Future climate risks to world cultural heritage sites in Spain: A systematic analysis based on shared socioeconomic pathways

Rapidly advancing anthropogenic climate change is a severe threat to cultural heritage worldwide. World cultural heritage sites (WCHS) are recognized by UNESCO as having outstanding international importance. Identifying and quantifying the impacts of climate change on the WCHS is therefore crucial for the development of long-term protection policies. Spain, the subject of the present study, is one of the most important world heritage countries in terms of the number of sites and is highly vulnerable to climate change under global scenarios.

This study identified the main climate risks faced by Spain's WCHS on the basis of future climate data from four shared socioeconomic pathway (SSP) scenarios under the most recent version of the Coupled Model Intercomparison Project (CMIP6), the most up-to-date global climate model available. Risks include sea level rise and coastal flooding, fire risk and drought risk, hydrodynamic scouring and corrosion, and biodegradation. Some WCHS are located in regions that are projected to experience surface warming exceeding the global average by 2100 under the SSP5--8.5 scenario, with a doubling of extreme climate risk (a gradient from scenarios SSP1--2.6, SSP2--4.5, SSP3--7.0 to SSP5--8.5). Under this shared socioeconomic pathway, three Spanish WCHS are at risk of being submerged by seawater by 2100. On the basis of historical data, we identified greater potential fire risk in regions where Spain's WCHS is located than in other regions in Europe, with eight WCHS experiencing weather-induced fire hazards exceeding 95 %. Considering the combination of LUC types within the Spanish WCHS, we identified two WCHS that exemplify this risk: 1) the archaeological site of Atapuerca, which is primarily occupied by broad-leaved forest, and 2) the Caliphate city of Medina Azahara, which is surrounded by natural grasslands, emphasizing the need for fire prevention in woodland and grassland areas. Furthermore, we quantified the hydrodynamic scouring risk, corrosion and biodegradation risk, and drought risk in the entire region where Spain's WCHS are located from 2081 to 2100 and clustered them on the basis of risk characteristics. We found that under the SSP1-2.6 scenario, the overall pattern of climate risk faced by Spain's WCHS did not change significantly from the present, but there were clear changes under the SSP5-8.5 scenario. We also identified that Spain's WCHS listings are at greater risk from different climate risks. This study predicts the potential impact of climate change on Spain's WCHS, emphasizing the crucial role of “carbon neutrality” in reducing various climate risks to Spain's WCHS and providing guidance for the development of future long-term protection policies.