Nearly Half of World Heritage Sites Now Face Severe Climate Risks, IUCN Warns

International

43% of natural and cultural heritage areas under high or very high threat — conservation experts urge immediate global climate action

Almost half of the world’s UNESCO World Heritage sites are now considered to be at high or very high risk due to the escalating impacts of climate change, according to the International Union for Conservation of Nature (IUCN). The organization’s latest World Heritage Outlook 4 report calls for urgent and coordinated climate action to safeguard these irreplaceable ecosystems and cultural treasures.

Climate Change: The Fastest-Rising Global Threat

The report assessed 271 heritage sites worldwide and found that 117, or roughly 43%, are under severe climate threat — up sharply from 33% in 2020 and 27% in 2017. This marks a 31-site increase in just five years, making climate change not only the most pervasive but also the fastest-rising danger to heritage preservation.

According to Tim Badman, Director of IUCN’s World Heritage and Culture Programme, the findings serve as a stark projection of the deteriorating conservation outlook across the globe. He warned that changing rainfall patterns, melting glaciers, rising sea levels, and marine heatwaves are already transforming ecosystems — from coral reefs and wetlands to mountain and desert landscapes.

“Seasonal flooding is shifting, glaciers are retreating, and rising seas are altering salinity and sediment patterns,” Badman explained. “We are witnessing a structural transformation of natural systems that once defined the resilience of these heritage sites.”

Biodiversity Under Pressure

The report reveals that sites rich in biodiversity are suffering the steepest declines. In 2014, 71% of such sites were classified as “good” or “low risk”; by 2025, that number had fallen to 52%, the lowest ever recorded. Overall, the share of heritage areas with a positive conservation outlook has dropped from 63% in 2014 to 57% today, signaling a global setback in biodiversity protection.

New Threats: Invasive Species and Pathogens

After climate change, the second-most severe global threat now comes from invasive species and diseases. The number of heritage sites reporting high or very high risks from pathogens rose from two in 2020 to 19 in 2025, while invasive species continue to spread rapidly.

Additional pressures stem from tourism, urban expansion, and industrial growth. Since 2020, threats from tourism have risen by 4%, from residential areas by 5%, and from commercial or industrial activity by 3%.

Regional Examples and Local Impacts

The IUCN assessment categorized all 271 sites into four levels: good, good with some concerns, significant concern, and critical.

In Türkiye, Pamukkale was rated as “good with some concerns”, while Göreme National Park in Cappadocia was downgraded to “significant concern” — a change linked to high visitor numbers and increasing vehicle traffic.

Some Progress, But Not Enough

Despite the worsening global picture, the report notes that 42% of sites have implemented effective adaptation or resilience measures. Examples include community-led and Indigenous conservation efforts in Mexico’s Monarch Butterfly Biosphere Reserve and the Tubbataha Reefs Natural Park in the Philippines.

Badman emphasized that while these initiatives show promise, the scale of global action remains insufficient.

“The decade-long surge in climate-affected heritage sites is a warning signal. We need far stronger, coordinated measures at every level to protect our shared heritage.”

A Call for Stronger Climate Commitments

The IUCN urged governments to reinforce their emission reduction pledges under the Paris Agreement and to adopt ambitious targets to keep global warming below 1.5°C. The organization also highlighted UNESCO’s Climate Action Policy for World Heritage as a key framework focusing on adaptation, mitigation, innovation, and research.

Protecting the Planet’s Legacy

Natural World Heritage sites, the IUCN stressed, play a vital role in carbon storage, water regulation, and disaster prevention. Losing them to climate change would have devastating consequences for ecosystems and human well-being alike.

“The rising number of sites at high risk is an unmistakable call for urgent and stronger climate action,” the report concluded.

“World Heritage sites are of outstanding universal value — protecting them means protecting our planet’s natural legacy.”