Water temperatures in the Great Barrier Reef reached 400-year highs in 2017, 2020, and 2024 according to research by University of Wollongong (UOW) Honorary Fellow and University of Melbourne Lecturer Dr Benjamin Henley, published this month in Nature.

The research reconstructs 400 years of summer sea surface temperatures in the Coral Sea, showing an unprecedented rise in sea temperature that has led to recent ocean heat, further triggering severe coral bleaching and destroying the world’s largest and most biodiverse reef ecosystem.

Although UNESCO’s World Heritage Committee made the decision not to list the Great Barrier Reef as endangered, Dr Henley is amongst many who feel this was the wrong decision.

“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,” Dr Henley said.

Professor Helen McGregor from UOW’s Environmental Futures, the second author of the study, said urgent action is needed to prevent devastation of one of the world’s most important ecosystems.

“The Great Barrier Reef is facing catastrophe if anthropogenic climate change is not immediately addressed. The very corals that have lived for hundreds of years and that gave us the data for our study are themselves under serious threat,” Prof. McGregor said.

According to the National Oceanic and Atmospheric Administration (NOAA), carbon dioxide absorbed into the ocean from the atmosphere is leading to low rates of reef-building and reef-associated organisms.

“Without urgent intervention, our iconic Great Barrier Reef is at risk of near-annual bleaching from high ocean temperatures. The Reef’s fundamental ecological integrity and outstanding universal value are at stake,” Dr Henley said.