Heat-resistant Corals Ignore Climate Change Threats

Doug L. Hoffman
The Resilient Earth
Thursday, May 28, 2009

Among the many catastrophes that are to befall our world due to global warming, the imminent demise of coral reefs is one of the worst. According to climate change proponents, as waters warm the ocean’s reefs will bleach out and die, leaving the seas aquatic deserts, devoid of life. Now comes news that scientists have discovered live, healthy corals on reefs already as hot as the oceans are supposed to get 100 years from now, according to IPCC predictions. Looks like the corals didn’t read the IPCC reports.

Climate catastrophists have warned that more than half of the world’s coral reefs could disappear in the next 50 years, in large part because of higher ocean temperatures caused by climate change. Supposedly, corals—tiny sea creatures that, working together, manage to build gigantic ocean reefs—are so delicate that a shift in water temperature of little more than 1 degree Celsius can cause them to whither and die. Corals create the most diverse ecosystems in the oceans: the beautiful and vibrant tropical reefs. If corals were to go extinct, the repercussions would likely affect all life on Earth.

Corals live in a symbiotic relationship with tiny, single-celled algae. It’s a partnership, with the corals provide a home for the algae and the algae provide nourishment for the corals. Rising temperatures can stress the algae, causing them to stop producing food. The corals evict the deadbeat algae, spit them out to fend for themselves. Without their algal partners, the reefs die and turn stark white, an event referred to as coral bleaching.

In a report this month in Marine Ecology Progress Series, Stanford University scientists have found evidence that some coral reefs are adapting and may actually be able to shrug off the worst of the IPCC’s predicted global warming. They discovered that some corals resist bleaching by hosting types of algae that can handle the heat, while others swap out the heat-stressed algae for tougher, heat-resistant strains.

“The most exciting thing was discovering live, healthy corals on reefs already as hot as the ocean is likely to get 100 years from now,” said Stephen Palumbi, a professor of biology and a senior fellow at Stanford’s Woods Institute for the Environment. “Corals are certainly threatened by environmental change, but this research has really sparked the notion that corals may be tougher than we thought.”

For their investigations, Palumbi and Tom Oliver, a former student, traveled to Ofu Island in American Samoa. Ofu, a tropical coral reef marine reserve, has remained healthy despite gradually warming waters. In cooler lagoons, Oliver found only a handful of corals that host heat-resistant algae exclusively. But in hotter pools, he observed a direct increase in the proportion of heat-resistant symbionts, suggesting that some corals had swapped out the heat-sensitive algae for more robust types. “These findings show that, given enough time, many corals can match hotter environments by hosting heat-resistant symbionts,” Oliver explained.

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• A d v e r t i s e m e n t

The whole matter of coral delicacy is a bit puzzling, since reef building corals have been around since at least the Permian period. All corals in the sea, particularly the familiar kinds that form reefs, have hard external skeletons. In a 2006 article in the Proceedings of the National Academy of Sciences (PNAS), a team of researchers led by Allen Collins dated the origin of stony corals to between 240 and 288 million years ago, much more closely matching the fossil record of corals than earlier estimates.

This means that corals survived the worst ever mass extinction event in the history of Earth—the Permian-Triassic Extinction, 251 million years ago—and lived through the Triassic, Jurassic and Cretaceous. During this span of nearly 200 million years, CO₂ levels were 5-10 times higher than they are now with temperatures as much as 10ºC higher than today.. After surviving the event that killed off the dinosaurs, corals have remained the ocean’s primary reef builders during the Cenozoic era, roughly the past 63 million years. Scientists should have known that any creatures who can live through all that are tough enough to put up with slight fluctuations in water temperature.

Careful scientific observation has revealed another over hyped horror story, put forth as an effect of global warming, to be inaccurate. True, many reefs do bleach and die, but others recover or strains of organism that are better adapted to altered local conditions move in. This is the way nature works. Given all the rapid temperature excursions in the past, the changing ocean temperatures and sudden influxes of fresh water from giant glacial lakes, wouldn’t you suspect that corals were a bit tougher than they seem—perhaps not as individuals but as a species or genus? While I do not believe that the IPCC’s predictions regarding global warming are accurate, it is nice to know that coral will be sticking around regardless.

Like all the other hype that surrounds global warming, the demise of the world’s coral has been greatly exaggerated. Once more the puffed-up, overwrought reports from the IPCC have been shown for what they are: committee generated collections of half truths and wild speculation buttressed by poor science and guesswork. I have never seen so many people, claiming to be scientists, so seemingly bent on destroying science’s reputation with the public. I fear we will not soon recover from this regrettable episode—and a whole generation of young people will turn their backs on science and engineering, dismissing them as the work of charlatans and frauds.

Be safe, enjoy the interglacial and, above all, stay skeptical.

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