CHAPTER FOUR C. MAUREEN CUNNINGHAM THE EFFECTS OF GLOBAL WARMING ON THE POPULATION, AGRICULTURE, AND EPIDEMIOLOGY TRANSITIONS IN THE SOUTH SAHEL REGION OF AFRICA The Sahel cuts a swath across West Africa from Senegal through Chad. It is the zone just South of the Sahara desert, and is the area into which the Sahara desert shifts in its movements southward (See Map following). Due to expansion and contraction of the Sahara (Tucker et al., 1990), it is difficult to define where the southern border of the Sahel falls. The Sahel is the major transition zone between the more humid tropics to the south characterized by two dry seasons and two growing seasons and the hot, dry, desert to the north. The southern part of the Sahel and the northern part of the humid tropics is the area under study made up of Northern Benin, Southern Niger, and Burkina Faso, called here the South Sahel region (see Map following). While there are some sociological and cultural differences in the different parts of the South Sahel region, the climate, lifestyles and modes of agricultural production are very similar throughout. The region is labeled the Sudano-Guinean Climate Zone (Martyn, 1992). It is dry and hot, with three identifiable seasons: The first, called the Harmattan, is dry and relatively cool, the second is hot and relatively humid, and the third is rainy and hot. Rainfall is low and unreliable compared to the more humid south where there are two relatively stable growing seasons per year (Simsik, 1993). The people living in the South Sahel region are agriculturists for the most part, depending on the one annual growing season to provide the bulk of their income and nutritional subsistence each year. Agricultural labor is accomplished with simple tools such as the short handled hoe and the machete (Simsik, 1993). With only these inputs to production, labor is of high importance. The land area under cultivation is fairly small for any given person or family due to the intensity of labor necessary to produce crops. Most farming is of subsistence crops such as millet and sorghum and some commercial crops such as cotton and groundnuts for export (Simsik, 1993, United Nations, 1994). It is important to study global warming in the South Sahel region in terms of the population-environment dynamic in order to develop policies which can be implemented by the governments involved to mitigate the societal and environmental problems that global warming exacerbates. The region has a highly constrained ecosystem. According to Agbo et al, "The greater number of types of ecosystem constraints involved and the greater degree of constraint of these components, the more tightly linked the population-environment dynamic will be in any region (Agbo et al., 1993). Tight linkages between population and environment mean that the more the environment changes, the more the population will be affected. As the population changes (for example grows larger), the environment is highly affected (Agbo et al., 1993). Population and environment are inextricably linked, and must be considered in terms of each other before any policy changes can positively impact a constrained ecosystem. There are three types of ecological constraints that are apparent in the South Sahel region. The first is geographical. The South Sahel is geographically constrained in terms of water availability which dictates where people can survive. The second type of constraint is ecological. Poor soils mark the entire region, limiting the number of people who can sustain themselves in any given area. Finally, there are economic constraints. These include the populations dependence on subsistence agriculture, as well as their dependence on the fluctuating global market economy over which the local people have virtually no control for the sale of their cash crops (adapted from Agbo et al, 1993). Interactions between the population and the environment are not the only ones that affect the region. In the world today, action or lack of action in one region can have a strong impact on other regions of the world. An important case in point is global climate change. The people and production of the South Sahel Region have not contributed a great deal to anthropogenic (human generated) climate change, yet global warming (a more simple term for anthropogenic climate change) may strongly change the environment in the region (Glanz, 1992). Through the environment, global warming may influence other sectors of the region such as the population, health, and agriculture. An appropriate way to look at the population-environment dynamic is through the transitions framework, developed by Dr. William Drake. In the physical world, there are a variety of factors which affect every sector. Transition theory makes explicit the interdependence of sectors, and is an attempt to look at change in a realistic yet manageable fashion (Drake, 1993) Given that the world is made up of interrelationships across regions and within them, it is admittedly impossible to foresee all aspects of change in any sector. Transition theory gives a framework for examining some of the aspects that cause change. There is a whole family of transitions which includes the environmental and population transitions, as well as the agricultural, forestry, urbanization, epidemiological and other transitions. A transition can usually be broken down into many others, depending on the specificity of the study. For example, one could study the population transition alone, or one could break it down to investigate the fertility transition as distinct from the mortality transition. A transition means a change from one state to another, but does not imply either positive or negative change. In transition theory, change is from some point of stability to another point of stability which may be entirely different from the first. For example, in marginal lands where scrub-cover is the stable state at present, the stable state following a forestry transition may be a desert. Transitions occur similarly on many different scales, both temporally and spatially. Transitions can and do interact with each other and affect each other. From a policy perspective, it is the timing and speed of transitions that may be realistically possible to change, not the actual occurrence of any given