Climate change has sharply increased the number of World Heritage ecosystems that have become under threat over the past three years, the international environment watchdog IUCN reports.

The International Union for Conservation of Nature said on Monday that more than a quarter of these 241 UN heritage sites are at risk, up from one in seven in 2014.

Coral reefs and glaciers have suffered the biggest damage, while wetlands and permafrost areas have also been affected.

The Switzerland-based IUCN, which keeps track of the world’s endangered species, released its report as delegates were meeting at the UN climate conference in Bonn, Germany.

Rising ocean temperatures have led to large-scale coral bleaching at the world’s largest reef, the Great Barrier Reef near Australia; as well as the large Aldabra Atoll in the Indian Ocean and the Belize Barrier Reef.

Warm temperatures have also melted World Heritage glaciers on Africa’s highest peak at the Kilimanjaro National Park in Tanzania, as well as on the Swiss Jungfrau-Aletsch area, home to the largest Alpine glacier.

“Natural World Heritage sites play a crucial role supporting local economies and livelihoods,” said Tim Badman, who heads IUCN’s World Heritage programme.

“Their destruction can, thus, have devastating consequences that go beyond their exceptional beauty and natural value,’’ he added.

Melting glaciers can lead to the release of heavy metals that were previously locked in by the ice, Badman said, pointing to the example of Peru’s Huascaran National Park.