Population People

Posted February 1998

Population Change - Natural Resources - Environment Linkages in East and Central Africa

by Alain Marcoux
Senior Officer, Population and Environment
Population Programme Service (SDWP)
FAO Women and Population Division
This note summarizes a paper written for the UNFPA Country Support Team for East and Central Africa. It deals with the 13 countries covered by that Team: namely Sierra Leone, Liberia, Ghana, Nigeria, Chad, Central African Republic, Uganda, Rwanda, Burundi, Tanzania, Kenya, Ethiopia and Eritrea.

1. Population and natural resources: the background

The sub-region has about 310 million inhabitants in 1997 (see Table 1), i.e. 52 percent of the population of sub-Saharan Africa. Population growth rates during 1990-95 varied considerably, from 3 percent or more in four countries to negative rates in the two countries that were subject to civil strife during that period. The growth rate for the total population of the sub-region was 2.8 percent, yielding a net addition of about 9 million yearly. This is slightly higher than the growth rate for Africa (2.7 percent) and much higher than the rate for all developing countries (1.7 percent).

The degree of urbanization also varies considerably in the sub-region, but it is never very high. It is very low in the mountain countries as well as in Eritrea, but reaches 40 percent and more in Nigeria, Liberia and the Central African Republic. (Nigeria is virtually the only country in the region to have an extensive urban network, while in others the urban population tends to be largely concentrated in the capital.) The overall proportion of urban population is 29 percent, significantly under the averages for Africa (36 percent) or all developing countries (38 percent).

The overall growth of urban population is rapid by world standards: 5.3 percent annually during 1990-95, despite negative growth rates in two countries affected by civil strife. (During the same period, the corresponding rate was 2.4 for the whole world, 3.4 for developing regions and 4.4 for Africa.) Despite this rapid growth, however, the urban proportion in the majority of the 13 countries is not expected to reach 50 percent before the year 2030.

The amount of cropland per caput for the whole sub-region as of 1993 was 0.27 hectare, which is the average for Africa (the world average is 0.26 hectare, and that for all developing countries is 1.8 hectare).

The amount of forest and woodland per caput for the sub-region was 0.67 hectare, but most countries had much lower values (without Chad and the Central African Republic, the average would fall to 0.40 hectare). By comparison, the African average is 1.16 hectare and the world average is 0.75 hectare.

Table 1. Some demographic characteristics and natural resources availability in East and Central Africa
  Population size 1997 (millions) Population growth rate 1990-95 (percent) Percentage urban 1996 Urban pop. growth rate 1990-95 (percent) Cropland per caput 1993 (ha) Forest/woodland per caput 1993 (ha) Renewable water per caput 1997 (m3/day)
Sierra Leone 4 428 1.0 34 3.0 0.14 0.50 94
Liberia 2 467 -3.9 46 - 2.5 0.17 0.77 231
Ghana 18 338 2.9 36 4.0 0.26 0.48 8
Nigeria 118 369 3.0 40 5.4 0.31 0.11 6
Chad 6 702 2.6 23 3.7 0.54 5.40 80
Central African Rep. 3 416 2.2 40 3.1 0.64 14.90 109
Uganda 20 791 3.3 13 5.7 0.37 0.30 9
Rwanda 5 883 -5.9 6 - 4.6 0.20 0.09 3
Burundi 6 398 2.0 8 5.6 0.24 0.01 2
Tanzania 31 507 3.0 25 6.3 0.12 1.19 6
Kenya 28 414 2.9 30 6.3 0.17 0.66 1
Ethiopia 60 148 3.2 16 5.9 0.26 * 0.49 * 5 *
Eritrea 3 409 1.9 17 3.5
All 310 270 2.8 29 5.3 0.27 0.67 11
Sources: United Nations (1996, 1997); FAO (1995); Engelman and LeRoy (1993).
* Ethiopia PDR (cropland and forest data: 1992)

Renewable water resources vary enormously from one country to another. The sub-regional average is 11 cubic meters (m3) per caput per day, to be compared with the world average of 19 m3. Nine countries appear to have a low unit supply of under 10 m3; Kenya, Burundi and Rwanda are particularly affected.

Where apparent water abundance is explained by the existence of a large or relatively large stream, caution must be exercised in interpreting the indices because, depending on population distribution, the portion of the population that is actually able to use the water resources may be quite limited (in general, much of this type of supply is lost to the sea or to the next riparian country). In addition, water that is not available at the right place and time can be considered as a resource in a practical sense only at great cost, if at all, so interpreting data on average water availability necessitates in all cases to take into account the discrepancies [i] between the spatial distribution of the population and that of water resources; and [ii] between the distribution of human needs over the year and the seasonal fluctuations of availability.