transition (Drake, 1993). In general ways such as those stated above, transitions are similar across space and time, but at a local level, transitions occur in very different ways and are changed by a myriad of local occurrences. In this paper, I will investigate three of the transitions occurring in the South Sahel, specifically the population transition, the agricultural transition, and the epidemiological transition. I will look at the position of the South Sahel in each transition now, and then look at how global warming may affect the progression of the transition, and finally how the governments involved can positively influence the timing and speed of the transitions to ease their negative effects on the population. Since data for the South Sahel specifically has not been gathered or calculated, I will use data from the three countries which each include part of the South Sahel. While such an amalgamation is not an exact proxy for the South Sahel, given the similarities of the region, an approximate average of the three countries rates and figures paints a close picture to what data collected exclusively for the South Sahel would illustrate. Where possible I include data for all three countries. Occasionally only one or two countries data is available for illustration and that is used as a rough guess of the South Sahels data itself. GLOBAL WARMING Leaders of less developed countries often see the problem of climate change as far out of their realm of control. Understandably, climate change is pushed to the side as something which, if it does occur, is seen as so far in the future, and is as yet so unpredictable that it is not necessary or possible to deal with at this time (Glanz, 1992). It is true that the effects of global warming on a regional scale are unclear. It is also true that developing countries have not been a primary producer of greenhouse gasses (those gases which cause global warming to occur) (Glanz, 1990). But climate change, whether human in origin or purely natural, highly affects those peoples who live closely linked to the environment (Agbo et al., 1993). Subsistence farmers, the bulk of the people in the South Sahel as well as much of the developing world, are harder hit by climate change of any type than are populations that have more of a buffer between the environment and themselves. This is true whether that buffer is a personal savings account or improved technology which allows high levels of agricultural production in the face of climatic variation. Policy makers in Benin, Niger, and Burkina Faso, as well as other developing countries need to address the possible impacts of global warming before they negatively affect their people. The Intergovernmental Panel on Climate Change (IPCC) is made up of researchers from all over the world working with the UN to study the causes, effects, and possible future scenarios of climate change. According to the IPCC, climate change due to human activity is definitely occurring globally. Anthropogenic climate change is caused by the emission of greenhouse gasses (GHGs) which include carbon dioxide, methane, nitrous oxide, halocarbons, and hydroflourocarbons. The most important of these is carbon dioxide (CO2) due to its high concentration and rate of increase in the atmosphere. Greenhouse gasses are produced through industrial production and transportation that depend on the combustion of fossil fuels as well as land use conversion (IPCC Draft Report, 1995). Once GHGs are released into the atmosphere, they act in much the same way as a greenhouse. They trap some of the radiation coming from the earth in the earths atmosphere and do not allow the earths natural cooling process to work as strongly as it would without the high levels of GHGs (Benarde, 1992). As of yet, the full effects of climate change are not known. A way to look at the possible effects is to set up modeling situations in which many variables at different levels are factored in, such as the rate of GHG production into the future (Benarde, 1992). Commonly accepted models point to a global temperature increase of anywhere from 1.5-4.5 degrees Celsius eventually (Schneider, 1994), and 1-3.5 degrees Celsius by the end of the next century (IPCC Draft Report, 1995). According to the IPCC, In all cases the average rate of warming would probably be greater than any seen in the last 10,000 years, but the actual annual to decadanal changes would include considerable natural variability (IPCC draft report, 1995). Experts on climate agree that temperature change is likely to be greater at the poles than at the equator (IPCC DRAFT Report, 1995). The IPCC projects a rise in sea level from 15-95 cm. by the year 2100 due to thermal expansion of the oceans and the melting of some of the earths water currently contained in ice. Modeling on precipitation is less precise than on temperature and sea level rise. Some models predict more severe droughts and floods, some models predict more severe precipitation events such as increased cyclone possibilities (IPCC draft report, 1995). While global effects of some degree are inevitable due to anthropogenic climate change, regional effects are highly uncertain to date, and the smaller the region of interest, the less certain the effects become (Stephen Schneider, personal communication). The IPCC predicted in 1990 that in the Sahel, the temperature will eventually increase from 1 to 3 degrees Celsius. Area mean precipitation will increase and area mean soil moisture will decrease in the hot season (Suliman, 1990). Soil moisture, as controlled by evapotranspiration, is extremely important--regardless of the amount of rainfall. If the water in the soil is evaporating at a relatively greater rate than the rate of increased rainfall, there is less water for plants to use for growth, a matter of vital importance to farmers depending on rain fed agriculture as are virtually all the farmers of the South Sahel region. In looking at the temperature data available for the South Sahel region which is collected and made available by the National Oceanographic and Atmospheric Agency (NOAA) some interesting, although inconclusive, evidence is apparent (see Figures 1-4). I chose four sites at which data is available for at least 50 years prior to the latest year of data available (usually 1992), and which correspond to my area of study. The four sites I chose are Natitingou and Kandi in Benin, Fada NGourma in Burkina Faso, and Niamey in Niger (see Map near front). Data for some of the sites went back further than what is included but was left out because there were periods of several years with no data whatsoever. For those years in which data is available, but in which not every month is available at a given site, the year is not included for that site only. When the years of complete data are graphed (represented by the black diamonds in Figures 1-4), a striking aspect of annual temperature is apparent. Obviously, even without the effects of anthropogenic climate change mean annual temperature varies widely at all four locations. By fitting a simple linear curve to the data available for each location, a surprising aspect becomes clear: In all cases except for Niamey, the temperature appears to be declining, albeit very slowly, over time. If, however, a linear curve is fit to the data since 1960, in all cases except for Natitingou, temperature is rising. Even in the case of Natitingou, temperature since 1960 is falling less quickly than temperature for all the years with data available. Since the early 1960s has been identified as the time that global warming may have begun to visibly affect global temperature, fitting the curves from 10 years prior to that time onwards helps ensure that natural variation in annual climate alone is not causing the trends that appear when a linear curve is fitted to the data. When these graphs are made fitting the curve from 1970 onward, temperature is increasing for each of the four cases. Figure 1 Figure 2 Figure 3 Figure 4Temperature data alone is not proof that global warming is affecting the region. It is however , an indicator that it may be occurring. But can national policy makers act on a probability? The answer is not only that they can, but that it is extremely important that they do so. In order to take action to protect their populations from the effects of global warming, policy makers need not know what the exact effects will be (Glanz, 1992). By choosing to implement No Regrets policies, the governments of these countries can benefit their societies now, and protect them against the possible effects of global warming in the future. No Regrets policies are those that cause no harm and create benefit without dependence on the future, but developed with a probable future in mind (Glanz, 1992).
THE DEMOGRAPHIC TRANSITION
According to demographic theory (Coale, 1974), the demographic transition as seen thus far has four stages. In the pre-transition stage, birth rates are very high, but are counterbalanced by high death rates. The overall effect is a population with little or no growth. In the early stage of the transition, death rates fall due to public health and medical improvements in the population. Birth rates remain high and a population explosion occurs. In the late stages of the transitions, births begin to fall, and although they still exceed deaths and population continues to rise, the rate of increase is slow. Finally in the fourth stage called the post-transition period, the birth rate falls to the point that it is roughly equal to the low death rate and the population reaches a steady state of approximately zero population growth. This model is based on the experience of more developed countries (Haub et al., 1994) where the transition has occurred smoothly and over a long period of time. There the decrease in death rates occurred slowly and was of endogenous (interior to the region) origin, caused by a gradual increase in knowledge about health and medicine. There was a lag in the fall of birth rates following the fall in death rates, but not so great as to create a large degree of stress either on the environment or on the population.
The South Sahel region, and indeed much of Africa, is experiencing a population transition much more violently and quickly than the more developed regions did. The South Sahel is currently at the point of change between the early and late stages of the transition. Changes to the death rate came relatively quickly (the early stage), beginning around 1950 in the form of life-saving vaccinations and medical technology provided in large part by international aid agencies (Haub et al., 1994).
Birth rates, on the other hand, have remained relatively constant. An amalgamation of the population growth for all three countries in the South Sahel region gives a fair idea of what the rates are, given the similarities between Northern Benin, Southern Niger and Burkina Faso. At the present time, the crude birth rate (CBR) per 1000 people in the population per year in Benin is 48.09. In Burkina Faso it is 48.8, and in Niger it is 57.35, while the crude death rates (CDR) per thousand people in the population per year is about one third of the birth rates at 14.8, 18.19, and 22.44 respectively (CIA, 1995). Since the growth rate percent (minus migration) is equal to births minus deaths divided by ten, the region has an overall growth rate percent of approximately 3 (3.1 in Benin, 2.8 in Burkina, and 3.4 in Niger (World Population Council, 1995). This number may not seem very high, but consider that a growth rate percent of three means that if the growth rate remains unchanged, the number of people in the region will double in only 20 years (see figure 6 below).
Figure 7 By the year 2025, the population in the region will be approximately three times its present level. Perhaps even more striking than the level of increase is the irrevocability of the increase. Due to population momentum and the slow speed of decrease in the growth rate, population will continue to climb throughout the foreseeable future even though growth rates are projected to begin falling in this decade. In the South Sahel region, population momentum rests to a large degree on the age distribution of the population. Nearly half of the population at the present time is under the age of 15. Thus, a huge majority of the population is in, or will be moving into, their reproductive ages within the next 15 years. Even if the number of children born per woman fell dramatically, the number of people having children will keep the population growth rate high (see Figure 7).
