Desertification: Earth's Silent Scourge

НазваниеDesertification: Earth's Silent Scourge
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I S S U E   I N   F O C U S

Earth's Silent Scourge

(Posted September 13, 2004)


"A nation that destroys its soil, destroys itself."

-- President Franklin D. Roosevelt

Internally displaced people walk through a dust storm, Denan, Ethiopia. (AP Photo/Brennan Linsley)
The word "desertification" may not be familiar to some readers; however, it goes to the core of global environmental concerns that increasingly preoccupy people on all continents of the globe.

This book, published by the State Department's Bureau of Oceans and International Environmental and Scientific Affairs and the Bureau of International Information Programs, attempts to define, explain, and offer suggestions about how to deal with the insidious process of land degradation in agricultural and forest areas worldwide that is known as desertification.

Although some aspects are hidden from human sight, desertification affects everybody on the planet by robbing global soil of nutrients, degrading agricultural production, spreading dust throughout the globe, contaminating water, and making it far more difficult to remedy poverty and hunger.

Some of the causes are natural cycles of weather; some relate to human population increase and farming practices. However, it is clear from many historical and contemporary examples that enlightened land management can mitigate or remedy the problem. Herein lies the hopeful side of the story.

Chapter 1 defines the scope and nature of the problem, noting that "the earth's landmasses are losing as much as 24 billion [thousand million] tons of topsoil every year." The chapter goes on to discuss the catastrophic human consequences, and finally the global attempt to deal with the issue embodied in the United Nations Convention to Combat Desertification that went into force in 1996.

Chapter 2 discusses the American experience of disastrous desertification, as reflected for the most part in the spoilage of Midwestern agriculture during the 1930s. Only government-mandated reforms in land management salvaged the environment and agricultural potential of the American Midwest.

Chapter 3 discusses the early signs of desertification that need to be tracked in order to "take action to reverse land degradation before it becomes severe." Such observation can involve data relayed from space satellites to computers, as well as local research and awareness.

Chapter 4, "Land Management," makes it clear that the solution to desertification lies ultimately in the practices of local people. Given sufficient ownership of land to profit from its fertility, and knowledge of simple practices that offset desertification, farmers in all parts of the globe can reverse the process.

Chapter 5, "Water," concludes the publication by showing how loss of land through desertification and loss of water are intrinsically interconnected, as irrigation systems needed to coax more crops out of deteriorating soil inadvertently deposit salt into soil, leading to a deadly cycle of environmental decay.

This book, then, is a wake-up call for those in all nations of the world concerned about the future of the natural planet. The causes of desertification vary from place to place, and the solutions have been defined only in part. Continued attention to this problem is needed as increasing human population makes demands on land, water and crop resources and the food and habitat they provide.



Linear transverse sand dunes impinging on a village, northern Sudan, 1985. The dunes move in response to regional northerly winds. (Courtesy of Ted A. Maxwell, National Air and Space Museum, Smithsonian Institution)
In the mind's eye, the word desertification may conjure up images of vast expanses of sand relentlessly invading neighboring fertile land. But, in fact, desertification is a much more subtle and insidious process that can take place far from vast, sandy deserts. In effect, desertification is a term that refers to the ongoing degradation of land. And this degradation begins when overcultivation or overgrazing robs heretofore fertile soil of nutrients, and destroys its vegetation, leading to wind and water erosion of fertile topsoil and loss of agricultural or forest productivity. When these forces combine to render the land virtually useless, the result is called desertification.

The term desertification itself is somewhat misleading. Desertification does not refer to the spread of existing deserts, which naturally expand and shrink with fluctuations in rainfall. Rather it describes what results when people overuse or misuse dry, semi-arid and dry sub-humid lands. Climate variations, especially drought, often hasten the process. In just a few seasons, precious topsoil that has built up over centuries can blow or wash away. The Worldwatch Institute estimates that the earth's landmasses are losing as much as 24 billion [thousand million] tons of topsoil every year.

The natural and social consequences of desertification can be devastating. It may take centuries for topsoil to rebuild or forests to regrow. And if the damage is too severe, the land may not recover. In addition, when aggravated by drought, desertification can lead to widespread famine, displacement of people from their homes, and social unrest and conflict. It is a pattern repeated throughout history, as author Alan Grainger has noted in his book Desertification: "When soil fertility was not replenished or the soil was allowed to deteriorate, civilizations either declined or colonized other areas. It is no coincidence that many ruins of great temples and palaces are today found amid sandy wastelands."

Significant regions of the planet are imperiled by desertification. But, as the peril continues, steps are also being taken to combat the problem. The Sahel region of Africa is famous for one of the great human tragedies of the 20th century. This band of semi-arid land -- which spans the continent between the Sahara Desert to the north and the moist savannas to the south -- has always been a fragile ecosystem. By the early 1970s, explosive population growth and rapid depletion of the land, combined with a severe, six-year drought, brought the Sahel to the breaking point. Faced with useless land and nowhere else to go, more than 200,000 people and millions of their cattle starved to death.

But out of this catastrophe came the first global attempt -- and the first legally binding global treaty -- to stem desertification. The Convention to Combat Desertification (CCD), a United Nations treaty that came into effect in 1996, broke new ground by stressing partnership among countries rich and poor, and between national governments and the local people most affected by the problem. It represents the best hope yet for stopping the march of desertification, which already threatens some 30 percent of the land on earth.

A 2003 dust storm near Kabul, Afghanistan, shrouds a child collecting cow dung for fuel. (AP Photo/Rafiq Maqbool)
The Disappearing Land

Desertification certainly is not new. As early as 2000 B.C., the Sumerians described land that turned to desert after all the trees were cut. In the fourth century B.C., Plato complained of land that "compared to what it was, is like the skeleton of a body wasted by disease." Today, on an increasingly crowded planet, desertification reaches most corners of the globe.

According to United Nations' statistics, the impact is staggering:

More than 250 million of the earth's inhabitants are directly affected by desertification; 135 million are in danger of being driven from their land. The livelihoods of one billion people -- nearly one-fifth of the world's population -- are at risk.

 70 percent of all drylands used for agriculture already are degraded.

 More than 110 countries have land at risk of desertification.

 The worldwide price tag for desertification: 42 billion dollars a year.

Unsustainable farming practices -- activities that deplete the land faster than it can recover -- are the main culprits behind desertification. Overcultivation, for example, exhausts the soil by robbing it of nutrients. Overgrazing by livestock destroys vegetation that protects topsoil from erosion and compacts the land so that it cannot retain moisture. Leveling forests for fuel wood or to clear land for unsuitable farming removes trees that bind the soil to land. Poorly drained irrigation turns land salty, leaving it worthless for growing crops. The United Nations likens the process to a disease on the planet with patches of degraded land erupting separately, then gradually merging to create, in effect, a new wasteland.

A woman carries branches gathered from a forest preserve in Haiti. So much land in Haiti has been cleared for fuel or farming that only one percent is still forested. (AP Photo/Daniel Morel)


A farmer in Senegal coaxes growth on still-functioning dryland. (Photo by Mike McGahuey/USAID)
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