Scientists gathered at the Royal Society in London yesterday to call for tougher targets for the world to cut emissions.
Sir David Attenborough, who co-chaired the meeting, said that the collapse of coral reefs meant the death of marine ecosystems.
"We must do all that is necessary to protect the key components of the life of our planet as the consequences of decisions made now will likely be forever as far as humanity is concerned," he said.
Open water absorbs around a third of the carbon dioxide in the air. At present, the concentration of carbon dioxide in the atmosphere is 387 parts per million (ppm).
According to Alex Rogers, the scientific director of the International Programme on the State of the Oceans, the figure will reach 450 ppm in the next 20 years if the world continues to burn fossil fuels at the current rate. Once that figure is reached, the ocean will become too acidic for corals to survive.
"The kitchen is on fire and it's spreading round the house. If we act quickly and decisively we may be able to put it out before the damage becomes irreversible. That is where corals are now," he said.
Coral reefs are living organisms that rely on calcium minerals called aragonite in the water to build and maintain their external skeletons.
But when the oceans absorb carbon dioxide, it mixes with the seawater to make carbonic acid, upsetting their and reducing aragonite levels needed by corals.
Mr Rogers said that once carbon dioxide levels in the atmosphere reach the 600 ppm mark, other organisms like plankton and sea snails will start to die and whole marine ecosystems could collapse.
"Five hundred million people are dependent on coral reefs for livelihoods, food and culture," he added. "The economic implications of the loss of coral reefs are absolutely huge."
Alongside other scientists from the Royal Society and Zoological Society of London, Mr Rogers is calling for world leaders to agree much tougher targets to cut emissions as part of any climate change deal decided in Copenhagen at the end of this year.
"Essentially coral reefs are on death row and Copenhagen is one of the last opportunities for a reprieve," he said. "Because if we carry on business as usual collapse is inevitable whereas if we decide to do something about it we can make a difference to the current trajectory."
Great Barrier Reef will be gone in 20 years, says Charlie Veron
Frank Pope, Times Online 6 Jul 09;
The Great Barrier Reef will be so degraded by warming waters that it will be unrecognisable within 20 years, an eminent marine scientist has said.
Charlie Veron, former chief scientist of the Australian Institute of Marine Science, told The Times: “There is no way out, no loopholes. The Great Barrier Reef will be over within 20 years or so.”
Once carbon dioxide had hit the levels predicted for between 2030 and 2060, all coral reefs were doomed to extinction, he said. “They would be the world’s first global ecosystem to collapse. I have the backing of every coral reef scientist, every research organisation. I’ve spoken to them all. This is critical. This is reality.”
Dr Veron’s comments came as the Institute of Zoology, the Royal Society and the International Programme on the State of the Ocean (IPSO) held a crucial meeting on the future of coral reefs in London yesterday. In a joint statement they warned that by mid-century extinctions of coral reefs around the world would be inevitable.
Warming water causes coral polyps to eject the symbiotic algae that provide them with nutrients. These “bleaching events” were widespread during the El Niño of 1997-98, and localised occurrences are becoming more frequent. (During an El Niño, much of the tropical Pacific becomes unusually warm.) Reefs take decades to recover but by 2030 to 2050, depending on emissions and feedback effects, bleaching will be occurring annually or biannually.
Although surface sea temperatures are rising fastest in tropical regions the other big threat to coral reefs comes from the higher latitudes. The cold water there absorbs atmospheric carbon dioxide more readily than warm water and acidifies more easily.
When carbon dioxide concentrations reach between 480 and 500 parts per million warm water is no barrier to acidification, and the pH in equatorial regions will have dropped so far, meaning higher acidity, that coral reef growth becomes impossible anywhere in the ocean.
“Coral reefs are the most sensitive of marine ecosystems,” said Alex Rogers, scientific director of IPSO.
“Increased temperature and decreased pH will have a double-whammy effect. Reefs were safe at CO2 levels of 350 parts per million. We are at 387ppm today. Beyond 450 the fate of corals is sealed.”
In the five mass extinction events in geological history, key was the carbon cycle, in which carbon dioxide is the primary currency. Its concentration in the atmosphere is higher than it has been for 20 million years. In the Permian extinction, as in all the big extinctions, tropical marine life was the hardest hit. Reef-building corals took more than ten million years to return.
The Great Barrier Reef, the world’s largest and most diverse marine ecosystem, is worth $4.5 billion (£2.8 billion) a year to Australia. Worldwide, reefs are worth $300 billion. “But that is trivial compared with the costs if coral reefs fail,” Dr Veron said. “Then it won’t be a matter of no income, it will be a matter of damage to livelihoods, economies and ecosystems.”
Yesterday’s meeting renewed calls for networks of marine conservation zones to boost the resilience of reefs.
Scientists warn carbon dioxide may soon make coral reefs extinct
Alok Jha, guardian.co.uk 6 Jul 09;
David Attenborough joined scientists today to warn that carbon dioxide in the atmosphere is already above the level which condemns coral reefs to extinction, with catastrophic effects for the oceans and the people who depend upon them.
Coral reefs support a quarter of all marine life, including more than 4,000 species of fish. They also provide spawning, nursery, refuge and feeding areas for creatures such as lobsters, crabs, starfish and sea turtles.
This makes them crucial in supporting a healthy marine ecosystem upon which more than a billion people depend for food. Reefs also play a crucial role as natural breakwaters, protecting coastlines from storms.
Attenborough said the world had a "moral responsibility" to save corals. The naturalist was speaking at the Royal Society in London, following a meeting of marine biologists.
