“This is not a cheerful talk, but it’s based on the best science available,” coral reef expert John “Charlie” Veron told the Western Pacific Fishery Management Council at its June meeting in Honolulu. And while Veron’s talk stuck out like a sore thumb amidst the routine fishing effort presentations, enforcement reports, and the like, council chair Sean Martin said that Veron’s report on the effects of climate change on the world’s oceans “is one we all need to hear.”
In a nutshell, Veron said that if greenhouse gas emission trends continue as they have been, the world eventually won’t be able to function. “Things are looking very nasty for our planet,” he said.
The weather phenomenon known as El Niño offers a hint of what global warming might do to the world’s reefs. El Niño, which “packages up the heat that the earth has been collecting” and sends it to the equatorial regions, is responsible for killing half of the coral colonies on the map, he said. While corals have a tremendous capacity to recover from bleaching, which can result from increased ocean temperatures, they can only do so when all other factors are relatively normal, he said.
In most climate change scenarios, corals will have to deal with ocean acidification, which occurs when carbon dioxide in the air is absorbed by the ocean at a rate faster than the ocean can assimilate it. Veron said that because carbon dioxide is more soluble in cold water, acidification is starting in the polar areas and is moving towards the equator. In a highly acidic ocean environment, any organism that uses calcium carbonate suffers, be it coral, fish, or tiny copepods. Already, Veron said, acidification is affecting plankton in the southern ocean.
In a highly acidic environment, bleached reefs will not likely recover. Veron presented a photo of a blackened, degraded reef at Papua New Guinea, which he said is what the world’s reefs will look like in an acidic environment. Almost nothing lives there, he said, adding that the reef is dominated by slime.
“By mid-century, if we carry on business as usual, all reefs will look more or less like this,” he said. The destruction of fish habitat is a big deal, he told the council, but is by far not the only thing. The physiology, reproduction cycles, and the distribution of all other marine life will also be affected, he said.
What’s more, he added, “The lack of coral reefs is only the tip of the iceberg. If we create an environment where we destroy coral reefs, it will destroy everything else.”
In an article titled “Climate Change Impacts on Marine Ecosystems,” he writes, “I cannot escape the conclusion that ocean acidification has played a major role in all five mass extinctions of the past. A particularly disturbing aspect of all this is that, following all mass extinctions, living reefs completely disappeared. Not just for thousands of years, but for millions.”
Despite the dour outlook, Veron ended his talk on a positive note, stating that although the world has only a decade to turn things around, “Humans can move very quickly if the motivation is there. We just have to declare the war.”
According to a biography distributed at the meeting, Veron has discovered and described 20 percent of all coral species of the world and is former chief scientist of the Australian Institute of Marine Science. He now heads his own organization, Coral Reef Research, and his latest book, A Reef in Time: The Great Barrier Reef from Beginning to End, “presents the case that if humanity continues to produce carbon dioxide at present rates for another decade, the coral reefs will be committed to wholesale destruction and the initiation of the sixth mass extinction,” the bio states.
— Teresa Dawson
Volume 18, Number 10 April 2008
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