13 de septiembre de 2010

Environmental Degradation Global Food Production, and Risk for Large-scale Migration

This article currently charged. It's been 16 years since it was published in the journal AMBIO held in the Royal Swedish Academy of Sciences. Its importance lies in the author's views on the issues today have become more acute such as the need for food, poverty, migration and global warming.


AMBIO A Journal of The Human Environment
Volume XXIII Number 2, March 1994 ISSN 0044-7447
Published by The Royal Swedish Academy of Sciences

Article, Bo R. Döös,

This paper attempts to estimate to what extent global food production is affected by the ongoing environmental degradation though processes, such as soil erosion, salinization, chemical contamination, ultraviolet radiation, and biotic stress. Estimates have also been made of available opportunities to improve food-production efficiency by, e.g., increased use of fertilizers, irrigation, and biotechnology, as well as improved management. Expected losses and again of agricultural land in competition with urbanization, industrial development, and forest have been taken into account. Although estimated gains in food production deliberately have been overestimated and losses underestimated, calculations indicate that during the next 30-35 years the annual net gain in food production will be significantly lower than the rate of world population growth. An attempt has also been made to identity possible scenarios for large-scale migration, caused mainly by rapid population growth in combination with insufficient local food production and poverty.


This paper aims to provide preliminary answers to the following question:
-          To what extent is ongoing and expected environmental degradation affecting the global food production system?
-          Can it be expected that the future capacity of the global food-production system will be sufficient to meet the demand of the rapidly growing world population?
-          Is there a risk that due to acute food shortage in many lessdeveloped countries within the next decades large-scale migrations will be set in motion?

Clearly, it is not possible to answare these questions with any accuracy. Nevertheless, this does not imply that attempts should not be made. The first question is undoubtedly the simplest one. Even if our knowledge about the state of the global environment is limited, we can make a reasonably reliable estimate of how human activities are currently affecting the capacity of the global food-production system.

The second question is, however, much more problematic. Basically, the difficulties we are confronting are of two kinds. (a) Both the capacity of the food-support system and the demands on this system are dependent on several factors (driving forces) which have very limited predictability. Examples of such factors are: the rate and geographic distribution of social and economic development, and the willingness of the nations to take action aimed at reducing the environmental degradation. (b) Our knowledge of the various physical, chemical, and biological processes involved, and the numerous feedback mechanisms which are at play within the global environment.

A reliable answare to the second question is a necessary but not sufficient condition for answering the third question. The risk for the occurrence of large-scale migration is usually a result of several interactive factor involving, e.g., political instability; lack of religious freedom; unemployment; and insufficient food-purchasing power. This paper, however, will not deal with the migration problem in all its complexities, but discusses the probabilities that an insufficient availability of food in certain regions of the less-developed world may be a major contributing factor in triggering mass migrations that are mainly directed to more development countries.


Figure 1 indicates the major factors that have a positive or negative influence on the future capacity of the global food-support system. In view of the difficulties in making reliable estimations of the magnitude of these factors the approach taken does not induce the most accurate forecast of the global food production. Instead, the aim has been to estimate what the future availability of food would be under comparatively favorable circumstances. The paper therefore deliberately:
-          underestimates the expected losses caused by various stresses on the system;
-          overestimates the possible gains which can be achieved; and
-          does not overstate the future demands on the system.

If such a projection indicated that serious insufficiencies are likely to occur in the near future, this would provide valuable guidance about the magnitude and urgency of the required response about the magnitude and urgency of the required response action. It should be noted that even if such a projection indicated that global food production equaled future demand, a problem still exists due to the fact that possible surpluses of food in some more-developed countries cannot be expected to be readily available in countries with insufficient food production, because of their low purchasing power.

Figura 1

Figure 1. Schematic illustration of the main factors which have a positive or negative influence on the capacity of the global food-production system.

Attempts have previously been made to estimate the impact of environmental stress on global food production. In particular, Brown (1) provides an evaluation of the present losses of grain caused by environmental degradation and also possibilities to increase its   production. The outcome of this study may best be summarized by his statement: “As we enter the nineties, the world has little to celebrate on the food front”.

This paper is restricted to a consideration of the changes in production of cereals, which represent about half of the human diet, and the production of which can be considered as the single best indicator of the health of agriculture and the nutritional status of whole populations (2). The availability of information about cereal production is also somewhat more extensive than for other food crops. In the less-developed countries most cereal products are used for human consumption while in the more-development countries about 50% in used as feed.


