Desertification is a term used to describe the gradual changes that take place over a region or area of land that ultimately result in the formation of a desert. Although many places in the world are called deserts, scientists usually define a desert as a region or area that receives less than 10 inches (25.4 centimeters) of water from precipitation (rain, slow, sleet, or hail) during a year.

Desertification harms many people. During the late 1960s and early 1970s, desertification brought on by a severe drought (an extended period with little or no rain) in the Sahel region of Africa devastated the local agriculture of six African countries located on the southern border of the Sahara Desert. International relief measures were unable to prevent the death of thousands of people who suffered from the resulting famine (lack of food). Millions of animals that normally relied upon eating the grass that...