Kareem Washington

 Desertification is the conversion of croplands into a desert environment  Caused by dehydration of the top layers of soil near existing deserts  Modern threat to agriculture

 Result of drought and increased evaporation near deserts  High winds and hot temperatures contribute to erosion  Lack of deep rooted plants to hold in soil

 Desertification occurs naturally but is accelerated by human activity  By leaving topsoil vulnerable to erosion by water/wind  Overgrazing by large livestock on small portions of land  Improper soil and resource management  Leading to erosion, salinization, waterloggging

 Cultivation of land with unsuitable terrain/soils  Deforestation and surface mining without adequate replanting  Soil compaction by farming machinery, cattle hooves, and raindrops on denuded soil  All intensified by high populations, poverty, and poor land management

 Drought, famine, and unsustainable agriculture  Costly process of regaining and fighting desertification  Disputes over farmable land  Leads to large number of “environmental refugees”

 35% of the Earth’s land surface, on which one- fifth of the world’s people survive is arid or semiarid desert  Rise in rural people affected by desertification  From 57 million in 1977 to 350 million in 2000

 Moderate desertification causes a 10-25% drop in agriculture  Many farmers can undergo without notice  Severe desertification causes a 25-50% drop in agriculture  Very severe desertification causes 50% or more drop in agriculture  Results in massive gullies and sand dunes

 Affected Ares:  Sub-Saharan Africa  Eastern and southern Africa  Australia  Western United States  Southern South America  South Central Asia  Over 2 billion acres of land in the last 50 years have become desertified  15 million more acres are desertified every year

 1977 government representatives gathered in Nairobi for United Nations Conference on Desertification  Plans to halt and reduce spread of desertification  Costs of plans priced at $141 billion  Cost of annual loss in agriculture: $26 billion  Inadequate funding have slowed efforts

 Environmental Science  Third Edition - G. Tyler Miller Jr.