Climate change: Land degradation and desertification

Land degradation is caused by multiple forces, including extreme weather conditions, particularly drought. It is also caused by human activities that pollute or degrade the quality of soils and land utility. It negatively affects food production, livelihoods, and the production and provision of other ecosystem goods and services. Desertification is a form of land degradation by which fertile land becomes desert.

Land degradation has accelerated during the 20^th and 21^st centuries due to increasing and combined pressures of agricultural and livestock production (over-cultivation, overgrazing, forest conversion), urbanization, deforestation and extreme weather events such as droughts and coastal surges, which salinate land.

These social and environmental processes are stressing the world's arable lands and pastures essential for the provision of food and water and quality air. Land degradation and desertification can affect human health through complex pathways. As land is degraded and deserts expand in some places, food production is reduced, water sources dry up and populations are pressured to move to more hospitable areas.

The potential impacts of desertification on health include:

• higher threats of malnutrition from reduced food and water supplies;
• more water- and food-borne diseases that result from poor hygiene and a lack of clean water;
• respiratory diseases caused by atmospheric dust from wind erosion and other air pollutants;
• the spread of infectious diseases as populations migrate.