Long-term recurrent exposure to excessive heat in the east Mediterranean and climate resilience development – a case study in Israel

This work studies long-term trends of observed meteorological parameters and of exposure to excessive heat over 74 years in Israel (1950–2023). We report an increasing trend of recurring exposure of the Israeli population to excessive heat during most of the summer noon hours, with the heat index often above the physiologically no-risk threshold. Specifically, since the beginning of the millennium, a significant increase in summertime decadal means of ambient noontime temperature (T_a), absolute humidity (AH), and heat index (HI) is evident relative to the 1950’s (T_a: 0.06 °C/year, AH: 0.06 g/m³year, HI: 0.09 °C/year). The experienced increase summertime thermal discomfort by the Israeli population results from the significant and synergistic increase in co-exposure to ambient temperature and humidity. Indeed, long-term satellite data (Landsat 1984–2021) of the east Mediterranean Sea Surface Temperature (SST) reveal a significant change (SST: 0.05 °C/year), which elucidates the corresponding increase in the absolute humidity. Leishmaniasis is a climate-related vector-borne infectious disease. However, the 1956–2017 leishmaniasis incidence rates in Israel do not correlate with the significant increase in the ambient temperature and heat index, representing development of climate resilience in terms of administrated prevention measures (namely, systematic adaptation) to this climate-related disease.