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Desertification

earth science Maturity 9-11 Next article →

Desertification is the gradual process where fertile land transforms into arid desert.

Somalia, Mudug, Dhinowda (02)
Somalia, Mudug, Dhinowda (02)

This degradation occurs in arid, semi-arid, and dry sub-humid regions. It is driven by a complex mix of natural climatic variations and human activities. While many people once thought desertification meant the physical expansion of existing deserts, the concept has evolved. Today, it is understood as the loss of land productivity. This process is critical because drylands cover approximately 40% to 41% of Earth's land area. These regions are home to more than 2 billion people.

Global distribution of dryland subtypes based on the aridity index
Global distribution of dryland subtypes based on the aridity index

The mechanism of desertification often begins with the loss of vegetation. Plants play a vital role in the biological composition of the soil. Studies show that higher vegetation cover decreases the rate of erosion and runoff exponentially. When plants are removed, the soil becomes unprotected. Dry soil surfaces are then easily blown away by the wind. They can also be washed away by flash floods. This leaves behind infertile lower soil layers. These layers bake in the sun to become an unproductive hardpan.

Soil erosion, Southfield - geograph.org.uk - 367917
Soil erosion, Southfield - geograph.org.uk - 367917

Many different factors influence this process. Human activities like tillage for agriculture and deforestation for fuel contribute to land loss. Overgrazing by livestock is another major factor. In some areas, intensive farming is used to maximize yields. However, this requires heavy use of fertilizers and pesticides. This continuous use rapidly depletes soil nutrients. Natural factors also play a role. For example, the Sahara Desert exists due to natural variations in solar insolation. This is caused by the orbital precession of the Earth. Such changes influence the strength of the West African Monsoon.

Village Telly in Mali
Village Telly in Mali

Scientific study of this issue has changed over time. The modern study of desertification emerged from studying the 1980s drought in the Sahel. Before this, there was significant controversy regarding definitions. In 2005, there were more than 100 formal definitions in existence. The most widely accepted definition comes from the Princeton University Dictionary. It describes the process as fertile land transforming into desert due to deforestation, drought, or inappropriate agriculture. This definition highlights how land management is interconnected with environmental health.

Harsh Vardhan addressing at the inauguration of the United Nations Convention to Combat Desertification (UNCCD) Asia-Pacific four-day Regional Workshop, in New Delhi (1)
Harsh Vardhan addressing at the inauguration of the United Nations Convention to Combat Desertification (UNCCD) Asia-Pacific four-day Regional Workshop, in New Delhi (1)

Different regions show different causes for land degradation. In the Mu Us Desert, soil health accounts for 37% of desertification events. In Inner Mongolia, soil benefits make up 34.7% of the environment. In these areas, meteorological and human activities make up the rest. Shaanxi serves as a unique counterexample. In Shaanxi, meteorological factors actually work against desertification. However, soil health in that region exacerbates the problem. These variations show that no two drylands are exactly the same.

Great green wall map
Great green wall map

The effects of desertification are widespread and serious. One major effect is the increase in sand and dust storms. Global annual dust emissions have increased by 25% since the late nineteenth century.

SHB-Red-Dust
SHB-Red-Dust

These storms can cause respiratory disorders like asthma and pneumonia. They can also pollute water and reduce the effectiveness of clean energy. Desertification also threatens global food security. Drylands contain 44% of the world's agricultural land. This land supplies 60% of the world's food production. As land becomes less sustainable, the demand for food may eventually overcome the supply.

Finally, desertification is closely linked to economic and social issues. At least 90% of dryland inhabitants live in developing countries. Land degradation reduces productivity and makes living conditions precarious. This often leads to mass migrations from rural areas to urban centers. In sub-Saharan Africa, environmental refugees may increase from 14 million in 2010 to nearly 200 million by 2050. To fight this, people use mitigation methods. These include improving soil quality, managing grazing, and reforestation. Reforestation involves planting trees to restore the land.

GreeningdesertTharIndia
GreeningdesertTharIndia
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🖼️ Images & Media (11)
File:Global distribution of dryland subtypes based on the aridity index.png
Global distribution of dryland subtypes...
File:Somalia, Mudug, Dhinowda (02).jpg
Somalia, Mudug, Dhinowda (02).jpg
File:SHB-Red-Dust.jpg
SHB-Red-Dust.jpg
File:Soil erosion, Southfield - geograph.org.uk - 367917.jpg
Soil erosion, Southfield -...
File:Village Telly in Mali.jpg
Village Telly in Mali.jpg
File:10-4-26 沙尘暴 - panoramio - 阿留申.jpg
10-4-26 沙尘暴 - panoramio - 阿留申.jpg
File:Harsh Vardhan addressing at the inauguration of the United Nations Convention to Combat Desertification (UNCCD) Asia-Pacific four-day Regional Workshop, in New Delhi (1).JPG
Harsh Vardhan addressing at the...
File:North Sahara. Anti-sand shields.jpg
North Sahara. Anti-sand shields.jpg
File:GreeningdesertTharIndia.jpg
GreeningdesertTharIndia.jpg
File:Tamarisk planted along roads in Xinjiang near Cherchen to slow desertification.jpg
Tamarisk planted along roads in Xinjiang...
File:Great green wall map.svg
Great green wall map.svg
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