Key issues pertaining to soils are degradation through water and wind erosion and through nutrient loss. Salinization, waterlogging and alkalization are major issues in irrigated areas, especially in large-scale irrigated schemes.

Population growth and demography

Population in CWANA will be about 1.2 billion by 2025; it is expected to reach 1.6 billion (17% of the world population) by 2050. The population is rapidly becoming urbanized in many countries of the region. By 2020 the percentage of the urban population to the total population will be 93% in Oman, 91% in Libya, 90% in Saudi Arabia and UAE, 85% in Turkey and 75% in Tunisia. In some countries of the region such as Afghanistan the urban population will remain under 30% (UNDP et al., 2003).

Water scarcity and its implication for agricultural production systems

Scarcity of water is the chief challenge to agricultural development in almost all CWANA countries. Freshwater scarcity threatens CWANA's ability to achieve food security, alleviate poverty and improve human health. Land scarcity compounds the problems of water scarcity, making people more vulnerable to the extremes of droughts and floods and leading to widespread exploitation of natural resources.

Access and use of agrobiodiversity

Due to the megadiversity of crop species in CWANA, major crops, wild relatives and landraces vary significantly in the region. They are important sources of useful genes for several characters such as adaptation to extreme conditions of abiotic stress, resistance to pests and diseases, high quality, and factors affecting productivity. They also play an important cultural and social role, and they secure evolutionary continuity.

The richness of agrobiodiversity and the existence of low-input farming systems in the region is key to food security and sustainable agricultural production in the region as well as outside. Many farmers in CWANA countries cannot afford expensive external inputs such as fertilizers, pesticides or seed of improved varieties adapted to the particular ecological and economic situation. Plant genetic diversity, at both intra- and interspecific levels, is crucially important in CWANA farming systems. So this existing diversity helps stabilize farming systems by maintaining the wide range of crop diversity.

Domestic animals contribute to food and agriculture in many ways, providing meat, milk and milk products, eggs, fiber, and fertilizer for crops, manure for fuel, and essential draft power. They are an extremely important economic resource, reducing risk, generating employment, and evening out seasonal farm labor demands. Some 4,000 breeds of cattle, horse, donkey, pig, sheep, buffalo, goat, chicken and duck have been developed and used worldwide. Animal genetic resources of breeds and strains and wild or semidomesticated relatives are important, their diversity being insurance against future adverse conditions. Farmers and breeders have successfully selected animals for a variety of traits and production environments, using their genetic diversity extremely effectively.

But because of the Green Revolution that took place in Pakistan and the adoption of high-yield varieties, genetic

resources in the CWANA region are being degraded. The shift from small-scale to large-scale farming systems using technical packages that feature mechanization and chemicals is contributing to biodiversity loss. Many governments are unaware that they should establish gene banks to conserve local varieties. The situation with livestock seems to be better. Foreign breeds, especially of cattle, have been imported in many countries but their adoption has been slow because they need large amounts of feed that farmers cannot afford. So farmers are still rearing local breeds of cattle, sheep and goats.

Climate change

According to the Intergovernmental Panel on Climate Change (IPCC, 2001), CWANA is among the most vulnerable regions in the world in predicted decreases in water and food security. Changes in rainfall and temperature patterns could also alter biodiversity, with many species not being able to adapt or migrate. However, the consequences of global climate change on agriculture and ecosystems are uncertain. The most likely impact on CWANA, based on various simulation models, is adverse consequences for its semiarid zone. These models show that doubling the CO2 concentration in the atmosphere will induce the following:

• In West Asia and the Arabian Peninsula, temperatures are projected to increase by approximately 4oC. Rainfall and soil moisture will decrease.
• In Central Asia temperatures will increase substantially in winter. More rainfall and a slight increase in soil moisture levels will result. Summer changes include a 6oC temperature increase, greatly varied changes in precipitation and a general decrease in soil moisture (Williams and Balling, 1994).
• In North Africa, the Nile Valley and the Red Sea, grain yields are projected to decrease, further diminishing food security. Desertification will be exacerbated by reductions in average annual rainfall and increased evapotranspiration. Significant extinctions in plant and animal species are projected, importantly affecting rural livelihoods (UNEP, 2002b).

The type of climate change expected will have a major impact on dryland soils, where most of the salinization will occur. These soils are inherently vulnerable to degradation, since they have low biological activity, organic matter and aggregate stability. The resilience of the dryland ecosystems to deficits in moisture, temperature extremes and salinity is still inadequately known.

Land and water access, tenure and management

Land and water access is greatly differentiated in CWANA and generally unequal. Few countries have conducted real land reform, but Turkey did in 1945. Major measures were applied under the rule of Mustafa Kemal in 1926: the tithe to the landholder was abolished in 1925 and the former tenures located on state-owned land were given to farmers (Dufumier, 2004). Land reform was conducted in irrigated areas in the governorates of Deir Ezzor and Rakka in northeastern Syria. Although many problems arose after the government distributed land to farmers, access to it was more or less equal. It created the basis for agricultural production.