Changing Water Resources and Food Supply in Arid Zones: Tunisia

The notion of water security in all arid country takes on another dimension when the comprehensive water balance concept is applied to water used by rain-fed agriculture and to the water equivalent of international food exchanges. In the case of Tunisia, this concept expands the prospects for improvements in national food security by optimizing the food balance and the corresponding virtual water flux. It also prompts reconsideration of criteria and indicators classically used to characterize water stress situations. The current situation shows that about 30% of the water used in Tunisia is imported as food (virtual water) that number is likely to reach 40-50% in 2025 due to climate change, diet change, demographic Growth, and improved water management. Asia and North Africa will most likely not be self-sufficient in terms of food production and will need to import food from other continents (e.g., South America). Africa, however, could be self-sufficient if its existing water resources are developed. Bioenergy production is likely to be limited to a small fraction of the global energy needs. Major food shortages ill cases of severe global droughts (e.g., during very strong El Nino events) may occur, however, with severe consequences in terms of food availability.