3.1 Contrary to what is widely believed, per caput energy requirements vary according to populations. They also vary according to changes in population structure, independent of the effects of population growth on global requirements.
3.2 It should also be recalled that nutritionists have continually lowered their assessments of human energy requirements since the Second World War.
3.3 It is useful to examine first the impact of population changes on population energy requirements. Within a context of rapid population growth, the increase in the number of people is obviously the dominating factor. But too much attention placed on the impact of absolute numbers has led to insufficient attention being given to the impact of changes in population structure. It will be seen that this has, in turn, led to a poor evaluation of the process through which the energy requirements change.
3.4 According to the latest United Nations projections (medium variant), there will be another large world population increase between 1995 and 2050 (72 percent), with the total growing from 5.7 billion inhabitants in 1995 to 9.8 billion in 2050 (Table 4) (Quesnel, Vimard and Guillaume, 1991).
3.5 This projection allows a variation of roughly 2 billion inhabitants over or under the average estimate for the year 2050 because of possible variations in fertility decline (medium variant: population of 9.8 billion; low variant: 7.9 billion; high variant: 11.9 billion) (United Nations, 1995a).
Table 4
PROJECTIONS OF ANNUAL
POPULATION GROWTH RATES FROM 1990 TO 2050
Figure 5 TOTAL POPULATION OBSERVED FROM 1950 TO 1990 AND PROJECTED FOR 1995 TO 2050, BY CONTINENT (medium variant)  |
3.6 The two extreme scenarios (high and low variants) are based on the assumption that all countries will simultaneously adopt schedules for reduction in fertility that are slow (high variant) or rapid (low variant). Because it is unlikely that either of these two scenarios will ever occur, the medium variant should be included since some countries will adopt schedules for a slow reduction in fertility, while others will mainly adopt schedules for a rapid decrease.
3.7 Using the medium variant, two continents, Asia and Africa, will represent the great majority of the world population in 2050 (Figure 5). This means that the demographic weight of the population consuming rice will be much greater in 2050 (Figure 6, Class 1). The population consuming mainly wheat will be greatly increased (Figure 6, Class 3). The demographic weight of the population consuming mainly cassava, yams or taro (Figure 6, Class 6) will be close to that of the population consuming maize (Figure 6, Class 2).
3.8 The current age structure of world population is the result of fertility rates that have remained high through the last several decades (United Nations, 1995a). Characterized by its youth, the present age structure holds the promise of large population increases in the coming decades, even if fertility were to fall rapidly. A great many of the women born during the first doubling of the world population are now reaching child-bearing age and are ensuring the replacement of their own numbers in daughters who will, by their capacity to procreate, be at the origin of a rapid population increase. Obviously, the number of children will be all the more important given that the fertility of these generations of women will remain high. This will probably be the case for sub-Saharan Africa.
3.9 According to the medium variant of the United Nations projections, the world�s population will increase by 4.7 billion between 1990 and 2050 (United Nations, 1992). Almost half of this increase is inescapable. Even if there were a sudden reduction of fertility to the level strictly needed to replace the population, the world population would still increase by more than 2 billion.
3.10 Changes in available natural resources per caput are not taken into account in the evaluation of population growth rates or in the evaluation of associated factors (mortality or fertility) that are used in population projections. Shortages in arable land or in renewable water supplies may result in some agriculturally dependent countries being unable to fulfil their food energy requirements. Currently used threshold measures of renewable water supplies per inhabitant (the stress level, under 1 700 m3 of water per inhabitant per year, and the chronic shortage level, under 1 000 m3 of water per inhabitant per year) should be discussed. They are defined on the basis of work by Malin Falkenmak, a hydrologist, and use norms of the more developed countries. However, there could be lower consumption, as is observed in Israel, especially regarding agricultural use, with the use of adapted technology and equipment as well as the meticulous management of water resources.
Figure 6 TOTAL POPULATION OBSERVED FROM 1950 TO 1990 AND PROJECTED FROM 1995 TO 2050, BY CLASS OF DIET (medium variant)  |
3.11 A more detailed scrutiny of the methodology used to make these projections reveals that they are generally based on the assumption of an increase in life expectancy of 2.5 years every five years when no information points to a stagnation or decline in mortality at the beginning of the 1990s. If there are signs that life expectancy has stopped improving, a stagnation or even a decrease could be projected for the future. Two other models of mortality trends, which assume rapid and slow increases in life expectancy respectively, have been used in certain cases. After 2025, it is assumed that life expectancy at birth will increase according to a model in which the average increase is shared by all countries.
3.12 Based on historical examples, all these models assume slower improvements in life expectancy as mortality is reduced and life expectancy rises. The highest life expectancy at birth allowed in these models is 87.5 years for females and 82.5 for males. The middle model assumes that male life expectancy at birth will increase by 2.5 years every five years until it reaches 60 years. The average five-year gain is then reduced gradually to 0.4 years until 77.5 years are reached and remains at 0.4 years thereafter. Female life expectancy at birth is assumed to increase by 2.5 years every five years until it reaches 65 years, after which the five-year gain is reduced gradually to 0.4 years at a life expectancy of 82.5 and over.
3.13 This assumption is why these projections describe a substantial reduction in differences in mortality or life expectancy among countries (Table 5). For example, the life expectancy of African populations is only eight years lower than that of North American populations for 2050.
3.14 The change projected for Africa corresponds to an acceleration in the increase in life expectancy from 1995 to 2000. From an increase of 1.2 years for the periods 1995-2000 and 2000-2005, Africa will reach a 2.2-year increase between 2000-2005 and 2005-2010, then a 2.5-year increase between 2005-2010 and 2010-2015.
3.15 These mortality projections are based on the assumption of regular economic growth and improvements in the food situation which may occur in Africa in the coming decades. They imply that the energy requirements of the projected populations will be satisfied, which is not guaranteed in countries with high fertility rates or in countries where there may be a shortage of natural resources following high population growth.
3.16 Changes in life expectancy at birth assumed by the United Nations for countries in sub-Saharan Africa, especially countries that consume cassava, yams or taro (Class 6), project an added 20 years of life expectancy, which seems to indicate an elimination of the major food deficits that are typical of these countries. This seems to be in contradiction to economic projections used by FAO that foresee a stagnation in average per caput food supplies by 2010 for the whole African continent.
3.17 These projections take into account the presumed impact of the acquired immune deficiency syndrome (AIDS) pandemic in those countries that are most affected. The impact of AIDS is also related to the fact that it provides an entry point for other diseases such as tuberculosis and malaria. Because of the particular age group affected by AIDS, no models of life tables represent the prevailing mortality structure by age and by sex in these countries.
3.18 One model made by the World Health Organization (WHO) in 1991 makes it possible to evaluate the number of future deaths caused by AIDS. This model uses estimated human immunodeficiency virus (HIV) infection data plus observed and estimated annual progression rates from HIV infection to AIDS and from AIDS to death.
3.19 In applying the model, the United Nations assumed that there would be no new adult HIV infections after 2010 but that mother-to-child infections will continue after this date and AIDS deaths will follow for many years thereafter as a result of the long latency period between HIV infection and AIDS.
3.20 The models used in this case should be discussed further since they account for the evolution of the phenomenon in urban areas but may not give a precise account of the pace of the evolution of the pandemic in rural areas. Another major unknown is the future course of the pandemic in Asia.
