Fifty years of observation in the Mediterranean Basin reveal several trends: increased warming in the summer and increased precipitation in the southeastern Mediterranean Sea as opposed to decreased precipitation in most of the Mediterranean Sea Basin, including countries near Israel such as Greece, Turkey and Cyprus.
The Chief Scientist of the Ministry of Environmental Protection, Dr. Yeshayahu Bar Or, warns that existing desalination plans will not respond to the water shortage which is anticipated in Israel due to climate change, pollution of water reservoirs and urbanization processes.
Dr. Bar Or will present his research study in the Jerusalem Environment and Nature Conference, organized by the Society for the Protection of Nature in Israel, on May 18 - 19, 2008. His findings on the consequences of global warming on the water economy in Israel will be presented within the framework of a session entitled "Till the last Drop: Nature's Right to Water in Light of a Global Water Crisis." Additional participants in this session will include Infrastructure Minister Binyamin Ben Eliezer, Knesset Member and Chairman of the Knesset Interior and Environment Committee, Ophir Pines, and representatives of the Water Authority and Mekorot - Israel National Water Co.
Impacts of Climate Change on Israel's Water Economy
According to Dr. Bar Or, the trend of global warming in all seasons, and especially during night hours, by some 2 degrees Celsius, will impact on Israel's future water economy. This trend began in the 1970s and was accompanied by an increase in the number of warm and cold days in July-August. This trend translates into an increase in the quantity of water required to irrigate agricultural areas and gardens.
Another impact on Israel's water economy is a reduction in the available water volume in Lake Kinneret (Sea of Galilee) and the Jordan Valley at an average of some 110 million cubic meters per year (about 6.5% of Israel's water consumption). Dr. Bar Or notes that this decrease is directly related to the decrease in precipitation, which is caused, it appears, by climate change, as well as an increase in the quantity of particulate air pollution during the second half of the 20th century.
According to different studies, temperatures in Israel are expected to rise by 3.5-5 degrees Celsius in 2071 - 2100 in comparison to 1961 - 1990. Precipitation quantities in the winter are expected to decrease at a range of 15 - 75 mm, equal to a 10%-30% reduction. In addition, the number of extreme weather events is expected to increase in comparison to the present climate.
According to Dr. Bar Or: "All these will lead to warming and aridity in the future, which may bring about a 35% reduction in the precipitation volume by the end of the present century. In addition, areas with inadequate infiltration capacity, such as heavy soils and built up areas, will experience more floods and at greater intensities, which will cause significant damage to human life, the environment, property and the economy. Wide scale building, especially on the coastal plain, will block the infiltration rainwater to the soil and the enrichment of groundwater, leading to a decrease in available drinking water from groundwater. In addition, sea level rise in the Mediterranean Sea may accelerate the desalination processes of the coastal aquifer."
Lake Kinneret is already experiencing changes. Since 1994, the lake has witnessed the appearance of cyanobacteria (blue-green algae) with a potential to produce new toxins. Their appearance is a warning sign of the lake's environmental conditions. The impacts of these algae include damage to the quality of drinking water which is supplied from the Kinneret and reduction of the lake's biological diversity.
Proposals for Action
In a recent letter dispatched by Dr. Bar Or to Prof. Uri Shani, director of the Water Authority, he states: "In light of these threats, a comprehensive plan, with wider horizons than what has been done to date, is needed to preserve the water economy. Desalination facilities, even at an increased scope of 500 - 8000 million cubic meters/year, cannot respond to the ever-growing shortage.
It is necessary to undertake a series of complementary steps, including the following:
1. Information: In my estimation, water savings in gardens cannot be achieved by enforcement alone. Comprehensive and ongoing information is necessary on possibilities of water saving gardening in public and private gardens. For this purpose, I propose cooperation with 50 associations of towns and municipal units for the environment throughout Israel.
2. Permeable infrastructure: A professional and detailed instruction program should be prepared for local authorities on means and methods for permeable infrastructure in sidewalks and open public areas. These measures should also be implemented during the routine upgrading of municipal infrastructure (a 3% annual replacement rate of infrastructures such as pavements is customary).
3. Rehabilitation of Contaminated Boreholes: A comprehensive program is necessary to rehabilitate contaminated boreholes, with special attention to treatment and removal of brines. Such a plan should also relate to the trends of increase in pollutant concentrations in pumped well water, even when they are still within the permitted range of values for supply. Moreover, a plan for pumping and treating contaminated water may, at least in some of the cases, also prevent the spread of a pollutant cloud to other wells which are not yet contaminated. We propose coordinated work with regard to the proper environmental disposal of brines, which may contain a high concentration of environmental pollutants."
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