19 Desertification

Dr. Shanawaz Ahmad Baba

    1.1 Introduction

1.2 Causes of desertification

1.3 Effects of desertification

1.4 Solution of desertification

1.5 Conclusion

Objectives

• Define desertification
• Explain causes of desertification
• Highlight desertification at global level
• Role of man in desertification
• Solution of desertification

1.1 Introduction

Desertification is the change of land and its vegetation that makes it unable to support life, becoming like a desert. This is a global problem that seems to be expanding out from arid and semi-arid zones of the planet. Desertification is considered a result of human activity that degrades the land beyond recovery. Overgrazing and over-farming combined with clear cutting and other techniques that cause erosion can lead to desertification, though there is some evidence that the dry areas are expanding and contracting based solely on patterns of drought and rainfall. Despite some conflicting evidence, most of the scientific community and the United Nations believe that desertification is an insidious condition that has become more serious during the last years of this century. Remediation is in the hands of the human community, through changes in all aspects of agriculture, including tilling, crop choice, rotation schedules, and livestock grazing. The United Nations and other public and private groups are encouraging nations to make policy changes to address this problem and attempt to reverse it before it is too late. Action plans and greater public participation in environmental issues will serve to handle the problem and hopefully make it a non-issue for future generations. Desertification reduces both resilience and productive potential to an extent which can neither be readily reversed by removing the cause nor easily reclaimed without substantial investment.

Defining Desertification:

• The term `desertification’ was coined in 1949 by the French Forester Aubreville.
• French Forester Aubreville described desertification as a general process of degradation starting with deforestation i.e. not necessarily in dry lands and ending in land turned into desert.
• Whitford 1992 defined desertification as “the diminution or destruction of the biological potential of the land leading to desert like conditions”.
• The United Nations at the 1992 Earth Summit expressed the condition as “land degradation in arid, semi-arid and dry sub humid areas resulting from various factors, including climatic variations and human activities.
• Nelson further defines it as,” a process of sustained land (soil and vegetation) degradation in arid, semi-arid and sub-humid areas, caused at least partly by man.
• The term conjures up images of desert sands expanding over areas previously green and fertile, but it can take many forms and is not limited to farmland adjacent to arid zones.

      (Eckholm 1977) “Deserts themselves are not the sources from which desertification springs.” (UNCOD 1977 in Mainguet 1994) Small areas of land degraded by human activity and/or drought may develop far from the desert, but these areas can expand and connect with other areas, creating desert-like conditions. (United Nations I). “Desertification breaks out, usually at times of drought stress, in areas of naturally vulnerable land subject to pressures of land use.” (UNCOD 1977 in Mainguet 1994) The United Nations Conference on Desertification equates these patches with “a skin disease, that links up to carry the process over extended areas.” (UNCOD 1977 in Mainguet 1994) Deserts act more like the ocean, ebbing and flowing on the meteorological tide. Desertification is generally identified as a manmade condition, a result of inappropriate farming and land management techniques, and so remediation of the problem remains in human hands. (Eckholm 1977) Such a change in the dynamics of Earth’s surface will prove to have dramatic effects on the ability of all species to survive into the future. Recognition of the problem now, at the turn of the century, has made it into a greater crisis, producing more interest by government and the public to address and resolve it. Actions taken by the United Nations and other organizations has led to greater awareness and more attempts to develop technology, change social attitudes, and modify land management. Desertification must be handled proactively because a wait-and-see attitude will only lead to further degradation.

Desertification is the permanent decrease in biological productivity of dryland areas. Drylands comprise 41% of the earth’s land area and are home to roughly 2 billion people, or 34% of the earth’s population. Currently, over 250 million people in more than 100 countries are directly affected by desertification and more are at risk. The situation is most severe in Africa, where 66% of the total land area is arid or semi-arid. Not only is desertification harmful to the earth and its inhabitants, but it is also expensive – each year, the world loses US$42 billion to desertification and its effects. It is a serious and growing problem in many regions of the world including: sub-Saharan Africa, the Middle East, western Asia, northern Mexico and south-eastern South America, western United States, prairies of Canada, and eastern Australia. Scientists estimate that 60,000 square kilometers of new desert are now annually created worldwide.

1.2 Causes of desertification

The causes of desertification are both natural and man-made. Drought, rain patterns, increasing global temperatures and climate change contribute to the drying out of already arid lands, but these areas are also extremely sensitive to human activity. 10-20% of drylands are already severely degraded and some reports trace 70% of soil degradation to human-induced reasons, particularly population growth, agricultural technologies, and unsustainable policies.

These factors degrade the land and create feedback effects that result in the loss of biodiversity as well as other negative outcomes that affect us all.

