UNESCO Sites Face Climate Risks

A new digital dataset maps 386 coastal UNESCO World Heritage Sites threatened by climate change. The database, created by researchers including Professor Robert Nicholls of the University of East Anglia, covers over 235 million hectares of culturally and naturally significant coastline.

Professor Robert Nicholls was inspired by watching the erosion of Hurst Castle Spit in England. This led him to co-create the first global high-resolution dataset of coastal World Heritage Sites. The tool aims to help assess vulnerabilities and improve resilience against climate threats.

Dataset Creation and Scope

The dataset was published in the journal Scientific Data in July. It includes cultural landmarks, biocultural sites, and unique ecosystems. Co-author Joanne Clarke, an archaeologist at the University of Durham, stated all are threatened by climate change and factors like erosion.

Creating the dataset was simple but tedious. The team started with UNESCO's list of 1,199 sites. They identified 386 sites less than 20 meters above sea level and near the coast. These comprised 289 cultural, 91 natural, and six mixed sites.

Researchers then hand-drew digital boundaries for each site using sources like Historic England's Open Data Hub. They did not use AI or machine learning. The 386 sites contain 1,250 individual polygons. "It's an enormous amount of work," Clarke said.

The Challenge of Local Data

Until now, detailed boundary maps were often unavailable. This made assessing vulnerability difficult. "In some cases, our data might be the best data that exists, even at the local scale," Nicholls noted.

Tom Dawson, a coastal heritage archaeologist at the University of St. Andrews not involved in the study, was surprised UNESCO lacked such maps. He said polygons are key for measuring environmental risks. He cautioned, however, that global datasets cannot replace local knowledge. "You really need to have the local climate models as well," Dawson said.

Compound and Cascading Risks

Evaluating risks is complex, especially for sites with both cultural and ecological value. Clarke explained that for cultural sites, the issue is protecting structures from erosion or flooding. For natural or biocultural sites, there are "compound cascading risks."

Climate events compound other threats. For example, water temperature increases cause coral bleaching in Australia's Great Barrier Reef. Wetlands face climate change alongside pollution and agricultural exploitation, as in Spain's Doñana National Park.

Marine species in warming oceans also face pressure from illegal fishing, such as at Colombia's Malpelo Island. Other sites are threatened by infrastructure development. The Sundarbans mangrove ecosystem in Bangladesh faces a planned power plant just 14 kilometers away. Clarke believes ecological heritage is "more fragile than some cultural heritage sites."

A Tool for Future Assessment

The database is seen as a vital tool for building complex risk assessments. Geologist Alessandra Bonazza of Italy's National Research Council, who was not part of the study, wants to integrate it into Mediterranean hazard maps. "It would be amazing to overlap our maps of climate hazards with this," she said.

The research team is already using the dataset to study flood implications from sea level rise in a forthcoming paper. Nicholls views this work as part of a broader global effort. "We're seeing a growth in global datasets of all kinds of things to do with the environment," he said. The dataset includes sites like Senegal's Djoudj National Bird Sanctuary and Greenland's fjords. The team hopes this data will help local authorities make these sites more resilient, as detailed in our stats on environmental pressures, and inform broader conservation standings.