2. Population and environment seen from Rio

At the occasion of the United Nations Conference on Environment and Development (Rio de Janeiro, June 1992) participating countries reviewed the state of their environment in order to present national reports at the Conference. Table 2 summarizes the environmental issues identified by the 11 countries of the sub-region who reported to UNCED.

2.1 Main environmental issues in the region

Forest degradation, including deforestation, is the most widespread environmental problem in the region(all but one country signal it. The causes usually are fuelwood collection and land requirements of shifting cultivation; overgrazing also has an impact in some countries. The next most pervasive problem is soil degradation, either on account of pollution or because of overexploitation leading to loss of soil fertility. Soil erosion is almost as widespread. In arid zones, it may lead up to desertification [1]. The combined damage of erosion and chemical degradation to agricultural resources is serious, considering the difficult balance between food requirements and production in this region (and in Africa in general). Another common problem for the countries reviewed here is water pollution. The most common sources of pollution seem to be the industrial sector (including mining), then household wastes/urban sewage, then agricultural chemicals. Finally, urban environment problems (poor housing and unsanitary living conditions due to inadequate waste management) seem to plague most of the countries in the region. These clearly have negative health implications.

Table 2a. Environmental issues and their main direct factors in East and Central Africa
(Main factors are between brackets)
Sierra Leone Soil erosion and degradation. Pollution (from mining).     (From mining and household wastes). Water-borne diseases.
Ghana Wind and water erosion (due to agricultural activities). Loss of fertility Soil compaction, surface crusting, loss of stability.   (From manufacturing, agro-chemicals, mining, waste disposal). Water-borne diseases.
Nigeria Erosion and desertification catastrophic in five states.
50 million affected.
Pollution (by heavy metals, agro-chemicals, petro-chemicals).     (Sewage, industrial effluents, silting, pesticides, fertilizers)  
Chad       Precarity due to bad climatic conditions.    
Central African Republic Soil erosion. Loss of soil fertility.     Water-borne diseases (rivers and wells often contaminated).  
Uganda (Quarrying) Pollution (agricultural chemical).   Lack of safe water supply. (Mining wastes; agricultural chemicals)  
Rwanda   (Overexploitation). Collapse of agriculture. Disappearance of pastures (demographic pressure). Lack of safe drinking water.    
Burundi   Overexploitation by agriculture.     (Water resources are unprotected)  
Tanzania Desertification (expanding agriculture; overgrazing).       (Insufficient treatment of industrial effluents)  
Kenya Desertification (aridity + increased human use). (Inappropriate farming practices)     (Domestic waste, sewage, industrial effluents)  
Ethiopia (PDR) Soil erosion. Land degradation.   Lack of safe drinking water (especially rural areas).    

Table 2b. Environmental issues and their main direct factors in East and Central Africa (continued)
(Main factors are between brackets)
Sierra Leone   Deforestation   Poor housing and unsanitary environmental conditions.   Overexploitation of fisheries.
Ghana (Largely from manufacturing industries) (Overgrazing , burning)   Inadequate housing; lack of safe drinking water. (Due to industrialization and urbanization) Overfishing.
Nigeria   Once extensive forests are greatly reduced. Around 500 plant species; 10 primate species; etc. Waste disposal is ineffective. (Sewage, industrial effluents, domestic waste, hydrocarbons) Overfishing; trend "is towards total collapse".
Chad   Deforestation due to over-exploitation of certain zones.        
Central African Republic Air pollution. Deforestation (shifting cultivation; slash-and-burn). Destruction of natural habitats and wildlife (fires, population pressure). Waste management inadequate.    
Uganda   Encroachment by human settlements. Overuse of wood (energy; construction). Plant breeding and seed multiplication activities have dwindled. Lack of sanitation and sewage disposal.    
Rwanda   Deforestation (fuelwood; agricultural needs).   Proliferation of slums.    
Burundi   Gradual disappearance of forests (fuelwood).        
Tanzania       Pollution (lack of adequate sewerage).   Coastal erosion. Destructive fishing.
Kenya   Deforestation. Loss of biological diversity. Inadequate waste management, infrastructure, sanitation.    
Ethiopia (PDR)   Deforestation (overgrazing).        

