2006 has been named "Year of Desertification" by the U.N.
Modern desertification has been caused by a variety of factors, ranging from climatic factors (minor) to human degradation of arable land areas. Most desertification now is caused by increasing populations growing crops and raising animals.
Overgrazing (as is the case of much of the southwest U.S. and northern Mexico, and hooves of pastoral animals compacting the substrata thus reducing the soil's ability to percolate water. This in turn encourages erosion.
In more seriously affected poverty areas (such as sub-Saharan Africa and parts of Asia, collection of firewood and reduction of biodiversity eliminates plants that helps bind the soil.
An estimated 2.6 billion people, almost 40 percent of the world's population, are either currently experiencing desertification, or are on the brink of being overrun by it.
Related Article: The World's Water Supply at Risk
