27 Desertification

Dr Sunil Mittal

1. Introduction

2. Types of Deserts

a) Hot Deserts

b) Coastal Deserts

c) Semi-arid Deserts

d) Cold Deserts

3. Indicators of Desertification

4. Causes of Desertification

5. Effects of Desertification

6. Remedial Measures

7. Programme to Combat Desertification

8. Case Studies

1. Introduction

Desertification is a long process of land degradation mostly due to climatic changes and human activities. This is an emerging problem faced by almost every country of the world. This is threat for ecological system and human survival. There are many factors responsible for the degradation of the land which if continued for long time ultimately leads to formation of deserts. There are two types of causes of desertification like direct and indirect. Direct causes include the climate of place and human activities like over exploitation, deforestation, overgrazing and improper use of irrigation technology. Indirect causes involve the poverty, population pressure, urbanization and unfair sharing of resources. One third of world land is arid or semi-arid and affects the 250 million people. It has been predicted that due to increase in global warming, the area under desert will increase up to 17% by end of this century. The figure 1 shows the area under desert, vulnerable and invulnerable area on globe.

Figure 1: Represents area under the desertification

Source: http://www.acegeography.com/what-is-desertification.html

Desertification not only causes deterioration of environment, but also increase poverty among the local people.About32% area of India is affected by land degradation and 25% geographical area is affected by desertification. Total area already under land degradation is 105.48 mha and 81.45 mha land area of country is undergoing the process of desertification. Dry lands cover a very huge area from the boarder in the north- west through the Peninsular to the southern side of India. Major parts of Rajasthan, Gujarat, Haryana and Southern Punjab and small portion of Andhra Pradesh, Karnataka and Maharashtra come under hot arid regions. The 12 western districts of Rajasthan fall within the hot arid zone. Great Indian Desert also known as Thar Desert comes under this belt. This hot arid region suffers ample of problems such as low rainfall, droughts, intense heat and high evaporation. There is drastic climate change which is responsible for land infertility and ecological system destruction by desertification. Developing countries are facing large problem due to land degradation of useful land to meet the demands of increasing population.

2. Types of Desert

There are various factors like location, climate, ground cover etc are responsible for the desertification. If talk about the deserts, the main idea comes in mind is that the deserts are hot but this not true. There are also cold, coastal and semiarid deserts (figure 2). The deserts of world are divided into 4 main types.

a) Hot Deserts

b) Coastal Deserts

c) Semi arid Deserts

d) Cold Deserts

Table 1: Deserts of world

a) Hot Deserts

These are located near to the equator. The temperature during day time is very high (40-45º C) and nights are relatively cold. In hot desserts, there is no cloud cover and it allows them to heat up and cool down quickly. Sahara is the world’s largest desert located in the northern Africa and covers area of 3.5 million square miles. The plants growing in this area have no or very small leaves and only grow after the rainfall. The plants growing in the area are called succulent or xerophytic plants. The lack of leaves helps in reduction in water loss during transpiration and leafless plants conduct photosynthesis through the green stems. Main plants of the area are different types of cactus (figure 3a), elephant tree, desert sage and saguaro. Nocturnal animals are found in this area. They are called nocturnal because they stay inactive during day and come out for activities at night when desert become cooler. These animals make burrows to escape the heat. Kangaroo rat is the best example to hot desert animals (figure 3b). Other animals are lizards, owls, jackals, snakes and scorpions.

b) Cold Desert:

These are also known as polar deserts and found far from equator located in the centers of continents and are high mountainous areas. During winter seasons, these are covered with snow and ice. South Antarctica and Argentina are examples of extreme cold desert. The main flora of cold desert are deciduous plants having spiny leaves and height between 15- 122 cm such as Nothofagus pumilio, Deschampsia antarctica, Colobanthus quitensis etc. Mostly Spadefoot toad is found in this area and during the hot dry spells covers itself with a substance or enters underground burrow to stay moist. It comes outside during heavy rainfall. For mating and laying eggs come in the temporary pools and toads return to burrows until the next heavy rains.

