The Great Barrier Reef in 2024, 2020, and 2017 reached the highest temperature in at least four centuries: a statistical model to study coral bleaching history

According to climate researchers, the Great Barrier Reef cooked at warmer temperatures than any it has experienced in at least four centuries. The finding that they published today in Nature1 is linked to climate change and comes as scientists rush to understand the consequences of the most intense and extensive coral-bleaching event ever recorded.

Ove Hoegh-Guldberg, the coauthor and professor of marine studies at the University of Queensland said in the press statement that the Great Barrier Reef is at risk of bleaching in the near future. Hoegh-Guldberg believes that this will happen in the next 10 years. While corals can survive bleaching, reefs generally need one or two decades to recover from severe mass bleaching, according to the related article.

Corals are animals that have skeletons. The skeletons of corals can grow for centuries and allowed for a deeper look into the past. Scientists can study like tree rings when they form bands as they grow. The chemical signatures that show heat stress are contained in them. The ratio of strontium to calcium and the oxygen isotope ratio in particular relate to the temperature of the water at the time the corals were still growing.

There isn’t a consistent data on sea surface temperatures before 1900. But the researchers were able to combine what data was available from direct measurements with data from skeleton core samples to build a statistical model that they then used to reconstruct temperatures going back to the 1600s. They focused on temperatures between January and March when waters surrounding Australia’s Great Barrier Reef tend to be the hottest.

That’s how they discovered that those periods in 2024, 2020, and 2017 reached the highest temperatures in four centuries. It was 1.73 degrees Celsius above the average between 1618 and 1899, and this was the most remarkable.

Future Coral Reefs in the Presence of an Accelerated Warming and a High-Temperature Rise: A Case Study of the Great Barrier Reef

“Corals can stay bleached for some time and still survive, so we won’t know the full impact until we are through the recovery phase,” Cantin says. “But if we continue to see this level of accelerated warming and more frequent bleaching, that recovery process is going to degrade pretty quickly.”

Policies currently in place to slash greenhouse gas emissions from fossil fuels still aren’t enough to stop things Global average temperatures are still on track to rise between 2 to 3 degrees Celsius higher than they were before the industrial revolution. Previous research has estimated that even a two-degree rise could be enough to wipe out 99 percent of the world’s coral reefs.

“We need to believe in it if we’re going to keep it going,” Hoegh-Guldberg said. It is possible, if we take the correct action on greenhouse gasses, to protect the corals that have a good chance of surviving this type of scenario, and we will set us up for a future with coral reefs.

The Great Barrier Reef wasn’t included on the list of World Heritage sites because of evidence, but according to the research, that may change in the future.

Scientists may not get a full picture of coral mortality for another six months due to the incomplete impacts of this year’s mass bleaching event. Around 30–50% of the reefs surveyed from the air are still at risk, says Neal Cantin, a coral biologist at AIMS, who helped to lead the surveys.

How to Publish or Perish? A new board game to challenge scientists to hysteresis in tropical dryland habitats

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Most researchers are familiar with the refrain ‘Publish or Perish’ — the idea that publications are the core currency of a scientist’s career — but now that can be played out for laughs in a new board game. Created as a way to help researchers “bond over shared trauma”, the game features many mishaps familiar to academics, scrambles for funding and scathing comments, all while players must compete to get the most citations on their publications. The story he published about the game for the nature podcasts is one that Max set out to avoid.

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