Study finds ocean warming has killed half the coral in Great Barrier Reef

A recent study found that ocean warming has killed half of the coral in Australia’s Great Barrier Reef. 

The study, published in the journal Proceedings of the Royal Society B on Wednesday London time, involved four Australian researchers who counted coral abundance over three decades starting in 1995.

The researchers discovered that “the abundance of large colonies on the crest” fell by up to 98 percent, while there was a minor 25-percent increase in coral on the southern slope. 

The unusually warm ocean temperatures affected coral of all sizes, almost all species and in shallow and deeper weather, Terry Hughes, a co-author, told The Washington Post.

Hughes, a professor at the ARC Center of Excellence for Coral Reef Studies in Queensland, said branching and table-shaped corals were the “worst affected” during record-high temperatures in 2016 and 2017.

“We expect this decline to continue,” Hughes said, citing the warming caused by humans. “The only effective way to improve the outcome for coral reefs is global action on greenhouse gasses. If global temperatures rise to 3 or 4 [degrees Celsius], the reef will be unrecognizable, so there is no time to lose.”

Andreas Dietzel, another co-author and professor at the ARC Center, told the Post that the coral recovering rates are going “very slowly” and are not keeping up with the destruction. 

“Corals are tremendously resilient because of their capacity to produce millions of babies but they/we desperately need a break from disturbances,” Dietzel said.

Gabby Ahmadia, the director of ocean science at the World Wildlife Fund, told the newspaper that some coral are establishing a resistance to warming, providing some hope. But she noted, “a lot of people say 90 percent of coral loss will happen by 2050.”

The Great Barrier Reef serves as a tourism draw for Queensland.

The Sydney Institute of Marine Science and the University of Sydney are working to create marine cloud brightening in an effort to block sunlight and prevent further warming of the coral. But experts said the action may not be enough as Australia is one of the highest coal exporters, the Post noted.