SYDNEY, Aug. 9 (Xinhua) -- Ocean temperatures in and around Australia's Great Barrier Reef have hit their warmest level in over 400 years and pose an existential threat to the iconic reef, researchers say.
In a new study, an Australian team of scientists reconstructed sea surface temperature data from 1618 to 1995 by analyzing coral skeleton samples from in and around the reef and coupled the dataset with recorded observations from 1900 to 2024.
They found that in 2024, 2020 and 2017, the Coral Sea, which lies off Australia's northeast coast and contains several reefs including the Great Barrier Reef (GBR), experienced the warmest temperatures recorded in 400 years, with 2024 the warmest year on record.
Researchers warned that warming temperatures and mass coral bleaching events are threatening to destroy the ecology, biodiversity and beauty of the GBR, the world's largest coral reef and a UNESCO World Heritage Site.
"In the absence of rapid, coordinated and ambitious global action to combat climate change, we will likely witness the demise of one of Earth's most spectacular natural wonders," Benjamin Henley, lead author of the study from the University of Melbourne, said in a media release.
Coral bleaching is a phenomenon that occurs when sea temperatures rise too high and coral under heat stress expel the algae living in their tissue, subsequently turning white.
According to the government-funded Australian Institute of Marine Science (AIMS), bleached coral are not dead but can die if conditions are prolonged or extreme.
The AIMS was one of three government agencies that in April confirmed the majority of the GBR experienced coral bleaching in the summer of 2023/24, marking the fifth widespread bleaching event since 2016.
The new research found that the recent mass coral bleaching events coincided with five of the six hottest years in the 400-year span measured in the study. ■