Coral Reefs Reach Their First Climate Tipping Point, but Astrangia coral offers hope
This past week, researchers announced that rising ocean temperatures have pushed coral reefs past their first climate tipping point. A climate tipping point is a major change in an ecosystem where the damage becomes irreversible.
Although coral reefs have been experiencing a massive bleaching event since 2023, this year has been the worst yet, as global ocean temperatures have risen by 1.4°C since pre-industrial times, causing mass mortality among warm-water reefs.
A new report from the University of Exeter, involving more than 160 scientists from 23 countries, confirmed that warm-water coral reefs have reached a critical threshold. The researchers estimate reefs begin to collapse when temperatures rise between 1.0°C and 1.5°C, with 1.2°C being the point where widespread die-off becomes unavoidable. Because the planet has already passed this level, the study warns that most tropical reefs could disappear “at any meaningful scale” unless global temperatures fall back below that mark.
“We can no longer talk about tipping points as a future risk,” said Professor Tim Lenton of the University of Exeter’s Global Systems Institute. “The first tipping of widespread dieback of warm-water coral reefs is already underway.”
One species dying may not seem like a big deal, but coral reefs are considered an indicator species because their health reflects the overall condition of the ocean. Nearly a quarter of all marine species rely on coral reefs to survive, providing shelter and acting as nurseries for growing populations. Without them, entire ocean ecosystems could collapse, affecting both biodiversity and the millions of people who depend on reefs for food and income.
However, there is still hope. Researchers studying a northern species called Astrangia poculata, a hardy coral found off the U.S. East Coast, are finding new clues about how some corals might adapt to changing oceans. Unlike tropical corals that depend heavily on warm, stable environments, Astrangia lives in cooler, more unpredictable waters and can survive without the symbiotic algae that tropical corals rely on for food.
At Roger Williams University in Rhode Island, Professor Koty Sharp and her team are studying Astrangia to uncover how some corals might adapt to these changing conditions. Sharp’s latest research—conducted with Anya Brown from the University of California, Davis, and Amy Apprill from the Woods Hole Oceanographic Institution—found that when Astrangia goes dormant, it sheds harmful microbes and strengthens beneficial ones that help it recover later. Understanding how this coral’s microbiome rebuilds after stress could help scientists design treatments or “probiotics” to help tropical corals recover from heat and pollution.
That is also why I have chosen to do my research specifically on how temperature change affects these corals, to see firsthand just how resilient they are. Learning about Professor Sharp’s work at Roger Williams University has shown me how much we can discover from Astrangia coral. By conducting my own experiments, I hope to contribute to this growing understanding of how corals adapt to changing environments and why protecting them is so essential for the future of our oceans.
While the University of Exeter report confirms that coral reefs have reached a dangerous tipping point, Sharp’s work reminds us that not all hope is lost. By learning from resilient species like Astrangia, researchers can help chart a future where coral ecosystems might still survive, even in a warming world.
Sources:
https://yaleclimateconnections.org/2025/10/corals-are-disappearing-pushing-earth-to-its-first-major-tipping-point/
https://time.com/7325086/coral-reef-climate-tipping-point-crossed/
