"Urban transport systems based on a combination of rail lines, bus lines, bicycle pathways, and pedestrian walkways offer the best of all possible worlds in providing mobility, low-cost transportation, and a healthy urban environment." –Lester R. Brown, Plan B 4.0: Mobilizing to Save Civilization.
Desertification, the process of converting productive land to wasteland through overuse and mismanagement, is unfortunately all too common. Anything that removes protective grass or trees leaves soil vulnerable to wind and water erosion. In the early stages of desertification, the finer particles of soil are removed by the wind, creating dust storms. Once the fine particles are removed, then the coarser particles—the sand—are also carried by the wind in localized sand storms.
Large-scale desertification is concentrated in Asia and Africa—two regions that together contain nearly 4.8 billion of the world’s 6.5 billion people. Populations in countries across the top of Africa are being squeezed by the northward advance of the Sahara.
In the vast east-to-west swath of semiarid Africa between the Sahara Desert and the forested regions to the south lies the Sahel, a region where farming and herding overlap. In countries stretching from Senegal and Mauritania in the west to Sudan, Ethiopia, and Somalia in the east, the demands of growing human and livestock numbers are converting more and more land into desert.
Nigeria, Africa’s most populous country, is losing 351,000 hectares of rangeland and cropland to desertification each year. While Nigeria’s human population was growing from 33 million in 1950 to 132 million in 2005, a fourfold expansion, its livestock population grew from roughly 6 million to 66 million, an 11-fold increase. With the forage needs of Nigeria’s 15 million cattle and 51 million sheep and goats exceeding the sustainable yield of the country’s grasslands, the northern part of the country is slowly turning to desert. If Nigeria continues toward 258 million people as projected by 2050, the deterioration will only accelerate.
Iran is also losing its battle with the desert. Mohammad Jarian, who heads Iran’s Anti-Desertification Organization, reported in 2002 that sand storms had buried 124 villages in the southeastern province of Sistan-Baluchistan, forcing their abandonment. Drifting sands had covered grazing areas, starving livestock and depriving villagers of their livelihood.
Neighboring Afghanistan is faced with a similar situation. The Registan Desert is migrating westward, encroaching on agricultural areas. A U.N. Environment Programme (UNEP) team reports that “up to 100 villages have been submerged by windblown dust and sand.” In the country’s northwest, sand dunes are moving onto agricultural land in the upper reaches of the Amu Darya basin, their path cleared by the loss of stabilizing vegetation from firewood gathering and overgrazing. The UNEP team observed sand dunes 15 meters high blocking roads, forcing residents to establish new routes.
China is being affected by desertification more than any other major country. Wang Tao, Director of the Cold and Arid Regions Environmental and Engineering Research Institute, describes the country’s accelerating desertification. He reports that from 1950 to 1975 an average of 1,560 square kilometers of land were lost to desert each year. Between 1975 and 1987, this climbed to 2,100 square kilometers a year. From then until the century’s end, it jumped to 3,600 square kilometers of land going to desert annually.
China is now at war. It is not invading armies that are claiming its territory, but expanding deserts. Old deserts are advancing and new ones are forming like guerrilla forces striking unexpectedly, forcing Beijing to fight on several fronts. Wang Tao reports that over the last half-century, some 24,000 villages in northern and western China have been entirely or partly abandoned as a result of being overrun by drifting sand.
People in China are all too familiar with the dust storms that originate in its northwest and in western Mongolia, but the rest of the world typically learns about this fast-growing ecological catastrophe from the massive dust storms that travel outside the region. On April 18, 2001, the western United States—from the Arizona border north to Canada—was blanketed with dust. It came from a huge dust storm that originated in northwestern China and Mongolia on April 5. Measuring 1,800 kilometers across when it left China, the storm carried millions of tons of topsoil, a vital resource that will take centuries to replace through natural processes.
Almost exactly one year later, on April 12, 2002, South Korea was engulfed by a huge dust storm from China that left people in Seoul literally gasping for breath. Schools were closed, airline flights were cancelled, and clinics were overrun with patients having difficulty breathing. Retail sales fell. Koreans have come to dread the arrival of what they now call “the fifth season,” the dust storms of late winter and early spring.
These two dust storms, among the 10 or so major dust storms that occur each year in China, are one of the externally visible indicators of the ecological catastrophe unfolding in northern and western China. Overgrazing is the principal culprit.
A U.S. Embassy report entitled “Desert Mergers and Acquisitions” describes satellite images showing two deserts in north-central China expanding and merging to form a single, larger desert overlapping Inner Mongolia and Gansu provinces. To the west in Xinjiang Province, two even larger deserts—the Taklimakan and Kumtag—are also heading for a merger. Highways running through the shrinking regions between them are regularly inundated by sand dunes.
In Latin America, deserts are expanding in both Brazil and Mexico. In Brazil, where some 58 million hectares of land are affected, economic losses from desertification are estimated at $300 million per year, much of it concentrated in the country’s northeast. Mexico, with a much larger share of arid and semiarid land, is even more vulnerable. The degradation of cropland now prompts some 700,000 Mexicans to leave the land each year in search of jobs in nearby cities or in the United States.
In scores of countries, the overgrazing, overplowing, and overcutting that are driving the desertification process are intensifying as the growth in human and livestock numbers continues. Stopping the desertification process from claiming more productive land may now rest on stopping the growth in human and livestock numbers.
Adapted from Chapter 5, “Natural Systems Under Stress,” in Lester R. Brown, Plan B 2.0: Rescuing a Planet Under Stress and a Civilization in Trouble (New York: W.W. Norton & Company, 2006), available for free downloading and purchase at www.earth-policy.org/books/pb2.