2.2 Population aspects of environmental issues and policies

This section examines to what extent the country reports for UNCED identified population dynamics as a factor in environmental problems, and addressed population dimensions in environmental policies [2].

In practice, although the countries recognized the role of population factors in environmental degradation, few mentioned population policy as a facilitating factor in environmental protection. Let us now see how governments looked at a qualitative aspect of population factors(one of special interest to UNFPA programmes(namely the dimension of women's roles and place in environment and development policies.

Finally, let us look at governments' declared intentions regarding environmental education, since programme-wise the latter can often be a convenient entry point for population themes:

Overall, attention to population dimensions is widespread but not deep. Phenomena other than population growth are rarely mentioned, despite e.g. the relevance of population distribution, migration and urbanization for natural resource use and reciprocal impacts of population and the environment.

On the policy side, only four countries see some value in slowing population growth to facilitate population-environment adjustments. Likewise, few countries seem to perceive qualitative dimensions such as the relationship between a key group like women and the environment (to the management of which they largely contribute), or to appreciate the necessity to invest in environmental education in order to start transforming the population's attitude and practices. Certainly some advocacy work is called for in these areas.

3. Land degradation and its factors

This section is based on of a world-wide assessment of soil degradation problems carried out around 1989, the GLASOD project (ISRIC, 1991). Table 3 presents the main results for the countries of the region.

3.1 Levels of degradation

At the global level, GLASOD found 15 percent of the land area to be degraded by human activities [3]. For seven countries in our group the proportion degraded is higher than this average, sometimes (like in Burundi, Rwanda and Nigeria) much higher.

The seriousness of de gradation also must be taken into account. A handy way of doing this is to assign weighting coefficients to the percentages of Table 3: assigning 1 to the percentage of lightly degraded areas, 2 to that of moderately degraded and 3 to that of strongly degraded ones, for instance, one sees that:

3.2 Types of degradation

Soil erosion under the action of water (rain, streams and floods) is the main form of land degradation in seven of the eight countries reviewed. Wind erosion is dominant only in Chad [4].

Chemical degradation has a relatively high impact in some of the countries reviewed here(Liberia, Sierra Leone, Burundi and Rwanda in particular. This class of problems includes: salinization; the loss of soil fertility (nutrients, organic matter), through depletion from cultivating poor or mediocre soils without sufficient fertilization or through erosion; and pollution.

Physical degradation has very little incidence in this sub-region. It consists mainly of soil compaction and the waterlogging of irrigated areas.

Table 3. Some characteristics of land degradation in East and Central Africa
N.B. Totals may not tally due to rounding; - = zero or negligible
Level of degradation (%) Types of degradation (%) Causes of degradation (%)
  Total Light Moderate Strong Water erosion Wind erosion Chemical degradation Physical degradation Defores- tation Overexp. wood cover Over- grazing Agricultural activities
Sierra Leone 18 3 4 - 5 - 95 - 47 - - 53
Liberia 5 1 3 - - - 100 - 62 - - 38
Ghana 11 2 5 4 88 - 12 - 34 5 18 42
Nigeria 29 2 10 17 80 4 8 8 7 25 23 45
Chad 20 13 6 - 8 81 3 8 4 30 62 3
Central African Rep. 3 1 1 - 85 1 9 4 47 19 26 8
Uganda 21 1 13 7 74 - 26 - 13 - 45 42
Rwanda 69 5 65 - 22 - 78 - 3 - - 97
Burundi 70 3 67 - 20 - 80 - 2 - - 98
Tanzania 12 5 5 2 81 - 13 6 23 - 38 39
Kenya 15 5 5 5 85 15 - - 15 - 58 26
Ethiopia + Eritrea 25 6 8 11 74 26 - - 36 - 50 14

3.3 Causes of degradation and population factors

If natural hazards are left aside, the causes of land degradation can be divided into direct and underlying causes. Direct causes are inappropriate land use and unsuitable land management practices, e.g. the cultivation of steep slopes without soil conservation measures. Underlying causes are the reasons why these inappropriate practices take place, e.g. the slopes may be cultivated because the landless poor need food, and conservation measures not taken because farmers lack security of tenure.

The GLASOD assessment addressed the direct causes of land degradation for each map unit, recognizing four causes:

Deforestation is a cause of degradation when the land that is cleared is steeply sloping or has shallow or easily erodible soils, and when clearance is not followed by good management. It is the dominant cause in only two countries here (Liberia and Central African Republic) and usually does not reach the level of its relative incidence world-wide, where it accounts for 36 percent of total degradation. But it affects most countries to a significant extent.