      As a result of human activities and decisions such as overgrazing, the relationship between seven key ecological factors – vegetation, albedo, temperature, precipitation, soil moisture, wind erosion, and water erosion – becomes unbalanced. These mutually reinforcing relationships are especially susceptible to instabilities due to feedback effects, and perturbations like unsustainable cultivation practices are only magnified over time, resulting in essentially irreversible effects. For instance, one of the main causes of desertification is unsustainable agricultural practices. This is the case in the Indian drylands of Maharashtra, Karnataka, Rajasthan, and Jhabua. In these areas, agricultural development and plantation expansions often rely on the overexploitation of scarce water resources to prevent crop failure. This mismanagement of water supply can include irrigation water, ground water, drainage systems, and the inadequate positioning of watering points. In addition, setting controlled fire to land promotes nutrient cycling when done correctly, but when done too frequently, it can permanently reduce the nutrient content of the land. Intensive well and canal irrigation methods and fires are only short term agricultural solutions and unsustainable in the long run. They remove moisture and nutrients from the soil beyond a reparable point and accelerate the conversion of dry environments into desertified ones.

The dangers of unsustainable land cultivation customs are exacerbated by high population growth rates in drylands. For example, the 2004 global population growth rate was 1.14%, but in Africa, the rate was 2.4%. This places additional strain on already delicate physical systems as vegetation and natural forest cover – earth’s natural defense against land degradation – are eliminated in an effort to sustain the population. The moisture content in the area decreases and soil becomes more vulnerable to both wind erosion and water erosion, resulting in problems like decreased water quality, increased sediment deposits, flooding, and dust storms. Additionally, the amount of land available for human inhabitance and livestock grazing diminishes. Traditionally, grazing occurs in cycles involving movement and migration – when one area becomes overgrazed, animals move to another area, giving the original land a chance to recover. However, the shortage of land causes overgrazing without replenishment and over time, the degradation becomes so severe that it renders the land permanently unproductive.

The severeness of desertification depends on factors which vary from one region, country, or year to another. These include:

The severity of the climatic conditions during the period considered (particularly in terms of annual rainfall);

Population pressure and the standard of living of the people involved;

The level of the country’s development, and the quality of the preventive measures taken.

1.3 Effects of desertification

The process of desertification presents a serious impact on the well-being and health of the people living in the areas affected by droughts and land degradation on an unprecedented global scale. The worst situations can be found in Africa, which is threatened because the land degradation processes affect about 46 percent of the whole continent and create a health risk to people living in the regions far beyond the affected areas. Asia, on the other hand is the most severely affected continent in terms of the number of people affected by desertification and drought. Dryland populations are often marginalized and unable to play a role in the decision making processes that affect their well-being, making them even more vulnerable.

Desertification has environmental impacts that go beyond the areas directly affected; it devastates people regionally and at the global scale. For example, dust emanating from the East Asian region and the Sahara has also been implicated in respiratory problems as far away as North America and has affected coral reefs in the Caribbean. Furthermore, loss of vegetation can increase the formation of large dust clouds that can cause ill health problems in more densely populated areas during the dry season, thousands of miles away.

Women and men are affected differently by desertification and land degradation according to different productive roles that each group carries out. Women and children are especially vulnerable to droughts. When the natural resources in close proximity to their communities start to disappear, women are exposed to higher stress in searching for food, water and fuel wood at increased walking distances, often in dangerous conditions. Nevertheless, desertification is not just a problem for developing countries or for particular groups of people in Africa or Asia.

Main effects

Loss of soil vulnerability

Loss of habitat and

species soil erosion

• salinity

   decreased humidity and rainfall sun baked crack soil

• gullying

    loss of plants and animals

famine, poverty, starvation

damage to waterways i.e fertilizers and

pesticides growth of deserts

increase in sandstorms

flashfloods

     The health impacts of desertification can be divided into malnutrition and famine, water borne diseases, other infectious diseases, respiratory diseases and burning injuries. Effects of malnutrition related to desertification and drought include growth and development retardation, major susceptibility to infections, blindness and anemia. In particular desertification can increase fecal- oral diseases and water-wash diseases, which spread from one person to another due to the lack of water for personal hygiene. The drying of water sources increases the use of heavily polluted water, leading to severe epidemics. The other effects of desertification are as,

(i)  The soil becomes infertile: As desertification occurs, the soil can be blown or washed away, and valuable soil nutrients are lost. Through the use of unsustainable irrigation techniques, salt can also build up in the soil, rendering the soil useless for growing crops or other plants. As the soil dries out, it hardens and it becomes difficult for any rainfall that does occur to penetrate below the soil’s surface. And what remains left is a lifeless pile of dust instead of a life-giving medium.

