Great Barrier Reef waters spike to hottest in 400 years, study finds

WASHINGTON — Ocean temperatures in the Great Barrier Reef hit their highest level in 400 years over the past decade, according to researchers who warned that the reef likely won't survive if planetary warming isn't stopped. During that time, between 2016 and 2024, the Great Barrier Reef, the world's largest coral reef ecosystem and one of the most biodiverse, suffered mass coral bleaching events. That's when water temperatures get too hot and coral expel the algae that provide them with color and food, and sometimes die.