Challenges related to Climate Change and Identification of Risks and Impacts in Jerusalem

Jerusalem City is unique in its diversity of populations with a total of 936,000 inhabitants (end of 2018) with 62% Jewish and 38% Arabs,
and is located exactly at the border of Mediterranean climate with a significant variability between the coastal area, including Jerusalem City (annual rainfall ~600 mm) and the most arid zone of the Dead Sea, 20-30 km east of the city (annual rainfall ~50 mm). The spatial-temporal variation of rainfall
intensity is the main and not well-known driver that generates the majority of flash floods in the nearby Judean Desert. Hence, its monitoring is crucial in this area as in other remote arid areas worldwide.

Recently, extensive research was performed related to global warming potential risks and their effects on rainfall and temperature over the East Mediterranean. Several major risks were pointed out including extreme temperatures, heat waves, colder nights and heavy rainfall. Important to notice is our first super-high-resolution global climate model projections that the ancient “Fertile Crescent” in the Middle East (considered as the cradle of civilization), will nearly disappear during this century by the year 2100 (Kitoh et al. 2008).

Jerusalem temperatures both maximum and minimum show that significant increases occurred during 1950-2020 (based on homogenized dataset, Yosef et al., 2019). Furthermore, enhanced increases are shown to have occurred from the 1980s of the temperature trends which are even more than double of the global average ones. A fact that led to definition of the Mediterranean as a “Hot Spot” of global warming. Comparison of Jerusalem temperatures increasing trends to the coastal upstream Bet Dagan station, at ~40 km to the west does show similar patterns of statistically most significant increases in the region as well as large inter-annual variabilities.

A general reduction in the annual amount was observed in the last four decades over Jerusalem. This tendency is expected to continue and become more pronounced under the "business as usual" scenario of RCP8.5. Some potential socioeconomic impacts will be presented.