After a summer of extreme heat in Australia, scientists at Australia's James Cook University and the Great Barrier Reef Marine Park Authority have reported the third bleaching event in the Great Barrier Reef in five years.
"That is unprecedented," Mark Eakin, coordinator for the National Oceanic and Atmospheric Administration's Coral Reef Watch program, told The Washington Post.
It's clear that major bleaching events can now be caused by climate change, Eakin said, noting that this year's bleaching did not coincide with El Niño, like several in the past did.
Bleaching is the result of coral being exposed to warm water for too long, leaving it under more stress and "subject to mortality," according to the National Oceanic and Atmospheric Administration. Coral reefs "support more species per unit area than any other marine environment," and their biodiversity is "considered key to finding new medicines for the 21st century," per the NOAA.
The intensity of this year's bleaching falls short of that of 2016, but is more expansive. In 2016, the southern reefs were "a rare bright spot," Kim Cobb, a coral reef and climate scientist at the Georgia Institute of Technology, told the Post. This year, corals from the north to south have been negatively affected.
Scientists agreed this indicates the reef is growing closer to annual bleaching events. Read more at The Washington Post.