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close this bookEco-restructuring: Implications for Sustainable Development (UNU, 1998, 417 p.)
close this folder1. Eco-restructuring: The transition to an ecologically sustainable economy
View the document(introduction...)
View the documentIntroduction: On sustainability
View the documentThe need for holistic systems analysis
View the documentEnvironmental threats and (un)sustainability indicators
View the documentSharpening the debate
View the documentNon-controversial issues: Population, resources, and technology
Open this folder and view contentsControversial issues: Pollution, productivity, and biospheric stability
View the documentFinding the least-cost (least-pain) path
View the documentConcluding comments
View the documentNotes
View the documentReferences

Non-controversial issues: Population, resources, and technology

There has been, and still is, great controversy as regards the essentiality (non-substitutability) of certain environmental resources. However, the controversy is largely over definitions and details, not fundamentals. Possibly this confusion has arisen because the issues were not formulated sharply enough, until recently. I think there is a reasonable consensus among experts on the fact that some environmental services are essential to long-run human survival on this planet. The existence of "critical" environmental resources is not seriously doubted by most people. The doubters are mostly conservative libertarians with a deep faith in the ability of markets to allocate scarce resources and to call forth technological (or other) substitutes in response to any perceived scarcity.

The weakness of this position is that markets for environmental services are virtually non-existent. Markets must function through price signals. Clearly we need food, sunshine, clean air, and fresh water. We also need the waste disposal services of bacteria, fungi, and insects. All are, at bottom, gifts of nature. Because they are not "commodities" that can be owned and possessed or physically exchanged, they have no prices. Moreover, since these services are not produced by human activity, price signals could not induce an increase in the supply. What is still doubted by many scientists, on the other hand, is the answer to the second half of the question: whether or not these essential environmental resources are truly vulnerable to human interference and possibly subject to irreversible damage.

One example of an essential environmental resource that appears to be subject to irreversible damage is the ozone layer of the stratosphere. The cause of damage, it is now agreed, is atomic chlorine, which originates from the inert chlorofluorocarbons (CFCs) that do not break down in the lower atmosphere and gradually diffuse into the stratosphere where they are broken up by high-energy ultraviolet radiation (UV-B). The chlorine atoms, in turn, react with and destroy ozone molecules, thus depleting the protective ozone layer. This phenomenon was very controversial 20 years ago, but the controversy has largely subsided, thanks to the discovery of annual "ozone holes" in the polar stratosphere, which were first seen in the mid-1980s.

Another example of increasing consensus concerns climate change. The climate is certainly an environmental resource. Even a decade ago there were still a number of scientists expressing serious doubts about whether the problem was "real." The major source of doubt had to do with the reliability of the large-scale general circulation models of the atmosphere that had to be used to forecast the temperature effects of a build-up of greenhouse gases (e.g. carbon dioxide, methane, nitrous oxide, CFCs). Since then, the models have been improved significantly and it has been established fairly definitely that climate warming has been "masked" up to now by a parallel build-up in the atmosphere of sulphate aerosol particles (due to sulphur dioxide emissions), which reflect solar heat and cool the earth. The two effects have tended to compensate for each other. However, the greenhouse gases are accumulating (they have long lifetimes) whereas the sulphate aerosols are quickly washed out by rain. In other words, the greenhouse gas concentration will continue to increase geometrically, whereas the sulphate problem may increase only arithmetically or not at all (if sulphur dioxide emissions are controlled). In any case, the Intergovernmental Panel on Climate Change (IPCC) has now agreed that the greenhouse problem is indeed "real." The controversy continues, however, with regard to likely economic damage and optimal policy responses.

There is already a near-consensus among experts that continued human population growth is not consistent with long-run sustainability (question 2.1) and that some natural resources must eventually be depleted (question 2.2). On the other hand, there is less agreement about whether or not increasing waste and pollution would constitute a limit on growth (question 2.3) or whether or not the balanced natural systems such as the carbon, nitrogen, and sulphur cycles are at risk (question 2.4).

The unacceptability of continued population growth (question 2.1) is a matter on which there is reasonably wide consensus. Malthus foresaw that population growth would eventually outrun the carrying capacity of the earth. Colonization of new lands in the western hemisphere, together with dramatic improvements in agricultural technology, forestalled the crisis for two centuries. Some conservative economists regard this as sufficient evidence that "Malthus was wrong" and that today's neo-Malthusians are unnecessarily alarmist. Nevertheless, the alarm has been raised once again, perhaps on better grounds: there are no more "new lands" waiting for cultivation, and the potential increases in yield available from fertilizers and plant breeding have already been largely exhausted.

Technological optimists - notably Herman Kahn and his colleagues (Kahn et al. 1976) - have unhesitatingly projected that early twentieth-century rates of increase in agricultural productivity can and will continue into the indefinite future. However, agricultural experts are much less sanguine. The potential gains from further uses of chemicals by traditional methods are definitely limited. Ground water is already becoming seriously depleted and/or contaminated in many regions of the United States and Western Europe, where intensive irrigation cum chemical agriculture have been practiced for a few decades. Such problems are now also becoming acute in places such as northern China. Over a decade ago Bernard Gilland wrote:

Since the onset of the rapid rise in the world population growth rate over 30 years ago, there has been speculation on the human carrying capacity of the planet. Most writers on the problem either hold, on technological grounds, that the Earth can support several (or even many) times its present population, or warn, on ecological grounds, that the Earth is already overpopulated and that human numbers should be reduced. I shall try to show that neither of these views is realistic, and that a plausible assessment of carrying capacity leads to the view that the world is not yet overpopulated but will be so in the second decade of the twenty-first century, when the population will be 60 percent larger than at present. (Gilland 1983, p. 203)

