Effects of Desertification

Environmental problems Of all the global environmental problems, desertification is, perhaps, the most threatening for poor rural people. The most accepted definition of desertification states that it is land degradation in arid, semiarid, and dry sub-humid areas resulting from various factors, including climatic variations and human activities. Drylands cover almost 40 percent of the total land surface of the world and are inhabited by approximately 1 billion humans dispersed over more than 100 countries. These people include many of the world's most vulnerable, marginalized, and politically weak citizens. In spite of the progress in the understanding of the ecological dimension of this phenomenon, few communities' wellbeing has improved by the myriad action plans and activities carried out by local, regional, or national organizations, particularly in Africa. A growing body of evidence suggests that a closer look at the social system and the role of its components is critical to understanding this frequent outcome. Drylands are characterized by water scarcity stemming from the conjunction of low water offer (i. e. , precipitation) and high water demand (i. . , water lost to the atmosphere as water vapor from soil via evaporation and from plants through transpiration). Drylands' precipitation is highly variable through the year and occurs in infrequent, discrete, and largely unpredictable events. In turn, the high evaporative demand of the atmosphere, resulting from high air temperatures, low humidity, and abundant solar radiation, determines that water availability is the dominant con trolling factor for biological processes such as plant growth and herbivore productivity. Thus drylands, though not barren, are ecosystems of low and highly variable productivity capable of limited human settlement and vulnerable to anthropogenic disturbance. The proximate causes of desertification are complex and vary from region to region. The European Mediterranean region has a long history of human misuse. War, urbanization, farming, and tourism have, over the years, altered vegetation to such an extent that, at present, virtually no natural vegetation exists there and soil erosion is ubiquitous. In contrast, Australian drylands have experienced extensive degradation only recently. The introduction of domestic livestock by Europeans in the late 1880s, together with the fences used to concentrate these animals and the suppression of fire, drastically reduced the abundance of perennial grasses, leaving more soil exposed to erosion by water or wind, and triggered shrub encroachment. In the Sahelian region of Africa, where the concept of desertification was first coined at the beginning of the 20th century, the replacement of the original vegetation by crops, the increase of grazing pressure over the remaining lands, and the collection of wood for fuel resulted in a reduction of the biological or economic productivity of the land. In particular, inappropriate use of heavy machinery, deficient irrigation schemes, and grazing management practices led to soil erosion, salinization, and overgrazing. Any attempt to assess the impact of desertification on human societies should first acknowledge the difference between the ways water-limited ecosystems shape the functioning of social systems and the effects of desertification itself. Desertification imposes an additional constraint on human well-being by further reducing the limited ecosystem goods (e. g. , food, timber, water) and services (e. g. , soil maintenance, erosion control, carbon sequestration) that drylands provide. Failure to address this difference would lead to an overestimation of the desertification effects. Additionally, the manifestations of desertification vary widely, depending on the capacity of each country to mitigate its impacts. For example, in Africa it resulted in declining productivity and intensifying food insecurity and widespread famines, whereas in the Mediterranean region desertification seriously threatens water supply, while many regions of northern Europe are experiencing an increase in dust deposition due to north African soil erosion. In poor countries with a large proportion of their territory in arid and semiarid regions, desertification may trigger a downward spiral where a significant amount of a nation's human and financial resources are devoted to combating past desertification effects, leaving less available to invest in health, education, industry, and governmental institutions. The ultimate precarious social conditions thus developed generally lead to migrations, exacerbating urban sprawl, and may bring about internal and cross-boundary social, ethnic, and political strife. Approaches to the desertification problem broadly fall into two competing perspectives: the predominant global environmental management (GEM) discourse and the populist discourse. Whereas the former discourse rests on neoliberal values and Malthusian thinking, the latter has its philosophical roots in the self-reliant advocacy derived from the dependency schools of the 1970s and 1980s. The GEM discourse depicts overpopulation in drylands as the main problem leading to the