Figure 4: (a) Nothofagus pumilio plant. (b) Spadefoot toad

Table 3: Cold deserts of world

Coastal Deserts by the Sea: Water never evaporates from a cold ocean as quickly as it does when water is warm. Air blown onto the coast from a cold ocean contains no moisture to fall as rain. During the day, water evaporates from the land and is responsible for the desertification. Namib and Atacama are well known coastal deserts. Coastal desert plants have thick and fleshy leave and stem can absorb large quantities for future use. Buckwheat bush (figure 5a) and Saltbush are well known plants of this area. Mainly owls, toads, lizards, coyotes (figure 5 b) and snakes are found.

Figure 5: (a) Buckwheat bush plant. (b) Coyotes

Semi-arid Deserts: These receive the rainfall between the 250 mm and 350 mm and summers are long and dry with moderate temperature between 20º C and 30º C. one third of Australia is the semiarid desert. In these deserts, three types of plants are present such thorny, hairy and waxy. Desert plants store their water in spongy tissue and animals try to eat but thorns protect these plants from animals. Hairs protect plants from sunlight to reduce evaporation. In waxy plants wax acts as the plastic wrapper to store the water inside. Prickly pear cactus (figure 6a), Old Man Cactus and Aloe are usually found in this area. In semi arid desert Jackrabbit (figure 6b) is found and uses the shadows of cactus and shrub to move one place to other.

Hot Desert in India: Thar Desert is the hot and largest desert of India. It is located in the western Rajasthan and forms a natural boundary between India and Pakistan. It has the area of 77,000 square miles and includes the cities like Pushkar, Jaipur and Udaipur as well as many tourist sports including temples and forts. It covers the area of 0.32 million km2. During summers, temperature generally varies between 40 and 45º C and during night decreases to 20-29º C. In this area, rainfall is less than 400 mm rainfall, high temperature and strong winds with 1800 to 2200 mm evapotranspiration responsible for negative water balance. Due to water problem, there is acute shortage of fodder, fuel, food and timber. The 682 plants species have been identified in the area which includes 107 grasses. The 45 species of grasses are endangered plant species. Most common plant species in hot deserts are Prosopis cineraria, P. juliflora, Tecomella undulata, Acacia tortilis and many more.

Cold Desert in India: Cold desert is spread from Ladakh district of Jammu and Kashmir to Kinaur district of Himachal Pradesh with area of 126400 km2. Indian cold desert bordered by the great Himalayan and inner Himalaya having extensive glaciers and snow fields. This area receives the less rainfall (300 mm) in the form of snow and misty drizzles. Temperature in clod desert is in the range of -20º C to -40º C. Major area is under waste land and alpine shrubs or pastures and only 1-2% is cultivated land. Juniperus, Caragana, Artemisea, Lonicera, Potentilla, Myricaria, Ephedra, Salix, Rosa, andRhododendron are cold desert plants.

White Salt Desert of Kutch: Also known as White Rann or Rann of Kutch and it is one of dustiest and hottest regions of India. It is also expanded around the 2898 square miles in Gujarat. This desert is covered with layers of white salt that gives the appearance of the snow. Average temperature during the summer can reach 50ºC and in winter cools to below freezing.

3. Indicators of desertification

a) Physical indicators

Drying of ground and surface water
Soil crust formation/compaction and decrease in soil depth Decrease in soil organic matter and fertility
Formation of sandstorms/dune Soil salinization or alkalinisation
Alteration in albedo (relative reflectance) of land

b) Biological indicators

Decrease in above-ground biomass/forest cover
Decrease in crop yield or decrease in crops
Alteration of key plant and animal species
Changes in distribution and frequency of flora and fauna

c) Animal indicators

Change in population of domestic animals which leads to change in key species distribution and frequency
Decline in livestock production and herd composition

d) Social/economic indicators

Change in population density
Increased resource competition due to change in land use/water use
Change in demographic parameters
Change in social indicators like increased poverty, decreased education, food habits, migration, dependence on cash crops