Figure 8 The effects of population density increase on the South Sahel region will be strongly felt. Whereas at present the population density is about 40 per square kilometer (49 in Benin, 38 in Burkina, and 6 in Niger (World Population Council, 1995), under the present UN projections for future growth, the population density will increase to about 90 per kilometer by the year 2025 even though population growth is falling (see Figure 8 below). Nigers population density is very low in the mostly empty upper portion of the country. The bulk of its population is in the South Sahel region where farming is difficult but possible, unlike the desertic North. A population density of 40 per square kilometer is not terribly high, but for a subsistence farmer with low crop yields, it may be close to what the land can bear and still provide sustenance for its inhabitants. Thus, the population density, while low compared to some regions is high for the South Sahel region due to the constrained ecosystem and the modes of agricultural production. People are not acting to limit their fertility general- ly in the South Sahel Region. Contraceptive use levels by women are
very low: approximately 9 percent of Benins women ever uses contraceptives,
and about 1 percent of Nigers and Burkinas women are contraceptive users.One possible scenario of what will cause population to fall eventually in the South Sahel is a Malthusian one of widespread death due to starvation when the population gets too high to support itself off the land, or death due to wars for land or rights to production. Another is that the population will eventually be artificially supported by the international aid community, and become a sort of welfare exclave of the western world (Hill, 1990). Neither scenario bodes well for the region, and policy makers need to address the problems of high population growth rates before the region moves any closer to either one.
The agricultural transition has followed a trajectory similar to the worldwide population transition. For many centuries, agricultural production kept pace with human population (Drake, 1993). There were periods of famine due to war, drought or other climatological disasters, but on a large scale, human populations were able to produce enough to feed themselves. Increases in agricultural production came through the increase of the amount of land under cultivation, and improved methods of production. Drake identifies the shift in increase from amount of land under cultivation to improvements in productivity per hectare as the beginning of the agricultural transition (Drake, 1993). The transition includes the period of increasing returns on inputs into fixed land holdings, and eventually reaches a stable point when a given area of land cannot profitably be made to produce more output. According to Drake, the shift from size to intensity is especially remarkable at the individual farmer or family level at which the amount of land owned or open to use may be fixed, leaving a farmer only one alternative to increase production: increased growth intensity. If increased intensity does not occur, but population continues to increase, rural to urban migration will occur, giving those who remain on the land more area to cultivate.
The South Sahel region is at the early stages of this transition. The vast majority of people in the region are farmers (over 90% of the labor force in 2 of the 3 countries involved are agriculturists (CIA, 1995), and almost all farmers work on small, family-run farms. Some cash crops, mostly cotton, are produced (CIA, 1995). Food crops are varied and include: sorghum, millet, cassava, rice, tubers, and others to a lesser degree (UN, 1994, and CIA, 1995). In general, women grow food crops and men grow both food crops and cash crops. Agricultural production is accomplished using traditional methods and only the most simple of tools: short handled hoes, shovels, and machetes. Agricultural production is highly labor intensive, and yields are low. For example, in Niger, the profit in terms of food produced per hectare of arable land is at about $120 in constant US 1985 dollars per year (WRD, 1995). Considering that a family with 4 people working can cultivate slightly more than 4 hectares of land on average (this statistic is for Tanougou in northern Benin, Agbo, 1993), the amount of food or profits produced is very low. Most land is broken into small plots of less than a hectare to one or two hectares, with one family farming several plots. Little in the way of technological advances have been brought in. Fertilizers and pesticides are used, but due to their high cost they are not used in the recommended amounts. Some livestock is raised, mostly for family consumption, except for Burkina Faso where a substantial number of cattle and sheep are raised for sale (UN, 1994, and CIA, 1995).
The soils of the region are relatively poor and non-productive. In the past, this was a manageable problem in that the population in any given area was low enough to allow long periods of fallow between periods of production which gave the land the opportunity to replenish its nutrient content. As population increases and more pressure is applied to the already constrained ecosystem-system, periods of fallow are decreased out of a necessity to use the land for food production. Land that used to be left fallow for a decade or more in between each several year period of use is now only being left fallow for 4 or five years. Another common practice which decreases the fertility of the soil is burning off the ground cover which grows up in times of fallow and between harvests. In a region of no winter to naturally break the insect and pest cycle, burning the fields helps to accomplish this vital task for production (Schneider, personal communication), but much of the organic matter on the land is in a sense wasted by being burnt off instead of being used to enrich the soil. Fire also destroys any unprotected trees which serves to increase the shortage of fuel wood in the area (Agbo, 1993). Finally, fire leaves the land open to wind and water erosion until substantial plant cover is replenished. Some fertilizers are used in an effort to substitute for the loss of soil fertility, but for the most part these inputs are too expensive for families to afford (Simsik) or unavailable to be used correctly. When they are used, fertilizers have their own long term debilitating effects on the soil which necessitates ever greater inputs of fertilizer .