degradation of the ecosystems on which they depend. As seen in the GEM discourse, the global problem of desertification requires a global solution. Therefore, GEM supporters promote topdown, interventionist and technocentrist solutions implemented through international institutions and conventions, such as the UN Convention to Combat Desertification. On the contrary, the populist discourse–populist in the sense that it positively portrays the acts of local people–emphasizes that the marginalization of smallholders and pastoralists started during the colonial period and was subsequently deepened by global capitalism, transnational corporations, and northern consumers as the principal causes of land overexploitation and degradation. International assistance in the form of debt per nature exchanges or technological transferences is regarded as part of the problem itself. Rather, the populist discourse focuses on local or traditional knowledge and community-based action as major sources to overcome environmental problems. However, despite its diametrically opposed explanations of the desertification problem, neither discourse denies an impending crisis caused by desertification. Why, almost a century after its first detection, does desertification continue to be among the most important environmental problems faced by humankind? Though no single answer exists, there are some arguments to sketch an answer. Undoubtedly the inherent complexity of the desertification phenomenon hampers almost every phase of the sequence leading to the mitigation or control of an environmental problem (i. e. , first detection, general recognition, agreement on regulation). For instance, a long period elapsed between when French foresters first perceived what they called â€Å"the desert advance† and the widespread diffusion of the desertification tragedy that took place in the Sahelian region of Africa after a series of drought years at the beginning of the 1970s; today improvements in our understanding of rangelands functioning and climatic variability allow for faster detection and prevention. These advances show that vegetation dynamics in drylands may remain seemingly unaffected by an increase in land use pressure until there is a sudden shift to a lower-productivity stable state, with stochastic climate events, such as severe droughts, acting as triggers. Additionally, incomplete or inadequate scientific knowledge, together with the urgent need of integrative solutions for the Sahelian drama, may have driven actors to resort to the first workable options, leading to erroneous regulations at that time. However, regulations of this kind are not dependent on scientific knowledge alone but also on political pressure mechanisms. Thus an explanation of the failure to achieve sound regulation needs to consider political issues as well. The predominance of the GEM discourse, despite the poor performance of top-down solutions to â€Å"unsustainable† resource management, can be explained by its convenience for the interests of three main groups involved in the desertification issue: national governments, international aid donors, and scientists. National governments benefit not only from foreign financial aid but also from the use of desertification as the basis for severely repressive social control. International donors and institutions find the problem of desertification a reason unto itself for their involvement, whereas scientists may highlight the global nature and severity of the desertification problem as a means to obtain research funds. On the contrary, the bottom-up approaches promoted by the populist discourse do not fit the terms and conditions of bilateral and multilateral funding and instead stress the principles of participation and decentralization. It is apparent that the progress achieved in our comprehension of desertification has not been matched by an improvement in the regulations aimed at mitigating its consequences. While the accumulation of knowledge generated during the past decades provides evidence against both discourses' main tenets, they nonetheless remain influential in the political and scientific arenas. Future contributions to the solution of the desertification problem require the synthesis of recent social and ecological advances into a new synthetic framework that overcomes the constraints upon the solutions imposed by the GEM and populist discourses. Social scientists hope that a new desertification paradigm–that is, the dryland development paradigm, which represents a convergence of insights from both discourses–is emerging. Bibliography: 1) Adger, W. Neil, Tor A. Benjaminsen, Katrina Brown, and Hanne Svarstad. 2001. Advancing a Political Ecology of Global Environmental Discourses. † Development and Change 32:681-715. 2) Herrmann, Stefanie M. and Charles F. Hutchinson. 2005. â€Å"The Changing Contexts of the Desertification Debate. † Journal of Arid Environments 63:538-55. 3) Reynolds, James F. and D. Mark Stafford-Smith. 2002. Global Desertification: Do Humans Create Deserts? Berlin: Dahlem University Press. 4) Veron, Santiago R. , Jose M. Paruelo, and Martin Oesterheld. 2006. â€Å"Assessing Desertification. † Journal of Arid Environments 66:751-63.