Climate change and air pollution impacts on cultural heritage building materials in Europe and Mexico

Climate and air pollution have adverse effects on cultural heritage building materials. However, the quantified damage due to modeled changes in climate and air pollution is still poorly studied. Here, we review first the damage affecting these materials and the associated damage equations in the literature. Across all relevant studies (n = 87), we found only nine independent equations to estimate different damage categories, mainly limited to limestones. Then, by using current meteorological data and future bias-corrected CMIP6 climate and air pollution data at high resolution (1 km; historical and business-as-usual scenario) and applying these equations, we quantified the relative contributions of climate and air pollution changes on the building materials of eight cultural heritage sites of the European project Sustainable COnservation and REstoration of built cultural heritage (SCORE) from 2020 to 2100. On average across the sites, a significant decrease in damage is projected in surface recession (−10 % ± 10 %), biomass accumulation (−20 % ± 18 %), and wind–rain erosion (−7 % ± 6 %) in response to future climate and air pollution changes, except in the regions where precipitation substantially increases (Northern Europe). A large uncertainty in the relative magnitude of the damage to built cultural heritage materials was found for the same site, changes in surface recession vary up to a 40 % difference across the equations. Moreover, thermal expansion and lifetime multiplier equations project an increase in the related damage while all the other types of damage are significantly reduced. Finally, in general, but not systematically, climate-induced damage was found to be predominant over the pollution-induced one. Our results allow prioritizing cultural heritage maintenance decisions in regions where damage will further increase. Beyond simulated damages which are still limited use, we urge more campaign studies to determine real in situ damage in different climate locations to validate or build the best equations.