Measuring the unmeasurable



Measuring the unmeasurable



ARTHUR LYON DAHL

examines different forms of sustainability and proposes a way of tracking progress towards them





Sustainable development has become the catchword of our decade, used and misused in many contexts. Yet it has been notoriously difficult to define. It implies a central focus on people. Our society, of course, functions in a natural environment. But we are seeking the sustainability of human society as it depends on, and intimately interrelates with, natural systems. This may be seen as anthropocentric but, in the present context of the international debate on development and equity, any other approach could be considered morally indefensible.



The concept of sustainability

In a dynamic system like human society, sustainability is fundamentally a question of balance, maintained over time. It thus cannot easily be scaled and measured, since it is a quality of motion rather than a fixed point. It may be more easily defined, in practice, as the lack of forces tending to upset an equilibrium over time. This is why most indicators are in fact measures of unsustainability, of the amount or extent of imbalances. As with a moving pendulum or an aircraft in flight, many different forces can act simultaneously to disturb an equilibrium; if one is reduced or eliminated, others become predominant. Sustainability can only be achieved when all forces upsetting the balance are removed.

Being dynamic, sustainability includes such characteristics as the speed or rate of change, the size of the mass involved in the change and thus the inertia of the process, and the significance of the amount and rate of change relative to the initial and resulting states. For instance, when determining the sustainability of a renewable resource harvest, it would be important to know the amount harvested, at what rate, over a given period, relative to the total stock of the resource at the beginning and end of the period, and the simultaneous rate of resource regeneration.

In any community or economic system, there can be many sources of unsustainability, such as the limited size of a resource, inadequate supply inputs, excessive demand for outputs, and damaging pressures such as pollution. Some of these may be controllable within the system, while others are subject to outside pressures. Since most systems are complex and not well understood, cause and effect relationships are not always apparent. The challenge is to find simple ways of presenting this concept despite the complexity and uncertainty.

While planners and politicians tend to look only five years ahead - and see the long term as 20 years - it would seem reasonable in the context of global systems and resources to view sustainability as stretching into the indefinite future - say, up to half a million years - as a time span over which our actions should not constrain future society. This would help to avoid the tendency to discount the long-term future, and would require adequate consideration to be given to fundamental, if gradual, processes of global balance and change.



The dimensions of sustainability

There are as many potential dimensions to sustainability as there are important dimensions of any human society. Accountants think in terms of fiscal sustainability, where deposits plus interest must balance withdrawals plus charges. A financial debt is a constraint imposed on future ability to meet needs; it is unsustainable to the extent that the present advantage procured is insufficient to reimburse the debt. Economists have a slightly broader view of sustainability which includes the maintenance of assets and capital value and productivity through investments at least equal to depreciation.

There is much concern over the ecological sustainability of human development, with population growth and resource consumption drawing down stocks of natural resources and their renewable potential, while increasing wastes damage natural systems and upset essential life-support processes. We are accumulating resource and pollution debts that can only be eliminated through extensive future investments. Many ecological processes are so complex and so poorly understood that it will be very difficult to derive indicators of ecological sustainability: at best we can use indicators of unsustainable pressures and impacts which should be minimized in a precautionary approach.

While there are now some indicators of human development, we have not yet really touched on what might be called human sustainability. People need education and training to develop their potential to become productive members of society. This is an investment like any other, and the poverty that results from the failure to make it is just as much a debt as a financial one, representing a burden of wasted potential weighing on the future. Since life-spans are limited, educational investment in individuals is ultimately depreciated and lost. Human sustainability thus includes the educational and cultural processes that preserve human knowledge and ensures its transmission between generations. Can we indicate whether a generation knows more than a preceding one? Scientific and technological knowledge may be increasing, but other kinds of knowledge and experience are being lost.

Dimensions that could be referred to as social sustainability may be just as crucial to what we should define as development, but have largely escaped existing systems of measurement and accountability. A developed society, for instance, has an elaborate legal system, built up over generations of legislative additions and judicial interpretations. This is also an investment in what should be considered an important part of national wealth, if only judged by its replacement value. Yet societies change and laws are dynamic. Can we measure how well a legal system is meeting social needs? Communities are structured into institutions ranging from government bodies through corporations to informal associations and religious organizations. Do we have measures of the effectiveness of this social structuring, its processes of communications and decision-making, and their evolution over time? Is social cohesion increasing or diminishing?

