Consumption : the other side of population for development *

World population is growing at an alarming rate, and thus population has become a major topic in sustainable development fora. In these debates, it is often asserted that developing countries with large populations pose a greater world environmental threat than developed countries with smaller populations. Because of this view, developed countries often appeal to developing countries to reduce their population growth. However, it is well known that developed countries have higher levels of consumption than developing countries and that consumption also exerts pressure on the environment. Although awareness of the importance of consumption for development and the recognition of the relationship between population and consumption are increasing, population still takes precedence over consumption as a major concern for sustainability. Our objective here is to present the importance of consumption vis-à-vis population for development and to discuss their direct linkages. We draw on the work by Vallentyne (1978: Verh Int Verein Limnol 20:1–12; and 1982: Biol Int 5:10–12), and use his ‘demotechnic’ index to combine and inter-relate population and consumption. By doing so, we are able to adjust population by consumption, obtaining estimates that allow fair comparisons of countries in terms of their global environmental stress. The conclusions obtained from the estimates of population adjusted by consumption seriously question the assumption that countries with larger populations pose a greater environmental risk. Sustainable development is premised on a balance between population and consumption within the overall limits imposed by nature. Therefore, it becomes clear that not only population but also consumption have to be reduced if sustainability is to be achieved.


Extract of an Introduction to this paper
"The objective of the paper is to present the importance of consumption vis-à-vis population and development and to discuss their direct linkages.It draws on the Vallentyne 'demotechnic' index to combine and interrelate population and consumption, obtaining estimates which allow fair comparisons of countries in terms of their global environmental stress.
The conclusions obtained from these estimates of population adjusted by consumption seriously question the assumption that countries with larger populations pose a greater environmental risk.They show, for example, that the US and former USSR each with relatively low populations, have 'consumption adjusted populations' that dramatically surpass those of the more populated but less developed countries of China and India.Sustainable development … is premised on a balance between population and consumption within the overall limits imposed by nature.It has become clear … that not only population but also consumption have to be reduced if sustainability is to be achieved.What is needed … is rolling back consumption levels in the North and reducing population growth in the South." Sir Shridath Ramphal at the International Conference on Population & Development, Cairo, September 6, 1994 OPEN PEN ACCESS CCESS

INTRODUCTION
World population is growing at an alarming rate.According to projections by the United Nations, annual increments in the world population above 90 million persons are likely to occur until the year 2015.
This increase in the world population, added to the fact that we live on a finite planet with many nonrenewable resources, presents a pessimistic scenario for the future generations.Therefore, population has become a major topic of discussion in sustainable development fora.Although population is one important factor to achieve sustainability, consumption is another important factor that often tends to be disregarded altogether.However, the birth of a child in a developed country imposes more stress on the global environment than the birth of a child in a developing country because of differences in consumption patterns.Furthermore, population and consumption are interrelated.
The Rio Declaration 1992 (www.un.org/documents/ ga/conf151/aconf15126-1annex1.htm) and Agenda 21 1992 (www.un.org/esa/dsd/agenda21/index.shtml)recognize the importance of population and consumption for sustainable development.Agenda 21 in particular proposes (1) to incorporate demographic trends and factors in the global analysis of environment and development issues; (2) to promote patterns of consumption and production that reduce environmental stress and at the same time meet the basic needs of huma nity; and (3) to develop a better understanding of the role of consumption and how to bring about more sustainable consumption patterns.However, while the importance and implications of a growing population are well understood, the 'growing recognition of the importance of addressing consumption has not yet been matched by an understanding of its implications' (Agenda 21,Ch. 4,Sec. 4.6).Furthermore, in spite of the fact that the Rio Declaration and Agenda 21 acknowledge the relationship between population and consumption, no concrete proposals have yet been made on how to integrate these 2 development variables.
Population and consumption are also reflected in the International Conference on Population and Development (ICPD) Programme of Action (www.un.org/ecosocdev/geninfo/population/icpd.htm).However, there is an explicit predominance of population in its programme as expressed in the objective 'to fully integrate population concerns into development strategies, planning, decision-making and resource allocation at all levels and in all regions, with the goal of meeting the needs, and improving the quality of life, of present and future generations' (ICPD Programme of Action, Ch. 3, Sec.A).
If population dominates the development discussion, then it is natural to consider population as a valid sustainable development indicator.In this view, sustainability can be operationalized by limiting population below the carrying capacity of the Earth.The international action called for, then, is to induce countries to limit their populations (see ICPD Programme of Action, Ch. 6).
Sustainable development is based on the premise that population and per capita consumption operate within the ability of the ecosystem to carry the demand on resources and assimilate the wastes, indefinitely.Population effects vary widely due to vast regional differences in effects and sensitivities.While large populations exert considerable stress on their ecosystems, small populations with high rates of consumption can eclipse the effect of larger populations operating at lower rates of consumption.Sustainable development requires that both population and consumption be taken into account.Per capita consumption of energy may exceed many times the physiological energy requirements of humans (Vallentyne 1982).Other authors have also suggested that the consumption multiplier is an important part of the 'net effect' on environment and sustainability (Goodland et. al. 1994).The consumption factor and its ability to amplify even small populations are examined further in the present study.

