Rising Temps & Heritage Sites: UNESCO at Risk?

Climate change is emerging as a significant threat to UNESCO World Heritage sites globally, adding to existing dangers from war and revolution. From ancient temples to historical monuments and natural wonders, these sites are facing increased erosion and deterioration due to rising temperatures, intensifying storms, and prolonged droughts.

Climate-Vulnerable UNESCO Sites

A 2025 study indicates that 80% of World Heritage sites are experiencing climate-related stress, as materials like wood and stone struggle to adapt to a warming world.

‘Cradle of civilization’: Ziggurat of Ur

Thousands of years of history are at risk in Iraq’s ancient southern cities as climate change drives extreme erosion across World Heritage-listed sites. The 4,000-year-old Ziggurat of Ur, a pyramid temple dedicated to the moon god Nanna, is crumbling due to shifting dunes and strong winds on its northern side.

Rising salty groundwater, linked to heat and drought, is also eroding the mud bricks of ancient Mesopotamian temples and religious sites. “These salt deposits appeared due to global warming and climate change,” said Kazem Hassoun, an inspector at the antiquities department in Dhi Qar province.

Hassoun warned that the salt deposits could cause the “complete collapse of the mud bricks” at the ancient Royal Cemetery of Ur, as salt crystals expand within the porous materials. Erosion due to high salinity levels also threatens the ancient city of Babylon’s clay-based structures.

At the Temple of Ninmakh, archaeologists are employing a 7,000-year-old technique to create desalinated mudbricks to combat salt erosion.

Mosques of Isfahan, Iran

The mosques of Isfahan, Persia’s grand religious monuments, are increasingly vulnerable to climate change, though war remains a recent threat. The Masjed-e Jame, or ‘Friday Mosque,’ a 12th-century structure embodying the evolution of mosque architecture, is considered a “museum of Iranian architecture” by UNESCO.

The nearby Meidan Emam World Heritage Site, a 17th-century central square, includes the Imam Mosque, famed for its blue-tiled dome and calligraphy. However, the Imam Mosque complex is suffering from land subsidence caused by groundwater over-exploitation and prolonged droughts, coupled with extreme temperatures and fluctuating humidity.

Gradual subsidence and earth fissures, which can reach 10 centimetres in width, are causing major stress to ancient monuments. “The cracks are getting deeper, and some columns have tilted,” said Bahram Nadi, a member of the land subsidence task force in Isfahan, adding that urgent action is needed to prevent the loss of this heritage site.

Easter Island’s ancient Moai statues

The Moai statues on Rapa Nui, or Easter Island, could be regularly submerged within 50 years, according to a 2025 University of Hawaii study. Ahu Tongariki, a ceremonial platform hosting 15 statues dating back around 800 years, is a UNESCO World Heritage Site.

The study indicates that the site could be battered by large seasonal waves driven by sea level rise, threatening 51 cultural assets. “This research reveals a critical threat to the living culture and livelihood of Rapa Nui,” said Noah Paoa, a University of Hawaii researcher and lead author of the study.

Paoa noted that the sites are essential for reaffirming identity and revitalizing traditions, as well as supporting the island’s tourism industry. Failure to address the threat could jeopardize the island’s UNESCO World Heritage status.

Great Wall of China

The Great Wall of China, extending over 21,000 kilometers across northwestern China, is eroding at an accelerating rate due to climate change. Sections built with rammed earth are at risk of “severe deterioration” from extreme wind erosion, heavy rainfall, and salinisation, leading to cracking, disintegration, and collapse.

Researchers estimate that only around 6% of the wall’s total length is well-preserved, while roughly 52% has already disappeared or is highly degraded. They are calling for urgent conservation measures, including enhancing the protective “biocrust” layer of moss.