Saturday, June 7, 2008

Scientist's oceanic plea warns of imminent reef eulogy

A healthy Barrier Reef (left) and one showing the effects of coral bleaching (right). The impact of ocean acidification is predicted to be far worse. Photo: Great Barrier Reef Marine Park A
  • Jo Chandler
  • The Age, June 7, 2008

JOHN Veron's fascination with the natural world saw him renamed Charlie, for Charles Darwin, as a kid, when he kept a blue-ringed octopus as a pet and his playground was in the shallows of the Sydney shoreline.

He came of age as the technology of scuba allowed entry to the underwater world. His first dive was at 18, plunging alone and untrained off Heron Island and on to the Great Barrier Reef, where the intensity of life made the surface world seem suddenly pale. In the 45 years since, he has barely come up for air.

He's logged 7000 hours diving all the major reefs of the world, discovering almost a quarter of the oceans' identified coral species and compiling a catalogue of books including the three-volume Corals of the World.

His latest book is different. A Reef in Time: The Great Barrier Reef from Beginning to End — a finalist in the UN Environment Awards presented in Melbourne last night — is not a chronicle of the life of coral reefs, but an anticipation of their death.

It is a work grounded in science, but which departed from the careful jargon of probability and possibility to become an impassioned, anguished eulogy delivered by a dear friend of the imminently deceased.

Australia's Great Barrier Reef, more than 25 million years in the making, is "an icon primordial wilderness", says Dr Veron — it is the greatest structure created by life on earth. The idea that it might be mortally threatened within the span of a generation or two he would once have considered preposterous.

"I was wrong," he says.

Twin assailants, both creatures of climate change, threaten the reef and oceans more generally. The lesser of these is the warming of the water, which turns the single-celled algae on which corals rely for their sustenance toxic, compelling the coral to expel them and probably die — the event known as coral bleaching — or to keep them and certainly die.

The worst bleaching events of history will become commonplace by 2030, says Dr Veron, and by 2050, "the only corals left alive will be those in refuges on deep outer slopes of reefs. The rest will be unrecognisable — a bacterial slime, devoid of life."

The even greater threat is ocean acidification — the dissolving of carbon dioxide into the sea, forming weak carbonic acid. This is the climate change frontier to which science is swinging increasing focus, as alarm grows at the threat it poses to marine ecosystems and to human food supplies and economies.

As human industry has pumped increasing levels of carbon dioxide into the atmosphere, reaching its highest level in the lifetime of the Great Barrier Reef, the oceans have worked to pull it into the depths, absorbing and neutralising it as it cycles through shallow and deep layers.

But as the ocean's appetite for carbon dioxide is exceeded, the chemistry changes. The acid levels create conditions where the capacity of marine creatures to produce their calcium carbonate skeletons is threatened. "The consequences are nothing less than catastrophic," he says.

His book travels back through the fossil record to the remote past, reflecting on the five great extinction events that wiped out much of life on earth and finding a thread of commonality.

"Coral reefs were hit hard by all five of them, because they are so closely linked to the carbon cycle. In the past it was not human activity but volcanic outpourings that pushed up the atmospheric carbon dioxide — and to levels way beyond those that exist now," says Dr Veron.

The crucial difference between those events and what scientists see happening now is time. Those historic events stretched over geological and evolutionary time frames of millions of years, not decades. Life, eventually, evolved solutions.

"We're in strife now because of the speed of the increasing carbon dioxide — not the amount, not yet," he says. If it continues, "the sixth mass extinction will be upon us, it will be of our own making, and it will be unstoppable by any means whatsoever," he says.

"The production of greenhouse gasses must be curbed dramatically and urgently if we are to have any chance of avoiding another coral reef-led marine extinction."

Dr Veron's visit to Melbourne this week coincides with the end of a workshop of 55 scientists in Hobart on emerging findings on ocean acidification, ahead of the launch next week of a new body — the European Project on Ocean Acidification# — to investigate, predict and advise governments of its consequences. Tomorrow is World Ocean Day.

A Reef in Time, by J. E. N. Veron, is published by Harvard University Press.

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