Danish fish fossil cliffs set to gain UNESCO status Andrew Zinin Chief Editor Two Danish coastal cliffs where paleontologists have uncovered 55-million-year-old fossils of prehistoric wildlife are likely to gain World Heritage status as UNESCO's committee meets in South Korea. The cliffs have for decades been known for what UNESCO terms "exceedingly well-preserved" fossils of early insects, birdlife and more than 80 different fish species, including ancient relatives of mackerel and herring. "It's very unique," said Jan Audun Rasmussen, a researcher and curator at Museum Mors, who co-authored the UNESCO bid.

"What we can show in these deposits is the early evolution of many of the fish lineages and bird lineages," he told AFP. Fifty-five million years ago, all of Denmark was covered by water, and Limfjord's low-oxygen clay seafloor provided a perfect time capsule for fish, birds and turtles that died and sank to the seabed. There was no oxygen for small organisms that would eat the bodies of dead animals, Rasmussen explained, standing below the towering 60-meter-high (200-foot) Hanklit.

"That means that the preservation of the fossils ... it's excellent." The cliffs are already on UNESCO's tentative list, and the International Union for Conservation of Nature (IUCN) has recommended that they be included on the World Heritage List. Climate change insight Beyond providing a glimpse into the distant past, Hanklit and Knudeklint might also offer lessons on the impact of climate change warming the planet.

The cliffs' rock layers capture a dramatic, 56-million-year-old global warming event—one of the largest climate catastrophes in Earth's history—when a massive release of greenhouse gases sent global temperatures soaring by between 5 and 8 degrees Celsius. "Obviously, warming causes a lot of changes in the animals," said Laura Jane Cotton of Denmark's Natural History Museum. Cotton told AFP the Limfjord cliff fossils—which include specimens from during and after the event—provide researchers with an environmental "snapshot" that was the "best analog for modern warming." "While we can't say exactly what went extinct when, we can get an idea of it if things disappear from this environment very suddenly," she said.

If listed, the Hanklit and Knudeklint cliffs on the fjord islands of Mors and Fur would become the fifth natural site on Danish soil to receive UNESCO World Heritage status—including one in the autonomous territory of Greenland. Discussions on a UNESCO bid began in 2010. The area is popular with amateur fossil hunters, and the "treasure troves" of Hanklit and Knudeklint have been protected for decades under Danish law.

Thomas Olesen, project leader for the local Skive municipality, believes UNESCO recognition will provide a welcome boost to tourism, particularly on the small island of Fur, home to just 700 residents. "Hopefully it will have a very positive effect on the local economy," said Olesen, standing atop the 30-meter (100-foot) Knudeklint cliff. © 2026 AFP