Compound climate events and their role in the decay of Greece's cultural heritage

The decay of porous materials in archaeological and built heritage is often accelerated by compound climate events, such as frost, salt crystallization, and prolonged rainfall. These processes threaten the definition of architectural surfaces, structural integrity and thus the heritage values of monuments built with porous inorganic materials. This study investigates the spatial and temporal distribution of these decay-inducing events across Greece, utilizing observational data and the Ensemble of five high-resolution climate simulations from EURO-CORDEX and EC-EARTH models. Focusing on the historical period (1980-2004) and future projections (2025-2049) under RCP4.5 and RCP8.5 scenarios and using a set of heritage climatology indicators, this work reveals regional vulnerabilities and highlights the impacts of climate change on the frequency of such events. The study revealed high vulnerability on most mountainous regions and most of Northern and Western Greece for the sum of annual events, exhibiting future reduction. Salt transitions yield no significant changes, while events of prolonged rainfall and frost show a declining trend. By mapping the pace of decay-inducing events across the Greek territory, this research makes a solid first step to assessing risk-prone areas, hence offering a layer new knowledge for better-informed, and more localized heritage preservation strategies.