Australia: Coral reefs are bleaching due to high temperatures – what do scientists say? [εικόνα]

Water temperatures in and around Australia’s Great Barrier Reef have risen.

In particular, the past decade was the warmest in 400 years, according to research published in the journal Nature.

Coral reefs are sensitive to temperature.

Coral reefs are sensitive to heat stress, and these warming periods increase the risk of mass bleaching and coral die-offs, likely due to human-induced climate change. The Great Barrier Reef, a UNESCO World Heritage Site, has already suffered a series of mass bleaching events in recent years, with the frequency of events increasing since the first recorded episodes in the 1980s.

In the current research, the scientists reconstructed sea surface temperature data from 1618 to 1995, using samples of coral skeletons from the Coral Sea, where the Great Barrier Reef is located. They then combined this dataset with sea surface temperature data recorded from 1900 to 2024.

The researchers found relatively stable temperatures before 1900, but from 1960 to 2024 they observed an average annual increase in January-March temperatures of 0.12 degrees Celsius per decade. They also noted that average January and March sea surface temperatures during the mass coral bleaching years of 2016, 2017, 2020, 2022, and 2024 were significantly higher than in any year of the reconstruction before 1900, and five of the six warmest years in the region over the past four centuries were recorded. Further models show that this post-1900 warming rate can be attributed to human influence.

The researchers note that there are still some uncertainties in the SST reconstruction data because some of the chemical ratios in the corals used to model temperatures are also affected by other variables. However, these uncertainties could be reduced by taking additional coral core samples from the region.

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