Deforestation and Desertification
Deforestation and Desertification
DEFORESTATION AND DESERTIFICATION
A common claim of defenders of tropical rain forests is that because of the shallowness of rain forest soils cutting down those forests for crops or cattle grazing will lead to massive soil erosion and eventually create deserts in areas where lush forests once grew and provided a high percentage of the earth's biodiversity (Sponsel, Headland, and Bailey 1996; Burch 1994; The Burning Season 1994).
Complexity of Causes
However, the causes of desertification are much more complex than this scenario would suggest. It is true, for instance, that in the Mediterranean Basin deforestation over centuries has been a significant factor in desertification from Spain and the western part of North Africa in the west to Lebanon and Palestine in the east. Nevertheless, cutting down forests was only one among several human factors that advanced desertification in that region, along with climatic factors:
First and most fundamental are climate factors. Here is one summary: Conditions [for desertification] are common in the Northern and Southern hemispheres between 20 and 30 latitude. … The most common factor in determining climate is the intense equatorial solar radiation, which heats the air and generates high levels of humidity. Warm tropical air rises; as it does it cools, and the atmospheric moisture condenses. That results in high rainfall patterns in the equatorial region. The rotating earth causes these air masses to move away from the equator toward both poles, and the air begins to descend on either side of the Tropic of Capricorn and the Tropic of Cancer around the 30 latitudinal band. As the air descends it warms and relative humidity declines, resulting in a warm belt of aridity around the globe (Mares 1999, p. 169).
This is the explanation for the existence of deserts worldwide, but for many people concerned with science, technology, and ethics the term desertification has a different meaning:
Desertification is the degradation of productive drylands, including the Savannas of Africa, the Great Plains and the Pampas of the Americas, the Steppes of Asia, the "outback" of Australia and the margins of the Mediterranean. Desertification is occurring to such a degree that some lands can no longer sustain life (Middleton and Thomas 1997, p. iv).
It is controversial whether humans can do anything about climate change, and so the basic formation of the world's deserts is of less interest here—specifically as an ethical or social problem to the mitigation of which science and technology might contribute—than is desertification in the latter sense. However, even with respect to desertification related to humans and their lifestyles over the millennia, the issue is enormously complex.
Attempts at Remediation
One area of increasing desertification is the Mediterranean Basin of southern and southeastern Europe, along with limited areas of western and eastern North Africa. The World Atlas of Desertification (Middleton and Thomas 1997) is a product of the United Nations Environment Program (UNEP) and is related to the United Nations Convention to Combat Desertification (CCD). The atlas contains a chapter, "Desertification and Land Use in Mediterranean Europe," that helps illustrate the complexities of the issue. For example, the atlas states: "The region has suffered from land degradation at least since the Bronze Age" (p. 129). There has been damaging "terrace construction over many centuries … [and] in recent years major changes in the population distribution have occurred with … the movement of people to the major cities and coastal areas [for tourism] and the development of irrigated agriculture and industry … [with attendant] flooding and erosion, groundwater depletion, salinization and loss of ecosystem integrity" (p. 129). One of the hardest-hit areas is southeastern Spain, in a country that has seen all these impacts for centuries, including massive deforestation and extensive irrigated farming in the Valencia region.
One of the goals of the UNEP/CCD program is to utilize the latest science and technology, including remote sensing techniques to map desertification advances, and the Mediterranean Desertification and Land Use (MEDALUS) project includes the Guadalentin Target Area in southeastern Spain: "The most degraded and eroding areas are … former common grazing lands that were taken into cultivation due to an expansion of mechanized agriculture in the 1960s and … were abandoned, as systems failed" (p. 131).
All these factors have been at work to varying degrees throughout the Mediterranean Basin, where there is ongoing desertification. MEDALUS scientific studies and rehabilitative efforts are ongoing throughout the region, from Portugal, to Italy, to Greece and Asia Minor.
Desertification is increasing rapidly in the world's best-known desert, the Sahara, and particularly along its southern border, the Sahel region. Two major causes are overgrazing, especially after prolonged drought beginning in the 1960s, and the use of brushwood as fuel in homes (Middleton and Thomas 1997, pp. 46–48 and 68–69, 168ff).
The World Atlas includes reports on the Middle East, southern Asia, Australia, China, and Mexico. A United Nations CCD conference report, Sustainable Land Use in Deserts (Breckle, Veste, and Wucherer 2001) covers the Aral Sea reclamation effort, changing patterns of overgrazing in South Africa, the monitoring of desertification in Uzbekistan and Kazakhstan, and reclamation efforts in Israel, among many other topics.
The ethics of desertification reflects extremely diluted responsibilities. Since the Bronze Age in the Mediterranean Basin, for example, up to the present (such as in Spain), farmers have tried in numerous ways to eke out a hard living in arid lands. Some people would lay blame primarily on government planning agencies for overirrigation and groundwater depletion, salinization, and other impacts of population density and tourism in arid regions. However, in any particular case it is difficult to lay too much blame on individual agents, although some environmental ethicists would blame a culture that is and has been for centuries heedless of impacts on arid lands.
In regard to science, technology, and rehabilitation/restoration projects such as those of UNEP/CCD, it may be too early to tell whether they will be effective in the long run against what is widely perceived to be rapidly advancing desertification.
PAUL T. DURBIN
Breckle, Siegmar-W.; Maik Veste; and Walter Wucherer, eds. (2001). Sustainable Land Use in Deserts. Berlin and New York: Springer.
Burch, Joann Johnson. (1994). Chico Mendes, Defender of the Rainforest. Brookfield, CT: Millbrook. Intended for younger readers.
The Burning Season: The Chico Mendes Story (1994). Warner Home Video. Theatrically released in 1981. Story of a man dedicating his life to saving the Amazon rain forest. Based on a novel by Andrew Revkin.
Mares, Michael A. (1999). Encyclopedia of Deserts. Norman: University of Oklahoma Press.
Middleton, Nick, and David Thomas, eds. (1997). World Atlas of Desertification, 2nd edition. London: Arnold.