4. Causes of Desertification

Unsustainable Agrarian Practices: These practices comprise of unnecessary and excessive use of fertilizers, pesticides, improper irrigation techniques, cropping patterns, unfit technologies etc. are responsible for desertification.
Unsustainable Water Management Practices: Inefficient irrigation practices, over pumping of ground water particularly in the coastal regions resulting in saline incursion into aquifers, are some of major unsustainable water management practices which lead to desertification in such regions.
Land Use variation: With the rapid urbanization and industrialization, alteration of land from forestry and agriculture to other land uses has been one of the primary causes of land degradation.
Deforestation: It is hard to separate the causes from the effects of deforestation and forest degradation. Some direct causes of deforestation are land permissions for agriculture (including shifting cultivation), other land use changes including unplanned urbanization, land transfers, different forms of encroachments, over-grazing, uncontrolled and wasteful logging, illegal felling, and excessive fuel wood collection.
Unchecked discharge of Industrial effluents into water bodies and soil: Industrial effluents and mining are also gradually emerging as important causes of desertification. In most cases in the core of the problem is the mismanagement by land users and poor execution of pollution control regulations. Industrial effluents and their discharge into nearby water bodies and irrigation with poor quality water in many parts of the world are rendering stretches of land getting degraded.
Population Pressure: The general problem of arid areas with large populations is essentially one of human ecology. The intrinsically limited resources within arid and semi-arid regions set the critical limit of production are finally dependent.
Lack of knowledge and awareness: There is inadequate quantitative data on current land use in arid and semi-arid regions of the country. Whatever information is available is scattered across many agencies and institutions and is not readily accessible to researchers, planners, and policy makers. Similarly, there is very little knowledge of land degradation and desertification issues among the general public, planners and policy makers and even among those who are directly responsible for the management of land resources
Climate Change: It has great impact on desertification. The increase in global temperature and frequent conditions of drought escalates desertification.
Natural Disasters: Sometimes natural disasters such as drought contribute to land damage. In such cases, there isn’t a lot that we can do except work to try and help rehabilitate the land after it has already been damaged by nature.

5.Effects of Desertification

Farming becomes next to impossible. If an area becomes a desert, then it’s become impossible to grow substantial crops there without special technologies. These technologies are very expensive so that many farmers will have to sell their land to apply them or leave the desert areas.

Hunger: Without farming in desert areas, the food that those farms produce will become much scarcer, and the people who live in those local areas will be deal with hunger problems.

Flooding: Without the plant life in an area, flooding is a lot more eminent. Not all deserts are dry; those that are wet could experience a lot of flooding because there is nothing to stop the water from gathering and going all over the place. Flooding can also negatively affect the water supply, which we will discuss next.

Poor Water Quality: when any area becomes a desert, the water quality is going to become a lot worse than it would have been otherwise.

Drought: Due to deficiency of rain number of droughts has been increased. Some seasonal and temporary droughts has been converted into permanent droughts owe to change rain pattern and amount.

Malnutrition: These droughts are further responsible for the decrease in the crop production that boosts the malnutrition problem.

Death of animals: Animals start to die due to shortage of the water in desert area. In this whole ecosystem is disturbed to unbalancing among food chains and webs.

Overpopulation: Desertification encourages animals and people to move to other areas where survival is easy. This causes gathering and overpopulation.

Poverty: Poverty also plays a role in this aspect. Inadequate food and water compel the people to thrive. They devote a lot of time to gather the basic necessities of living.

6.Remedial Measures

Agro forestry: It is a part of land use management in which tree or shrubs are grown around or among the lands those are at the edge of desertification to form more diverse, productive and ecologically rich.

Sand Dune Stabilization: It is the best way to control the desertification by planting the vegetation on prone area to reduce the impact of the water and soil erosion.

