DESERTIFICATION

 

•  Desertification is often considered the greatest threat to the planet.

•  Over one third of the world’s land surface ( 38 Percent ) threatened with desertification, according to a new study published in the International Journal of Life Cycle Assessment 

Meaning of Desertification

•  Desertification is the process in which the productive potential of arid or semiarid land    falls by 10% or more as a result of poor land management, human and climatic factors.

•  Moderate desertification is 10-25% drop in productivity , severe desertification causes more than 50% drop in productivity often creating huge gullies and sand dunes.

•  Desertification occurs mainly in semi-arid areas (average annual rainfall less than 600 mm) bordering the deserts.

• In the Sahel, ( the semi-arid area south of the Sahara Desert), for example, the desert moved 100 km southwards between 1950 and 1975. 

•  Also the Sonoran and Chihuahuan deserts are about a million years old, yet they have become more barren during the last 100 years. 

• Desertification is therefore not the literal invasion of desert into a non desert area rather it includes degradation of the ecosystems within as well as outside the natural deserts. It involves conversion of rangelands and irrigated or even rain-fed croplands to desert like conditions in which agricultural productivity decreases

CAUSES OF DESERTIFICATION

1. Overgrazing – is the major cause of desertification worldwide. Plants of semi-arid areas are adapted to being eaten by mammals such as dogs, elephant, Tiger, Lions, Guerilla, Bear, Horse and etc.

2. Destruction of Vegetation 

3. Incorrect Irrigation Practices – in arid areas can cause salinization, (that build up of salts in the soil) which can prevent plant growth. 

4. Drought 

5. Increasing Human Population and Poverty – As poor people may be forced to overuse their environment in the short term, without the ability to plan for the long term effects of their actions. Livestock has a social importance beyond the Food, people might be reluctant to reduce their stock numbers.

6. Deforestation – Depletion of Ground Water

7. Excessive Mining and Quarrying – activities etc. lead to loss of fertile soil and vegetal cover in healthy areas within moderate dry lands. 

8. Over farming – Overworking the land eventually drains the soil of its nutrients and leaving it unable to produce crops

The Effects of Desertification

• Desertification reduces the ability of 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. South Africa losing approximately 300-400 million tonnes of topsoil every year. As vegetation cover and soil layer are reduced, rain drop impact and run-off increases.

•   Water is lost off the land instead of soaking into the soil to provide moisture for plants. Even long-lived plants that would normally survive droughts die. 

•  Floods

How Widespread is Desertification?

The area at risk to desertification is thus large and likely to increase.

•   About one third of the world’s land surface is arid or semi-arid. It is predicted that global warming will increase the area of desert climates by 17% in the next century. 

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