Climate change impacts on bioclimatic conditions in the Eastern Mediterranean

Climate and weather are significant factors in planning to visit a touristic destination, especially taking into consideration the global warming. In this respect, touristic areas will be significantly affected by the potential adverse effects of climate change. This is the case of the Mediterranean which is considered one of the most vulnerable regions in global climate change, regarding the observed but also the expected future thermal risk. The goal of this study is to highlight the bioclimatic conditions anticipated to prevail in the eastern Mediterranean, studying five touristic destinations; namely, Heraklion, Crete Island (Greece), Antalya (Turkey), Limassol (Cyprus), Valletta (Malta) and Cairo (Egypt).

One of the most popular and widely applied human thermal index, the Physiologically Equivalent Temperature (PET), based on human energy balance, is utilized to quantify the regime of present and simulated future bioclimatic conditions. Air temperature, humidity, wind speed and global solar radiation (estimated at 1.1m where is the gravity center of the human body and builds the reference level for human biometeorological studies) are the parameters needed for the assessment of PET, using the RayMan model. The meteorological datasets concern 3-hour data from the SMHI RCA4 regional climate model (Rossby Center, Swedish Meteorological and Hydrological Institute, Norrkoping Sweden, spatial analysis 11 km), for the historical period 1971-2000 (reference period), as well as for the periods 2021-2050 and 2071-2100 under the two Representative Concentration Pathways, RCP4.5 (intermediate) and RCP8.5 (extreme).

As far as the historical period is concerned, the findings of the analysis showed that Heraklion, Crete Island, appears the most favorable bioclimatic conditions at midday (UTC 12:00), followed by Limassol and Malta, while Cairo and Antalya show high frequency and duration of strong/extreme heat stress within the year. Regarding evening hours (UTC 21:00) during summertime, there is a slight cold stress/thermal comfort in Heraklion and Malta, followed by Limassol, Antalya and Cairo with worse bioclimatic conditions.

Based on climate model simulations for 2021-2050 (near future) and 2071-2100 (far future) under RCP4.5 and RCP8.5, for midday (UTC 12:00), Heraklion, Crete Island depicts the best bioclimatic conditions, which can be attributed to the increased frequency and intensity of the Etesians winds, blowing during the summer period of the year contributing to the mitigation of the strong/extreme heat stress. The frequency and the duration of thermal comfort in the evening (UTC 21:00) is expected to increase for both RCPs. Malta shows similar bioclimatic behavior to Heraklion during evening hours, followed by Limassol, Antalya and Cairo, where the light/moderate heat stress occurs with increasing frequency and seasonality.

The results of the bioclimatic analysis will help in the management/dissemination of climate information for tourism purposes. In addition, the methodology used, based on bioclimatic (PET) diagrams, can provide detailed information in order to assess and quantify the climate change impacts on the tourism potential in the eastern Mediterranean.