This could be extended to moral, ethical or spiritual sustainability. An effective society depends on a shared set of values or ethical principles that define acceptable behaviour, and motivate people to work together in the common interest. As the basic rules for human interaction, these are an essential support to development. A society that is losing its moral core may appear materially successful before declining into anarchy. In theory, at least, this should be included in a broad concept of the sustainability of human society, even if the practical problems of developing indicators are daunting.



The temporal dimension

Any comprehensive approach to indicators for sustainable development must include both new kinds of indicators and new ways of accounting for sustainability over time. Any measure of balance cannot look only at the static situation at one moment, but must examine measures integrated over time to document processes and trends. Such accounts should include past trends leading up to the present, and projections of what will be needed to achieve or maintain sustainability in the future. Present economic balance sheets are thus doubly flawed: they exclude many capital stocks and flows as externalities, and they are not adequately summed over time, particularly with respect to future implications of the current situation.

Nothing is permanent on this planet. Wealth is created and destroyed; energy is degraded; materials are concentrated and dispersed; useful information is increased and lost; things wear out; objects and materials have a useful life and then become wastes; old technologies are replaced by new ones. Aging and death are as much part of life as reproduction and growth. Sustainability requires accounting for all this over time. For the ultimate balance to be sustainable, the processes of maintenance, replacement and renewal must equal or exceed the process of depreciation, degradation and loss.

We cannot automatically assume that capital replacement will take place. This requires investment, and may have preconditions which have to be taken into account. We can make some reasonable assumptions for people now alive - disallowing the possibility of cataclysm - but can we be so certain about future birth rates? What, for instance, if some common pollutant caused widespread sterilization? Can we assume the maintenance of agricultural productivity if soils are eroding, new diseases are evolving, the genetic resource base is shrinking or being privatized, and research is declining, so that the necessary investments to maintain productive potential are not being made? Industry may invest in a factory with a 30 year productive life, over which its depreciation is calculated and its potential profits determined - but if a new technology makes the product obsolete in five years, 25 years of investment will be lost.

Any accounting system for sustainability must be able to spot failures to reinvest, damage to future productive potential, and the resulting impact on integrated total productivity over time. This requires accounts that show all existing investments, capital stocks and productive capacity, and the present rate of production (often well below the peak capacity). They should incorporate projected depreciation, and necessary investments for maintenance, renewal or replacement. Technological innovation and its impact must be modelled, insofar as there are rational bases for predicting it. An integrated accounting methodology should try to take into account all significant interactions, such as damage caused by one activity (say pollution from industry) on another (like agricultural production). It should include available skills and knowledge, and their replacement as generations change.

Such integrated accounting over time should help to eliminate unrealistic assumptions about the future, by incorporating the real dynamics of possible rates of change and the capacities of such systems and resources as water, primary productivity, available land area, and population size and density. Energy throughput, from both renewable and non-renewable sources, will be one critical factor. The sum of the dynamic indicators for the movements over time of all these dimensions of our total accounts will begin to define real sustainability.

On this basis, some industrialized, 'developed' countries may show frighteningly unsustainable accounts, demonstrating that their prosperity is based on heavy borrowing from future potential, or relying on highly optimistic assumptions about technological replacements which will require difficult and expensive industrial and social transitions.



Beyond sustainability to sustainable development

We will need to distinguish between various kinds of economic activity and the wealth they create if we are to begin to address sustainable development. We need measures of what might be called real or 'strong' development, as compared to simple economic activity or gross national product (GNP). Transfers or redistributions from one account or place to another do not themselves create wealth: they may represent equal exchanges, or increasing wealth compensated by a corresponding increase in poverty. Harvesting bananas cheaply in Central America and delivering them to a European table may raise their price, but does not really generate wealth: the price increase just reflects the transport, storage, middle-man costs and increased profit margin. The intrinsic value of the bananas for nutrition is the same; only the scarcity and willingness/ability to pay have changed with the location. Real value added comes from primary productivity or from transformation or processing to add functionality, utility, durability, or other kinds of information content. To determine real value, every cost and input should be accounted for, and hidden subsidies in production should be avoided.

Maintaining capital is also neither wealth creation nor real development - but running in order to stand still. One does not become wealthier by replacing a leaking roof, filling potholes in the street, washing dishes, cleaning up pollution, or buying a replacement vehicle. Real development is when new value is added by innovation or creation, the quality of life is increased, or a larger net mass of goods and services is produced and maintained, after all the costs of production and depreciation have been subtracted. This will probably be both a much lower percentage, and involve different kinds of growth, than that measured using today's GNP indicators.