Shortening fallow periods and field burning is impoverishing the soil and ever decreasing yields per hectare. This creates the need to try to cultivate even more land to produce enough to survive. The need for labor to work the increasing landholdings leads to an increased need for children. More children serve to increase the pressures on the land, both through need for agricultural production and need for the fuel wood and other resources that the land provides. This cycle will continue to reproduce itself and expand until the population can feed itself without relying on the practices that serve to keep the cycle in motion.
EPIDEMIOLOGICAL TRANSITION The basic epidemiological transition is highly related to both the agricultural and demographic transitions described above. In the early stages of the transition, most death is caused by infectious disease and malnutrition related disease (Drake, 1993, and Dewey, 1986). There is a high probability that any individual will contract a mortal disease and die before they reach old age. As public health and sanitation measures take effect, such as clean water provision and food safety standards, the first stage of the transition begins. Infectious disease and malnutrition related disease take fewer young lives, and people begin to live longer on average. As medical technology improves, vaccinations are administered against many infectious diseases, and food becomes more and more secure due to agricultural improvements. Living into old age becomes the norm. Death is no longer caused by infection or malnutrition for the most part, instead it is due to a whole host of degenerative diseases such as heart disease and cancer. Degenerative diseases existed previous to this stage, but since they affect the elderly much more often than the young, they were rarely seen. This last stage has been reached in much of the more developed world, and life expectancies at birth have soared into the 70 and 80 year ranges (Population Reference Bureau, Inc., 1995). The majority of people in the West live into their retirement years and experience one or more of the degenerative diseases from which they eventually die (Drake, 1993, and Dewey, 1986).
Figure 9 In the South Sahel region, the transition is underway to some extent, but it has come about in a very different manner than it did in the West. Instead of a decrease in illness and death at young ages beginning with public health measures as was seen in the West, the initial decrease in death rates in the South Sahel came primarily from vaccinations and improved medical technology. For example, in the South Sahel region today, only about 35% of the rural population has access to safe drinking water (43% in Benin, 31% in Burkina Faso, and 32% in Niger) (WRD, 1995). Sanitation services, such as latrines are in even shorter supply with approximately 12% of the population having access to them (5% in Burkina Faso, 4% in Niger, and 35% in Benin). On the other hand, a large proportion of infants are immunized now against the childhood killers including tuberculosis, diphtheria, polio, and measles (WRD, 1995). Thanks to the World Health Organization, small pox has been wiped out. Antibiotics are now available to those who can get to health care facilities. Access to medical facilities is low however, with overall access to a clinic or hospital at less than 50% (WRD, 1995). The effect of the changes in health care and medical services has increased the life expectancy dramatically since international aid agencies began working in earnest in the 1950s (see Figure 9 above), but in all three countries of the South Sahel, life expectancy is still quite low by more developed countries standards. Since life expectancy is a measure of the average age at death, it is also an indicator of general ages of death across a population. A low life expectancy such as that seen in the South Sahel Region is indicative of deaths due to infectious disease and malnutrition related disease because it shows us that a large percentage of the population is dying before they reach old age when degenerative diseases generally set in. Infant mortality rates also can be used as rough indicators for death rates across all age groups. In a region with high infant mortality, there is likely to be high death rates across all age groups, indicating high death rates from infectious and malnutritional diseases. Infant mortality has declined somewhat in the South Sahel mostly due to improvements in vaccinations and medical technology available, but it remains very high, at 109 per thousand live births annually for Benin, 134 per thousand for Niger, and 137 per thousand for Burkina Faso (WHO, 1991).
