Desertification is a process wherein semi-arid arable land is turned into desert, unable to sustain plant or animal life. Although desertification can be caused by natural processes, like climate change, it is generally agreed that human influences are greatly accelerating the rate of desertification worldwide. As pressures on the Earth grow due to increased population and global warming, it is estimated that the rate of desertification may start to rapidly increase, and it is already causing serious social and environmental problems in some African nations.
In the United States, one of the most famous historical examples of desertification is the Dust Bowl of the 1930s, although the rapid destruction of grassland in the American west is comparable. In Africa, the rapidly expanding Sahara and serious desertification occurring in the Sahel region of West Africa are being cited by numerous humanitarian organizations as issues of concern. For humans, the reduction of usable land through desertification has a serious impact, especially on impoverished indigenous people who cannot readily adapt to new systems of living.
Desertification often starts in drought conditions, although it does not always occur in a drought. The top layer of hardy plants is stripped away from the earth, meaning that there are no roots to hold the soil down. Winds carry the nutritious topsoil elsewhere, leaving sand behind, and forming large drifts of sand and dead plant material which encroach on human civilization. Animals are unable to forage for food in these conditions, meaning that nomadic peoples lose much of their herds, and because all the plant life is dead, alternative food sources are not available. The soil is also at a greater risk of flooding, and erosion starts to clog nearby water sources with soil.
Climate change is obviously a factor in desertification, but so are harmful human practices such as poorly practiced irrigation, which concentrates salts in the soil and kills plants. In addition, deforestation and stripping land of all available plant life also contributes to the problem. Especially in the delicate transitional zones between arid desert and fully arable land, desertification can happen very quickly and be utterly irreversible. As the topsoil vanishes along with the plants, the desert is unable to retain even minimal water supplies, and quickly becomes utterly arid.
Efforts are underway by many humanitarian organizations, including the United Nations, to put a halt to desertification and attempt to reclaim usable land. These include education about land use and reclamation tactics such as embedding straw mats and retainer walls in the soil in an effort to keep it from blowing away. Sturdy rooted plant life is also being planted in an effort to hold the soil down. Numerous campaigns to end hunger are also involved, as desertification poses serious risks to proper nutrition: shipments of food and nutritional education are provided to areas which are experiencing desertification, in the hopes that providing food will give the delicate transition areas a chance to recover.