Perhaps an unusual topic, and yet so vital to our very survival and health. (For a more detailed explanation, see Chapters 5 and 8 in Plan B 2.0: Rescuing a Planet Under Stress and a Civilization in Trouble available for free downloading.)
In 1938, Walter Lowdermilk, a senior official in the Soil Conservation Service of the U.S. Department of Agriculture (USDA), traveled abroad to look at lands that had been cultivated for thousands of years, seeking to learn how these older civilizations had coped with soil erosion. He found that some had managed their land well, maintaining its fertility over long stretches of history, and were thriving. Others had failed to do so and left only remnants of their illustrious pasts.In a section of his report entitled "The Hundred Dead Cities," he described a site in northern Syria, near Aleppo, where ancient buildings were still standing in stark isolated relief, but they were on bare rock. During the seventh century, the thriving region had been invaded, initially by a Persian army and later by nomads out of the Arabian Desert. In the process, soil and water conservation practices used for centuries were abandoned. Lowdermilk noted, "Here erosion had done its worst....if the soils had remained, even though the cities were destroyed and the populations dispersed, the area might be re-peopled again and the cities rebuilt, but now that the soils are gone, all is gone."
Now fast forward to a trip in 2002 by a U.N. team to assess the food situation in Lesotho, a small country of 2 million people imbedded within South Africa. Their finding was straightforward: "Agriculture in Lesotho faces a catastrophic future; crop production is declining and could cease altogether over large tracts of the country if steps are not taken to reverse soil erosion, degradation, and the decline in soil fertility." Nearly half of the children under five in Lesotho are stunted physically, too weak to even walk to school.
The health of a people cannot be separated from the health of the land itself. A large share of the world's 852 million hungry people live on land with soils worn thin by erosion.
Perhaps a third or more of all cropland is losing topsoil faster than new soil is forming, thereby reducing the land's inherent productivity.
The accelerating soil erosion over the last century can be seen in the dust bowls that form as vegetation is destroyed and wind erosion soars out of control. The overplowing of the U.S. Great Plains during the late nineteenth and early twentieth centuries, for example, led to the 1930s Dust Bowl. During this tragic era in U.S. history, thousands of farm families were forced to leave their homes on the Great Plains. Many migrated to California, a move immortalized in John Steinbeck's The Grapes of Wrath.
Three decades later, history repeated itself in the Soviet Union. The Virgin Lands Project between 1954 and 1960 centered on plowing an area of grassland for wheat that was larger than the wheatland in Canada and Australia combined. Initially this resulted in an impressive expansion in Soviet grain production, but the success was short-lived as a dust bowl developed there as well.
Kazakhstan, at the center of this Virgin Lands Project, saw its grainland area peak at just over 25 million hectares around 1980, then shrink to 14 million hectares today. Even on the remaining land, however, the average wheat yield is scarcely 1 ton per hectare, a far cry from the nearly 8 tons per hectare that farmers get in France, Western Europe's leading wheat producer.
A similar situation exists in Mongolia, where over the last 20 years half the wheatland has been abandoned and wheat yields have also fallen by half, shrinking the harvest by three fourths. Mongolia now imports nearly 60 percent of its wheat.
Dust storms originating in the new dust bowls are now faithfully recorded in satellite images. On January 9, 2005, the National Aeronautics and Space Administration (NASA) released images of a vast dust storm (nearly 3,300 miles long) moving westward out of central Africa. Had the storm been over the United States, it would have covered the country with room to spare.
Saharan dust storms—once rare—are now commonplace. Among the countries in the region most affected by topsoil loss from wind erosion are Niger, Chad, Mauritania, northern Nigeria, and Burkino Faso. In Mauritania, in Africa's far west, the number of dust storms jumped from 2 a year in the early 1960s to 80 a year today.
The 2 to 3 billion tons of fine soil particles that leave Africa each year in dust storms are slowly draining the continent of its fertility and, hence, its biological productivity. In addition, dust storms leaving Africa travel westward across the Atlantic, depositing so much dust in the Caribbean that they cloud the water and damage coral reefs there.
This is just the tip of the erosion problem. Eliminating these excesses and the resultant decline in the earth's biological productivity depends on a worldwide effort to restore the earth's vegetative cover.