Partly because of climate change, the U.S. government is protecting 20 types of colorful coral by putting them on the list of threatened species.

As with polar bears, much of the threat to the coral species is because of problems expected in the future due to global warming, said David Bernhart, an endangered-species official at the National Oceanic and Atmospheric Administration.

The newly designated coral species are already being hurt by climate change "but not to the point that they are endangered yet," he said.

Climate change is making the oceans warmer, more acidic which encourages coral diseases like bleaching — and those "are the major threats" explaining why the species were put on the threatened list, Bernhart said in a Wednesday conference call.

Other threats include overfishing, runoff from the land, and some coastal construction, but those are lesser, Bernhart said.

“Coral reefs are one of the most biologically diverse ecosystems on earth, providing habitat for many marine species,” Eileen Sobeck, NOAA’s assistant administrator for fisheries, said in a statement.



Five species can be found off the Atlantic and Gulf of Mexico coasts of Florida, Puerto Rico and the Virgin Islands. They include pillar coral, rough cactus coral and three species of star coral. The other 15 are in the Pacific Ocean area near Guam and American Samoa, but not Hawaii.

The agency looked at listing 66 species, but Wednesday listed only 20 for various reasons. All are called threatened, not endangered. Two coral species were already listed.

Coral reefs are important fish habitats and have declined significantly worldwide — some individual species have declined by at least 90 percent, according to NOAA.

Protecting the corals under the Endangered Species Act means that activities that harm the corals could be restricted in the future. The agency did not create any new rules yet that would prevent coral from being harvested or damaged.

"There is a growing body of expert scientists talking about a risk of mass extinction in the sea and on land," said Elliott Norse, founder and chief scientist of the Marine Conservation Institute of Seattle. Coral "are organisms on the front line of anything that humans do."

"I hope this wakes people up and we don't have to lose more coral," Norse said.

Coral reefs are among the planetary systems that, if pushed beyond their limit, could trigger a chain reaction of abrupt climate consequences, according to a March report by the American Association for the Advancement of Scientists. Other systems that could cause such global disruption include large-scale ice sheet melting, the collapse of the Gulf Stream and destruction of the Amazon rain forest.

Once started, those chain reactions become unstoppable even if humans do not add any more CO2 into the atmosphere, the scientists warned.

Al Jazeera and The Associated Press