Cuts in CO2 emissions said necessary to save world's coral reefs

WASHINGTON, June 28 (UPI) -- Deep cuts in carbon dioxide emissions are needed to stop the world's coral reefs from dying off from inhospitable ocean chemistry, U.S. researchers say.

Katharine Ricke and Ken Caldeira of the Carnegie Institution in Washington say coral reefs around the globe will be engulfed in such conditions by the end of the century if civilization continues along its current emissions trajectory.

Carbon dioxide absorbed by the ocean increases acidity, which makes it more difficult for many marine organisms to grow their shells and skeletons.

Coral reefs use a naturally occurring form of calcium carbonate; CO2 in ocean water forms carbonic acid, threatening coral reefs the world over, Ricke and Caldiera said.

"Our results show that if we continue on our current emissions path, by the end of the century there will be no water left in the ocean with the chemical properties that have supported coral reef growth in the past," Caldiera said in a Carnegie release Friday.

Chemical conditions that can support coral reef growth can be sustained only with very aggressive cuts in carbon dioxide emissions, the researchers said.

"We can't say with 100 percent certainty that all shallow-water coral reefs will die [without cuts], but it is a pretty good bet," Caldiera said.