3.21 Three hypotheses have been used: in the medium variant, fertility is assumed to reach and stabilize at the replacement level of 2.1 children per woman: in the high variant, fertility is assumed to stabilize at about 2.6 children (or will rise to that level if currently below); and in the low variant, it is assumed to stabilize at about 1.6 children, i.e. below the replacement level.
3.22 In all three variants, the assumed target period at which fertility will stabilize is determined through a range of socio-economic factors such as population policies and programmes, adult literacy, school enrolment levels, economic conditions [gross domestic product (GDP) or gross national product (GNP) per caput], infant mortality and marriage, as well as historical, cultural and political factors.
3.23 The fertility schedules are based on the work of experts rather than on mathematical models because of the uneven quality or even the lack of data and because of the qualitative nature of some of the data.
3.24 One remarkable fact revealed by the projections is that fertility rates in African countries will decrease. According to United Nations projections, in the medium variant, the reduction in fertility rates that might be observed in African countries between 1990-1995 and 2045-2050 would be almost as rapid as the one observed and estimated for Latin American countries over a period of the same length, between 1960-1965 and 2015-2020 (Table 6).
3.25 It must be pointed out that it is extremely difficult to forecast fertility levels and changes. The fertility decline in Latin America at the end of the 1960s surprised many experts. Once they observed the phenomenon, they agreed that increased urbanization and literacy, indicators related to fertility reduction, had been determining factors in triggering this decline and could have been used to forecast the trend (Chesnais, 1985). So even though the factors that determine the fertility rates of the social categories in a given country are relatively well known, little is known about the factors that determine reductions in fertility. This has led scientific literature to show the effects of development first, and then the effects of extreme poverty, on fertility reduction (Cosio-Zavala, 1992; Quesnel, Vimard and Guillaume, 1991), which has gradually changed the original meaning of the term �demographic transition�.
3.26 Making projections is difficult because some populations are still reticent to accept family planning programmes. That is why, as the statements presented by the Chinese delegation to the Population Commission in 1994 and 1995 suggest (Peng, 1994, 1995), it is difficult to predict changes in fertility in a country such as China. It is made even more difficult because current fertility is perhaps underestimated, especially fertility in rural China. According to the Chinese Institute of Family Planning, on the basis of a survey of 32 villages, fertility in rural China could be underestimated by as much as 37 percent and urban fertility might, in some cases, be underestimated by 19 percent. If such observations were verified on a large scale, fertility for the whole of China could be underestimated (Zeng, 1995; Wang and Wang, 1995). The United Nations projections already have taken into account this possible underestimation.
3.27 On the other hand, some experts now claim that fertility in developing countries will fall so rapidly that the United Nations low variant projection should be used (Chesnais, 1985); however, there is some question as to the basis for such arguments.
3.28 During the expected period of continued high population growth between 1995 and 2050, as during the last 50 years, increases in energy requirements will mostly be affected by increases in population numbers. This represents a global increase of 72 percent based on the medium variant, 38 percent based on the low variant and 108.4 percent with the high variant (Figure 7).
3.29 Changes in energy requirements since the Second World War have been evaluated retrospectively by following the evaluation method adopted by FAO.
3.30 The results presented in this document were obtained by applying the ENREQ 2 program to population evaluations by age for the three variants used in the United Nations projections (United Nations, 1995a). Calculations of future requirements have taken into account the impact of urbanization described in the United Nations projections (United Nations, 1995b) as well as the possible impact of the increased height of populations.
3.31 Changes in age structure are increasing the energy requirements of developing countries. Energy requirements increase during the first 25 years of a person�s life (until 18 or 25 years according to case and source used) and decrease slightly after the age of 60.
|
Figure 7 CHANGES IN ENERGY REQUIREMENTS FROM 1995 TO 2050, BY LEVEL OF DEVELOPMENT (low, medium or high variant)  |
3.32 Thus, the ageing of a population is initially driven by the decline in fertility and in the proportion of children; as such, it brings about an increase in per caput energy requirements (see Paragraph 2.5). Later, it is mostly driven by the decline in mortality and the rise in the proportion of older people; this causes a decrease in average energy requirements. Developing countries for the time being are concerned mostly with the former process, and developed countries with the latter (Table 7).
3.33 These influences on average per caput requirements remain moderate at a global level (+2 percent) but hide important regional variations.
3.34 Therefore, the impact of structure by age varies between two extremes: a 7 percent increase is expected in the average energy intake required between 1995 and 2050 for Africa (7.8 percent for populations consuming cassava, yams or taro, 8.1 percent for populations consuming millets or sorghum, 8.2 percent for Central Africa and 8.5 percent for East Africa) and a 1 percent reduction for developed countries.
3.35 The increasing height of individuals increases per caput energy requirements. A better diet at a young age results in an increase in average height. The height of populations, therefore, depends partly on children�s diets. Very rapid responses to diet changes have been observed (Piazza, 1986), such as height increases of substantially more than 1 cm per decade in certain regions of China.
Table 7
ESTIMATED EFFECTS OF
DEMOGRAPHIC FACTORS ON THE NERGY REQUIREMENTS OF THE POPULATION AND THE
FOOD SUPPLIES NEEDED TO SATISFY THESE REQUIREMENTS IN 2050 (base year1995
(1.00))
3.36 In the hypothesis of improved diets in developing countries and of the gradual disappearance of malnutrition by the year 2050, the average height of populations could increase by 1 cm per decade. That is the growth assumed in this document, with a limit set at a height of 1.75 m. Such an increase in the average height of populations would bring about an increase in their average energy requirements.
3.37 This increased height could lead to a 1 percent increase in average energy requirements in the world between 1995 and 2050. The needs of developing countries would be increased by 2 percent and the increase could reach as much as 3 percent in southern Africa or in East Asia.
3.38 It would seem that urbanization leads to a reduction in energy requirements. This reduction is expected to be especially perceptible in developing countries where the urbanization process is likely to be rapid (Popkins, 1994). It could then result in a 3 percent fall in requirements between 1995 and 2050. Urbanization is expected to produce the greatest impact in Asia (-4 percent) and Africa (-3 percent). It should also be noted that new technologies and lifestyles can have other effects on food energy requirements; for example, traditional food prescriptions for pregnant women and babies may be modified. However, data on such effects have not been collected on a national scale.
3.39 The potential impact of a smaller number of pregnancies on the energy requirements of populations as a result of fertility declines was found to be negligible (Table 7). It will represent a reduction of about 1 percent for developing countries. In the case of a sharp decrease in fertility, in the Near East for example, the decrease could reach 2 percent. Although all pregnancies are treated equally in this document, the issue of adolescent pregnancies needs to be further explored.
3.40 Overall, the factors increasing energy requirements have a greater impact than those leading to decreases. The cumulative effect of factors determining increases can exceed 10 percent, whereas the cumulative effect of factors determining decreases never reaches 5 percent.
3.41 A remarkable fact is that changes in a population�s age composition can lead to reductions in average energy requirements because of the increased percentage of older people. Thus, the combined effect of ageing and urbanization will reduce food energy requirements in Europe by 2 percent.
