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Little reliable data is available on the extent of land degradation in Africa. However, anyone who has travelled through the continent has observed that land degradation is widespread and serious. The presence of gullies and sand dunes, of degraded forests and grazing lands are obvious, although the effects of sheet erosion and declining soil fertility are less noticeable.
The wealth of Africa depends on her ability to conserve and manage her land resources. It is a well known fact that soil degradation not only results in decreased food production but also in droughts, ecological imbalance and consequent degradation of the quality of life. In Africa, the most conspicuous symptoms of the negative impact of land degradation on food production are stagnating and declining yields and increasing levels of poverty.
Throughout the continent, regardless of the climatic zone, meteorological records show that unpredictability of rains is a common feature. In the Sahel, variations in total annual rainfall can be up to 30 or 40 per cent. Even, the humid and sub-humid zones are subject to rainfall fluctuations of 15 to 20 per cent. In most cases, the rainfall is rarely gentle and even. It usually comes as torrential downpours, which are destructive to soils and harmful to plants.
The continent can be divided into four major climatic zones:
Africa also suffers from geologically induced and inherently low soil fertility as the bedrock consists of mostly granites and gneiss. African rocks are among the oldest in the world. The relationship between the parent soils and the soil forming factors are very complex because the land surface has undergone a series of shifts in vegetation and climate. Nearly one-third of the central plateau of Africa is of Pre-Cambrian age (over 600 million years old). The rest of the surface is covered with sand and alluvial deposits of Pleistocene age (less than 2 million years old). A recent volcanic activity occurred mainly in the eastern and southern parts of the continent, principally between Ethiopia and Lake Victoria. For this reason, most of the soils in Africa are characterized by a low proportion of clay, making them easy to work, but also easy to lose.
Not only is Africa geologically old and afflicted with a harsh climate, but also large parts of the continent have been occupied by human beings much longer than in other continents. Human activities in obtaining food, fibre, fuel and shelter have, therefore, significantly altered the soil.
Though degradation is largely man-made, and hence its pace is governed primarily by the speed at which population pressure mounts, irregular natural events, such as droughts, exacerbate the situation. The 1982/85 drought, for example, had a dramatic effect on the speed of land degradation and desertification. Essential though food aid is in such emergencies, it clearly does nothing to alleviate environmental damage.
Many African countries have already lost a significant quantity of their soils to various forms of degradation. Many areas in the continent are said to be loosing over 50 tones of soil per hectare per year. This is roughly equivalent to a loss of about 20 billion tones of Nitrogen, 2 billion tones of Phosphorus and 41 billion tones of potassium per year. Serious erosion areas in the continent can be found in Sierra Leone, Liberia, Guinea, Ghana, Nigeria, Zaire, Central African Republic, Ethiopia, Senegal, Mauritania, Niger, the Sudan and Somalia.
Nomadic herders, grazing animals on arid and semi-arid lands, are particularly vulnerable to drought, since it depletes their most precious assets: their livestock herds. In northern and eastern Kenya, we saw the drought of 1992 decimate the livestock herds of pastoral communities, forcing herders to sell cheaply to local traders. At the same time, shortages of cereals forced 4p prices of food staples. The result has been widespread malnutrition, with an estimated 1.7 million people left dependent on relief assistance. In Somalia, drought in 1991 and 1992 forced the nomadic pastoralists of the central region to sell off their herds at a time of escalating food prices caused by ethnic and tribal armed conflicts and civil wars, exposing them to severe hunger.
Desertification is a serious problem in the continent. It has been estimated that 319 million hectares of Africa are vulnerable to desertification hazards due to sand movement. An FAO/UNEP assessment of land degradation in Africa suggests that large areas of countries north of the equator suffer from serious desertification problems. For example, the desert is said to be moving at an annual rate of 5 km in the semi-arid areas of West Africa.
Desertification, of course, did not begin with the recent drought. Archaeological records suggest that Africa's arid areas have been getting progressively drier over the past 5 000 years What is new is the coincidence of drought with the increasing pressures put on fragile arid and semi-arid lands by mounting numbers of people and livestock. This is basically what is accelerating land degradation throughout much of Africa. In the wetter areas, however, there is a better chance that degradation can be halted and the land restored.
