Cultural heritage at risk from climate change

Many cultural heritage sites are suffering damage or loss due to anthropogenic climate change. Causes include sea rises and coastal erosion, the increased incidence of extreme weather events such as storms and cyclones, changes in rainfall patterns, extreme periods of drought, and bushfires.

Climate change is an increasing focus of cultural heritage organisations such as the International Council on Monuments and Sites (ICOMOS). UNESCO's List of World Cultural Heritage in Danger includes "threatening impacts of climatic, geological or other environmental factors" as a category of threat.

Sites at risk of loss or damage due to climate change are often also at risk from other social and political factors, such as war, land use and agricultural practices, and tourism.

Africa
Sea level rise and coastal erosion are causing loss of structures and archaeological material in the historic port city of Kilwa Kisiwani. Portions of some monuments are already underwater. Mitigation strategies under development include engineered structures (gabions) to minimise the effect of wave action.

Chan Chan archeological site, Peru
The ancient city site of Chan Chan has experienced both more extreme rainfall and periods of drought, due to El Nino weather patterns. This area has always experienced extreme weather events, but the frequency of events is increasing. Rising groundwater is destabilising building foundations. Mitigation has included strategies to control the rising water table, stabilisation of perimeter walls, architectural documentation, local skills development and awareness-building campaigns, and a disaster preparedness plan.

Ivvavik /Vuntut/Herschel Island (Qikiqtaruk), Canada
Due to decrease of sea areas and higher exposure to storms, the 19th century whalers' settlement of Hershel Island had to be relocated inland to keep the buildings dry and avoid flooding of low lying structures. If coastal erosion continues another relocation might be needed and lead to the abandonment of some structures. The deterioration of the permafrost compromises graves structures and leads to buried caskets tumbling and breakage. (Case studies on climate change and World Heritage, Unesco)

Mosque City of Bagerhat, Bangladesh
Building structures in the Mosque City of Bagerhat are decaying due to rising water and soil salinity. Salt crystals that become embedded in the rock expand in the presence of moisture and hasten the disintegration and weathering of stone buildings.

Rapa Nui, Polynesia
Also known as Easter Island, Rapa Nui has been a World Heritage Site since 1995. The stone statues on Rapa Nui are threatened by sea level rises and coastal damage from storms. An increase in ocean swells and wave heights causes undercutting and erosion of rock faces and loss of archaeological remains.

Coastal Great Britain
Increased coastal erosion and rising sea levels threaten several historic castles in Great Britain, including Hurst Castle in Hampshire, Tintagel in Cornwall, Piel Castle in Cumbria, Bayard's Cove Fort in Devon, Garrison Walls in the Isles of Scilly and Calshot Castle in Southampton. According to site managers English Heritage, it will be necessary to repair walls and improve defences against storms to prevent further damage.

Edinburgh, Scotland
Increased rainfall and extreme weather events are also increasing the risk of flooding and slope instability in the old city of Edinburgh. Annual rainfall has increased 13% since 1970. Increased wetting and drying is eroding the sandstone used to build Edinburgh Castle and eroding the volcanic rock on which it is built.

Venice, Italy
Rising sea water and inundation threaten the city of Venice and its lagoon.