3.42 The four demographic structural effects examined previously work in opposing directions in developing countries, and this contributes towards reducing their final impact. Trends in age structure always have a greater impact than the others. The positive effect of height increase on energy requirements of populations cancels out the negative effects of both urbanization and the reduction in the proportion of pregnant women in countries with high fertility. Thus, the resulting impact of these factors is equal to that of age structure, for example, +7 percent for Africa. A similar observation can be made, but at a higher level, for the countries with the highest fertility in Africa, for example, countries that consume cassava, yams or taro, for which the impact is also equal to that of age structure, but at the level of +8 percent.
3.43 Except for developed countries as a whole, the effect of population growth in numbers on energy requirements is definitely more important than the effect of changes in population structures (Tables 7 and 8).
3.44 For developed countries, the 4 percent increase in population between 1995 and 2050 projected by the United Nations under the medium variant compensates for changes in population structure (-2 percent).
3.45 The outlook changes entirely in the case of developing countries. Requirements resulting from population growth will increase by as much as +95 percent, whereas the combined effect of changes in structure will be hardly more than +3 percent.
3.46 As a result, a 76 percent increase in requirements is projected for the whole world, +74 percent as a result of population growth and +2 percent because of changes in population structures.
3.47 At a global level, the combined effect of population changes means that a 75 percent increase can be expected in energy requirements. This result is not surprising, nor is it particularly worrying, given that stagnation or even regression of total world agricultural production or agricultural production per caput is caused by big cereal exporters putting the brake on production, which curbs their capacity to expand. But this should not be considered a major finding of this study.
3.48 The average change in food energy requirements masks very strong regional differences (Table 8), (Figure 8). The requirements of European countries will diminish and those of North American countries will increase by only one-third. Asian countries and countries in Latin America and the Caribbean will probably have to cope with increases reaching 69 and 80 percent, respectively, from 1995 to 2050. Africa, on the basis of the medium variant of United Nations projections, will have to deal with a trebling of its food energy requirements (Figure 8).
3.49 Countries that get their energy from wheat, mainly Arab countries and especially those on the Mediterranean rim, will probably see their energy requirements increase by 142 percent (Table 8), (Figure 9, Class 3). This suggests that grain imports in these countries will increase substantially, as long as the countries remain solvent.
3.50 In Africa, the contrast between countries that belong to Class 3 and those that belong to Classes 5 and 6 is expected to increase. Countries in Class 3 will probably be faced with a doubling of their food energy requirements, while the others will have to deal with more than a trebling of their energy requirements because of population changes. Countries that consume mainly millets or sorghum (Figure 9, Class 5) and those that get most of their food energy requirements from cassava, yams, taro or plantains will undergo 243 percent and 251 percent increases in energy requirements, respectively (Figure 9, Class 6).
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Figure 8 CHANGES IN ENERGY REQUIREMENTS FROM 1995 TO 2050, ACCORDING TO CONTINENT (madium variant) 
|
3.51 The United Nations projections have made it possible to work until now with a medium variant trend in fertility which assumes that fertility will stabilize at the replacement level, in other words, at 2.1 children per woman. As mentioned earlier, this globally favourable scenario is based on the assumption that a sharp increase in life expectancy resulting from improved living conditions and diets will be combined with a sharp decline in fertility. It is hardly likely that all the countries in the world will follow the projections made for them. Some will change faster than others.
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Figure 9 CHANGES IN ENERGY REQUIREMENTS FROM 1995 TO 2050, ACCORDING TO CLASS OF DIET (medium variant)  |
3.52 Stabilization of the number of children at a much lower level than that of replacement would greatly affect changes in food energy requirements (Figure 7). Instead of doubling their requirements, as in the medium variant projection, developing countries would be faced with an increase of only 59 percent. Energy requirements in Africa would increase by 165 percent instead of doubling as projected using the medium variant (Figure 10), although in extreme situations where there is no demographic transition, or where it is delayed, they would basically not be modified from the earlier scenario. The energy requirements of countries consuming millets or sorghum or of countries consuming cassava, yams, taro or plantains would treble, whereas in medium variant projections they would increase by 250 percent from 1995 to 2050 (Figure 11, Classes 5 and 6). The challenge facing countries with such a pronounced food deficit would remain huge. The issue at stake here is the mode of development. If appropriate action is taken, however, population could increase in line with the United Nations low variant scenario because, as noted in the Programme of Action (Paragraph 1.8) adopted by the International Conference on Population and Development held in Cairo in 1994 (United Nations, 1995c), strategies do exist to slow future population growth, especially in the longer term. They regard reproductive health, including family planning, which also facilitates the achievement of food security and food projection objectives.
3.53 If for some reason the demographic transition is postponed, a much larger proportion of the world will face challenges of incomparable dimensions. Africa may have to provide for an increase of more than 250 percent of its energy requirements (Figure 12). Countries consuming maize, or even those consuming rice, may have to deal with a doubling of their requirements, whereas countries consuming wheat may have to deal with a trebling of their requirements. As a result of population changes, requirements in countries that consume millets or sorghum and cassava, yams, taro or plantains could quadruple from 1995 to 2050 (Figure 13, Classes 5 and 6). This highlights the importance of implementing fully the Programme of Action of the International Conference on Population and Development (United Nations, 1995c; UNFPA, 1995).
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Figure 10 CHANGES IN ENERGY REQUIREMENTS FROM 1995 TO 2050, BY CONTINENT (low variant)  |
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Figure 11 CHANGES IN ENERGY REQUIREMENTS FROM 1995 TO 2050, BY CLASS OF DIET (low variant)  |
3.54 There could also be deviations from the average assumption. For example, estimates of future fertility rates in East Asia are as unsure as those of the current fertility level. A high fertility level in East Asia and the resulting new doubling of its energy requirements would necessitate a new green revolution with even greater challenges, because the preceding green revolution already benefited from the allocation of the best lands, especially irrigated lands.
3.55 It is possible that the demographic transition will be postponed in certain African countries. The consequences would probably be very serious. The solution to the quadrupling of food energy requirements mentioned earlier would require a completely different infrastructure and a completely different macroeconomic context if the countries are not in a position to import cereals.
3.56 While the possibilities are recognized, it seems that the demographic transition is spreading in Africa, and it is encouraging to note the acceptance and rapid spread of population programmes there despite the poverty and economic difficulties of many of the countries concerned. A decline in fertility is occurring in poor areas. Urbanization also seems to be a strong factor determining the decrease in fertility.
|
Figure 12  |
3.57 There is no information
allowing the reliable forecasting of dietary trends for 2050. This being said,
unless there is major environmental degradation and humankind is incapable of
providing the development needed to satisfy its food energy requirements, two
basic trends could be expected. The first would be a change in available food
supplies to satisfy the energy requirements of humanity. This trend is the
subject of the present section. The second
would be a
move towards diversification in the composition of diets. This would lead to
changes in patterns partly brought on by urbanization and would help provide
populations with important nutritive supplements (vitamins, essential amino
acids, etc.). This second trend will be dealt with in the following section.
|
Figure 13 CHANGES IN ENERGY REQUIREMENTS FROM 1995 TO 2050, BY CLASS OF DIET (high variant)  |
3.58 An essential point should be stressed: the projections developed in this document in no way imply that the food problem should be solved only by measures intended to increase per caput food supplies. Whatever the projected level of food supplies, these measures must be an integral part of policies aimed directly at the roots of the food problem � poverty and its gender dimensions and the lack of access to food for the poor, both in rural and in urban areas. These policies work in tandem in countries where, at present, most of the poor work in agriculture.