The role of population dynamics vis-à-vis other factors in deforestation is a much debated issue. In much of the sub-region forest clearance appears to have occurred mostly under the pressure of needs for more cropland and pastures; in addition, forest degradation occurs because of excess livestock grazing in wooded areas as well as collection of wood for human use, especially fuel.

Overcutting of vegetation occurs when people cut forests, woodlands and shrublands(to obtain timber, fuelwood and other products(at a pace exceeding the rate of natural regrowth. This is frequent in semi-arid environments, where fuelwood shortages are often severe. The phenomenon is significant in three countries here (Chad, Nigeria and Central African Republic).

Overgrazing is the grazing of natural pastures at stocking intensities above the livestock carrying capacity; the resulting decrease in the vegetation cover is a leading cause of wind and water erosion. It accounts for 35 percent of the total extent of degradation world-wide. Here it affects eight countries, with a very high relative incidence in Chad, Kenya and Ethiopia/ Eritrea (50 percent or more of the degraded area).

Agricultural activities that can cause land degradation include shifting cultivation without adequate fallow periods, absence of soil conservation measures, cultivation of fragile or marginal lands, unbalanced fertilizer use, and faulty planning or management of irrigation(in other words, land mismanagement in general. At the global level they account for 28 percent of the total land degradation. In this sub-region they are a prominent factor in almost all countries (the exceptions being Chad, the Central African Republic and Ethiopia/Eritrea) and by far the major factor in Rwanda and Burundi.

The role of population factors in land degradation processes obviously occurs in the context of the underlying causes. Population pressure operates through giving rise to land shortages, and through other mechanisms as well. Improper agricultural practices, for instance, occur only under constraints such as the saturation of good lands under population pressure which leads settlers to cultivate too shallow or too steep soils, plough fallow land before it has recovered its fertility, or attempt to obtain multiple crops by irrigating unsuitable soils.

4. A note on water resource issues

Because of the water scarcity problem, population growth "is at the heart of the problem of semi-arid development [...] The fundamental importance of water both for habitability and for rural access to biomass for food, fodder, fuelwood and timber makes water scarcity a crucial problem in the struggle for a higher quality of life of poor rural populations"; where habitability is reduced by water shortages, emigration is a habitual consequence (Falkenmark, 1990).

Water issues in Africa are serious, generally due to the irregularity and unreliability of supply over time and space. Average (per caput) supply at the country level is often low, and continued population growth constantly reduces that supply as resources are fixed. In effect, situations in 2025 have been projected based on recent population projections and renewable water supply estimates (Engelman and LeRoy, 1993) using the classical scale of levels of competition for water [5]. Those calculations show that:

Finally, in terms of the respective roles of agriculture, industry and domestic uses of water the region is characterized by:

  1. a relatively high share of domestic uses in most countries: seven countries are at or above 20 percent; in five cases this is due to a level of agricultural uses substantially lower than the African average;
  2. a low share of industrial use, in line with African characteristics, except in Liberia, Ghana and Nigeria; and
  3. a level of agricultural use mostly in line with African standards, except for the five countries mentioned above.

An implication of these patterns is that there still is quite some potential for increases in water demand, as economies diversify and living standards rise. Unless large gains are made in efficient use of irrigation water and conservation or rehabilitation of damaged irrigated areas, the crunch is likely to severely damage economic competitivity in addition to health and the quality of life.

Annex: Regional patterns of land degradation

The extent of the degradation problem and its patterns vary notably among regions:

- Africa has 25 percent of wasteland (the highest proportion among regions), 12 percent lightly or moderately degraded and 4 percent strongly or extremely degraded land (also the highest proportion). The main type of degradation by far is the loss of topsoil (76 percent of the degraded area) followed by the loss of soil nutrients (9 percent). Burkina Faso, Burundi, Ethiopia (the then PDR), Lesotho, Madagascar, Morocco and Rwanda are particularly affected.

- North and Central America has 6 percent wasteland, 6 percent lightly or moderately degraded and 1 percent strongly degraded land. The main types of degradation are the loss of topsoil (75 percent of the degraded area) and terrain deformation from water erosion (16 percent, but 40 percent in Central America). Costa Rica, El Salvador and Panama are the most affected countries.

- South America has 1 percent wasteland, 11 percent lightly or moderately degraded and 1 percent strongly or extremely degraded land. The main types of degradation are loss of topsoil from water erosion (39 percent of the degraded area), loss of soil nutrients (28 percent) and terrain deformation from water erosion (12 percent). Brazil is particularly affected.

