Coral reefs may be able to adapt to moderate climate warming, improving their chance of surviving through the end of this century, if there are large reductions in carbon dioxide emissions, according to a study funded by NOAA and conducted by the agency’s scientists and its academic partners.
Results further suggest corals have already adapted to part of the warming that has occurred.
“Earlier modeling work suggested that coral reefs would be gone by the middle of this century,” said lead author Cheryl Logan, an assistant professor in California State University Monterey Bay. “Our study shows that if corals can adapt to warming that has occurred over the past 40 to 60 years, some coral reefs may persist through the end of this century.”
Warm water can contribute to a potentially fatal process known as coral bleaching, in which reef-building corals eject algae living inside their tissues. Corals bleach when oceans warm only 2-4 degrees F (1-2 degrees C) above normal summertime temperatures. Because those algae supply the coral with most of its food, prolonged bleaching and associated disease often kills corals.
“The hope this work brings is only achieved if there is significant reduction of human-related emissions of heat-trapping gases,” said Mark Eakin, director of the NOAA Coral Reef Watch monitoring program. “Adaptation provides no significant slowing in the loss of coral reefs if we continue to increase our rate of fossil fuel use.”
According to the “Status of Coral Reefs of the World: 2000” report, almost 20 percent of reefs globally were lost due to high temperatures during the 1998-1999 El Niño and La Niña, and 80 percent of coral cover in the Caribbean has been lost.
The study is published online in the journal Global Change Biology.