3.59 In order to cover average energy requirements, food supplies in developing countries will probably have to exceed energy requirements by a great margin in 2050. Food demand will increase even more if equality of internal distribution improves. It will also take into account household losses (resulting from cooking, domestic storage of staple foods, etc.).
3.60 How, then, should the effort required be evaluated? FAO (1992) has estimated the number of people suffering from malnutrition in the world by combining each country�s average food supply, a food distribution indicator and an evaluation of minimum requirements. However, this does not give any information concerning the extent of the food deficits of countries where hunger is still rife. It does not indicate what the reduction in the proportion of undernourished people would be if food supplies were increased by 10, 20 or 30 percent. It is necessary, for the purpose of this study, to suggest an order of magnitude. The task is difficult because the two main explanations for the discrepancy between energy requirements of populations and availability of needed food supplies (i.e. losses realized between retailing and consumption of products and losses caused by inequalities in distribution within the countries) probably vary greatly in importance from country to country, according to the degree of poverty.
3.61 It is known that losses sustained between retailing and consumption can vary greatly from one country to another and from one year to the next. Losses in the order of 10 percent have been quoted when reserves have been made to guarantee against insecurity. Food losses at the household level will probably be reduced by 2050. Household appliances can be expected to improve, and market regulation will save households from having to keep food products stocked over long periods of time.
3.62 According to FAO (1992), when there is unequal food distribution, the proportion of the population suffering from malnutrition is 10 percent if average national daily food supply per caput amounts to 2 700 Calories and 15 to 35 percent when this supply is between 2 200 and 2 500 Calories. Therefore, in order to guarantee total security in food supplies the level should be more than 2 800 Calories, or perhaps 2 900 or 2 950 Calories if it is considered that in much improved conditions losses could be substantially reduced (maybe under 5 percent). This should be evaluated only on the basis of reliable technical information which could eliminate any risk of error.
3.63 It is feared that distribution problems will remain in 2050. It is true that these problems have never been totally eliminated in human societies. By the year 2050, however, it is hoped that populations will be coming to grips with these inequalities and reducing them further. The health of a large proportion of the world�s population the population�s ability to take control of its own future depends on this.
3.64 It is assumed that developing countries will need to increase their food supplies to 30 percent above their food energy requirements, which would create the conditions for malnutrition reduction. With average requirements of developing countries at 2 160 Calories per person per day in 1990, food supplies should reach a minimum of 2 808 Calories. This estimate is above the current estimate of available world per caput food supplies (2 700 Calories, FAO estimate 1988-1990) as well as the average energy requirement projected by FAO for all developing countries for 2010 (2 730 Calories) but less than the average energy requirements projected by FAO for the whole world for 2010 (2 860 Calories). The same 30 percent rule has been retained for 2050.
3.65 These adjustments have been applied even though the countries concerned differ greatly in levels of food losses and in inequality of access to food. This choice can be explained by two reasons, which pertain to the underlying logic of this study. First, these necessary increases in food supplies must be evaluated according to the average requirements of the populations of each country. The method used for estimating these must be the same for all countries and must not be influenced by a lack of information on a given country (especially concerning loss of food and unequal distribution of resources). This procedure does not imply that increasing food supplies will solve the problem of malnutrition. The real challenge is to solve the problem of access to food for the poor. But as most of the poor in the world live in rural areas and make a living in agriculture, the supplement referred to here is a necessary one.
3.66 Fixing a minimum food supply for the poorest countries increases average per caput supplies in the world considerably. This would mean a 14 percent global increase from 1995 to 2050 and an 18 percent increase in developing countries. On average, these countries would fall in line with the energy intake projected by FAO for East Asia for 2010 (FAO, 1995a), that is, 3 040 Calories.
3.67 The amount of catching up (supplementary supplies) needed depends on the current situation and varies considerably according to the region. An increase of one-third is required in food supplies for Africa in general, but only an increase of one-half for East Africa. The required increase in supplies is lower for Asia (+14 percent) and Latin America and the Caribbean (+8 percent).
3.68 The countries that consume mainly millets or sorghum and those that consume mainly cassava, yams, taro or plantains would have to increase available food supplies by 40 percent. This greatly adds to the already considerable task facing countries that are expected to undergo high population growth.
3.69 There is no more information available on the future trends in diets of developed countries than there is for developing countries.
3.70 The populations of some developed countries are still increasing their energy intake to well over 3 500 Calories, resulting in problems of obesity. Other populations are lowering their energy intake to 3 200 or even 2 900 Calories. After increasing over one or two decades, the average energy intake of populations in developed countries may eventually come close to that observed in certain countries of northern Europe (3 000 to 3 200 Calories). FAO (1995a) also projects for 2010 a high average energy intake of 3 470 Calories. In the absence of more detailed information, it is assumed in this study that the energy intake for those countries where supplies observed in 1990 were more than 30 percent over the nutritional requirements projected for them for 2050 (3 400 Calories) will not vary from 1990 to 2050.
3.71 Diet trends are now evolving in opposite directions. Nutritionists have observed significant declines in the quantities of food energy consumed in certain developed countries. By contrast, an important part of the world�s population is diversifying and could continue to diversify its diet. This diversification allows populations to introduce dietary components that are indispensable for health, such as amino acids, vitamins and micronutrients. This is the case in certain large countries such as China and India and in some subregions where there is robust and steady economic growth and effective demand is growing. Such populations constitute a large proportion of humanity, and their numbers are increasing. They will probably contribute to this continuing trend and, in turn, affect the level of available food necessary to sustain populations.
3.72 Economic growth brings changes in food habits. With the introduction of meat, seafood, fruits and vegetables, daily food rations become less rich in cereals. Meat consumption does not always increase when there is an increase in food intake. This can be verified by classifying all countries according to available food energy and isolating only the two deciles for which availability has increased most between 1962 and 1990, i.e. the ninth decile, which has experienced an increase of 535 to 789 Calories per inhabitant (average 630 Calories) and the tenth decile, which has seen an increase of 814 to 1 629 Calories per inhabitant (average 995 Calories). It can thus be observed that the contribution of meat to such increases, which varies between 0.79 and 56.56 percent, differs in various countries. Furthermore, the countries where meat contributed the least (between 0.79 percent and 4.89 percent) are those that, in 1962, had less available food than the countries where meat represented a larger share of the diet (contributing between 5 and 56.56 percent). There is a difference of some 350 Calories. The countries where meat contributed least (under 5 percent) are those in which cereals contributed most and oil-producing crops contributed least.
3.73 Evidence shows that the structure of consumption evolved differently in developed and in developing countries where the increase in average energy intake was high. Average energy intake in Egypt, for example, went from 2 290 Calories in 1962 to 3 310 Calories in 1989, whereas meat consumption nearly doubled, from 10 to 18 kg per inhabitant per year. This level is still low compared with that of developed countries, where meat consumption reaches 80 kg. The increase in energy in developing countries was mostly achieved by an increase in cereal consumption.
