Speaker warns of climate risk

Most predictions of global warming and resulting sea-level rise are underestimates, the keynote speaker at the Hawaii Conservation Conference said yesterday.

Based on prehistoric records, when Earth averaged just 2 degrees Fahrenheit warmer on average than it is now, sea levels were 24 to 27 feet higher, said Thomas Goreau, president of the Global Coral Reef Alliance.

And that was before humans started burning fossil fuels, he told 800 people at the Hawai'i Convention Center yesterday. The annual meeting for conservation workers continues today and tomorrow with the theme "Sustainability: Mauka to Makai."

"We still get people denying the greenhouse effect, saying it's not real," Goreau said. "But it's a law of nature. If you increase the concentration of gas that absorbs radiation, the gas heats up."

That gas is our atmosphere, and the burning of fossil fuels is speeding up the process, he said.

"The only real question about carbon dioxide-induced climate change is how hot it will get and how fast," said Goreau, who has a doctorate in biogeochemistry.

Goreau said effects of global climate change will include:

Coral reefs are probably the most sensitive ecosystem on the planet, he said.

Changes of 2 degrees Fahrenheit or less, when sustained for a month, can cause coral to "bleach," or lose the symbiotic algae that give it color. If the higher temperature is short-lived, the coral could recover. If the water stays hot for too long, the coral itself will die, Goreau said.

Goreau estimates that "alarming increases in sea-surface temperatures" will eventually put all coral reefs at risk -- even if people stopped all fossil fuel use right away.

In the face of such a dire prediction, his nonprofit organization is sharing its technique for growing and maintaining coral that can survive temperature stress 16 to 50 times better than in nature.

Goreau's method involves growing live coral over man-made "Bio-Rock" -- calcium carbonate that accumulates on metal with a low-voltage electric current when placed in sea water. The electrified rock base enables coral grown on it to survive much larger fluctuations in temperature than normal, he said yesterday in a preview of his public talk tonight.

Though the process will not save all the world's reefs from death as sea temperatures rise, it could create oases of living reef, Goreau said.

"We've done this in 20 countries using solar panels or tidal energy to provide the electric charge," he said. "I call them coral arks or bio-reefs. I'm trying to keep corals alive despite global warming."

One project under construction is in the Philippine province of Negros Occidental.