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Climate Change
Desertification is exacerbated by climate change and vice versa. As severe weather events increase in frequency and severity due to climate change, dryland degradation tends to increase. Worse still, desertification and climate can form a ‘feedback loop’ with the loss of vegetation caused by desertification reducing carbon sinks and increasing emissions from rotting plants. The result is more greenhouse gases in the atmosphere, and a continuation of the vicious cycle involving climate change and desertification.
In Africa alone, a total of more than 650 million people are dependent on rain-fed agriculture in environments that are already affected by water scarcity and land degradation, which will be further exacerbated by climate change. If this trend continues, two-thirds of the region’s arable land could be lost by 2025 (FAO 2009), and the livelihoods of millions of small farmers along with it.
On the other hand, drylands can also play an important role in mitigation, for example through carbon sequestration in soils. While drylands have relatively low sequestration potential per unit area, their large expanse makes them important. This creates both risks and opportunities for mitigating climate change. While soil degradation emits greenhouse gases, soil restoration prevents such emissions and even creates storage capacities for greenhouse gases already in the atmosphere.
Carbon sequestration is the process by which carbon sinks (both natural and artificial) remove CO2 from the atmosphere, primarily as plant organic matter in soils. Organically managed soils can convert CO2 from a greenhouse gas into a food-producing asset. Combined with sequestration in nonagricultural soil, the potential for land to hold carbon and act as a sink for greenhouse gases is unparalleled.
This should help confer new value on land, because of its ability to sequester and literally “breathe in” the excess blanket of CO2. In turn, CO2 enriches the soil, giving life to trees and vegetation, which then can generate more carbon sinks. In areas where the soil is depleted, this process of carbon sequestration is literally switched off.
Water availability aff ects domestic life as well as the development of certain agricultural techniques. In drylands more than anywhere else, water availability is often critical. These areas are characterized by a high evaporation rate and surface waters such as rivers and lakes tend to disappear relatively quickly. Water scarcity and poor water quality threaten public health, food and energy production, and regional economies. It is estimated that 40 per cent of the world’s population suff ers from water shortages. In the drylands, practically all water reserves are utilized and are often threatened with pollution, which may help to spread numerous diseases.
While irrigation could improve food production, its ineffi cient application can also be a risk, especially in terms of salinization. For example, about 10 per cent of the world’s irrigated land has been damaged by salt, compounding the threats to food security. The build-up of salts in the soil lowers yields and can damage the land beyond economic repair. Salinization is reducing the world’s irrigated area by 1-2 per cent every year, hitting the arid and semiarid regions the hardest (FAO 2002).
Land degradation in the drylands can have direct consequences on the water cycle. If there is low rainfall, drought ensues: groundwater reserves do not refi ll, water sources become depleted, wells run dry, plants and animals die and humans have to migrate to more hospitable regions. Conversely, during periods of high rainfall, the ensuing fl oods kill people and animals, notably in regions where the vegetation cover is reduced or totally destroyed. The torrential rain fl ow causes a substantial loss of soil, which is fl ushed out by the rains and when the land dries again, a hard crust forms on the surface making it impermeable, and reducing water infi ltration.
Environmental Migration
Desertification is a global issue, which threatens development, sparking an exodus from the affected regions because when land becomes uneconomic to farm, people are often forced into internal or cross-border migration. This can further strain the environment and cause social and political tensions and conflicts. Because of its link with migration, desertification is a truly global problem, in the same way as climate change or biodiversity loss.
In some countries, land degradation has led to massive internal migrations, forcing whole villages to flee their farms for already overcrowded cities.
Fifty million people are at risk of displacement in the next ten years if desertification is not checked (UNU 2007). Implementing sustainable land and water management policies would help to overcome these increasingly extreme challenges.
Problems occur in the urban environment as well as in rural areas still unaffected by land degradation, but which receive new migrants.
Desertification can drive whole communities to migrate towards cities or regions where survival conditions are initially more promising but grow increasingly difficult and threaten social stability and cultural identities. The makeshift dwellings, which are insanitary and illegal, are sometimes sources
of ethnic or religious conflict. Desertification also causes political instability and has played a part in sparking off some of the armed conflicts currently underway in the drylands.
Poverty Eradication
The majority of people who are directly affected by desertification live below poverty line and without adequate access to fresh water.
Poverty drives populations to over-exploit the remaining natural resources, triggering a vicious cycle of accelerating land degradation and greater poverty. Poverty is thus both a cause and a consequence of desertification.