3.74 Dietary patterns are strongly influenced by history and culture. Modifying diets depends on economic changes and societies� levels of exposure to foreign ideas, goods and people. Long-term forecasting has always been risky. This paper, therefore, does not develop any food consumption scenario for the year 2050.
3.75 It is nonetheless useful to note that urbanization influences dietary patterns considerably. Trends in food consumption will probably be strongly affected by the supplies reaching cities. It is sometimes easier to buy food in import markets than in local markets. The diversity of foods available as well as the constraints placed on women by changing lifestyles could have a major impact on dietary trends because women usually decide on the foods produced, purchased and cooked. Studies of the relationship between evolving gender roles and food security would be very useful for policy-making. Market conditions also have an impact on dietary trends. For example, it can be less expensive to borrow for the brief period between purchasing and selling than for lengthier periods because of long-term agreements made with local producers. This can lead to an increase in imported food supplies in preference to locally produced foods. In addition, changes in the dietary patterns of populations in developing countries will probably be linked to the increasing number of high-yielding poultry- and pork-raising facilities.
3.76 The energy requirements of populations are obviously not influenced by changes in their dietary structures. The amount of energy necessary to satisfy nutritional needs can be obtained from a diet rich in livestock rather than from one rich in plant-derived energy. However, for similar quantities of energy intake, a livestock-rich diet will require additional plant-derived energy in order to produce the livestock-based foods.
3.77 The consumption of livestock products means greater pressures on natural resources. These pressures increase much faster than the energy consumption of the population itself. This is why it is necessary to push the study further by also assessing the amount of plant-derived energy required to produce food rations. Admittedly, the lack of data hinders such a study, but it is necessary to have some idea of how fast pressures on natural resources increase with dietary diversification.
3.78 As the energy value of the daily rations of populations increases, so does the quality of the products. At the same time, the demands made on natural resources appear to increase faster than consumption. This is a difficult phenomenon to interpret. The problem cannot be addressed directly in this paper. In any event, the available data would be insufficient.
3.79 Diversification of dietary patterns leads to inclusion of animal products in the diet, and the production of livestock requires great quantities of plant-derived food energy.
3.80 Because of the lack of data concerning the composition of individual countries� livestock herds (species and breeds according to sex, age and weight), the following estimates have been adopted arbitrarily from working documents used by FAO. It takes:
3.81 The basis for calculation is debatable and these figures should be considered rough estimates. Such standards vary according to the constitution of the herd and methods used to raise the livestock. A herd of cattle raised without much attention to productivity can have a ratio of 50 or more Calories to 1. It is probable, moreover, that averages have declined, especially for industrially raised herds, which are more and more prevalent. But, as mentioned above, the relevant information with respect to each country is not available. In fact, there are no statistics by country in this field, and scientists at FAO have no country-based assessments from which to work on animal nutrition.
3.82 Considering the implications of diet changes on farm production, a rough estimate is better than none at all. It is therefore in the interest of this study to estimate the amount of food energy necessary to produce a given ration of food and to evaluate the process of transformation of plant-derived energy into consumed energy.
3.83 The results thus obtained should be interpreted by taking the following factors into account:
3.84 The difficulty is in assessing the relative importance of such effects and the conditions under which the effects are produced. It should be mentioned here that the extension of grazing for cattle, in some cases by deforestation, can result in environmental costs.
3.85 The figures set out above indicate that any quantity of livestock-derived products added to food rations puts a demand on natural resources that is at least four times the level of energy it can deliver. The remainder of this study is based on this type of observation.
3.86 To be complete, it should be noted that this manner of computing plant-derived energy requirements does not take into account food from ocean or lake fishing or from aquaculture. Food products from hunting are likewise not counted. It would have been difficult to factor in these products.
3.87 It would be possible to count products from aquaculture activity, especially its most intensive forms, which use artificial fish feed. These practices are used particularly in China. Other developing countries do not employ on a large scale the expertise acquired in China. These factors could not be measured, however, with the information available.
3.88 No projection for a date as far into the future as 2050 can be made. Therefore, only an assumption can be ventured. This assumption takes into account the problems of urbanization that contribute both to the diversification of diets and to import of food supplies from other countries. The ratio of the number of plant-derived Calories necessary to produce the Calorie intake in an average food ration to the number of Calories in that ration, i.e. 1.783 in 1990, was taken into account. For the purpose of simplification, it can be assumed that all countries that were below that level in 1990 will have reached it by 2050. According to this assumption, developing countries will require 5 477 plant-derived Calories per person per day to produce the various foods in their diet � a diet richer in livestock products than it was in 1990. This figure is clearly larger than the number of plant-derived Calories necessary to produce the average energy requirements for the world (4 900 Calories in 1995). In 2050, with 5 477 plant-derived Calories necessary to produce 3 040 consumable Calories, populations of developing countries will have a diet close to that reported for Mexico in 1988-1990.
3.89 The necessary data or reliable analyses are not available that would allow it to be stated that the average diet of a country would provide all of the nutrients required to keep the population in good health. No country can be cited as a model in this respect, so targets cannot be proposed for countries. Therefore, a crude assumption is selected for the purpose of this study. It is assumed that, with the existing levels of energy supplies, the current level of diversification of the global food pattern would ensure the elimination of serious nutritional deficiencies. So, with the average conversion rate of plant-derived Calories to consumed Calories (1.783 in 1990), the composition of each country�s diet would be the same in 2050 as it was for the world population in 1990. Beyond the average conversion rate of plant-derived Calories to consumed Calories, the composition of each country�s diet is assumed to be constant between 1990 and 2050 unless the energy level of such diets increases (as indicated in Paragraphs 3.59 to 3.65). As was suggested for the energy ration, and for lack of more reliable information, it can be assumed that populations whose ratio of necessary plant-derived Calories to consumed Calories per ration was higher than 1.783 in 1995 will not modify their diets between now and 2050. It is, of course, a different case for those countries whose energy requirements in 1990 were not 30 percent higher than their projected requirements for 2050.
3.90 Dietary diversification sharply increases the quantity of necessary plant-derived energy. The underlying assumption for 2050 is therefore that all countries of the world will have access to a diet that implies a minimum ratio of necessary plant-derived Calories to consumed Calories per average ration per inhabitant. This minimum ratio is 1.783, obtained on the basis of observations made on a global scale in 1990.
3.91 This leads to the following consequences:
3.92 The needed rate of increase of plant-derived energy varies considerably depending on the region. It is 20 percent in Asia and 23 percent in Africa. Likewise, it varies considerably within the African continent. It reaches 29 percent, for example, in countries whose populations consume mainly rice and 46 percent in those with diets based on cassava, yams or taro.
3.93 The impact of the two trends examined above, added to the higher per caput energy requirements and diversification of diets, considerably increases the effects of population changes. Changes in the populations of developing countries could be the cause of a 28 percent average increase in the plant-derived energy necessary to fill global needs and a 40 percent increase in their own requirements.
3.94 The impact of the two possible trends varies considerably by region. They are without effect for North America and Europe and would result in an increase in requirements of only 7 percent for Latin America. However, Asia would have a 38 percent increase and Africa would experience a 64 percent increase. Populations that consume cassava, yams or taro would have to double the plant-derived energy necessary to meet their requirements.