Soil degradation caused by deforestation is also a serious threat in Africa. Deforestation exposes the soil to high temperatures which break down the organic matter, increase evaporation and make the soils vulnerable to erosion. Thirty-seven million hectares of forest and wood lands in Africa are said to be disappearing each year (FAO, 1986). More serious still is the gradual removal of trees in farms and pastures, which are crucial for protecting productive land from erosion.
To summarize, available evidence leaves no doubt that soil degradation caused by erosion, desertification, deforestation, and poor agricultural practices is undermining the very resources on which African farmers and their families depend for their very survival. In many areas of Africa, the manifestations of this calamity include the creation of deep gullies, of crusts that water cannot penetrate, rock-hard layers, laterite that handtools and plant roots cannot pierce, and shifting sand dunes that swamp villages and fields. UNEP has estimated that more than a quarter of the African continent is at present in the process of becoming useless for cultivation due to degradation.
In the drier parts of Africa, millions of hectares of grazing land and rangeland are also threatened with degradation- in the arid north, the semi-arid south, the Sudano-Sahelian countries and in the drier parts of Cameroon, Ethiopia, Kenya and Nigeria. The 1983-85 and recent droughts killed huge numbers of livestock there, with the result that good breeding stock was lost and the structural balance of herds distorted. Nevertheless, the herds are now recovering, but within five or ten years the trend of increasing overgrazing could be re-established - until the next drought reduces livestock numbers again.
The rangeland itself has been changed for the worse, with many of the perennial grasses being replaced by nutritionally poorer annual grasses. This has permanently Impaired the rangeland's potential for recovery and decreased its carrying capacity. As the vegetation has been removed or reduced, the wind has also winnowed out the small amount of silt that the soil contains, reducing its ability to retain moisture. When it does rain, the chances of the range recovering are correspondingly reduced.
Africa's forests and woodlands are also being depleted, threatening one of the continent's most important resources. In Africa, trees play an important role in protecting the environment. They are the principal source of rural energy, and provide countless medicinal and industrial products used in both the home and in small-scale industry. They often supply food and feed, are the main source of building materials in the countryside and, directly and directly, are a source of employment and income for many rural Africans.
Nearly 4 million hectares of this resource are now being deforested or degraded annually, largely in humid and sub-humid West Africa. The rate of destruction is alarmingly high in the Cameroon, in Côte d'lvoire and in Nigeria. The cause of deforestation is mainly clearing for agriculture but uncontrolled logging, gathering for fuelwood, fire and overgrazing are also taking their toll. In most parts of Africa, the current trend cannot be continued indefinitely: in some places, deforestation rates exceed planting rates by a factor of 30:1.
Despite the great potential in Africa for irrigation estimated by FAO to be about 27 million hectares, only one-sixth has so far been developed. As most of Africa has little tradition of irrigation, it is likely that its rapid expansion will not happen soon and certainly not under conditions in which the practice is fully managed by the farmers themselves. Consequently, rainfed cultivation accounts, and will continue to account, for any increase in food production in Africa.
One of the causes of degradations is that population pressure is forcing farmers to cultivate increasingly marginal land. In Malawi, for instance, escarpment land that has a slope of more than 12 per cent - and that should therefore be forested - is being cultivated, causing erosion, the flooding of fertile crop land below, and the situation of stream beds and irrigation canals. Thus erosion is threatening the future of one of the few countries in Africa that is successfully feeding itself.
FAO's 1985 study of the carrying capacity of land in developing countries compared Africa's projected future population with its food production potential. According to the study, the number of countries that will be unable to feed themselves from home production using the present low level of inputs will rise from 22 out of 49 in 1975 to 32by the end of the century and to 35 by the year 2025. Indeed, even as early as the year 2000, 16 countries will have a critical food shortage even if they use intermediate inputs. They include the five North African countries together with Mauritania, Niger, Somalia, Rwanda, Burundi, Kenya, Lesotho, Namibia and the Indian Ocean islands of Mauritius, Reunion and the Comoros. Nigeria and Ethiopia would be close to being in a critical state. These predictions are based on the assumption of using every scrap of suitable and marginal land to grow nothing but crops. If we consider only production from land that is likely to be actually cultivated, and deduct one third for non-food crops and unequal food distribution, the results are very alarming. By 2000 A.D. Africa would be able to feed only 55 per cent of its population with low inputs. By 2025, it would be able to feed only 40 per cent of its population.
