ABSTRACT

Except for its most northwestern part, arable land in the northeastern Fertile Crescent (precipitation ~300 mm/year) falls entirely into climatic zones, classified

as semiarid or arid [1]. The need to satisfy the rising food demand of a rapidly growing population forces authorities to press for higher agricultural yields and for the development of new agricultural areas [2,3]. Demands, however, can only be met by expanding agriculture into less fertile rangeland areas [4], which requires additional dam constructions and the expansion of an already dense irrigation network [5,6]. An increasing dependence of agriculture and, consequently, of food supply on irrigation water is the result [7,8]. Neglecting climate change, recent developments in irrigation projects and in dam constructions will lead to a water deficit in Syria by 2020 at the latest [9]. These developments, however, fall into a time where climate models predict substantial temperature increases in this region [10] with adverse impacts on the water budget, which may cause water shortages to occur even earlier. Irrigation water is either pumped from renewable and nonrenewable aquifers or diverted from river water [3] originating in the Taurus Mountains (Turkey) and the Zagros Mountains (Iraq) [11]. Due to lower transportation costs (pumping vs. mostly gravity flow), farmers give preference to river water wherever possible. Snowfields in the Taurus Mountains are the main source of river water for the Euphrates. This water is gradually released during springtime (March to May) and ensures a continuous water flow through the dry season from May to October. The predicted climatic changes are likely to change this balance, with impacts on downstream agriculture (Figure 12.1).