Australian scientists say that a marine heat wave in 2016 killed far more coral in the Great Barrier Reef than previously understood, with some coral suffering a “catastrophic die-off.”

Researchers from the ARC Centre of Excellence for Coral Reef Studies found that 29 percent of the 3,863 reefs that make up the Great Barrier Reef were lost during a nine-month period in 2016.

When water temperatures rise, corals expel the living algae they need to live, causing them to turn white in a process known as bleaching. Typically, weather events like El Nino or cyclones kill between 5 or 10 percent of corals this way.

While the new information is alarming, scientists say the massive ecosystem can still be saved.

"It's certainly premature to give up on the Great Barrier Reef but what our study shows is that climate change is a serious problem for the reef here and now,” said Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies. “The mix of species has changed quite dramatically, surprisingly quickly in just the last two years. So where the Great Barrier Reef ends up, in future decades, is really critically contingent on whether Australia and other countries can reach the two degree target of the Paris Agreement.”