Annual rainfall levels in Israel have not changed drastically over the last 90 years, but temperatures have seen a sharp increase over the last two decades, according to a climate change report published last week by the Israel Meteorological Service.
- Mideast climate change: Hotter, drier and more dangerous
- Weekend storm dumps snow and rain across Israel
- Jerusalem closed off as blizzard hits Israel; 17,000 homes without power
The new analysis updates a report published by the IMS four years ago. It is based on temperature data from 1951 onward and rainfall data from as far back as 1921.
The temperature analysis was based on data from five weather stations throughout Israel, representing all the different types of terrain in Israel – spanning from Safed in the north to Eilat in the south. The calculations were based on the average monthly minimum and maximum temperatures.
The data shows there was a downward trend in temperatures during the 1970s. However, there has been a sharp increase in temperatures since the 1990s, which leveled out after the year 2000 to an average higher than the average during the 1950s.
The most drastic changes were noted in average minimum temperatures. The hottest series of years on record is 1998-2011, during which the average temperature was 20.5 degrees Celsius (68 degrees Fahrenheit).
Rainfall data was based on 15 measuring stations that have been compiling records since 1921 (except for the Golan Heights, which exists only from 1968 onward). Comparison of rainfall data was done with average precipitation over three different periods, spanning 1921-1950, 1951-1980 and 1980-2010.
The primary conclusion is that there has not been a significant change in rainfall in Israel over the last 94 years. At the same time, the IMS noted that, over the last 11 years, even the largest rainfall level was 10% less than the multiyear average.
One question that particularly interested the researchers concerned possible downward trends in rainfall at the regional level, primarily around the Sea of Galilee. No significant change was recorded in any region aside from the northern Negev, where there has been a significant drop in rainfall over the past 15 years, compared with previous periods.