Most countries of the Sahel and mountainous East Africa will face severe problems. Ethiopia's 1983 population of 36 million will more than treble to 112 million in 2025, forty-four million more than it can feed with intermediate inputs. Nigeria's population in 2025 is projected to reach 338 million, 123 million in excess of its carrying capacity with intermediate inputs. Even with high inputs, Kenya's lands can support only 51 million people a total that will be passed by 2010. By 2025 there maybe 83 million Kenyans, with as many as 111 million before the population reaches its plateau.
Central Africa will face no land shortage even if it is still using low inputs. With intermediate inputs, Zaire alone can feed 1,280 million people, 95 per cent of the projected total for the whole of sub-Saharan Africa in the year 2025. But this enormous surplus capacity is based on clearing most of the rain forest for agriculture. Even if this were to be done, it would not solve the food problems of the Sahel or East Africa any more than North America's present surplus could. The only way this huge potential can alleviate population pressure elsewhere is the occurrence of massive migrations into Central Africa from the surrounding areas, a solution which is fraught with political and environmental problems.
The belt of land running through the West African Sahel region and the Sudan to northeast Ethiopia and Kenya is particularly vulnerable. Around 90 percent of rangelands and 80 per cent of rain-fed farmlands in the area are affected by degradation - including soil erosion, deforestation, and loss of woody vegetation which makes them less able to bear crops and pasture.
These grim prospects are all based on the assumption that past trends continue. They are entirely realistic and they point towards disaster. Africa is the world's nightmare, a continent of recurrent drought, famine and bloody tribal, ethnic conflicts and civil warfare, perpetually dependent on food aid handouts with spreading deserts and shrinking forests.
The facile response to these prospects is to point out that many developed countries are not self-sufficient in food or energy and that they pay for their imports with exports of manufactured goods or services. Could not Africa's food-deficit countries do the same ? The problem here is that the prospects of industrialization in Africa are dimmer than those in any other region of the world. The developed countries are price-takers and competitors among themselves in protected markets for their exported agricultural products. Apart from the oil-rich countries and a few city-states deluged with foreign investment, no country has industrialized without a reasonably healthy agricultural base. Africa seems to be caught in a trap; industrialization could solve her food problems, but with agriculture stagnant, the chances of industrialization are slim. In addition, with the level of income of the 80 % of population living in the rural sector very low, chances of having a market for industrialization are further very slim.
In countries with limited cultivable land and high population-growth rates - such as Kenya, Ethiopia, Malawi, Burundi, and Rwanda - fallow periods are no longer sufficient to allow soil fertility to be restored, so that crop yields have fallen. In response, farmers have been forced either to bring increasingly marginal lands into cultivation, or to migrate into tropical forest areas, exacerbating problems of land degradation and deforestation.
Nowhere is the lethal interaction of poverty and environmental degradation more evident than in Ethiopia. About half of the country's highland area is significantly eroded, reducing yields by between 2 per cent and 3 per cent a year. According to a 1986 study by the UN Food and Agricultural Organization, over 1,900 million tons of soil are lost from the highlands annually. If the trend continues, some 38,000 square kilometres will be eroded down to bare rock by the year 2010, and a further 60,000 square kilometres will have a soil depth of 10 centimetres, below which the soil would be too shallow to support cropping. About 2 million hectares of farmland are already estimated to be beyond recovery.
As stated by FAO, raising agricultural productivity to achieve greater self-reliance in food especially in Low Income and Food Deficit Countries (LIFDC), will require major changes in the policy priorities of African governments especially regarding the conservation of the natural resource base. In the past, there has also been an anti-poor bias in agricultural policy across much of the region, notably through over-taxation of crops; inadequate spending on market infrastructure for small-holder producers; insufficient investment in research on local food staples; and an undue concentration on rainfed, rather than irrigated agriculture.
These trends are worrying, because agriculture is the backbone of most African economies, accounting on average for more than a third of GDP and more than three-quarters of employment. It follows that agricultural performance has a critical bearing on both national and household incomes. In addition, food imports now constitute a major strain on Africa's balance of payments, accounting for about 15 per cent of total imports.
Future prospects must be assessed against this background of diversity. For many countries, a simple extrapolation of current trends in per caput consumption to derive estimates of future food availability would be highly inappropriate. Trends that either continued a downward spiral or a rapid improvement in diet are unlikely to be sustained for long. The threat or existence of mass starvation, for example, would provoke corrective action at the national or international level, or both. This analysis, therefore assumes that, except in emergencies, per caput food supplies are not allowed to fall below. 1,750 calories a day, or below what is the internationally recommended requirement.
