Climate change is increasingly damaging the UN’s most cherished heritage sites, a leading conservation agency said on Wednesday. It said that Australia’s Great Barrier Reef and dozens of other natural wonders face severe threat. Shrinking glaciers, bushfires, floods, droughts and the bleaching of coral reefs are among the troubles caused by climate change facing 83 of the 252 World Heritage Sites listed by Unesco, the UN’s cultural agency. Sixteen World Heritage sites have deteriorated since the last World Heritage Outlook was released three years ago, while only eight improved, said the International Union for Conservation of Nature (IUCN), made up of governments and civil society groups and advises Unesco on natural threats to those sites. “Natural World Heritage sites are among the world’s most precious places, and we owe it to future generations to protect them,” IUCN director general Bruno Oberle said. “Climate change is wreaking [havoc] on natural World Heritage, from shrinking glaciers to coral bleaching to increasingly frequent and severe fires and droughts.” The report says the Great Barrier Reef, where ocean warming, acidification and extreme weather are adding to the coral decline and shrinking marine species populations, were one of four sites in Australia under “very high” threat. The islands of protected areas in the Gulf of California in Mexico have also entered the critical category in the listing. Spain’s Garajonay National Park, Olympic National Park in the United States, and Mexico’s Monarch Butterfly Biosphere Reserve are among those under “very high” threat, the new report said. Human activities such as tourism, hunting and fishing, and livestock grazing have also had an effect. In a shift from the previous two IUCN reports, climate change has eclipsed “invasive alien species” – such as when foreign rodents, fish or plants are transplanted, accidentally or not, to new environments – as the most potent threat against such sites.