Climate change and warming oceans could spell doom for almost all of the earth's coral reef habitats by the end of the century, according to new research.

"By 2100, it's looking quite grim," said Renee Setter, a biogeographer at the University of Hawaii at Manoa, "Honestly, most sites are out."

The research, presented at the annual Ocean Sciences Meeting being held this week in San Diego, California, projects 70 to 90 percent of coral reefs will disappear over the next 20 years as a result of climate change and pollution.  Based on projections of sea surface temperature, ocean acidification, wave energy, pollution, and fishing practices, only small portions of Baja California and the Red Sea will be viable.  And even then, these locations are not ideal for coral reefs because of their proximity to rivers.

It's a blow to efforts to protect oveans by cleaning up garbage dumped in our seas, or trying to replant coral reefs.

"Trying to clean up the beaches is great and trying to combat pollution is fantastic.  We need to continue those efforts," said Ms. Setter.  "But at the end of the day, fighting climate change is really what we need to be advocating for in order to protect corals and avoid compounded stressors."