"A coral reef is the canary in the cage as far as the oceans are concerned," said Attenborough. "They are the places where the damage is most easily and quickly seen. It is more difficult for us to see what is happening in, for example, the deep ocean or the central expanses of ocean."
Global warming means warmer seas, which causes the corals to bleach, where the creatures lose the symbiotic algae they need to survive. Carbon dioxide also makes seas more acidic, which means the corals find it difficult to prevent their exoskeletons from dissolving.
"We've already passed a safe threshold for coral reef ecosystems in terms of climate change; we believe that a safe level for CO2 is below 350 parts per million," said Alex Rogers of the Zoological Society of London and International Programme on the State of the Ocean, who helped organise today's meeting.
Carbon dioxide in the atmosphere has risen from 280ppm before the industrial revolution to around 387ppm today. Environmentalists say that any new global deal on climate must restrict the growth of CO2 levels to 450ppm, though more pessimistic scientists say that the world is heading for 550ppm or even 650ppm.
"When we get up to and above 450ppm, that really means we're into the realms of catastrophic destruction of coral reefs and we'll be moving into a planetary-wide global extinction," said Rogers.
"The only way to get to 350ppm or below is not only to have major cuts in CO2 emissions but also to draw CO2 out of the atmosphere through measures such as geo-engineering."
Coral Reefs Exposed To Imminent Destruction From Climate Change
ScienceDaily 6 Jul 09;
Coral reef survival is balancing on a knife edge as the combined effects of ocean acidification and ocean warming events threaten to push reefs to the brink of extinction this century, warned a meeting of leading scientists.
Organised by ZSL, the International Programme on the State of the Ocean (IPSO) and the Royal Society, the meeting identified the level of atmospheric CO2 predicted to result in the demise of coral reefs.
At anticipated rates of emission increase, it is expected that 450 ppm CO2 will be reached before 2050. At that point, corals may be on a path to extinction within a matter of decades.
By 2050, the remaining coral reefs could fall victim to ocean acidification. Such a catastrophe would not be confined to reefs, but could start of a domino-like sequence of the fall of other marine ecosystems.
Sir David Attenborough who co-chaired the meeting said “We must do all that is necessary to protect the key components of the life of our planet as the consequences of decisions made now will likely be forever as far as humanity is concerned”.
Scientific evidence shows that we have long passed the point at which the marine environment offers reefs a guaranteed future.
“The kitchen is on fire and it’s spreading round the house. If we act quickly and decisively we may be able to put it out before the damage becomes irreversible. That is where corals are now.” said Dr Alex Rogers of ZSL and IPSO.
The meeting was held to identify tipping points for corals and to expose the issues raised by the plight of coral reefs. A statement detailing these concerns will be submitted to the UN FCCC process currently underway.
Until now, world leaders negotiating emissions reductions have not taken the ocean into serious account, but with so much at risk, the oceans can no longer be ignored.
Now, there is every reason to believe that the oceans may in fact be the most vulnerable sector of our planet to climate change – with dire consequences for us all.
Adapted from materials provided by Zoological Society of London (ZSL).
Reefs could perish by end of century, experts warn
Michael Kahn, Reuters 7 Jul 09;
LONDON (Reuters) - Increasingly acidic oceans and warming water temperatures due to carbon dioxide emissions could kill off the world's ocean reefs by the end of this century, scientists warned on Monday.
The experts told a meeting in London the predicted pace of emissions means a level of 450 parts per million of carbon dioxide (CO2) in the atmosphere will be reached by 2050, putting corals on a path to extinction in the following decades.
The two dozen coral reef specialists and climate change exerts represented universities, government research offices and the Intergovernmental Panel on Climate Change.
"The kitchen is on fire and it's spreading around the house," Alex Rogers of the Zoological Society of London and the International Program on the State of the Ocean, said in a statement.
"If we act quickly and decisively we may be able to put it out before the damage becomes irreversible."
Oceans absorb large amounts of CO2 emitted by the burning of fossil fuels. But scientists say the oceans are acidifying as they absorb more carbon, disrupting the process of calcification used by sea creatures to build shells as well as coral reefs.
Researchers around the world have been urging governments to take more account of such threats to the oceans in a new U.N. treaty on fighting global warming due to be agreed in Copenhagen in December.
Coral reefs -- delicate undersea structures resembling rocky gardens made by tiny animals called coral polyps -- are important nurseries and shelters for fish and other sea life.
They also protect coastlines, provide a critical source of food for millions of people, attract tourists and are potential storehouse of medicines for cancer and other diseases.
PATH TO MAJOR DEGRADATION
"If CO2 is allowed to reach 450 ppm, as is currently widely regarded as being the most optimistic threshold target for world leaders to agree at Copenhagen, we will have put the world's reefs on a path to major degradation and ultimate extinction," John Veron, the former chief scientist of the Australian Institute of Marine Science, told the meeting.
"Such a catastrophe poses a dire threat to the future wellbeing of all humanity."
The scientists agreed that governments should strive for a level of 320 parts per million of carbon dioxide, saying 360 was a breaking point for reefs to survive.
At the current level of 387 parts per million of carbon dioxide, reefs are in serious decline, they said. This will have a future knock-effect that threatens other marine and coastal ecosystems.
Coral covers about 400,000 square km of tropical ocean floor, but needs sustained sunlight, warmer waters and high levels of carbonate to flourish.
The biggest is the Great Barrier Reef, a collection of 2,900 reefs along 2,100 km of Australia's north east coast in a marine park the size of Germany.
(Reporting by Michael Kahn; editing by Anthony Barker)
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