Gilland went on to conclude:

Estimates for global carrying capacity and long-range demographic projections are admittedly subject to wide margins of error, but the consequences of relying on an excessively optimistic assessment of the future population food supply balance would be so serious that a conservative assessment is justified. (Ibid., p. 209)

Admittedly, Gilland's assessment was based on conventional agriculture using land now classified as "arable." Julian Simon argued that this is not a fixed quantity, and that so-called arable land had actually been increasing at a rate of about 0.7 per cent per annum (from 1960 to 1974) (Simon 1980, p. 1432). This is one of the reasons food shortages projected earlier did not occur. But most of the "new" cropland was formerly tropical forest (the rest was grassland, such as, for instance, the vast and ill-conceived "new lands" projects of Soviet central Asia). Deforestation has now become an acute problem throughout the tropics, and most tropical forest soils are not very fertile to begin with and are rapidly exhausted of their nutrients by cropping. There is no basis for supposing that the amount of arable land can continue to increase much longer, if indeed it has not begun to decrease already for the reasons noted above. In any case, erosion and salination are taking a constant toll of the lands already in production.

With regard to the possibility of continuing to increase the productivity (yield) of existing arable land, there is a continuing push to develop improved varieties and higher photosynthetic efficiencies. Biotechnology is now beginning to be harnessed to increase food production. There is optimistic talk of a "second green revolution." For some years past, global grain production per capita has actually been declining. Thus, incremental improvements will be needed just to keep up with population growth.

Gilland also did not take into account several theoretical possibilities, including such "high-tech" schemes as genetically engineered bacteria capable of digestion of cellulose or crude oil, large-scale hydroponics, and massive irrigation of tropical deserts such as the Sahara using desalinated sea water. Certainly, these possibilities must be taken seriously, and some of them may play an important role before the end of the twenty-first century. On the other hand, there is no chance that any of them could make a difference within the next 20 or 30 years. In short, there are strong indications that agricultural technology cannot continue to outpace population growth in the third world for more than another few decades. For these reasons, the majority of demographers, and most economists, now take it for granted that population growth must be brought to an end as soon as possible if sustainability is to be achieved (e.g. Keyfitz 1990, 1991).

As regards concerns about resource exhaustion (question 2.2), the "neo-Malthusian" position was taken very seriously by some alarmists, such as Paul Ehrlich, in the 1970s. The argument was made that economic growth is inherently restricted by the limited availability of exhaustible natural resources (e.g. Meadows et al. 1972). However, it is now widely agreed among both economists and physical scientists that energy or mineral resource scarcity is not likely to be a growth limiting factor, at least for the next half-century or so. The Malthusian "limits to growth" position adopted by some environmentalists in the 1960s and 1970s has been largely discredited, both by empirical research (e.g. Barnett and Morse 1962; Barnett 1979) and by many theorists. The main reason for the change of perspective is that the neo-Malthusian view was naive in two respects.

First, the neo-Malthusians neglected the fact (well known to the fuel and mineral industries) that there is no incentive for a mining or drilling enterprise to search for new resources as long as it has reserves for 30 years or so. This is a simple consequence of discounting behaviour. It explains why "known reserves" of many resources tend to hover around 20-30 years of current demand, despite continuously rising demand. Secondly, they gave too little credit to the power of market-driven economies to call forth technological alternatives to emergent scarcities (e.g. Cole et al. 1973; Goeller and Weinberg 1976). However, as it turns out, it is overused "renewable" resources, such as arable land, fish, fresh water, forests, biodiversity, and climate, that are more likely to be limiting factors.

The existence of feasible strategies to achieve population stability (question 3.1) is now generally accepted. The subsidiary question of the most appropriate means remains murky. This optimism is based partly on evidence of a slow-down in global population growth in recent decades. However it is admittedly unclear whether the observed slow-down (mostly in China, so far) can be extrapolated to other countries, particularly in the Muslim world. Still, the majority of experts seem to believe that the required "demographic transition" is economically and institutionally feasible, in principle. Here the central problem is seen to be to achieve near-universal literacy, equal rights and legal standing for women, a social security net for the poor, and real economic growth to finance all of this, at a rate fast enough to reach that "middle-class" standard within a few generations.6

Demographers and social scientists generally agree that these are the preconditions for radically reduced birth rates. A few years ago Jessica Matthews of the World Resources Institute (WRI) had the following comment:

The answer is emphatically that there is a realistic path to global population control. The demographers measure what they call unmet needs for contraceptives. That's the place where action has to begin - with women and couples who express a desire to use contraceptives, but who currently have no access to them. The cost is about $10 per couple per year. The need is several times world spending on contraception - a trivial, almost infinitesimal sum, compared to defense spending. I dare say it would probably be covered by the cost of one B-2 bomber, about $500 million.... The second most important realistic, feasible, direct intervention is through women's education. For reasons that are not entirely understood, even primary school education makes a huge difference in women's fertility rates. Therefore education of women in developing countries, and expansion of that opportunity, will have a huge effect. (Matthews 1990, pp. 27-28)

The 1994 Cairo Conference on Population and the Status of Women echoed most of Matthews' themes. Although there were passionate objections to the conference itself, and to the manifesto signed by most attendees, they scarcely challenged the cause-effect relationships set forth by Matthews. On these issues, there is a wide consensus among experts. The most passionate debates with regard to population policy centre on moral (and, of course, political) questions of methods of birth control and, especially, the legitimacy of abortion. These arguments are not within the realm of science or scientific debate.