Desertification means land degradation in arid, semi- arid and dry sub- humid area resulting from various factors, including climate variations and human activities.

Desertification can only be reversed through profound changes in local and international behavior, these changes will ultimately lead to sustainable land use and food security for a growing world population.

Due to Iran's geographical situation and topographical features, about 80% of Iran's total area have arid or semiarid climate.

Land degradation and desertification in Iran have accelerated during recent decades due to the following factors:

• Population has doubled during last 25 years (since 1979).
• More agricultural and pastoral products have forced people to use land extensively or convert forest and rangelands to cultivated land.
• Over use of wood and plants as fuel for household cooking and heating And use of natural regulation tends to denude the soil and intensify desertification. Denuded soil is exposed to wind erosion and shifting sand dunes destroy orchards, gardens, farming lands and threaten industrial and economical centers and leads to total collapse of economy, devastation of the environment, abandonment of settlements and migration of people to other cities and residential centers.
• Irregular and uncoordinated exploitation of water resources.

The policies and programs to rehabilitate and develop renewable natural resources, with consideration for desertification control are as follows:

• Public awareness about the importance of renewable natural resources (using the mess media).
• Socio-economic development in rural areas (to prevent the migration of farmers to major cities (Tehran, Shiraz, Esfahan, Tabriz).

• Conservation of water resources including Ghanats system and water supply installations.
• Protection of roads and communications networks.
• Protection of the environment and restoration of ecological stability.
• Reclamation and Rehabilitation of degraded land.
• Sand dune stabilization to minimize negative effects on farmland.And other valuable economic infrastructure.

Desertification is a global concern not limited to specific geographical regions. Desertification has become a longstanding and increasingly severe problem in many parts of the world, and in developing countries in particular.

In the case of Iran: Wind erosion and its effects on natural resources and the environment has been a serious problem in the last 25 years.

Iranian researchers carried out experiments and projects for decades on dune stabilization and rehabilitation of decertified lands.

Two of the major environmental hazards affecting the planet are deforestation and desertification, in terms of the nature and magnitude of the problem as faced by the developing world including Iran. Much of the earth is degraded, or is at risk of degradation. Marine, freshwater, atmospheric, near-space and terrestrial environments have suffered and continued to suffer degradation. Shifting agriculture is the primary cause of deforestation.

More than 250,000 ha of tropical forest are destroyed annually in 14 developing countries in South America, Africa, and South- East Asia. The growth, development and decline of forests have always reflected the integrated effects of many variables.

The expansion of communication, the construction of large dams, the failure to assist the poor, and climatic anomalies of fire and drought only aggravate this problem further. Desertification and deforestation involve a drastic change in microclimates. Global warming and the greenhouse effect, which have their origin in deforestation and desertification.

Deforestation and desertification adversely affect agriculture productivity, the health of humans as well as of livestock, and economic activities such as eco-tourism.

References:

*The international day of desertification combat.
*Desertification and its control in Iran.
*Desertification and deforestation in developing countries (R.K. Pachauri).