Figure 10 Due to a lack of reporting, morbidity rates (rates of illness) are not well known for most of the world. A study was carried out in Burkina Faso which indicates that the leading causes of visits to health clinics and hospitals for children under five in that country are, in order of rates, malaria, diarrheal disease, respiratory infection, and malnutrition related disease (See figure 10) (Konate et al., 1994). This information roughly corresponds to the World Banks assessment of mortality causes for children in demographically developing countries (World Bank, 1993). Children under five bear a large percentage of the burden of communicable disease. In Sub-Saharan Africa, when infectious disease occurs, 63.5% of the time it is to a child under five; 32.1% of non-communicable disease (including malnutrition) is borne by children under five. The corresponding figures for children in the more developed countries of the world are: 29.3% of communicable disease and only 4.3% of non-communicable disease (World Bank, 1993). The overall infectious disease rate for people of all ages is extremely high in the developing world. The daily adjusted life years lost (DALYs) due to any given disease or adverse situation (such as malaria or lack of clean water) is a useful measurement of disease rates. It takes into account both loss of life and loss of health while alive. In Sub-Saharan Africa, the rate of DALYs lost to people of all age groups due to infectious disease is estimated at 408.7 per 1000 people. The corresponding rate due to infectious disease in the more developed world is only 11.4 DALYs lost per 1000. On the other hand, in the more developed world the non-communicable disease rate is closer to that of sub-saharan Africa at 92 DALYs lost per thousand people. Sub-Saharan Africas non-communicable disease rate is 111.4 DALYs lost per 1000 people. This rate is slightly higher than in the more developed world, but it is apparent from these figures that proportionally, the vast majority of disease burden is caused by infectious disease in Sub-Saharan Africa, while the majority in the more developed countries is caused by non-communicable, degenerative disease. The epidemiology and agricultural transitions include a change from food production for individual use to crop production for sale. As productivity increases, a family can grow more than they themselves need. Selling the excess production, or growing strictly cash crops, is a way to save what is produced and create a buffer against times of famine or hardship (Dewey, 1986). Such saving is virtually impossible in a purely subsistence farming situation for longer than the year or so that excess food can be conserved. This transition can be enforced by the government by the need to pay taxes or the need to have money available for other things such as school fees and transportation. Once farmers move from purely subsistence farming to some subsistence and some market crops, food consumption is no longer equivalent to what is produced. A movement to cash crops takes control of productivity, in terms of profit, out of the families hands and puts it into the markets. For farmers with large and highly productive landholdings, this change means more luxury and diversity of diet, but for a marginal farmer the switch can lead to a decrease in nutritional intake if the farming family does not make enough money to purchase adequate food (Dewey, 1986). Often the most fertile land is converted to cash crop use, leaving the more marginal land on which to produce food crops for family consumption. In periods of low rainfall or other climatic catastrophe, those marginal lands produce little to nothing. The more fertile lands may still be made to produce crops, although to a lesser extent than in high rainfall years, but money has many uses besides food purchases. Income from the sale of these crops may be used up before food is gone for other things such as paying taxes and school fees. Over time, if a farming family is successful and the market remains high for their cash crops, the savings lead to the ability to increase either holdings or intensity of farming. The increase leads to more savings and more increase. This cycle, where it is possible, can lead to smaller farmers being pushed out because they cannot compete with the higher technology production of the neighboring farmers who can afford to sell their products for less (Dewey, 1986). Rural to urban migration is the result, as we have seen in the United States. The South Sahel region is at present in the very early stages of this part of the transition. Some cash crops are grown, mostly cotton, but, as are so many developing world producers, the ability to make profits is at the mercy of the international market. Farmers frequently turn their best land over to cotton growth, with the idea of including it in their regular crop rotations. Despite the high nutrient use of cotton plants (Simsik, 1993). The soil becomes impoverished, and when it no longer will produce cotton in large quantities, it is turned back over to food crop production.
Figure 11 Another result of a change to cash cropping is a decrease in the variety of what is grown (Dewey, 1986). Evidence shows that very traditional cultures practicing subsistence farming generally have highly nutritional diets. In the South Sahel, it appears that in years without drought the area is very close to food self-sufficient in terms of calories (see Figure 11). In terms of nutrition there is a deficiency of vitamins and nutrients leading to high rates of malnutrition especially in children. The prevalence of malnutrition for children under five is estimated at 46% in Burkina Faso, 49% in Niger, and 35% in Benin (World Bank, 1993). The epidemiological transition is underway, but due to limited access to care, agricultural constraints on good nutrition, and poor public health and sanitation, the transition is moving very slowly. THE EFFECTS OF GLOBAL WARMING The demographic, epidemiologic, and agricultural transitions are all in progress in the South Sahel. The timing and speed of all three are influenced by many factors, not least of all each other. Perhaps already, but more likely in the near future, the rate of change in these transitions will begin to be influenced by the effects of anthropogenic climate change. Although we are far from understanding all the effects global warming may have, when we look through the lens of the transition theory, we can predict some of the possible effects of human induced climate change. In general, the most likely changes that global warming will bring are to exacerbate the negative effects of transitions already in progress. Perhaps the most direct change due to global warming will be in the agricultural transition. In the South Sahel, rainfall amount and timing