[Vision2020] Fwd: Earth Policy News - Losing Soil

[Tom Trail]

>Visionaries--a timely article on soil erosion.


Tom Trail

>Earth Policy Institute
>Plan B 2.0 Book Byte
>For Immediate Release
>June 27, 2007
>
>LOSING SOIL
>
>http://www.earth-policy.org/Books/Seg/PB2ch05_ss3.htm
>
>Lester R. Brown
>
>In 1938, Walter Lowdermilk, a senior official in the Soil Conservation
>Service of the U.S. Department of Agriculture, 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 United Nations 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.” Michael Grunwald reports in the Washington Post that nearly
>half of the children under five in Lesotho are stunted physically. “Many,”
>he says, “are too weak to walk to school.”
>
>Whether the land is in northern Syria, Lesotho, or elsewhere, the health
>of the people living on it 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.
>
>The thin layer of topsoil that covers the planet’s land surface is the
>foundation of civilization. This soil, measured in inches over much of the
>earth, was formed over long stretches of geological time as new soil
>formation exceeded the natural rate of erosion. As soil accumulated over
>the eons, it provided a medium in which plants could grow. In turn, plants
>protect the soil from erosion. Human activity is disrupting this
>relationship.
>
>Sometime within the last century, soil erosion began to exceed new soil
>formation in large areas. Perhaps a third or more of all cropland is
>losing topsoil faster than new soil is forming, thereby reducing the
>land’s inherent productivity. Today the foundation of civilization is
>crumbling. The seeds of collapse of some early civilizations, such as the
>Mayans, may have originated in soil erosion that undermined the food
>supply.
>
>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. Among those that stand out are the Dust Bowl in the U.S. Great
>Plains during the 1930s, the dust bowls in the Soviet Virgin Lands in the
>1960s, the huge one that is forming today in northwest China, and the one
>taking shape in the Sahelian region of Africa. Each of these is associated
>with a familiar pattern of overgrazing, deforestation, and agricultural
>expansion onto marginal land, followed by retrenchment as the soil begins
>to disappear.
>
>Twentieth-century population growth pushed agriculture onto highly
>vulnerable land in many countries. The overplowing of the U.S. Great
>Plains during the late nineteenth and early twentieth centuries, for
>example, led to the 1930s Dust Bowl. This was a tragic era in U.S.
>history, one that forced hundreds of thousands of farm families to leave
>the Great Plains. Many migrated to California in search of a new life, 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 (44 millions acres) 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--a country almost
>three times the size of France with a population of 2.6 million--is now
>forced to import nearly 60 percent of its wheat.
>
>Dust storms originating in the new dust bowls are now faithfully recorded
>in satellite images. In early January 2005, the National Aeronautics and
>Space Administration (NASA) released images of a vast dust storm moving
>westward out of central Africa. This vast cloud of tan-colored dust
>stretched over some 5,300 kilometers (roughly 3,300 miles). NASA noted
>that if the storm were relocated to the United States, it would cover the
>country and extend into the oceans on both coasts.
>
>Andrew Goudie, Professor of Geography at Oxford University, reports that
>Saharan dust storms--once rare--are now commonplace. He estimates they
>have increased 10-fold during the last half-century. 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 Bodélé Depression in Chad is the source of an estimated 1.3 billion
>tons of wind-borne soil a year, up 10-fold from 1947 when measurements
>began. 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.
>
>In China, plowing excesses became common in several provinces as
>agriculture pushed northward and westward into the pastoral zone between
>1987 and 1996. In Inner Mongolia (Nei Monggol), for example, the
>cultivated area increased by 1.1 million hectares, or 22 percent, during
>this period. Other provinces that expanded their cultivated area by 3
>percent or more during this nine-year span include Heilongjiang, Hunan,
>Tibet (Xizang), Qinghai, and Xinjiang. Severe wind erosion of soil on this
>newly plowed land made it clear that its only sustainable use was
>controlled grazing. As a result, Chinese agriculture is now engaged in a
>strategic withdrawal in these provinces, pulling back to land that can
>sustain crop production.
>
>Water erosion also takes a toll on soils. This can be seen in the silting
>of reservoirs and in muddy, silt-laden rivers flowing into the sea.
>Pakistan’s two large reservoirs, Mangla and Tarbela, which store Indus
>River water for the country’s vast irrigation network, are losing roughly
>1 percent of their storage capacity each year as they fill with silt from
>deforested watersheds.
>
>Ethiopia, a mountainous country with highly erodible soils on steeply
>sloping land, is losing an estimated 1 billion tons of topsoil a year,
>washed away by rain. This is one reason Ethiopia always seems to be on the
>verge of famine, never able to accumulate enough grain reserves to provide
>a meaningful measure of food security.
>
>Fortunately there are ways to conserve and rebuild soils. These will be
>discussed in the next Earth Policy Institute Book Byte.
>
>#     #     #
>
>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 on-line at
>www.earthpolicy.org/Books/PB2/index.htm
>
>Additional data and information sources at www.earthpolicy.org
>
>For information contact:
>
>Media Contact:
>Reah Janise Kauffman
>Tel: (202) 496-9290 x 12
>E-mail: rjk (at) earthpolicy.org
>
>Research Contact:
>Janet Larsen
>Tel: (202) 496-9290 x 14
>E-mail: jlarsen (at) earthpolicy.org
>
>Earth Policy Institute
>1350 Connecticut Ave. NW, Suite 403
>Washington, DC  20036
>Web: www.earthpolicy.org
>
>
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Dr. Tom Trail
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