3.95 Whatever the country, whatever the region, the consequences of demographic changes for levels of energy requirements are far more significant than those of changes in dietary patterns. This is partly because of the conservative nature of the assumptions made in the preceding section. The impact of population developments on the levels of plant-derived energy requirements is magnified for countries with high fertility rates (in Africa, for example) because the multiplication factors are 2.94 for demographic effects of all types and 1.64 for the effects of dietary changes. In countries with the highest levels of food shortages � populations whose main source of food is roots or tubers � the respective multiplication factors are 3.51 and 2.04. Here again, demographic effects have far more significant consequences than dietary modifications.
3.96 The effects of changes in age structure on energy requirements could appear negligible in comparison with those of changes in population growth. In the case of developing countries, the respective increases of 3 percent for the former and 90 percent for the latter are not of the same magnitude (see Table 7). However, the impact caused by changes in age structure should not be overlooked. For example, the increase in needs generated by the changes in age structure by 2050 would correspond to that created by adding a new country the size of Bangladesh. Furthermore, these effects will vary from country to country; in some cases, they will result in an increase in energy requirements of more than 8 percent.
3.97 The combined effects of demographic changes and dietary modifications on the level of plant-derived energy requirements lead to results, whose reliability should be discussed (Tables 9 to 11).
3.98 The plant-derived energy would need to double for Asia and Latin America and the Caribbean. (Plant-derived energy would be multiplied, respectively, by 2.34 and 1.92.) This corresponds to annual growth rates (referring to growth in the production of plant-derived energy necessary for the production of food supply of plant or animal origin) of 1.6 percent in Asia and 1.2 percent in Latin America and the Caribbean during a 55-year period. Such growth rates are lower than those achieved by the green revolution in rice-producing Asia or by the introduction of hybrid maize in Latin America. Faster-moving research into new varieties of cereals will certainly be a basic factor for maintaining present levels for 55 years in regions where infrastructures are more favourable than in Africa. It remains to be seen whether these growth rates are sustainable.
3.99 The fivefold (precisely 5.14) increase in plant-derived energy required in Africa and the sevenfold (7.17 exactly) increase in countries with diets based on cassava, yams, taro or plantains have another meaning. They suppose annual average growth rates of 3.0 and 3.6 percent, respectively, for 55 years. These results suggest a complete change in the scale of development. Such a rate of development would be close to the rate evident in East Asia between 1975 and 1990, which was the highest growth rate in East Asia�s history: 4.3 percent annually. But the overall economic growth context in Asia at that time created an environment extremely conducive to rural development. The economic backdrop of sub-Saharan Africa is by no means as favourable; the highest growth rate observed in this region during a 15-year period was 2.4 percent between 1971 and 1990 (FAO, 1995a).
Table 9
EFFECTS IN 2050 OF
DEMOGRAPHIC FACTORS AND DIVERSIFICATION OF DIETS ON PLANT-DERIVED ENERGY
REQUIREMENTS, BY LEVEL OF DEVELOPMENT (base year 1995 (1.00))
3.100 This change of scale implies a need for a very determined effort to increase national potential for constructing basic infrastructure, with agricultural policies and international supply policies adapted to this extreme type of situation. In the face of such an omen, only the ineffectiveness of the national and international struggle against poverty can be highlighted. This ineffectiveness has been responsible for the lag in demographic transition.
3.101 In this regard, certain countries were already identified by FAO in 1980 as facing high risks concerning their food security before the year 2000 (FAO, 1982). Some have already experienced serious ethnic or religious confrontations that were probably caused to some extent by competition for natural resources. These countries are now part of the regions or country groupings mentioned above that face serious long-term risks, but this time on a wider scale. Can the factors of local conflicts be thwarted? Can international migrations be contained? Will it really be possible to continue to ignore the significant risk of extreme social disorders for entire subregions? The logical consequence of the inability to produce or import food would be an absurd solution to agrodemographic problems, namely, an increase in mortality, the opposite of the trend envisioned by the United Nations.
Table 10
EFFECTS IN 2050 OF
DEMOGRAPHIC FACTORS AND DIVERSIFICATION OF DIETS ON PLANT-DERIVED ENERGY
REQUIREMENTS, BY CONTINENT (base year 1995(1.00))
Table 11
EFFECTS IN 2050 OF
DEMOGRAPHIC FACTORS AND DIVERSIFICATION OF DIETS ON PLANT-DERIVED ENERGY
REQUIREMENTS, BY DIET CLASSIFICATION OF COUNTRIES (base year 1995 (1.00))
3.102 The stabilization of the fertility rate at 1.6 (the United Nations low variant), 2.1 (medium variant) or 2.6 children per mother (high variant) would imply that the African continent must multiply its available plant-derived energy by 4, 5 or 6. The populations that consume mainly cassava or other roots or tubers would have to increase their available plant-derived energy to 6, 7.2 or even 8.4 times their present quantities.
3.103 Such prospects of pressure on resources can lead to the hasty conclusion that whatever the lower level reached by fertility, there is no possible solution. In this paper, it is emphasized that this observation runs counter to reason.
3.104 Admittedly, these results show the inertia of demographic phenomena and their transmission effects over the generations: high fertility of one generation determines the number of women of child-bearing age for the next generation, some 15 or 20 years later, and brings a minimum number of children born to that generation of daughters, even assuming reduced fertility. This is why the consequences of demographic changes on growing demand for food energy in high and low fertility conditions were presented in Table 8, despite the fact that these extreme hypothetical cases, when applied on a global scale, are purely academic.
3.105 Nonetheless, the facts have to be faced: lower fertility rates make the necessary economic changes appear less absurd and closer to the realm of possibility. Thus, in the case of Africa, for each scenario of fertility decline there is a different corresponding development model and rate of growth of production of energy of plant origin required for the production of food supply. This growth rate would be 2.6, 3.0 and 3.3 percent per year over 55 years for the three scenarios, respectively. Each of these rates surpasses the observed maximum rate of agricultural production for sub-Saharan Africa between 1971 and 1990 (2.4 percent), but remains lower than the maximum rate for East Asia for the same period (4.3 percent). Asia, however, is the most densely populated region in the world, with more developed infrastructures, a greater degree of human capital development (in terms of literacy, etc.) and a more dynamic general development context than in Africa. The situation appears more acute in countries whose populations consume cassava, yams, taro or plantains, because the growth of plant-derived energy required would have to reach levels as high as 3.3, 3.6 and 3.9 percent per year in the different scenarios � growth rates approaching the maximum attained in East Asia. These are probably very difficult goals to achieve, perhaps impossible in the current economic and structural context of Africa.
3.106 The lateness of Africa�s demographic transition, and thus its development, explains the different results from those obtained for East Asia. East Asia is the most highly populated region in the world, where the food situation will still be a problem in 2010 and where the growth of agricultural production should be maintained at a rate of 2.2 percent per year until 2010. It is therefore obvious that Africa faces a major challenge to the capacity for sustainable development.
3.107 Rationalization of budgetary choices and the priority given to urgent food security problems explain why heavy investments in agricultural research have been centred mainly on highly populated (especially rice-growing) regions. Efforts must now be oriented towards the regions where agriculture has been neglected and investment is urgently needed because of the rapidly growing population. These regions already contain the greatest number of the poor in the world. Such investments should be made in cultivars of roots, tubers and pulses which provide indispensable protein for populations that eat little meat or plantains. Even these technical changes will probably not suffice. It will be necessary to bring together all the required infrastructure-oriented factors for true development in these countries.