However, large increases in per caput consumption will not be maintained either partly because there are physiological limits to how much people need to eat and partly because the economic outlook is much less favourable than it was. Subject to these reservations, a continuation of the trends in demand would mean a small increase in per caput food availability in North Africa, and continued stagnation for sub-Saharan Africa. Measured from the more normal levels of 1979/81, per caput food supplies in sub-Saharan Africa would actually decline.
Even this outcome is probably optimistic, particularly for the low-income countries of sub-Saharan Africa: their food deficits would soon become so great that no plausible combination of commercial food imports and food aid could meet them. In 1982/84, the food imports of sub-Saharan Africa amounted to US$5.2 thousand million and accounted for two-thirds of all agricultural export earnings. Projecting current trends implies that by 2010 food imports would cost US$28.5 thousand million at constant prices, compared to agricultural export earnings of at most US$12 thousand million. The cereals gap alone would grow to 100 million tonnes, of which 58 million tonnes would be in sub-Saharan Africa.
It is difficult to see how these food gaps could be bridged. Except for some of the more industrialized countries of North Africa, present and potential oil exporters, some mineral producers and a few net agricultural exporters, it is unlikely that foreign exchange earnings would be sufficient to pay for substantial imports, particularly in the low-income countries that account for half the projected deficit.
Developed countries could produce enough surplus to meet the deficits, but food aid would have to be increased many times by the year 2010, and even more in drought years. This would be beyond the existing, and probably the foreseeable, transport and distribution facilities of many African countries. The most likely result is that food availability would therefore tend to decline even further. The word 'trend' is used here because this report does not include speculation over what might happen if per caput food supplies were to fall to levels normally associated with famines.
A continuation of current trends would place many countries on the edge of survival, even if they were provided with substantial international support. Some countries, however, most of which depend for their incomes on sectors other than agriculture, should be able to preserve and even improve their nutritional standards.
This outcome is not a sustainable one either, in at least two major ways. From what has been said, it is clear that the food shortages that would prevail in Africa if current trends were allowed to continue would produce perilous and unpredictable consequences that would affect not only Africa but most other regions as well. In addition, it is also clear that the land would not be atoll to sustain the pressures on it arising from the growing human and livestock populations and inappropriate land use systems. Severe degradation is already occurring, with rates of soil loss reaching at least ten times the natural rate of soil formation. Unchecked, this would result, by the year 2010, in an African landscape that had a greatly reduced potential for agricultural production. Irreversible damage would have occurred over huge areas, and it is doubtful whether reclamation would ever be possible on an economic basis.
If the present trend of stagnating or declining productivity found over much of Africa is to be reversed, land degradation will have to be halted. The problems, as well as their underlying causes, vary greatly from country to country and even within individual countries. Consequently, the approaches used, techniques applied and methods adopted will have to be adapted to the specific needs of different environments.
Drought and conflict have left many countries in sub-Saharan Africa critically dependent on food and emergency aid. The provision of that aid is vital to the region's food security, and for local efforts at post-drought and post-conflict reconstruction. Unfortunately, for several countries, gaps between local needs and donors' pledges remain. This is why Northern governments should be pressed to respond more favourably to UN appeals. At different levels, a myriad of responses have been offered and/or tested to solve the problem of land and environmental degradation and diversification in Africa. Unfortunately the results have not-been up to expectations and the situation continue to worsen. The recent Paris Conference on Desertification brought no consolation.
The belief of the World Commission on Environment that economic development need not be environmentally degrading and that growth should in fact create the capacity to solve environmental problems should be shared by all.
In short, the heart of the problem is that the natural resource base of Africa is being degraded and destroyed at a rate which will soon make food and agricultural production un-sustainable. Poverty, coupled with increasing population pressure, is the biggest single cause of this degradation. The rural poor, the overwhelming majority of Africa's citizens, destroy their own environment, not out of ignorance, but simply to survive. Peasant farmers preoccupied with survival over-crop marginal and because there is no alternative employment and no better technologies they can afford. Pastoralists overstock to improve their chances of surviving the next drought. Rural dwellers strip trees and shrubs for fuelwood because they need fuel. In the context of the short-term basic needs of an individual, each decision is rational; in the long-run, the effects are disastrous.