(ii) Vegetation is damaged or destroyed: Desertification reduces the ability of land to support plant life. Loose soil bury plants, or their roots become exposed and cannot fulfill their function. With plants dying, rainwater gets washed away instead of being drawn into the soil, which only scales up the problem as remaining plants do not have enough moisture to survive dry spells as they used to.

(iii) Additionally, if the land is used for grazing at this stage, it only results in a quicker loss of plant species and total degradation.

(iv)  Soil erosion: The reduction in plant cover increases the erosion of the soil due to increased runoff and direct exposure to wind. This results in the decrease of water storing capacity of soils. The process of desertification is worsened as the soil becomes increasingly arid, and there are no more plants to hold it in place and distribute nutrients. Soil erosion is the final step that closes the loop of continual soil deterioration that is impossible to revert.

(v) Disasters: Desertification makes natural disasters worse. Events such as flooding, dust storms, and pollution, all become stronger in areas with heavily degraded soils. Without any plants stabilizing the soil and slowing down the runoff, rainwater easily accumulates and floods human settlements in the blink of an eye. Except causing damage, flood water also picks up unwanted pollutants while making its progress through urban areas, and that’s how pollution spreads over vast areas.

(vi) Polluted sources of drinking water: Vegetation plays an important role in cleaning our water. Plants and trees function like natural filters, storing pollutants such as heavy metals from water in their own bodies. Barren soils lack this green filter, and therefore, more of these harmful substances enter our groundwater reservoirs.

(vii) Famine, poverty, and starvation: Due to drought conditions and a loss of productive land, local people find themselves experiencing famine and poverty, as well as potentially the starvation of themselves and their livestock.

(viii) Collapse of civilizations: There are many historical accounts of how various people groups throughout human history experienced collapse of their civilization as drought and desertification occurred to their lands. These accounts include the Carthage Civilization, the Harappan Civilization, people groups in Ancient Greece, the Roman Empire, and people groups in Ancient China.

(ix) Mass migration: Desertification events have been a major driver behind the migration of large human populations throughout history. When soils are not able to support their civilization, people set on the move to look for better locations. One historical record of such a migration are Sea Peoples who during the Bronze age sailed their ships to Egypt, Syria and Cyprus most likely from Southern European countries.

(x) Extinction: Species that once lived in a fertile and productive climate may not survive in a newly desertified region. With a changing ecosystem, species must adapt to their new climate or migrate to a more favorable climate. Unfortunately, some of them also become extinct for their inability to cope with a sudden change of their environment.

1.4 Solution of desertification

The international community has long recognized that desertification is a major economic, social and environmental problem of concern to many countries in all regions of the world, and is one of the central challenges as it aims to achieve the Millennium Development Goals (MDGs-goal 7) by 2015.

The United Nations has created various programs to prevent desertification and to handle the problems arising from drought and crop failure. The United Nations Conference on Desertification, in 1977, produced the Plan of Action to Combat Desertification, made up of guidelines and recommendations for countries to use when developing their environmental action plans. The delegates at the United Nations Conference on Environment in 1992 demanded that a Convention to Combat Desertification in those countries experiencing Serious Drought and/or Desertification, Particularly in Africa, be created by June 1994. Some of the Convention guidelines include:

Active support of the efforts of affected developing country parties by developed countries;

Provision of financial resources from developed countries to developing ones;

Provision of access to technology and knowledge about desertification from developed countries to developing ones;

Establishment of strategies for combating desertification;

Promotion of awareness and participation by the local population in action to fight desertification; and

Provision of laws, policies, and action programs to effectively handle desertification.

The Convention emphasizes a “bottom-up” policy, encouraging the use of local and traditional concepts and technology to prevent desertification. It promotes public participation in formulating action plans and implementing them successfully. These plans require dramatic changes in public and governmental policy, as well as decentralization of authority and the empowerment of historically ignored groups. The Convention entered into force in 1996.

     Nelson from the World Bank has identified a number of strategies that should be employed to handle desertification and lead to its reversal.

A permanent national system of land monitoring should be created to track long-term conditions.

More money should be spent on expanding technology and understanding of the problem. Research into determining the carrying capacity of dry areas in contrast to humid areas must be done to prevent catastrophic consequences like famine and political strife.

Research into the unique conditions and causes of desertification in particular areas should be performed so that remedies can be tailored to suit them. Appropriate technologies also vary based on population and use density, affecting which crops are chosen and whether fertilizers need to be used.

Uniform global solutions cannot be implemented to handle the problem.

National programs to fund experimental projects and technology should be created to promote participatory development. Land distribution and control are important for appropriate agricultural uses and should be promoted from the local level upwards and by financial institutions.