Shelter Belt Plantation: It is a technique in which tree and shrubs are planted in the rows to provide shelter from wind to reduce soil erosion.

Minimum Tillage: It is an ideal tool to protect the agricultural lands from the desertification. Minimum tillage is contrary to intensive tillage and soil conservation system like strip till with the goal of minimum disturbance with soil structure.

Policy Changes to Other Types of Land Use: The land which is used by public to get natural resources should be governed by the policies that are built to save the land. The policies should be changed as per the need and the type of land use.

Education: Environmental education may impart the values of protecting our surroundings from damage. Awareness among farmers and society about sustainable methods of agriculture and land use may reduce desertification.

Putting Together Rehabilitation Efforts. Present advances in science and technology may help to rehabilitate the land that has already been pushed into desertification by putting together time and money.

Sustainable practices: Sustainable practices provides plethora of remedial measures that can be applied to factors that cause desertification.

7. Programme to combat desertification

The National Action Programme to Combat Desertification: This program was submitted to UNCCD in 2001 and identifies the need to address and incorporate the following into integrated planning for sustainable development like natural resource management, socio-economic issue. This programme focuses on water conservation and production systems. All approaches and strategies to combat desertification under UNCCD are described in this programme.

National Capacity Needs Self-Assessment: It was prepared in 2001 and suggested that India has capacity for meeting UNCCD obligations. Main purpose of this program was to address all causes of desertification in implementation of national action plan to combat the desertification. Mainstream of program was focused to work for lands those are not degraded by providing proper facilities to combating the desertification.

Sustainable Land and Ecosystem Management (SLEM) Programme: It is a joint plan between the Government of India and Global Environmental Facility under the latter`s country Partnership Programme under the GEF four funding cycles. The objective of SLEM is to prevent and control of land degradation by restoration of degraded lands by biomass covering and harvesting in ways that maximize productivity as well as biodiversity conservation, carbon sequestration and sustainable use of natural resources.

8. Movements

Bishnoi Movement: Amrita Devi from Marwar region of Rajasthan could not tolerate the destruction of the village’s sacred trees and she hugged the trees to protect and encourage the others. She wanted to save sacred trees from the king’s soldiers and 365 villagers were killed in this movement.

Chipko Movement: This movement was witnessed in Garhwal district of Uttarakhand during 1973 and Sunder Lal Bahuguna was the leader of this movement who enlightened the villagers by conveying the importance of trees in our environment. A woman of Advani village tied a sacred thread around the trees and hugged them, hence it is called Chipko movement or hug the tree movement.

Appiko Movement: it is also called southern version of Chipko movement and locally known as Appiko Chaluvali. It started in Uttra Kannada and Shimoga districts of Karnataka in 1983 against the cutting and commercialization of natural forest and ruining of the livelihood.

Conclusion: Desertification is a rising problem which is faced by the whole world. There are many alternatives tried and many are under process but these are not efficient to control the process of desertification. People awareness is also useless because human beings are selfish and they do not bother about this situation and its seriousness. In future, there is needed to take strong actions in this field to control the desertification.

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References

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Sharma, S. K., & Sharma, M. C. Desertification in India: Challenges and Remedial Measures.
Tewari, V. P., & Kapoor, K. S. (2013). Western Himalayan cold deserts: biodiversity, eco-restoration, ecological concerns and securities. Ann. Arid Zone, 52, 225-232.
Darkoh, M. K. (1989). Desertification in Africa. Journal of Eastern African Research & Development, 1-50.
Reynolds, James F., D. Mark Stafford Smith, Eric F. Lambin, B. L. Turner, Michael Mortimore, Simon PJ Batterbury, Thomas E. Downing et al. “Global desertification: building a science for dryland development.” science 316, no. 5826 (2007): 847-851.
Sinha, R. K., Bhatia, S., & Vishnoi, R. (1996). Desertification control and rangeland management in the Thar desert of India. RALA Report No, 200, 115-123