Numeracy and Sustainability
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ETHICS IN SCIENCE AND ENVIRONMENTAL POLITICS 2003, 83–91 Published November 20 ESEP PAPER Numeracy and sustainability John Cairns, Jr.* Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA ABSTRACT: Sustainable use of the planet is based on the assumption that humankind can maintain conditions suitable for inhabiting the planet indefinitely. No robust evidence supports this assump- tion nor rejects it, and adequate evidence on this issue may not be available for centuries. Numeracy is the ability to use or understand numerical techniques of mathematics. Even if adequate numerical data were available, the important decisions humankind makes regarding sustainable use of the planet should not be guided by numerical information alone, such as economic numbers, but by eco- and sustainability ethics, which provide a values framework that indicates how the numbers should be used and interpreted. KEY WORDS: Sustainability · Numeracy · Eco-ethics · Sustainability ethics · Sustainable develop- ment Resale or republication not permitted without written consent of the publisher The trouble with our times is that the future is not what it used to be. Paul Valery INTRODUCTION and interpreted. The emphasis on severely limited numbers is a major weakness of the United Nations Sustainable use of the planet is based on the Commission on Environment and Development (1987) assumption that humankind has the right to alter the report, which focused on development (commonly planet so that human life can inhabit Earth indefinitely. regarded as synonymous with growth). Development In doing so, environmental conditions of the planet is just one metric valued by one species. Sustainability may be shifted so that they are optimal for one species, involves a variety of metrics for a complex, multivariate but not necessarily for all species or even a majority of living system called the interdependent web of life. species now alive. Clearly, humankind does not value Sustainability is the study of patterns involving all all life equally. Sustainability is based on the assump- forms of life and the conditions necessary for them to tion that acceptable environmental conditions can be flourish as a community. One can place an infinite maintained. The assumption has not been validated, value on human life and on other life forms as well. nor is it likely to be for centuries, if ever. Numeracy is One can place an infinite value on one’s own life but be the ability to use or understand numerical techniques willing to sacrifice it to protect one’s offspring. This of mathematics (a useful introduction is available in example illustrates that there can be more than one Bartlett 1994). However, the important decisions value for infinity. Sustainability involves a similar humankind makes should not be based on numbers, situation — humankind must place infinite value on even economic numbers, but rather on eco- and personal life, on the lives of its future generations, and sustainability ethics, which provide a values frame- on those of other life forms. Balancing these seemingly work that indicates how the numbers should be used incompatible values will never be fully achieved since *Email: [email protected] © Inter-Research 2003 · www.int-res.com 84 ESEP 2003:83–91 life consists of dynamic and stochastic events that will calculated by dividing the growth rate into 70. A 2 % frequently alter the factors affecting this precarious population growth rate per year (considered modest balance. Sustainability policies may be developed for these days) results in a doubling time of 35 years. An individual components (e.g. agriculture, transporta- island with a carrying capacity of 256 people would be tion, energy, communities, fisheries), but achieving in deep trouble with a single doubling. By ignoring sustainability will not be possible unless the policies simple numbers, humankind places itself at great risk. are integrated into a master policy and plan that does not adversely affect other components. Numeracy will be helpful in establishing component balancing. ECOLOGICAL FOOTPRINTS The average ecological footprint of a North Amer- USING AVAILABLE NUMERICAL DATA ican (essentially the amount of land that would be nec- essary to support a defined economy sustainably at its Numbers influencing sustainability are simple and current material standard of living) is 4 to 5 hectares straightforward but are either ignored or misunder- (Wackernagel & Rees 1996). At a 2 % annual human stood by policy makers and the general public. As a population growth rate, 8 to 10 hectares would be need consequence, unethical and unsustainable practices in 35 years to maintain the footprint size. On a finite and behaviors are termed ‘practical,’ ‘essential,’ ‘good planet, unrestrained exponential growth is idiocy! for the economy,’ ‘compassionate,’ and even ‘reli- The Netherlands (National Institute for Public gious.’ Arguably, the greatest threat to sustainability is Health and Environmental Protection 1992) has a the misinformation on the dangers of human popula- smaller ecological footprint (3.32 hectares per capita) tion growth (Bartlett 1998). As Bartlett (1998) notes, the than the US and Canada, but a standard of living more optimistic the prediction the greater the proba- above the average for the entire planet. However, even bility that the prediction is based on faulty arithmetic a small population growth rate can quickly reduce the or no arithmetic at all. The human population cannot available hectares per capita. At a 1 % annual human continue to grow exponentially and indefinitely on a population growth rate, the doubling time would be finite planet. The debate on population growth began approximately 70 years. The ecological footprint size over 200 years ago with Malthus’ (1798) insightful pub- would be reduced to 1.66 hectares per capita in the lication. At the root of this controversy is the denial of Netherlands (and consequently a much lower standard limits. Hardin (1993) provides a superb illustration of living) if the resource base remained constant. This (starting with a single lily pad of a specific size in a situation would result in halving the per capita pond of a specific size and a specific rate of increase) of resources if the resource base were not doubled. Obvi- how rapidly a limit can be reached when exponential ously, humankind cannot send the entire population growth occurs even when no problem is apparent at ‘surplus’ to other planets during the 70-year doubling present. This illustration could be applied to a popula- time. tion of any species on the planet — including humans. In stark contrast, the ecological footprint size in India When will the pond be covered with lily pads? Assum- is 0.38 hectares per capita (Wackernagel & Rees 1996). ing a daily doubling rate, the capacity will be reached Worse yet, the estimated footprint size of the average on the 30th day. However, the pond would only be half person in India in the bottom 50% of income earners is covered on the 29th day. Seeking new resources will roughly 0.2 hectares per capita (Wackernagel & Rees not avert reaching the limits since doubling the size of 1996). Thus, the present condition is already unsatis- the pond will only postpone saturation (i.e. reaching factory. If the global carrying capacity for humans is the capacity) for one day; quadrupling the size of the reached or exceeded on a finite planet, then consump- pond would only add two days. In short, all appears tion by the rich must be markedly reduced to shift well until the final doubling. After the 30th day, the lily resources to the poor or the latter will suffer or die. This pads produced would suffer seriously due to lack of problem is one of eco-ethics, although numerical data space. Clearly, other life forms in the pond would also provide useful information on how much needs to be suffer at this stage. Emotional reasons that could lead done once it is decided what to do. Living at higher to refusal to accept this reality for populations of densities reduces the ecological impact because it does humans may ultimately cost billions of lives. not require as much land for urban sprawl and, prop- This important issue of exponential growth can be erly managed, has a lower energy consumption. Wack- examined by anyone with a pocket calculator or a pen- ernagel & Rees (1996) provide an excellent illustration cil and a sheet of paper. For example, starting with one of comparative ecological footprint size for traveling of anything, ten doublings will produce the astonishing 5 km each work day — bicycles, approximately number of 512. An estimate of doubling time can be 122 square meters/capacity; buses approximately Cairns: Numeracy and sustainability 85 301 square meters/capacity, and automobiles; 1,442 pendent web of life, provide services upon which the square meters/capacity. In addition, food is also a survival of humankind and its economic system major factor that determines ecological footprint size. depend (e.g. Daily 1997). The combined value of these Brown (2000) estimates 1.1 billion hungry people on services has been estimated to be in excess of US $33 the planet. Since poverty and hunger are closely trillion per year (Costanza et al. 1997). The survival of related, it should be no surprise that the World Bank both humankind and its unique economic system (1997) estimates 1.3 billion people are living in poverty depend upon natural systems, yet human society is act- (defined as US $1.00/day or less). The precision of ing as if only the numbers related to economic systems these numbers is important, but, for this article, the are of primary importance. The two sets of numbers important issues are ethical. The numbers keep chang- are related. ing, but the ethical problems are constant. Brown (2001) notes that economists see the environ- The ethical question of resource distribution and ment as a subset of the human economy, and environ- allocation within the human species is of paramount mentalists see the human economy as a subset of the importance.