are vital to the growth of crops. If global warming creates either more drought in the Sahel or increased volatility in precipitation as many predict (Suliman, 1990, Glanz, 1992, IPCC, 1995), the effect will be to increase the speed of the present circular trend of decreasing production per hectare leading to the necessity to cultivate more land which in turn decreases the revitalizing fallow periods and impoverishes the soil further. Increased drought and failed crops leave the earth open to wind and rain erosion when the rain does fall. Erosion leads to increased desertification and impoverishment of soil fertility (WHO, 1990). Increased drought or precipitation volatility due to global warming may also lead to an increase in out-migration to urban areas due to a decrease in the ability to survive (Doos, 1994) in the South Sahel. The migration and urbanization transitions were not discussed in detail in this paper, but in brief, if jobs or other sources of survival are not available in the urban centers where people of the South Sahel migrate, migration will serve only to swell the already existing problems of urban poverty and unemployment. Due to a decrease in the ability to produce at the lower latitudes, global warming is expected to necessitate a net increase in imports of cereals from 20-50% into the developing world (Fischer et al., 1994). The average decrease in crop yield of cereals due to global warming in the developing world is 10% (Fischer et al., 1994). There is no reason to believe that the South Sahel region will be immune to these effects. Policy options must be considered and implemented soon to try to avoid the negative agricultural effects global warming will cause. Global warming will indirectly effect the population transition. Population, poverty and environmental degradation are intertwined in a positive feedback loop (Dasgupta, 1993). Global warming, through increased drought and volatility will add inputs into the loop in the form of worsening environmental conditions in the South Sahel. As the environmental conditions worsen, people will need to have even more children to do the work necessary to survive. As cereal production and other crop production decreases due to worsening agricultural conditions, the already tenuous state of nutrition of the South Sahel may worsen. There will be 40-300 million more people at risk for hunger due to climate change worldwide (Patz, 1995). More malnutrition will lead to a higher risk of death, especially for young children. As childhood mortality increases, people may feel that they must have more children to replace the children they have lost, to insure that a certain number of children survive, or to insure their own futures when they become too old to work (Dasgupta, 1995). This trend is already occurring in the South Sahel. Global warming will serve to increase the problem however and cause it to move forward at ever increasing rates. On another level, the worsening agricultural conditions due to global warming and the already occurring population dynamics will lead to increased poverty in the already poor region. Increased poverty leads to fewer economic possibilities, and also less money to pay school fees. Parents in the South Sahel are extremely unlikely to send their girls to school if they cannot afford to enroll all their children. Instead, boys go to school when the parents can afford to send any children at all. Since educational and economic opportunities for women tend to decrease fertility (Dasgupta, 1995), the opposite is also true-- where fewer women have such opportunities, fertility tends to increase. Global warming will not alter the path of the population transition as it is occurring now, but it may drastically increase the rate at which it is occurring. Fertility rates are high at present, and will get higher still if the effects of global warming are not mitigated. Policy changes cannot stop increases in population, but they can help to slow down the increases to give governments more time to provide infrastructure and services to the growing population. The effects of global warming on the epidemiologic transition are in many ways tied to the population and agricultural transitions. According to the World Health Organization, global warming may directly increase health risks, especially for those people who have immature regulatory systems, such as infants and young children, and those with failing cardiovascular, respiratory, renal, and other systems (WHO 1990). Increasing malnutrition is likely to occur, as described above. Malnutrition will also potentially increase due to less diversity in diets. As the climate warms, and drought increases in the South Sahel, it is likely that some varieties of edible plants will not be able to adapt to the quickly changing climatic conditions. Since the population of the South Sahel relies for the most part on the crops the people themselves can grow or gather, a decrease in varieties of crops may lead to a decrease in the nutritional value of the local diet. Temperature is a major determinant in disease vector infectivity. It affects replication, maturation, and length of infectivity of vectors (Patz, 1995). Infectious disease rates are very likely to change due to changing climatic conditions. While droughts are likely to intensify in the South Sahel, the amount of rainfall is expected to increase. Increased evapotranspiration will remove a greater percentage of moisture from the soil, making both the earth drier and the humidity higher than at the present time. Increased temperature and humidity tend to intensify the biting behavior of most insects (Patz, 1995). Since many infectious diseases in the South Sahel, most notably malaria, are passed through insect bites, it is likely that the rate of infection of such diseases will increase. Incubation periods for many viruses such as dengue fever, one of many arboviruses found in sub-saharan Africa, may decrease. For example, it was found that at 30 degrees Celsius (a temperature experienced in all parts of the South Sahel during certain months) the incubation time for dengue fever is 12 days. When the temperature is raised to 32-35 degrees Celsius as it may be with global warming, the incubation period is only 7 days. This effect alone leads to three times the transmission potential of dengue fever (Patz, 1995). With global warming, the relative burden of infectious disease on the population will probably increase from its already high levels in the South Sahel, as will the relative burden of malnutrition and malnutrition related disease. POLICY CHANGES TO MITIGATE THE NEGATIVE EFFECTS OF GLOBAL WARMING Since the exact effects and magnitude of effects of global warming on the South Sahel are not known, it is important that any policy implemented will also benefit the