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| Sunday, 12 December 2004 |
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Junior Observer |  |
| News Business Features Editorial
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Desertification - When Mother Nature turns cruel Forests that spread across hundreds of acres of land, waterfalls which take our breath away and beautiful beaches along which we feel like walking for hours are all wonderful gifts of Mother Nature. However, when humans destroy these amazing gifts, Mother Nature could unleash her cruelty on us and desertification is one of the best examples of her fury.
Desertification refers to the formation and expansion of degraded soil. In simple words, it means the decline in the biological or economic productivity of the soil in arid (annual rainfall less than 600 mm) and semi-arid areas resulting from various factors, including human activities and climatic variations. Desertification reduces the ability of the land to support life, affecting wild species, domestic animals, agricultural crops and people. The reduction in plant cover that accompanies desertification leads to accelerated soil erosion by wind and water. As the vegetation cover and soil layers are reduced, the impact of rain drops hitting the ground and the soil getting washed off increases. Water is lost off the land instead of being soaked into the soil to provide moisture for plants. Even long-living plants that would normally survive droughts would die. A reduction in plant cover also results in a reduction in plant nutrients in the soil and plant production drops further. As the protective plant cover disappears, floods become more frequent and severe. Desertification is self-reinforcing - once the process has started, conditions are set for continual deterioration.
The world's great deserts were formed by natural processes interacting over long periods of time. In some regions, deserts are separated sharply from the surrounding, less arid areas by mountains and other contrasting landforms that reflect the basic structural differences in regional geology. In other areas, desert fringes form a gradual transition from a dry to a more humid environment, making it more difficult to define the desert border. Desertification occurs in croplands, pastures and woodlands. Loss of soil, deterioration of soil and loss of natural vegetation all lead to desertification. Drought can cause loss of vegetation, which in turn leads to desertification. Poor land management and increasing populations promote increased irrigation, improper cultivation or overcultivation and increased numbers of livestock. These increase chances of desertification. Desertification is complex. It involves multiple causes and proceeds at varying rates in different climates. Desertification may intensify a general climatic trend and lead to no rain at all or it may change the local climate. Areas far from natural deserts can degrade quickly to barren soil, rock or sand through poor land management. The presence of a nearby desert has no direct relationship to desertification. Unfortunately, areas undergoing desertification are brought to public attention only after the process is well underway. Scientists still question whether desertification, as a process of global change, is permanent or how and when it can be halted or reversed. Increased population and livestock are the main contributors towards desertification. In some areas, nomads moving to less arid areas disrupt the local ecosystem and increase the rate of erosion of the land. Nomads try to escape the desert, but because of their land-use practices, they are bringing the desert with them. Other factors including poverty, politics, disrupted social institutions and the pursuit of short-term economic opportunities may work together to promote desertification. The provision of water for irrigation can cause desertification. Nearly all irrigation water contains some salt. If an irrigation system lacks a good drainage system, then salt accumulates in the soil. This has now destroyed about one-third of the world's irrigated land. In most cases of desertification, there is a reduction in total species richness, an increase in the proportion of exotic plants and a decline in overall bio-diversity. Once desertification has started, it often causes changes that accelerate the process. Desertification has become a large scale problem. Arid and semi-arid regions, known as dry lands, account for one-third of the world's land area and support a combined population of about 900 million people. Soil degradation reduces crop output and is a major concern economically. Most efforts to combat desertification require temporary reductions in economic productivity or increases in investment. Experts recommend decreasing herd sizes, changing ploughing practices, planting windbreaks, planting less profitable crops which do not rob the soil of nutrients and allowing each field to lie fallow on a rotating basis. In irrigated agriculture, more expensive and intensive water management is recommended, requiring improved water delivery systems, field preparations and drainage systems. Increasingly poor populations however cannot absorb a reduction in income, cannot usually invest in improvements and may not have sufficient labour available to implement even simple measures. **** The Dust Bowl period Desertification became well known in the 1930s, when parts of the Great Plains in the United States turned into the 'Dust Bowl' as a result of drought and poor practices in farming, although the term itself was not used until almost 1950. During the Dust Bowl period, millions of people were forced to abandon their farms and livelihoods. Greatly improved methods of agriculture and land and water management in the Great Plains have prevented that disaster from recurring, but desertification affects millions of people in almost every continent. |
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