An Emblematic, Transdisciplinary, and Multi-Hazard Monitoring Infrastructure on Delos Island (Greece) for the Protection of UNESCO World Heritage Monuments from Climate Change

Delos, a UNESCO World Heritage archaeological site on a small rocky island in the Aegean Sea, hosts monuments of exceptional historical value within a pristine natural setting. Despite being uninhabited, the site is increasingly exposed to climate-related and geophysical risks that threaten its cultural and natural heritage. To address these challenges, a multi-hazard environmental monitoring facility was installed in 2025, combining predictive climate modelling with satellite and in situ real-time monitoring of seismic, atmospheric, and oceanographic conditions. Downscaled projections from global climate models indicate that, beyond sea-level rise, the monuments of Delos will be exposed to substantially higher temperatures in the future, resulting in increased thermal stress. These projections also support the expectation that extreme weather events will become both more frequent and more intense, further exacerbating pressures on the island. In situ atmospheric measurements show that Delos is intermittently affected by elevated pollutant concentrations. These episodes appear to be linked to ship emissions, transport from nearby islands such as Mykonos and Tinos, and, at times, long-range atmospheric transport from more distant regions. Meteorological data from seven stations distributed across the island reveal pronounced north–south gradients in temperature and relative humidity, reflecting the persistent influence of northerly winds throughout the year. Hourly averaged sea-level measurements from spring to fall of 2025 show a variability exceeding 0.3 m, with driving mechanisms including astronomical tides, atmospheric pressure variations, and inter-seasonal changes in sea temperature. Delos lies at 140 km distance from Santorini. Τhe intense seismic activity during the winter–spring of 2025, between Santorini and Amorgos, was well recorded, indicating some minor measurable effects on the island. The data records collected by the model seismic station (seismometer and accelerometer sensors are included) installed at Delos Archaeological Museum are presented and discussed in comparison to the records of the accelerometric station installed in Mykonos Archaeological Museum.This work has been performed in the framework of the project “Development and installation of an integrated system for the monitoring of the impacts of climatic change on the monuments of Delos” that has been funded by benefit foundations of "Protovoulia ‘21“.