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close this bookSustaining the Future. Economic, Social, and Environmental Change in Sub-Saharan Africa (UNU, 1996, 365 p.)
close this folderPart 2: Environmental issues and futures
close this folderTowards sustainable environmental and resource management futures in Sub-Saharan Africa
View the document(introduction...)
View the documentIntroduction
View the documentThe concept of sustainable development and its implications
View the documentDriving forces
View the documentLevels of environmental effects of human activities and sustainability concerns
View the documentConstraints on sustainable development in Sub-Saharan Africa
View the documentRecommendations
View the documentReferences

Levels of environmental effects of human activities and sustainability concerns

The environmental impacts of development activities occur at the local, national, regional, and global levels. Concern about them also occurs at all levels but the magnitude of the adverse effects of certain activities may be more seriously felt at one level than at the others. Similarly, measures to be taken in dealing with the problems caused by adverse environmental impacts may be more effective if taken at one level than at another.

Table 7.3 Major driving forces and some of their main environmental impacts

Driving forces Some of the main environmental impacts
1. Agriculture, livestock production, fishing and hunting Under high population pressure and intensification of farming, traditional farming systems become out moded, causing land degradation including erosion.
  Increasing livestock numbers beyond carrying capacity also cause land degradation.
  Cash cropping can result in excessive deforestation, loss of biodiversity, and environmental pollution.
  Mechanical clearing and excessive tillage cause land degradation and erosion.
  Land degradation causes expansion of farming and grazing often into more marginal areas, resulting in more deforestation and land degradation.
  Deforestation and damage to vegetation cover in farming and grazing, in addition to unregulated fishing and hunting, result in rapid loss of biodiversity.
  Burning of vegetation in farming and pasture management produces greenhouse gases, which pollute the air, smoke, and suspended particulate matter.
  Ruminants produce methane, which pollutes the atmosphere.
  Intensification of farming without adequate fertilizer/manure application causes land degradation, while excessive use of fertilizers and pesticides also causes environmental pollution.
  Soil erosion and excessive runoff cause siltation of streams and rivers, with adverse effects on aquatic resources.
2. Population growth Rapid growth intensifies pressures on resources, resulting in excessive deforestation and environmenal degradation because sustainable traditional farming systems cannot cope.
  Population growth drastically reduces available land per capita, resulting in removal of all natural vegetation and loss of biodiversity of plants, animals, and micro-organisms. This either eliminates national parks and reserves or causes sharp declines in areas available.
  High population pressure on forestry and fishery resources also causes serious loss of biodiversity.
  Population concentration generates enormous amounts of waste, which pollutes the environment, while concentrations of livestock also degrade the environment.
3. Industrialization Some industrial technologies and processes cause atmospheric pollution, with greenhouse gases, acidrain, and loading of the air with suspended particulate matter.
  Undegraded plastic products produced by industry constitute a major environmental hazard.
  Industry produces enormous quantities of solid and liquid waste in addition to toxic chemicals, which pollute the environment. Some of these hazardous wastes in developed countries are transported to Africa.
  Industrial accidents (such as the one that occurred in Bhopal in India) endanger life and property in addition to destroying the environment.
4. Urbanization Urbanization causes climatic, hydrological, geomorphological, vegetational, and environmental quality changes.
  The production of large amounts of liquid and solid waste, in addition to contaminants, causes pollution of land, water bodies, and atmosphere.
  Urban transport produces greenhouse gases and smog.
  Urbanization increases flooding and lowers water quality and hydrological amenities.
  Urbanization increases crime rates and drug traffficking and breeds slums.
5. Fuelwood and energy management Over 80% of the energy in Sub-Saharan Africa comes from fuelwood and biomass.
  The collection of fuelwood and charcoal to satisfy this demand results in rapid rates of deforestation, which exacerbate the environmental degradation caused by forest clearing for agriculture, pastures, ranges, and other land uses.
  The making of charcoal and burning of fuelwood produce greenhouse gases and particulates that pollute the atmosphere and contribute to climate change and ozone depletion.
  The building of large dams for hydroelectric power results in eutrophication. Sedimentation behind dams for irrigation increases the incidence of parasitic waterborne diseases such as bilharzia, aquatic weed problems, etc.
6. Poverty and affluence The poor have limited access to resources and wreak havoc by exploiting the environment to the extent that there is rapid irreversible degradation.
  The poor, who cannot purchase inputs for farming, mine the soil, thereby causing land degradation.
  The poor cannot afford to provide sanitation services, with the result that land, water, and atmosphere are polluted.
  Affluence causes people to destroy the environment through the excessive use of chemicals and pesticides and the maintenance of unsustainable livelihoods.
7. Other miscellaneous activities and phenomena Examples of miscellaneous factors that also have adverse impacts on the environment include greed,
  excessive consumption patterns, war and social conflicts, etc., which result in environmental degradation and damage to life and property.

