Researchers report that sea temperatures in the Great Barrier Reef have reached their highest levels in 400 years over the past decade, warning that the world’s largest living ecosystem is unlikely to survive unless global warming is halted. A new study published by a group of researchers from across Australia demonstrates that temperatures around the impressive 2,400-kilometer-long coral system have been remarkably stable for several centuries, but have significantly increased in recent decades due to human impact.
According to the study published in the scientific journal Nature, sea temperatures around the reef have been rising annually since 1960, with particularly high spikes during recent massive coral bleaching events, where large portions of the reef have turned white due to heat stress. Benjamin Henley, an academic from the University of Melbourne and co-author of the study, stated, “The world is losing one of its icons. I find this to be an absolute tragedy. It is hard to understand how this can happen in our time. So it is very, very sad.”
Helen McGregor, also a co-author of the study, expressed her “extreme concern” for the reef and described the temperature increases as “unprecedented.” “These are corals that have lived for 400 years, and these are the warmest temperatures they have ever experienced. These are the redwood trees of the reef,” she told AFP (Agence France-Presse).
The world-renowned reef has suffered through five rounds of massive coral bleaching since 2016 as a result of rising temperatures, a deadly trend affecting reefs worldwide. These bleaching events occurred in five of the six hottest years in the past four centuries, according to the study.
To conduct the research, scientists utilized ship and satellite data, as well as drilled samples from corals to analyze samples that help them understand changes in sea temperature dating back to 1618. The temperature began to rise in the early 20th century and has increased by an average of approximately 0.12 degrees Celsius from January to March from 1960 to 2024.
The reef is home to a vast array of biodiversity, including 600 species of coral and 1,625 species of fish alone. It also plays a significant role in Australia’s tourism sector, contributing around 4.2 billion dollars to the national economy each year. The United Nations (UN) has recommended adding the Great Barrier Reef to the list of World Heritage Sites at risk, but Australia has declined these initiatives over fears that it might damage the reef’s appeal to tourists.