3.108 This study needs to be taken further. Throughout this document, attention has been drawn to problems of insufficient data, estimates and information.
3.109 The most important development would be the analysis of the effects that limited available resources (in human resources, earth and water) would have on various productivity assumptions of the factors of rural development. This would require each country to have the necessary information to analyse all interacting factors, such as population, basic training, professional training, the food situation, qualitative and quantitative assessments of available renewable natural resources, infrastructure and vegetation.
3.110 The technology useful to the development of such studies is advancing rapidly. Available data have increased greatly, and techniques for gathering data have changed. For example, remote sensing provides a considerable amount of geographical and human information that could be useful for this subject.
3.111 Techniques for analysis have improved. The studies of interrelationships have increased at the local level in the form of pilot studies, especially studies of the links between changes in plant cover and population changes. Such studies could be assisted by using remote sensing.
3.112 Nonetheless, at present, data and analyses are often incomplete. The determinants of mortality are not well known, particularly the link between undernourishment and mortality. The interactions between water availability and usage and mortality have not been sufficiently studied. The quality of fertility estimates is often insufficient. Moreover, the determinants of fertility decline have not been clearly identified. The data-gathering situation is alarming. The recording and quality of vital statistics are not progressing in many countries. The socio-economic structure of populations is often badly assessed, and the number of persons active in agriculture or fisheries is only roughly estimated.
3.113 From the agrogeographical perspective, the situation is not as good as it was in 1980 when the FAO agrodemographic study was conducted (FAO, 1982), because the geographic data based on soil terrain conditions have been only marginally extended and improved in quality. Global plant cover has still not been established. There are still significant gaps in data relating to agricultural resources, land use by agro-ecological zone (AEZ), the state of deterioration of irrigated lands and erosion damage to land in rain-fed regions, as well as in quantitative and qualitative data on water resources. Because of this lack of information on the present situation, it is difficult to determine the trends of agricultural resources in terms of degradation, maintenance and enhancement.
3.114 Information about environmental conditions is also insufficient. The available information concerning elements such as humanity�s impact on the current state of the planet�s photosynthesis, the population carrying capacity of various lands, the effects of agricultural intensification on climate and changes in genetic diversity is inaccurate.
3.115 All these issues are essential in order to measure the state and evolution of natural-resource capital and to determine which factors are necessary to establish conditions for sustainable development (FAO/UNESCO/WMO, 1977; UNESCO, 1985a,1985b; World Commission on Environment and Development, 1987).
3.116 Studies on the links among the various factors influencing agricultural production are too often lacking. Some examples in which population phenomena are often involved are provided here.
3.117 The purpose of this document is to describe broadly the trends in energy requirements and the food supply necessary to fulfil such needs. It is not intended to propose political or economic solutions to the resulting problems. Nonetheless, it is important to present some of the political implications of the trends identified.
3.118 Certain regions of the globe .� and, hence, all of humanity � will face a real social and economic challenge because of the lag in the development of certain regions and the related delay in demographic transition.
3.119 Those who are being challenged are the weakest and least able to face the difficulties. They have barely (or not at all) begun their demographic transition and are suffering from food shortages and continuing high mortality rates. They are facing tremendous difficulties in breaking out of the high-poverty/high-fertility mortality cycle. For example, to escape poverty, the temptation to migrate often becomes irresistible. Besides the ethical issues involved, the success or failure of these populations will have regional and global impacts.
3.120 The decrease in agricultural production growth rates observed since the mid-1980s is exclusively the result of lower production by the main net exporters of cereals. This decrease did not boost world prices; in fact, those prices have declined. Therefore, it cannot be interpreted as a harbinger of food shortages or as some production limit reached as a result of environmental conditions regulating agricultural activities. The observed pace of production is able to meet growing effective demand. The decline in production can be explained mostly by the slowdown in production growth by certain large exporting countries in order to avoid lower prices that could result from insufficient sales and accumulated surpluses.
3.121 A major problem is thus the slow growth of effective demand, or, in other words, the issue of poverty. It can be observed, then, that trends in large exporting countries result in limitations on the growth of available food per inhabitant in a social context where over 800 million people should be able to consume more to meet their food energy requirements, but do not have the necessary income to purchase additional food. Poverty acts as a brake on demand and, therefore, on food production. The world�s agricultural production facilities are fully capable of increasing the quantity produced, but, in order to do this, demand must increase. At the same time, it is also important to contain growth in food energy requirements through deceleration of population growth.
3.122 Development is, above all, growth in consumer demand. Economic development, at least in the initial stages, lies mainly in the growth of domestic consumer demand and especially in the growth of the production necessary to meet such demand. It depends only very marginally on the development of exports, especially where chronic malnutrition exists (East Asia, South Asia, sub-Saharan Africa, etc.).
3.123 The growth of internal consumption depends significantly on the continuing decline in real prices of food and, in order for this to occur, on the continuing support of sustainable agricultural development by governments and the international community. This effort requires sufficiently strong stimuli in the different factors of production (human resources, land, water) to generate significant gains in income and an increase in effective demand, plus policies to promote health, nutrition and education of the entire population. In the context of malnutrition, such investments in the factors of production could have high returns (Rosegrant, Agcaoili-Sombilla and Perez, 1995).
3.124 Agriculture remains the main activity in the developing world. The population active in agriculture has not been the majority of the world�s economically active population since 1980-1984, but it does constitute the greater part of the active population of developing countries (over 55 percent) (FAO, 1993a). With demographic growth, the population of the developing world continues to increase. Since 1980, it has been over 1 billion people.
3.125 Furthermore, the great majority of the most impoverished live in rural areas and work the land (World Bank, 1990). The rural population of developing countries was estimated at 3.1 billion in 1995.
3.126 This means that, for most of the population of the developing world, agriculture brings in both food for the family and the revenues needed to purchase the essential goods people cannot produce themselves.
3.127 The growth of agricultural production is an essential means of fighting poverty. It is already known that individuals must meet the basic nutritional needs that allow them to maintain a minimum level of activity; this is a condition governing populations� abilities to control their destinies. It has also become obvious that as long as developing countries remain heavily dependent on agriculture, the struggle against poverty will depend on increasing food production and agricultural productivity and enabling women to produce food under better conditions. The struggle against poverty and efforts to increase food production cannot be separated at the level of development where agriculture plays the major role.
3.128 Further capacity for intensifying agricultural production is still accessible. Any attempted projections in this domain are uncertain because of the inadequacy of available forecasting methods in evaluating changes in technological innovations. In the past, this has often led to a systematic underestimating of yield increases.
3.129 Cereal production will probably increase by 40 percent by the year 2010 (FAO, 1995a). The average yields of the three main cereals (rice, wheat and maize) could be expected to increase significantly between 1988/89 and 2010 (by 36, 42 and 39 percent, respectively). An annual increase in cereal yields of over 1.5 percent can therefore be expected.