Land degradation also weakens populations and institutions rendering them more vulnerable to global economic factors. For example, the shortfall in tax receipts as a result of low productivity impacts governments’ capacity to repay their foreign debt and develop national socio-economic programmes.
The occurrence of desertification and prolonged drought reduces national food production and increases the need to turn to foreign products.
Moreover, food aid can eventually lead to a reduction in local agricultural production, especially if it becomes more costly to produce locally than to resort to imports that are distributed for free by the international community.
Although both rich and poor are affected when disasters occur from desertification, land degradation and drought, the poor are hardest hit because their ability to cope with, and recover from, these events depends on their access to assets such as land, and their ability to mobilize resources.
For example, when drought strikes, rich individuals, groups or communities can invest their assets elsewhere to meet short-term needs, whereas that is not an option for the poor.
Loss of Biodiversity
Drylands are often seen as being devoid of life, but in fact they contain an incredible diversity of species that are well adapted to the difficult climatic conditions. The biodiversity we see today is the result of thousands of millions of years of evolution, shaped by natural processes and, increasingly, the influence of humans. It forms the very web of life of which we are an integral part and upon which we so fully depend.
More than anywhere else, societies in the drylands depend on the use of biodiversity for their daily needs and their economic and spiritual development. Since dryland biodiversity is fragile and specialized, and adapted to a very specific set of physical conditions, land degradation and climate change can have significant and irreversible negative impacts on drylands species.
Biodiversity underpins many livelihoods in drylands, including pas toralism, agriculture and tourism. Nature-based tourism is a particularly important source of income for people living in sub-Saharan Africa where community management of biodiversity yields positive benefits both for biodiversity conservation and sustainable use, as well as for sustainable livelihoods. For generations, traditional pastoral and agricultural practices have evolved in harmony with biodiversity in such a way that people rely on indigenous biodiversity, such as traditional livestock varieties that are more resilient to drought and disease than imported varieties. At the same time, the structure and composition of grasslands, including the variety of species, is reliant on sustainable grazing.
As a consequence of land degradation, animal species that are dependent on vegetation have to migrate to other areas to find sufficient resources or they risk disappearing altogether. Their loss is significant because animal and plant species from the drylands are particularly well adapted to this extreme environment. They act as indicators of environmental conditions and their disappearance is a sign of significant habitat degradation. In addition, local species constitute important resources for the population, so their disappearance increases food insecurity and the impoverishment of the world’s most fragile populations.
Taking all these factors into account, desertification reduces the natural capital available to drylands species and people, making them more vulnerable to change. The loss of dryland biodiversity also limits the extent to which drylands can recover from temporary reductions in productivity.
Avoided Deforestation
Deforestation and desertification adversely affect agricultural productivity, the health of humans as well as of livestock, and economic activities such as ecotourism. Forests and tree cover combat land degradation and desertification by stabilizing soils, reducing water and wind erosion and maintaining nutrient cycling in soils. The sustainable use of goods and services from forest ecosystems and the development of Agroforestry systems can, therefore, contribute to poverty reduction, making the rural poor less vulnerable to the impacts of land degradation. Desertification and the associated loss of vegetation cause biodiversity loss and contribute to climate change through reducing carbon sequestration.
A key factor on how deforestation triggers desertification is linked to a drastic change in microclimates where vegetation is removed. For instance, if shrubs and trees are felled, the noonday sun will fall directly on formerly shaded soil; the soil will become warmer and drier, and organisms living on or in it will move away to avoid the unaccustomed heat. The organic litter on the surface - dead leaves and branches, for example - will be oxidized rapidly and the carbon dioxide carried away. So too, will the small store of humus in the soil.
The problem of developing arid lands and improving the well-being of the people dependent on them, is vast and complex. Forestry has a major role to play in any strategy to tackle it:
• it plays a fundamental role in the maintenance of the soil and water base for food production through shelterbelts, windbreaks, and scattered trees, and soil enrichment;
• contributes to livestock production through forest pastoral systems, particularly by the creation of fodder reserves or banks in the form of fodder trees or shrubs to cushion droughts;
• produces fuelwood, charcoal, and other forest products through village and farm woodlots;
• contributes to rural employment and development through cottage industries based on raw materials derived from wild plants and animals and the development of wildlife-based tourism; and
• provides food from wildlife as well as from plants in the form of fruits, leaves, roots, and fungi.