Agricultural production is affected in numerous ways by human-induced degradation on the environment. In Figure 2 an attempt has been made to identify the most severe environmental stresses, which either directly or indirectly have an impact on the food-support system.

Figura 2

Greenhouse-gas Induced Climatic Change

Give the estimation of emissions and atmospheric concentration of the mayor greenhouse gases, current climate models can project temperature on a continental scale with reasonable accuracy. It must be recognized, however, that predictions on a sub-continental scale (regional prediction) cannot be considered reliable, and that precipitation changes are particularly uncertain. Nor can it be expected that a substantial improvement in these limited area forecast can be achieved in the near future. Nevertheless, based on recent studies, some conclusions about the possible impacts of a climatic change on agriculture have been drawn by the Intergovernmental Panel on Climatic Change (3).

-          If global warming is at the upper end of the range projected (1.5-4.5°C for a doubling of CO2), the impact on agriculture may be serious.
-          An increased variability of the climate is likely to be more serious than a slowly changing climate. This may, for example, lead to an increased frequency of droughts and flooding.
-          Agriculture in arid and semiarid areas (particularly in Africa and Asia) are likely to be most vulnerable due to expected enhanced water scarcity.
-          At higher latitudes where the warming is projected to be most pronounced, the agricultural production can be expected to increase. This potential may, however, be reduced due to increased damage by agricultural pests and diseases.
-          An increased atmospheric concentration of carbon dioxide will undoubtedly enhance plant growth. It is at present far from clear, however, to what extent this direct fertilization effect is dependent on other factors which are critical in determining the net effect of increased CO2, e.g., nutrient limitation and water shortage.
-          The existing agricultural system can, to some extent, be adapted to climate change through, for example, changes in land use (farmed area, crop type, and location) and changes in management. Other possibilities include the development of more heat and drought tolerant crop (4)

On the whole, in can be concluded that the advantages of warming at higher latitudes would not compensate for reduced potential in current major cereal-producing regions in mid-latitudes (5). The Second World Climate Conference Task Group on Agriculture (6), estimated that the overall effects of climatic change and CO2, fertilization effect on the net global food-production potential, range from +10% to -20%.


Comparatively large-scale migrations have occurred in the past, due to various causes. In some instances, initiated through unfortunate circumstances; e.g. repeated harvest failures and agricultural crises, political instabilities leading to armed conflicts.

 In other cases, the causes have been more complex, and have involved several interactive driving forces of a socioeconomic and political nature.

In Figure 3 one particular type of cause-effect chain is indicated. Here, the major driving force is rapid population increase in combination with limited capacity for food production. This can lead to environmental degradation and a further reduction in food availability and in turn, may generate social unrest and migration and thereby cause national and international conflicts. The process may also be initiated at other stages and be further amplified though feedback processes.

Figura 3

Returning now to the question of the risk of occurrence of large-scale migrations due to food shortage within the next few decades. A definite and conclusive answer can clearly not be given. However, taking into account the very pessimistic prospects for increasing food production at the same rate as world population growth, and that this is particularly pronounced in certain large-scale (sub-continental) regions, provides a very definite indication that they are likely to occur.

The problem we are concerned with is thus not so much to judge whether or not there will be mass migrations, but rather to examine the possibilities of predicting where and when they are likely to occur, and what their magnitude might be. However that would be to go beyond our present knowledge about the dynamics of large-scale migration and the availability of the data required. At present to models exist which could provide reliable answers to such detailed questions, and in view of the many interactive factors involved, it is not likely that the situation will change  in the near future. In the absence of such tools, we have to accept the only very tentative and simplified answers can be given to these questions.

-          The assumption is that the regions from which major outflows can be expected are those where rapid population growth coincides with low food production and insufficient food purchasing power., i.e., regions with criterion only, some comparatively extensive regions have been identified  (S. Öberg , The People´ Museum, Stockholm, unpubl.) that could be particularly vulnerable. Figura 4.

Figura 4

-          An additional criterion in identifying vulnerable region is the expected scarcity of water. By applying this criterion, vulnerability to food shortage and emigration can be enhanced, particularly in North-and West Africa, and western Asia.

