12 Aug 2019 - (CNN) An international group of scientists has surveyed more than 2,500 coral reef systems across 44 countries to determine how to save them in the face of damage caused by climate change and humans, according to a new study.
A hundred scientists were involved in the survey that looked at coral abundance in the Indian and Pacific oceans. Many of the reef systems were found to be full of complex species that created distinctive structures and were functioning in spite of deadly marine heat waves in recent years.
The study was published Monday in the journal Nature Ecology and Evolution.
"The good news is that functioning coral reefs still exist, and our study shows that it is not too late to save them," said Emily Darling, the lead author of the study and a Wildlife Conservation Society scientist leading the global coral reef monitoring program. "Safeguarding coral reefs into the future means protecting the world's last functioning reefs and recovering reefs impacted by climate change. But realistically -- on severely degraded reefs -- coastal societies will need to find new livelihoods for the future."
Heat stress affected many coral reefs during the El Niño event between 2014 and 2017. But 450 reefs in 22 countries survived in protective cool spots. The scientists believe those areas should be the focus of urgent protection and management efforts.
Previously, the Indo-Pacific reefs were also hit by mass coral bleaching and heat stress in 1983, 1998, 2005 and 2010, before the world's most intense, longest and largest bleaching event between 2014 and 2017.
Coral bleaching occurs when ocean temperatures rise and corals release the algae that lives in their tissues, causing them to turn white, according to the National Oceanic and Atmospheric Administration.
Carbon emissions, pollution, development and overfishing have also impacted reefs.
"Saving reefs will require combining local and global efforts, such as reducing local dependence on reef fish to maintain a reef's important functions while also reducing carbon emissions to keep warming below 1.5 degrees Celsius," said Tim McClanahan, co-author of the study and Wildlife Conservation Society senior conservation zoologist.