Drylands provide energy resources to local populations as well as to global markets. These resources include woodfuels, a variety of fuel minerals as well as a large potential for solar energy. Energy is essential to poverty reduction and economic transformation, yet the world’s hunger for energy is also one of the main drivers of desertifi cation. The availability and use of energy will, to a large extent, determine how and if countries increase agricultural productivity, provide safe water, achieve higher levels of industrialization, and effi ciently use information and communications technologies to become integrated into the global economy.
The use of fi rewood is one of the principal causes of desertifi cation. In tropical arid areas, wood is the principal source of domestic energy for cooking and lighting both in rural and urban populations. Wood energy data tend to be scarce, with a high degree of uncertainty and many gaps. However, several organizations have attempted to present consistent statistics from the best national knowledge or fi eld surveys. These organizations include the Food and Agriculture Organization of the united Nations (FAO) and the International Energy Agency (IEA).
FAO reported that woodfuel consumption in Africa reached 623 million cubic metres in 1994 — the highest per capita woodfuel consumption of any continent. Many African countries depend heavily on wood for energy, with fuelwood often representing more than 50 per cent of primary energy consumption. Due to the lack of water in the drylands, forest regeneration is very slow, reducing the growth of vegetation. However, practices such as allowing for rest periods from grazing and increasing fallow periods, generally have spectacular regenerating eff ects on the forest.
Energy crops can off er an alternative to wood and non-renewable energy sources if managed responsibly. The jatropha plant is one such crop that grows in low-rainfall regions on wasteland, does not compete with food crops on cultivated land and can contribute to sand fi xation. In drylands therefore, careful selection of non-food crops could not only signifi cantly reduce competition between food and energy security, but could also provide income-generating possibilities, as well as opportunities to reduce soil degradation. Furthermore, agrofuel crops could have the potential to increase soil organic carbon stocks while simultaneously curbing the amount of carbon released into the atmosphere through soil degradation. This in turn would contribute to climate change mitigation. Several developing countries such as India and Mali are implementing a number of jatropha projects.
Food security
One of the reasons why desertification is considered a major global environmental issue is the link between dryland degradation and food production. Meeting the food demand for the projected population increase by 2050 (which will be mostly urban and richer) will be difficult to achieve even under favourable circumstances. If desertification is not stopped and reversed, food yields in many affected areas will decline. Malnutrition, starvation, and ultimately famine may result.
Meeting global food targets and sustaining a breakthrough in terms of yields will require more land and therefore more water, or at least more production per unit area or volume of water. Farmers will need to adapt, possibly by using new technologies and crops to be more frugal in their water use. A movement towards an increased utilization of drought- and heat-tolerant crops could be extremely important.
Food security can ultimately be put at risk when people already living precariously face severe droughts and other environmental disasters. Famine typically occurs in areas that also suffer from poverty, civil unrest, or war.
Drought and land degradation often help to trigger a crisis, which is then made worse by poor food distribution and inability to buy what is available.
The relationship between soil degradation and crop yields, however, is seldom straightforward. Productivity is affected by many different factors, such as the weather, disease and pests, farming methods, external markets and other economic forces.
Many people living in the drylands engage in agricultural and pastoral activities. However, communities engaged in these activities display different patterns of asset ownership and access. For example, in agricultural communities men own the land and produce cash crops, and thus obtain credit and other facilities. Women, on the other hand, rarely own land and are often confined to the production of subsistence foods. In Uganda, for example, although 97 per cent of women have access to land, 8 per cent have leaseholds, but only 7 per cent actually own land and have access to credit. In such communities, women’s access to critical resources is mediated by relationships with men.
Therefore female-headed households are at an even greater disadvantage, which makes them more vulnerable to the environmental and economic crises caused by land degradation. They suffer from the effects of male migration since the men leave for the cities in search of alternative lifestyles and to support their families.
Conversely, women are the primary natural resource managers, providers of food security, and repositories of knowledge and expertise on indigenous plants, medicines, food and water. As key players in both agricultural and pastoral production their role in dealing with soil fertility and crop failure in degraded and drought-prone areas is crucial. One problem is that women, especially the most impoverished among them, often lack organizational and environmental management strategies, due to limited access to information and education compared to men. As the most disadvantaged in asset Access and ownership, women in drylands encounter great difficulty in adjusting to the extreme effects of desertification. Support and training in sustainable practices to reverse land degradation could be targeted towards women to maximize their impact.


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