Wars and political upheaval have long endangered cultural treasures — most recently in Iran and Ukraine — but a new and accelerating menace is climate change. Rising temperatures, more intense storms, prolonged droughts and sea-level rise are accelerating erosion and decay at UNESCO World Heritage sites worldwide. A 2025 study found that about 80% of World Heritage sites face climate stress as traditional building materials such as wood, mudbrick and stone struggle to cope with a hotter, wetter and more variable climate.
Ziggurat of Ur: erosion and salt damage
Iraq’s ancient southern cities, including the 4,000-year-old Ziggurat of Ur, are seeing rapid deterioration. The mud-brick pyramid temple to the moon god Nanna is being worn away by shifting sand, strong winds and rising salty groundwater linked to extended heat and drought. Salt crystals deposited within porous foundations expand and destroy mudbrick, a process Kazem Hassoun, an inspector in Dhi Qar’s antiquities department, warns could lead to the “complete collapse of the mud bricks.” Nearby sites such as Babylon face similarly high salinity; at the Temple of Ninmakh archaeologists are reviving ancient desalination techniques to produce more salt-resistant mudbricks for repairs.
Mosques of Isfahan: subsidence and humidity swings
Isfahan’s historic mosques and plazas, including the Masjed-e Jame (Friday Mosque) and the Meidan Emam complex with the Imam Mosque’s blue-tiled dome, are increasingly threatened by climate-driven groundwater depletion and land subsidence. Over-extraction of groundwater, exacerbated by prolonged drought, is creating earth fissures and differential settling. The UNESCO Land Subsidence International Initiative reports fissures in Isfahan Province can reach decimeters in width, a scale that, combined with uneven sinking, can “tear buildings apart.” Extreme heat and rapid humidity changes also stress fragile tiles, plaster and timber elements across centuries-old structures.
Rapa Nui’s Moai: rising seas and coastal flooding
On Rapa Nui (Easter Island), a 2025 University of Hawaii study warns that many coastal ceremonial platforms and the Moai statues they support could be regularly flooded within a few decades. Ahu Tongariki, which holds 15 monumental statues dating to roughly 800 years ago, faces increasing exposure to large seasonal waves driven by sea-level rise. Researchers estimate coastal flooding could threaten dozens of cultural assets in the region; the study’s lead author, Noah Paoa, cautioned that loss of these sites would be “critical to the living culture and livelihood of Rapa Nui,” undermining identity, traditions and the tourism that sustains the island. If the damage continues, the island’s World Heritage status itself could be imperiled.
Great Wall of China: wind, rain and crumbling rammed earth
The Great Wall, a network of fortifications stretching more than 21,000 kilometers across northern China, is also eroding faster as climate stressors intensify. Sections built from rammed earth are particularly vulnerable to wind erosion, heavy rains and salinization, which cause cracking, disintegration and collapse. Researchers estimate only about 6% of the wall’s total length is well preserved while roughly 52% has already disappeared or is highly degraded. Conservationists are pressing for urgent measures, including encouraging protective biological crusts and other interventions to stabilize exposed earthen segments.
A widening challenge
These cases illustrate how climate change adds a new dimension to threats against cultural heritage: deterioration that is widespread, progressive and linked to global environmental change rather than a single human act. Protecting these sites will require combining traditional conservation skills and local knowledge with new scientific approaches, improved water and land management, coastal defenses where appropriate, and international cooperation and funding. Without such responses, irreplaceable monuments that anchor cultural identity, history and local economies risk being irretrievably lost.
Edited by Teresa O’Connell