INTEGRATING POPULATION AND CONSUMPTION
Humans not only exert pressure on the environment because of basic physiological needs for survival, but also due to their activities aimed at converting raw materials into products and services.Therefore, a measure of the stress of humans on the environment must reflect the needs of the physiological system as well as those of the technological system used for production and consumption.
In this regard, technology can be considered as an extension of human metabolism, and the requirements for this technology can be related to physiological needs.This argument provides the basis for calculating a 'consumption-adjusted population', which is obtained by adding to the existing population an equivalent number of individuals with energy demands for their physiological needs equivalent to the country's energy requirements for its technological system.This conversion is analogous to the use of 'horsepower' in inter-relating the power of horses and machines.The adjustment to the population is made by means of the demotechnic, or D-index (Vallentyne 1982), which is equal to the ratio of technological energy consumption to physiological energy consumption, expressed in the same units (see Appendix 1 for details on calculation).
Estimating the consumption of resources is extremely difficult, and thus energy consumption, al though imperfect, is the best available surrogate for consumption (Goodland et al. 1994).Therefore, we use the D-index to interrelate population and consumption.

POPULATION ADJUSTED BY CONSUMPTION
Table 1 presents the D-indexes, populations and consumption-adjusted populations for countries ordered in descending magnitude by D-index for 1990 (see the supplement at www.int-res.com/articles/suppl/e012p015_supp.pdf for this information ordered alphabetically by country).The Dindexes vary from 198.49 in Qatar to 0.39 in Comoros.Countries towards the top of the list use a higher proportion of energy for their technological system (production/consumption) as compared to the physiological needs of their inhabitants, revealing larger consumption patterns.This list is headed by countries in which energy is relatively cheap and financial resources are available.Developing countries, on the other hand, are at the bottom of this list.
Fig. 1 shows the national populations and consumption-adjusted populations in 1990.Clear differences between these 2 maps can be observed.The USA and the (former) USSR, each with relatively low  namely the use of resources to satisfy basic human needs.However, populations can vary in their demands for resources needed for production/consumption.A better indicator of global environmental stress is obtained by adjusting population by consumption.
The reduction of population has been the driving force in international events and negotiations re garding sustainable development.But population and consumption are 2 sides of the same coin.Sustainability is a function of scale.On a national level, population tends to be more important than consumption-adjusted population, whereas the reverse is true on a global level.Therefore, a reduction of population growth in developing countries and a reduction of consumption in developed countries are both needed to achieve sustainability.

Fig. 1 .
Fig. 1.Map of the world showing (A) population and (B) consumption adjusted population (CAP) by country

Table 1 .
Demotechnic (D-) indexes, population (in thousands), and consumption-adjusted population (CAP, in thousands) by country for 1990 ordered by D-index.Data are taken from the Human Development Report 1993 (http://hdr.undp.org/en/reports/global/hdr1993/)and the World Resources Data Base 1992-93 (now known as the World Resouces Institute [WRI] Earthtrends Data Base; http:// earthtrends.wri.org/searchable_db/index.php?theme=6&variable_ID=351&action=select_countries).The D-indexes for 1990 use population data for 1990 and energy data for 1989 due to the availability of published data at the time of preparation of the present study populations, have consumption-adjusted populations that dramatically surpass those of China and India.Similarly, Canada, with less than 4% of the population of India, has almost the same consumption-adjusted population as India.Table2presents the data for these 5 countries.Table3lists countries that have the greatest opportunities and responsibilities to lower the consumptionadjusted population of the Earth.

Table 3 .
Highest contributing countries according to consumption-adjusted population (CAP; in thousands) in 1990