-          Predictions of future number of undernourished people, which according to the United Nations World Food Council were  512 million in 1983 -1985 (2), can be made with some degree of accuracy. However, estimates of the outflow of people from the regions which suffer most severely from food shortages are considerably more difficult to make. Considering rapid population growth in these areas, the growth rate may be several million per year in the early part of the next century.

-          Extensive migration may also be caused by a climate-change-induced sea-level rise which will affect low-lying agricultural coastal areas. Particularly sensitive will be areas in East Asia where much of the fertile land is near sea level, e.g., in Bangladesh and Indonesia.

-          The trajectories of migration are expected in general to be from less-developed countries (LDCs) to more-developed countries (MDCs) i.e., from South to North, although also from East to West and from South to South (17). For example, migration in Africa, which has mainly been of a comparatively short-range nature can in the future be expected to be directed towards Europe and be massive dimensions. Migrations from western and southern Asia are also likely to be mainly in the direction of Europe.

-          What is most difficult to predict are the possibilities the migrants may have of reaching their destinations. The more-developed countries can be expected to be increasingly determined to resist immigrations, as is reflected in stricter immigration policies. How effective the receiving countries will be in enforcing these policies remain to be seen.


The aim of this paper has not been to find accurate and conclusive answers to the three basic questions presented in the introduction. The consequences of the ongoing degradation of the global environment have instead been somewhat underestimated. Nevertheless, the results obtained suggest that this development may lead to a decline in the capacity of global food-production system to feed the rapidly growing world population, and this in turn may lead to mass migrations directed from the less-developed to more-developed countries within the next few decades.

Even if such a projection cannot be considered to be perfectly convincing, the very fact that such a development can not be excluded indicates the need to carry out a more detailed and refined assessment. This would require a dedicated multidisciplinary research program involving physical, biological, socioeconomic and political sciences. In view of the complexity of the processes involved, this type of prediction has a wide range of uncertainty, and is more probabilistic than quantitative prediction. However, this does not imply that our existing knowledge can not form the basis for decisive actions to reduce environmental degradation; to improve land productivity; and for the development of a global strategy aimed at reducing the number of undernourished people in the world. This action could reduce the risk for an escalation of the occurrence of famines and hunger-driven migrations.  

Professor Bo R. Döös was professor of meteorology at the University of Stockholm until 1970. He was deputy director of the International Institute for Applied System Analysis and leader of its Environmental Program between 1988-1992. 1971-1982 Director of the Join WMO/ICSU Planning Staff for the Global Atmosphere Research Programme. 1980-1982 Director of the WMO/UNEP/ICSU World Climate Research Programme in Genova (World Meteorogical Organization/UN Environmental Programme). 1982-1986 Manager of the UNEP/WMO/ICSU international assessment of greenhouse-gas problems and the associated impacts on natural and managed ecosystems. 1986-1988 Visiting scientist at the US National Climate Program, Washington, DC, responsible for the development of a US five-year National Climate Program 1989-1993. He is currently scholar of the international Institute for Applied Systems Analysis. Between 1971 and 1988 Professor Döös held top executive positions with several International organizations. His address: Jordangasse 7/13, A-11010 Vienna, Austria.

(1) Brown, I.R. 1990 Feeling the World in the Nineties in Sustainable Development, Science and Policy. The Norwegian Research Council for Science and the Humanities, Norway, 579 p.
(2) World Resources Institute. 1990. World Resources 1990-91: A guide to the Global Environment. Washington, DC, USA, 383 P.
(3) Intergovernmental Panel on Climatic Change (IPCC). 1992. The 1992 IPCC Supplement. World Meteorological Organization and United Nations Environment Programme, 70 p.
(4)Parry, M. 1990. Climate Change and World Agriculture. Earthscan Publications Ltd., London. 157  p.
(5) Parry, M. and Zhang Jiachen. 1991. The Potential effect of climate change on agriculture. In: Climate Change: Science, Impact and Policy. Jäger, J. and Ferguson, H.L. (eds). Proceedings of the Second World Climate Conference, Cambrdge University Press, UK, 578 P.
(6) The Second World Climate Conference, October 1990. 1991. Climate Change: Science, Impacts and Policy, Proceedings of the Second World Climate Conference, Cambridge University Press, UK, 578 p.
(17) Döös, B.R. 1992. How critical is the state of the global environment. In: Proceedings of the International Conference on Environmental Cooperation in Europe. Austrian Institute for International Affaires, Luxenburg, Austria.



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