state and the people if global warming does not impact the South Sahel region as is expected. In the South Sahel the most likely effects of global warming are to increase the speed and magnitude of the already occurring negative effects of transitions. No Regrets policies are relatively simple to envision in this case: they must be policies which have the power, when implemented, to decrease the speed and magnitude of the most likely problems approaching. They must also lead to positive changes for the environment and societies now. By implementing No Regrets policies, the governments involved can provide the local population time for the international community and the domestic communities to discover effective, long term mitigative procedures. If no policy is taken to mitigate global warming now, a very real possibility is that the state of the population and environment will deteriorate to such a great degree that long term solutions are impossible or are made extremely costly and difficult. Since pertinent policy changes will all have some cost associated with them, it is necessary to chose policy changes carefully which could possibly be implemented by the governments involved. The international communitys assistance in funding new policy implementation may be of extreme importance. Also, since global warming is itself mostly a result of activities in the developing world, ideas such as debt swaps in return for policy implementation should not be ruled out. One of the gravest dangers that global warming poses to the South Sahel region is to decrease the populations ability to produce or purchase adequate amounts and types of food to achieve and maintain a healthy diet. There are several fairly low cost policies which could be implemented to help alleviate this problem, while improving already low nutritional standards. First, the governments involved should enlarge the agricultural extension services to the rural regions of the South Sahel. Through these agencies, the states need to encourage the maintenance of food crops for local consumption as well as home gardens to improve both available calories and available nutrients no matter what the state of the international economy for cash crops is. At the same time, extension agents should educate local farmers about the depletive effects of cotton production on the soil, not in an effort to cut out cash cropping, but instead to ensure that cultivators do not turn their most productive lands away from food crops. Agricultural extension workers should train cultivators in methods of composting, interplanting, cropping of fallow lands with nitrogen fixing plants, and erosion reduction techniques to improve and maintain the fertility of the soil. Agriculture extension agents can also play a key role in introducing drought resistant varieties to the area. Reforestation efforts should be supported by the extension offices. Decreasing land cover opens up the land to greater degradation and loss of fertility, especially in times of drought when new growth is likely to be slow in covering and protecting the land. Reforestation can also directly decrease the work load of the population by providing replenishable fuel wood to the population. Secondly, the local social centers, health and nutrition centers, and clinics should be enlarged and the staffs retrained. The staff of these health related centers should become more actively involved in educating families about nutrition and maintaining a healthy diet using locally grown foods. If possible it would be beneficial to expand both the health and agricultural sectors to a village level whereby each village had trained members who could both disseminate information to the public and receive new information and techniques from the government. One low cost alternative would be to train school teachers in health and agricultural techniques. School teachers are respected members of the community in the South Sahel, and many people are willing to listen to them. If they were trained well, they could act not only as teachers of children, but also leaders in new technology. Improving food security may of itself decrease population growth, but without more inputs it is doubtful that the effects on population would come quickly enough to help avoid the worst problems of overpopulation. The governments of the South Sahel need to ensure that the population has access to contraceptive education as well as contraceptive methods. Health clinic staff should be trained to provide both at low cost. Men and women should be targeted for contraceptive education since both are of vital importance to decisions of fertility. Efforts should be made to improve educational and economic opportunities for women also since such opportunities have the effect of lowering fertility. One way that this could be done would be to insist that development agencies provide equal opportunities to small business projects to both men and women. Often, development projects target men because they are at liberty to take on new projects, while projects that target women must take children and family responsibilities into account. Education for girls can be encouraged by lowering school fees and by educating the public, perhaps through school teachers, as to the advantages of educated women in terms of improved nutrition and health for the whole family and improved earning potentials. The increase in the infectious disease burden that will be borne by the people of the South Sahel due to global warming can also be mitigated to some extent. Again, education can play an economical and important role. The local clinics and health centers, if properly staffed and trained can provide education and services to the populations to avoid and treat malaria and other infectious diseases. Techniques to decrease the number of dengue fever and malaria carrying mosquitoes should also be disseminated through the clinics and village health centers. The use of bed nets should be encouraged, especially for children, to prevent infection at night, and if possible should be provided at low cost. The people of the South Sahel must react to the threat of global warming. They cannot do this however without the support of their governments through the provision of training, salary for staff, and supplying of local outreach offices. By implementing these policies now, the governments involved can mitigate the potential negative effects of global warming. At the same time, they can alleviate some of the problems already at play in the region. If governments do not take action until they know the exact extent and form of damage due to global warming, the result will necessitate greater input to reverse the negative trends and not alleviate many of the problems of climate change.
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