3.130 Several factors will have an important role.
3.131 The efficient use of fertilizers is another important factor for increasing yields (Treche, 1995). It is difficult to forecast the future development of this area. However, the study of such issues is essential in view of the size of the investments involved and related questions on production, transport costs, etc. In many developing countries, inadequate quantities of fertilizer are applied, which leads to land degradation. It should be kept in mind that rehabilitation is a very costly and long-term endeavour. One of the challenges remains the intensification of agriculture in a subsistence context.
3.132 These remarks should not lead to the conclusion that genetic improvements constitute a panacea. Also relevant are some of the essential characteristics of rural development in countries within Class 6 (cassava, yams, taro and plantain). These countries generally have important humid land reserves on which crops can be expanded. In this respect, it should be kept in mind that soil quality can constitute a serious problem. Some of these countries, such as the Congo, have very small populations. In these conditions, the expansion of the cultivation of roots and tubers can constitute a solution to their food situation (Lee et al., 1988). It should be noted that the cultivation of cassava does not require a high level of technical ability, while the cultivation of yams, used in particular in Nigeria, requires greater technical abilities. Furthermore, the land reserves of countries such as Cameroon, Gabon, C�te d�Ivoire and Togo are limited and gains in yields are therefore necessary. Finally, Rwanda and Burundi face a different situation because of the strong pressure they exert on their natural resources. These two countries derive a large part of their energy requirements from roots or tubers but complement their diets effectively with pulses rich in protein. Therefore, these countries need to increase the productivity of each production factor (human resources, land and water).
3.133 A substantial proportion of exploitable rain-fed land is still available. Many developing countries still have an important quantity of unexploited land available that is well adapted to rain-fed crops. The available land is about equivalent to the surface area already being farmed (over 700 million hectares). These lands do not include areas inhabited by human beings, forests or protected areas. To inhabit them could require important population movements.
3.134 This land is available especially in sub-Saharan Africa, to a lesser degree in East Asia (except China) and Latin America (which has a large area of forest land in reserve) and to a minor degree in South Asia. However, it should also be taken into account that forests have a role that may be important in contributing to agricultural incomes. It would appear that these lands are not very fertile naturally and that the colonization programmes aimed at new lands over the last few years have never absorbed large excess rural population groups. Furthermore, part of such lands will be used for expanding population settlements. According to FAO, the increase in cultivated arable lands will probably not surpass 12 percent by the year 2010.
3.135 Future development is largely dependent on dissemination of technical expertise. The acceleration of rural development will depend greatly on the dissemination of farming techniques and low-cost distribution of improved cultivars. This will apply especially to countries that possess particularly arable land and where available land is more limited. Good infrastructure, market access and competition in labour costs all stimulate such dissemination.
3.136 The factors that influence development � setting up agricultural infrastructure, input supply policies, methods of preservation, extension policies and training, farm market regulation, development of banking service infrastructure and political and credit infrastructure � are not addressed in this paper.
3.137 However, it is necessary to point out that once there are productivity gains as a result of enhanced inputs and improved cultivars, the continuing struggle for productivity depends increasingly on human resources. It is only by recognizing the value of human resource development that this quest for productivity can be successful. Professional training and integration of farming populations into the process of development must therefore be added to improved health conditions, improved nutritional conditions and increased literacy levels of populations.
3.138 This document considers populations as groups of individuals who have not only fertility, mortality or migration characteristics at certain ages, but also energy requirements and diets that change over time. From such a perspective it is sufficient to raise questions about development strategies, considering the magnitude of the direct demographic challenges, especially those caused by population growth, as well as the indirect demographic challenges of factors such as dietary patterns. It is certain that holistic rather than isolated sectoral strategies are necessary at all levels. The challenges can be met, but not if population or agricultural policies are implemented without regard for each other. A carefully planned synergy of these areas is urgently needed. In order to be more effective, population programmes need to take into account the food security and the biophysical, social, economic and institutional environments of rural populations which can influence their demographic behaviour. Agricultural strategies can be either assisted or endangered according to the demographic characteristics and trends of the populations they are meant to serve. This document has highlighted the enormousness of the challenges: to be effective, decision-makers need to implement solutions that are truly commensurate with the magnitudes identified. Finally, in view of the inertia of demographic factors and the various time frames required for human resource and agricultural development, time is an essential consideration. Finding and implementing solutions that address the combination of the magnitudes in relation to the problems of time is the crux of the matter.
4.1 The world will inherit a very diversified food situation at the end of the second millennium.
4.2 The positive aspects of the picture can be summarized as follows: coming from a very acute food deficit in 1962, Asia has continually improved its coverage rate of energy requirements by its food supplies and is catching up with the situation of Latin America, where, after a period of increase in coverage, a stabilization can now be observed.
4.3 On the negative side, Africa has not managed to improve its food situation. Furthermore, some countries .� those that consume mainly cassava, yams or taro � have experienced an acute decline. Demographic transition in Africa would facilitate the process of achieving food security; the annual growth rate in available plant-derived energy would be 2.6 percent in the low variant, as opposed to 3.3 percent in the high variant of the United Nations population projections.
4.4 Energy requirements of developing countries will increase towards the year 2050 because of the growth of their population numbers and also, to a lesser degree, as a consequence of change in their population structure. The ageing of the population and the increase in its physical height as a consequence of better nutrition are factors increasing energy requirements, whereas declining fertility and increasing urbanization are factors reducing energy requirements. As a result, by the year 2050, energy requirements will be doubled in developing countries as a group (but more than trebled in sub-Saharan Africa).
4.5 Developing countries will have to complement their national diets in order to create the prerequisite conditions for eliminating chronic undernutrition. As a result of differences in food distribution inside countries, this process could require an increase in plant-derived food energy availability of 30 percent in Africa (but 40 percent for sub-Saharan populations), 15 percent in Asia and less than 10 percent in Latin America.
4.6 In order to achieve well-balanced diets (in terms of amino acids, vitamins and nutrients), diets will need to be diversified. As a result, Africa would have to improve its plant-derived energy by another 25 percent (46 percent for countries consuming mainly roots and tubers) and Asia by 21 percent.
4.7 All included, developing countries would have to increase their plant-derived energy by 174 percent. This means that while countries of Latin America and Asia would roughly have to double their plant-derived energy, African countries would have to multiply theirs by five (by seven for the root- and tuber-consuming countries).
4.8 While for Asia or Latin America such a perspective represents a lower rate of productivity growth than was seen in the last 15 years, Africa would have to accelerate the growth of its productivity drastically.
4.9 Climatic change could be a crucial factor for food production in the future. This complex issue will create new challenges to satisfy human food energy requirements and changes in diets and could modify plant, animal and human pathologies as well as the distribution and location of human settlements.
4.10 Where land becomes scarce, increases in yield will be achieved mostly by drawing more heavily on natural resources and through the development of human capacities. Because of the existing level of education in Asia, many Asian countries seem to be well prepared for the change in the nature of development. On the other hand, the current development level of economic infrastructure and human resources will constitute a serious handicap in Africa. Africa will thus be faced with the obstacle of improving its human and infrastructure resources while dealing with a very difficult food situation. In doing so, Africa would also be preparing the basis for solving its food security problem in the long term, after the year 2025.
4.11 In view of the importance of the interrelations between population trends and food, decision-makers and researchers face the continuing challenge of harmonizing agricultural and population policies and programmes in order to help develop an approach towards achieving universal food security for the benefit of humanity.
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