Desertification

Download Activity (PDF)                             Download Activity (Word)

Download Answer Sheet (PDF)                     Download Answer Sheet (Word)

Download Background PDF

 

BACKGROUND

Desertification, deforestation, and land degradation. Three different words, with different meanings, but at times are connected and impact the land in ways that also impact humans.

Land degradation has accelerated during the 20th century due to increasing and combined pressures of human activities, deforestation, and extreme weather events such as droughts and coastal surges which salinate land.  Land degradation leads to a significant reduction of the productive capacity of land. Human activities contributing to land degradation include unsustainable agricultural land use, poor soil and water management practices, deforestation, removal of natural vegetation, frequent use of heavy machinery, overgrazing, improper crop rotation and poor irrigation practices. Natural disasters, including drought, floods and landslides also contribute. Land degradation is not permanent like desertification. Desertification, is a form of land degradation, by which fertile land becomes desert.

global-soil-degradation_eeea

Overview of the state of global soil degradation in the world. The loss of arable land has been caused by a number of factors, many or most of which are tied to human development. The primary causes are deforestation, overexploitation for fuelwood, overgrazing, agricultural activities and industrialization.[i]

 

Despite the name, desertification is not the advancement of sand dunes through inhabited areas. Rather, it is the permanent degradation of land that was one previously fertile and supporting plant life. Land becomes desertified when it can no longer support the same plant growth it had in the past. Thus, on a human time scale, the change is permanent. Many things can cause desertification. Drought, overgrazing, fire, and deforestation can thin out vegetation, leaving exposed soil. If the nutrient-rich top soil blows or washes away, plants may not be able to return. Overfarming or drought can change the soil so that rain no longer penetrates, and the plants lose the water they need to grow.

sahel-land

The Sahel is the semi-arid transition region between the Sahara desert to the north and wetter regions of equatorial Africa to the south. It extends from the Atlantic in the west to the Indian Ocean in the east. It has high variability of rainfall, and the land consists of stabilized ancient sand seas. It is one of the poorest and most environmentally degraded areas on earth.[ii]

 

Desertification affects about two-thirds of the countries of the world, and one-third of the earth's surface, on which one billion people live, namely, one-fifth of the world population. The vulnerability of land to desertification is mainly due to the climate, the relief, the state of the soil and the natural vegetation, and the ways in which these two resources are used. If the changing force is lifted—drought ends or cattle are removed, for example—but the land cannot recover, it is desertified. The loss of productive land for a season or even a few years is one thing, but to lose it effectively forever is clearly far more serious.

20111206_ClimateChange_AnneHolmes

Dwindling resources make tasks like finding firewood a challenge.[iii]

 

Together these changes on the landscape are influenced by human activity and have in turn, consequences on human health. These social and environmental processes are stressing the world's arable lands and pastures essential for the provision of food and water and quality air. Land degradation and desertification can affect human health through complex pathways. As land is degraded and in some places deserts expand, food production is reduced, water sources dry up and populations are pressured to move to more hospitable areas. The potential impacts of desertification on health include:

  • higher threats of malnutrition from reduced food and water supplies
  • more water- and food-borne diseases that result from poor hygiene and a lack of clean water
  • respiratory diseases caused by atmospheric dust from wind erosion and other air pollutants
  • the spread of infectious diseases as populations migrate

In addition to the impacts deforestation has on the ecosystem and the land, its impacts on humans varies greatly. All these changes create a complex system between a changing climate and the impact on humans.

 

REFERENCES AND RESOURCES

WordPress Appliance - Powered by TurnKey Linux