- Asia has 11 percent wasteland, 15 percent lightly or moderately degraded (the highest proportion among regions) and 3 percent strongly or extremely degraded land. Again the main type is loss of topsoil (71 percent of the degraded area), the next being terrain deformation (16 percent); salinization (7 percent) is significant. China, India, Thailand and Vietnam are the most affected countries.

- Australasia has 11 percent wasteland, 11 percent lightly or moderately degraded and a negligible proportion of strongly or extremely degraded land. For 95 percent, degradation consists in the loss of topsoil.

- Europe has a negligible proportion of wasteland, 22 percent lightly or moderately degraded and 1 percent strongly or extremely degraded land. The main types of degradation are loss of topsoil from water erosion (61 percent of the degraded area) and compaction (15 percent).

The Table below quantifies the area not affected by degradation or wasteland, as a proportion of total land area, by region:

Annex Table. Proportion of total area in stable and other terrain, not degraded by human action (wasteland excluded), by region
North America91 percent
South America85 percent
Australasia78 percent
Europe77 percent
Asia71 percent
Central America62 percent
Africa59 percent
World74 percent


1. The United Nations Conference on Desertification, which popularized this word, defined it as "the reduction or destruction of the land's potential, finally resulting in the appearance of desert conditions" (United Nations, 1977). Although one should use the concept only in reference to processes which have resulted in desert conditions or will shortly and inevitably do so, it is often used in a broader sense. The term "desertification" has other annoying aspects. It gives no information on the nature of the degradation, hence on possible corrective actions. It misstates the problems: "the concept of expanding deserts and advancing sand dunes has become the dominant image in the public's eye rather than [...] less visible and much more serious problems" (Liamine, 1993), in particular "more subtle, more complex, pulsating deteriorations [...] radiating out from centers of excessive population pressure (Nelson, 1990). And it seems to designate an absolute evil, while the salinization of an irrigated area, although reversible, may be a greater loss than the washing away of the last inch of topsoil in a marginal area. For FAO (1986) desertification "is only one extreme aspect of the widespread deterioration of ecosystems under the combined pressure of adverse climate and agricultural exploitation".

2. All the quotes in this section are from United Nations (1992).

3. For a comparison of land degradation patterns among regions of the world, see the Annex.

4. Globally 83 percent of land degradation is in the form of erosion (70 percent mere loss of topsoil and 13 percent more severe terrain deformation). About 12 percent is in the form of chemical degradation and 5 percent in that of physical degradation.

5. Population pressures under 600 persons per flow unit (P/FU; 1 FU = 1 million cubic meters) are not considered a serious issue, although water quality problems and dry season supply problems may occur. Between 600 and 1000 P/FU, chances of more recurrent quantitative or/and qualitative supply problems increase notably: this is called the "water stress" stage. Between 1000 and 2000 P/FU such problems are common and affect human and economic development; this is the "scarcity" stage. 2000 P/FU is seen as the maximum population pressure that can be handled in the present state of technology and management capabilities; it has been labeled "water barrier". This scale was developed from the observation of areas where both per caput supplies and resource use problems were well documented.

6. Scarcity-related concepts are indicative, in view of the different adaptive capacities of countries. In particular, the water barrier concept should not be taken literally; even if water shortage is indeed a medium-term barrier to development, there is a priori no indication that solutions for the long term cannot be found. Rather than impending absolute physical limits, the indicator points to steeply increasing costs of supply on account of increased investment and recurrent expenditure for water supply, treatment and/or re-use; in turn, the cost issue points to likely social problems for cost recovery. On the other hand, "in arid conditions, the problem is more complex because of considerable seasonal variations in rainfall. The largest need for irrigation water is during the dry season when the water accessible to people can be as low as 10 percent of the annual flow. Even countries with an average competition level of only 50 [P/FU] have considerable allocation problems during the dry season"; in addition, "national figures do not reflect the stress on water resources quality in local areas exerted by rapid urbanization and industrialization" (Falkenmark and Widstrand, 1992).


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Falkenmark, M. and Widstrand, C. (1992): 'Population and water resources: a delicate balance'. "Population Bulletin" (Population Reference Bureau, Washington), vol. 47 no. 3.

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Liamine, N. (1993): 'Desertification - The issues and challenges', "Ecoforum", vol. 17 no. 1/2 (April) pp. 11-21.

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