Rising sea levels, melting glaciers, increased risks of flooding and reduced marine and land biodiversity could all have potentially disastrous effects on the 830 sites inscribed on the UNESCO World Heritage List, the report said.

UNESCO Director-General Koïchiro Matsuura called for “an integrated approach to issues of environmental preservation and sustainable development,” warning that climate change will constitute an enormous challenge over the next century.

The report, which featured 26 case studies, focused on five areas: glaciers, marine biodiversity, terrestrial biodiversity, archaeological sites, and historic cities and settlements.

One of the at-risk sites is the Great Barrier Reef, off the north-eastern coast of Australia. The report found that rising sea temperatures and increasing oceanic acidification mean that corals are more and more likely to bleach and turn white, jeopardizing the numerous fish species which rely on the reef.

The Italian city of Venice and its surrounding lagoon face the threat of more frequent flooding because of rising sea levels, the report noted, while rising water levels could endanger the historic areas of many other famous cities, including London and Prague. The decorative surfaces of many of the buildings in these cities are considered to be at particular risk.

In Tanzania, the rapidly diminishing glaciers on Mount Kilimanjaro, Africa’s highest peak, could lead to the complete disappearance of its ice fields within the next 15 years.