[1] In this study, the consistency of trends in radiation and temperature records and their implications for the hydrological cycle and especially the trends in reference evapotranspiration are examined during the period 1950-2001. The new reference evapotranspiration model for complex terrains (REMCT), with monthly time step, is used for estimating trends of reference evapotranspiration in Greece. REMCT is applied after developing a methodology for calibrating its parameter values with Penman-Monteith estimates. The calibrated REMCT estimates are independently validated against available pan evaporation measurements. The evolution of available sunshine duration anomalies measured in Athens during the period 1951-2001 are used for highlighting global dimming or brightening periods in Greece. The sign of trends in the modeled reference evapotranspiration and precipitation are examined according to the dimming or brightening periods 1950-1983 and 1958-1983 (for 16 and 22 stations, respectively) or 1983-2001 (for 16, 22, and 29 stations). The trends of REMCT estimates, precipitation, number of rainy days, and mean, maximum, and minimum air temperature for all sets of stations considered "as a whole" are evaluated during the same periods. The results show that the annual calibrated reference evapotranspiration trend shows a decline from 1950 until the early 1980s, followed by an upward trend until 2001, while the annual precipitation and rainy days indicate a downward trend during the whole period 1950-2001. The trends of mean, maximum, and minimum air temperature are found almost negligible during the dimming period and rather increased during the brightening period.

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The paper presents the analysis of a sub-set of high-resolution bias-adjusted simulations from the EURO-CORDEX initiative, in order to examine the changes in the mean climate and the extremes in three Mediterranean islands, namely, Sicily, Crete and Cyprus, in the near future (2031–2060) compared to the present climate (1971–2000), under two future scenarios, i.e. RCP4.5 and RCP8.5. The analysis entails commonly used climatic indices of interest related to the islands’ agricultural sector. The results indicate robust increases for both the mean maximum and minimum temperatures on a seasonal basis, as well as for the temperature related extremes under both climate scenarios. On the contrary, the changes in precipitation are less pronounced as the changes in the seasonal precipitation are not found statistically significant for the three islands under both scenarios. The projected warming combined with the projected unchanged precipitation pattern in the future, especially in spring and summer, might expose the crops to conditions with a negative impact on the plants’ phenology, leading to implications on crop production and quality. The results presented here might be the basis for the development of an adaptation strategy specifically targeted on the three islands but also replicable to other Mediterranean islands.

The Mediterranean area is one of the most visited tourist destinations of the world, but it has also been recognized as one of the most vulnerable to climate change areas worldwide with respect to increased thermal risk. The study focuses on a top worldwide tourist destination of the Mediterranean, Santorini Island in Greece, and aims to assess the past, present and future thermal environment in the island based on the advanced Universal Thermal Climate Index (UTCI). The study utilizes historical observations capturing past (late 19th to early 20th century) and more recent (1982–2019) time periods, while future projections are realized based on four regional climate models (RCMs) under the weak mitigation scenario (RCP4.5) and the non-mitigation scenario with high emissions (RCP8.5). The frequency of cold stress conditions at midday decreases during winter and early spring months by up to 19.8% (January) in the recent period compared to the historical one, while heat stress conditions increase in summer by up to 22.4% (August). Future projections suggest progressive shifts of the UTCI towards higher values in the future and an increase in the exposure time under heat stress depending on the RCM and adopted scenario. The increase in moderate and strong heat stress conditions is mainly expected during the summer months (June, July, August); nevertheless, a noticeable increase is also foreseen in September and May. The highest occurrences of favorable (no thermal stress) conditions are also projected to shift by one month, from June to May and from September to October, in the future.