Local impacts

Certain effects of human or development activities may be highly localized. For example, if a whole tree falls in a tropical forest it knocks down or carries with it broken branches of surrounding vegetation or lianas and may smash and kill several small seedlings, herbs, and shrubs that are in its way. Within the damaged area, called the chablise, some light is allowed into the canopy. Within a short time most of the non-woody and succulent material decomposes and releases nutrients to the soil, from where they are recycled in a more or less closed cycle. Within a few years the chablise is covered by vegetation and there is no movement of materials outside the ecosystem. Similarly, a small clearing in the forest for shifting cultivation may have only a limited localized effect and even the gases produced in the slash and burn clearing do not travel very far away since the volume of the gases produced may be very small.

National and regional impacts

Most environmental effects that might attract attention or have impacts at the national level start in a small way locally and then gather momentum to become important at both national and international levels. For example, many river basins cut across several countries. According to UNEP (1992), the proportion of river basins in Africa that are international, out of a total of 56 river basins, is 26 per cent, compared with 22 per cent in Europe, 19 per cent in Asia, 17 per cent in South America, and 16 per cent in North and Central America. It is obvious that in such river basins as in the Niger and the Nile, development activities and natural disasters such as floods upstream may have trans-boundary effects along the river basin. Although small isolated forest fires have only local effects in Africa, during the dry season north or south of the equator fires in hundreds of small clearings produce smoke and gases that combine to contribute a considerable amount of greenhouse gases, which in turn gather momentum to have regional impacts. When they join jet streams in the upper atmosphere they may have global effects. It is obvious from this example that some of the environmental impacts, whether local or regional, are related to time. For example, whereas Africa's contribution to the global load of carbon dioxide and greenhouse gases constituted less than 100 million tonnes in 1900, by 1980 the CO2 released by burning fuelwood and by deforestation, which minimizes the sink capacity for CO2, amounted to about 700 million tonnes per year (see fig. 7.3).

The activities and impacts of tropical deforestation also occur at different levels. In fact, Wood (1990) observes that "at the local level deforestation primarily affects shifting cultivators and a growing population of rural peasants" but "the same problem multiplied over thousands of locations and combined with extensive logging can exacerbate the global issue of accelerated build-up of carbon dioxide." Wood (1990) likens the environmental politics of deforestation, consisting of four expanding layers of eco-political interaction at local, national, multilateral, and global levels, to the four sides of an upside-down pyramid (fig. 7.4). Each of the sides of this "upside down pyramid" -number of actors; number of political jurisdictions; complexity of ecological cause and effect relationships; and institutional obstacles to enforcement -represents an attribute of the deforestation problem that is compounded as it moves up the hierarchy. Thus deforestation not only becomes more complex ecologically as it moves from the local level to the global but also becomes more intransigent politically.

Fig. 7.3 Annual carbon release for the biomass system of the world's four major regions, 1900-1980 (Note: Whereas Africa's CO2 emissions from petroleum fuels in the 1980s were low - 0.25 tons/capita, equivalent to 8% of the figure for the United Kingdom - its CO2 emissions due to deforestation were about 700 million tons, or 1.5 tons/capita, at a time when such emissions were negligible or negative for European countries. Source: G. Leach, Agroforestry and the way out for Africa, in M. Suliman, ea., The Greenhouse Effect and Its Impact on Africa, London: Institute for African Alternatives, 1990)

A peculiar kind of trans-boundary environmental impact involves locally generated toxic waste in developed countries, which is transported across the seas to be deposited at minimum cost in some developing countries. This made it a global problem and the United Nations had to step in and formulate a convention to deal with such wastes.

Problem of transmission of cultural behaviour and standards at the international or global level

An aspect of modernization that could have very adverse effects on sustainability is the globalization of culture and economy that has exposed Africans and some indigenous peoples to advertisements via global television, video, radio, newspapers, and other media. Not only is it possible to advertise by television and radio, but fashion shows and behaviour patterns of people in Europe and America are projected to Africans in their own bedrooms, thereby making them interested in the material luxury consumption propensities of the North.

Fig. 7.4 Hierarchy of eco-political interactions in tropical deforestation (Source: Wood 1990)

Not only fashion but also criminal acts and lifestyles that are by no means sustainable are being "marketed" through the media. There is no doubt that the lack of strong cultural discipline in Africa as compared with Asia is one of the reasons that the level of savings in Africa is much lower than that in Asia. Although we have considered environmental impacts that start locally and gather momentum at the regional level to become global and affect millions of people physically, there is also a situation where people's attitudes and cultures are altered at the global level, and whereas certain global conventions have been passed to combat the former situation, it is not so easy to inculcate sustainable lifestyles or attitudes in the face of market forces and the globalization of culture that have become or are fast becoming deeply entrenched.