Nearly all of the world’s coral reef ecosystems are at high risk of collapse within the next 50 years, mainly due to ocean warming and heat waves, according to a global assessment report released Thursday.
An assessment announced by the International Union for Conservation of Nature on the sidelines of the United Nations Biodiversity Conference in Albania found that 96 percent of shallow-water coral reef systems are already critically endangered and could disappear by 2075.
Most of the world’s famous coral reef systems – including Australia’s Great Barrier Reef, the Coral Triangle in the Western Pacific and Southeast Asia, the Mesoamerican Barrier Reef System and the Red Sea reefs – are critically endangered, the highest level of threat.
“The risk of coral reef collapse is escalating, but this must be a wake-up call, not a cause for despair,” said Mishal Gudka, scientific lead for the IUCN Red List assessment of coral reef ecosystems.
“Coral reefs have shown an extraordinary ability to recover from devastating bleaching events,” he said. “There are still some surviving, resilient coral reefs that can remain in the future, so we must do everything we can to make them successful.”
The assessment is the latest bad news for coral reefs, which are important sources of seafood and tourism and often serve as buffers from coastal erosion and storms. Sometimes called “rainforests of the sea,” they contain some of the richest biodiversity in the world. They support a quarter of all marine species as well as coastal communities and businesses.
When a reef collapses, hard coral disappears and is replaced by algae, debris and sponges. As a result, coral reefs no longer support diverse ecosystems, ranging from tiny invertebrates to reef fish such as groupers.
“Coral reefs are one of the most visible signs of life in our oceans,” IUCN Director General Grete Aguilar said in a statement.
The assessment, which covers 127 tropical and subtropical ecoregions covering 72,726 square miles (188,362 square kilometers) of coral reefs worldwide, calls climate change “the single most persistent threat leading to global coral reef decline.”
A week ago, another IUCN study published in the journal Nature found that nearly 44% of reef-building coral species face a higher risk of extinction due to climate change. A year ago, a survey found that 84% of the world’s coral reefs were experiencing harmful coral bleaching, the worst such event on record.
2024 is the hottest year on Earth’s record, and much of it goes into the oceans. The average annual sea surface temperature of the oceans away from the poles reaches 20.87 degrees Celsius (69.57 degrees Fahrenheit).
Experts say that in addition to combating rising global emissions, efforts to reduce pollution, overfishing and coastal development can help coral reefs survive.
“We know what is needed: ambitious emissions reductions, stronger conservation and restoration efforts, and continued investment in resilient coastal ecosystems and the communities that rely on them,” Aguilar said.