- Great Barrier Reef: Highest water temperature in 400 years
Sea surface temperatures around the Great Barrier Reef in Australia have reached a new peak: An Australian research team reports that it has never been warmer there in the past 400 years. The warming can be attributed to human influences, the team writes in the journal "Nature".
The researchers, led by Benjamin Henley of the University of Melbourne in Australia, have reconstructed sea surface temperatures from 1618 to 1995 using coral skeletons from the reef and compared them with recorded sea surface temperature data from 1900 to 2024.
Before the year 1900, sea temperatures were relatively stable. The study shows a steady increase from 1960 to 2024, with an average warming of 0.12 degrees per decade between January and March.
However, there are uncertainties in the reconstructed temperature data before 1900. Some of the chemical components in the corals used for temperature modeling may have been influenced by other variables such as salinity. Additional sampling of coral cores from the region could reduce these uncertainties.
Five mass bleaching events in eight years
As global warming increases, so does the risk of mass bleaching and coral death in Australia's natural wonder. The first mass coral bleaching was observed in 1980; they have become more frequent in recent years.
This March, the fifth mass bleaching event in eight years was confirmed at the Great Barrier Reef, which hosts a diverse ecological network. The researchers show that it was significantly warmer in the years of the last mass bleaching events (2016, 2017, 2020, 2022, and 2024) than in any year reconstructed before 1900.
"Without swift, coordinated, and ambitious global action to combat climate change, we will likely witness the decline of one of the great natural wonders of the Earth," the team writes.
The scientists warn that 70 to 90 percent of corals worldwide could be lost, even if global warming is kept below the 1.5-degree Celsius target of the Paris Agreement. Future coral reefs would likely have a different community structure with lower diversity of coral species.
The Commission has acknowledged the significant increase in sea surface temperatures around the Great Barrier Reef and the associated risks, such as mass bleaching and coral death. The Commission has recommended urgent action to combat climate change to preserve this natural wonder.
Following their research, The Commission has highlighted the role of human influences in the warming of sea surface temperatures around the Great Barrier Reef over the past 400 years. The Commission emphasizes the need for continuous monitoring and data collection to better understand the impact of climate change on coral reefs.