Programs should be developed and implemented on the local, rather than regional level because of the uniqueness of each dry area. (Nelson 1990) Experience and research data should be shared, even if actual methods cannot be transferred from one location to another.

Governmental policy should be changed to promote local responses to problems in lieu of government intervention to bring resolution.

Policies for handling and possible promoting migration from dry areas should be created so that if migration does occur, it will not produce political, economic, social, and environmental instability.

Long-term planning and land development should be promoted to the extent they are needed without overwriting current management plans that are able to handle changing environmental conditions.

Farmers need to be encouraged to look beyond short-term gains when considering implementation of more environmentally viable technology.

1.5 Conclusion

Adjusting methods of farming and irrigation in conjunction with international programs appears to be the best plan for handling encroaching desertification. At a minimum, allowing for longer fallow periods and reducing erosion will help to slow down the rate of arid land expansion.

Greater understanding of droughts and rainfall must also be gained to provide a balanced picture for resolving the terrestrial conflict. Reducing population growth is also a goal, but adjusting farming techniques and irrigation provides a quicker, less controversial solution for handling desertification right now. Changing social ideals, political frameworks, and general attitudes toward the environment will take more time and effort to bring to fruition. Recognition of the problem as the century ends has given it greater urgency, and perhaps that is appropriate. Global responses must be swift, organized, and effective to prevent further degradation.

References:

• Dregne, H.E. 1976. Desertification: Symptoms of a crisis. In Desertification, Process, Problems,Perspectives. University of Arizona Press.
• Gaur M K and Moharana P C. 2014 Environment, People and Development: Experiences from Desert Ecosystems. New India Publishing Agency, New Delhi.
• Glantz, M. H., and N. S. Orlovsky. 1983. Desertification: A review of the concept. Desertification Control Bulletin 9: 15-22.
• Glantz, M.H. (ed.) (1977). Desertification: Environmental Degradatian in and around Arid Lands.Boulder, Westview Press.
• Interim Secretariat for the Convention to Combat Desertification (CCD). 1997. United Nations Convention to Combat Desertification – An explanatory leaflet. <www.unccd.ch/leaflet.htm> United Nations Environment Programme Information Unit, Geneva, Switzerland.
• Jornada Long Term Ecological Research Project. 1999. Jornada LTER: Overview. <http://jornada.nmsu.edu/site/overview/overview.htm>
• Kassas, M. 1977. Arid and semi-arid lands: Problems and prospects. Agro-Ecosystems.
• Kerr, R.A. 1998. The Sahara is not marching southward; expansion of African desert attributed to climate variation. Science. No. 5377 Vol. 281 Pg. 633. American Association for the Advancement of Science.
• Kumar M, Singh S K, Raina P and Sharma B K. 2011. Available major and micronutrients in arid soils of Churu district of western Rajasthan Journal of the Indian Society of Soil Science.
• Mabogunje, A.L. 1995. The environmental challenges in Sub-Saharan Africa; Cover Story. Environment. No. 4 Vol. 37 Pg. 4. Helen Dwight Reid Educational Foundation.
• Mouat, D. Lancaster, J. Wade, T. Wickham, J. Fox, C. Kepner, W. Ball, T. 1997. Desertification evaluated using an integratd environmental assessment model. Environmental Monitoring and Assessment 48: 139-56. <www.epa.gov/naaujydh/pag…lications/abstracts/mouat97.htm>
• Nelson, R.  1990.  Dryland management:  The “desertification” problem.  World Bank Technical Paper Number 116. The World Bank, Washington, D.C.
• Rapport, D.J. and Whitford, W.G. 1999. How ecosystems respond to stress. Bioscience. Mar 99 Vol. 49 Issue 3 Pg. 193. American Institute of Biological Science.
• Steele, G.V. 1997. Drowning in sand; environmental effects of desertification. E. No. 1 Vol. 8 Pg. 15. Earth Action Network Inc.
• UNESCO.  1995. Drylands and deserts.  UNESCO Courier.  Pg. 43.  UNESCO (France).
• United Nations. 1997.  Land degradation; threats of desertification. UN Chronicle.  No. 2 Vol. 3 Pg. 26. United Nations Publications.  (hereinafter “United Nations I”)
• United Nations. 1997. What’s being done; desertification remedies. UN Chronicle. No. 2 Vol. 34 Pg. 29. United Nations Publications. (hereinafter “United Nations II”)
• USEPA. 1999. Global warming:  Deserts. <www.epa.gov/oppeoee1/glo…ming/impacts/deserts/index.html>
• Whitford, W.G. 1992. Biogeochemical consequences of desertification. The Science of Global Change: The Impact of Human Activities on the Environment. American Chemical Society, Washington, D.C.