This net approach to growth may have important implications for national interest rates and thus for calculations of sustainability. The real rate of interest on capital should probably not exceed the real rate of creative wealth it generates. Most of what goes into today's interest rates and rates of return on investments are 'growth opportunities' that either compensate for inflation or represent hidden resource transfers and subsidies produced by failures in true accounting. They come, for instance, from treating natural capital resources as externalities or from exploiting poorer countries or social groups.

The present economic system of accounting and indicators has produced a financial system which manufactures money as a commodity, through credit mechanisms that allow cumulative borrowing and reborrowing, aided by banking and accounting delays and manipulations. As money circulates, particularly through electronic accounts, it multiplies by the play of interest rates and layer upon layer of debts in more and more compartments of the system: government debt, corporate debt, consumer debt, resource debts, etc. Does the present system of accounts add up all those debts across the whole society and place them against net assets valued over time? Does it identify real wealth creation, investment and maintenance rates as compared to debt, depreciation and resource draw-down rates? Are there indicators for all the key components in this process? Complex issues like these must be faced if indicator systems are to approach the real nature of sustainable development.



The varieties of sustainable development

Some developing countries and cultures suspect that environmental and sustainable development indicators will be used to force Western values on them or to impose conditionality. This is aggravated because indicators of sustainability need to be evaluated against some target or limit. Yet setting these involves value judgments that are inherently culture-bound. If they are to be relevant worldwide, indicators of sustainability must be designed to have sufficient flexibility to measure common themes, dimensions or trends while remaining universally culturally appropriate. They should be capable of covering the full spectrum from the 'superpowers' to the small island developing states, from indigenous subsistence to postindustrial communities, from high-tech to no-tech situations.

There may be an objective scientific basis for setting targets or limits for environmental indicators, such as the level of pollution causing health effects, the reduction in chlorinated compounds necessary to protect the ozone layer, or the amount of forest cover needed to maintain a particular level of water flow in a catchment. At least science can define a gradient of environmental quality along which each society can set its appropriate limit. However, limits or targets are much more value laden on the social and economic side: indicators cannot be absolute but must relate to each society's concepts, goals and values. They can only be decided within a country or culture, preferably on the basis of wide consultation and participation. Thus the concept of international performance indicators for sustainable development is, at least at present, politically unacceptable. States do not want anyone else judging their performance or the way they define development, and they want to choose how to report their progress.



Indicating sustainability

One way to express the concept of sustainability without falling into value judgments about development would be to produce 'vector' indicators, showing the direction and speed of movement toward or away from a goal. These would allow each country to define how it imagines its ideal future sustainable society (an instructive exercise in itself), and then to report, for each indicator, whether it is making progress towards its own goal, and at what rate. A country could, for instance, determine its optimal population, calculate the growth curve necessary to stabilize numbers at that level, and then measure the deviation of its actual population curve from that needed to reach its target. A policy maker could thus see immediately whether the trend was in the right direction, and how long it would take to achieve the desired result. The national goals or targets so set would need to be flexible and subject to change as technological possibilities, new discoveries and social visions changed. Vector measures would also allow countries to report progress in reducing damaging activities, even if they had not yet defined clear goals for sustainability.

The concept of sustainability as a process of balance can also help to determine the relative weight given to different indicators. Indicator values can be ranged on a non-linear scale, where more extreme problems or larger deviations from the desirable level carry more weight than small ones. This weighting should be calculated according to the specific characteristics of each phenomenon (indicators diagrams). A pollution indicator might have no significance at low concentrations, might rise somewhat as moderate levels affected amenity values, and then increase sharply as the pollutant harmed health at high concentrations. Similarly, depleting the first 5 per cent of a resource may have little significance, while depleting the last 5 per cent may have enormous impact. There may be an optimum indicator level, with deviations in either direction becoming increasingly harmful. One extreme problem may be much more threatening to sustainability than many minor ones. Using such non-linear scaling can facilitate rational aggregation of indicators by providing a more objective criterion for relative weighting than an arbitrary combination or equal treatment. Each indicator, in effect, weighs itself according to the significance of its impact.

We should try to develop standard graphic forms to plot indicators of sustainability. Several characteristics need to be incorporated into such plots to illustrate how the idea of sustainability can be communicated (see trajectories, right).

First, the particular target that has been set locally should be combined with a projection of the planned or preferred trajectory of the indicator to reach it at the agreed time. If this trajectory to sustainability is agreed in the planning process, it will help decision makers to visualize the commitment they are making and the effort needed to achieve their goal. It will then be possible to plot the deviation of the actual situation or location of the indicator relative to the projected level or trajectory. This could be a deviation both in the value of the indicator (above or below the target) and in its vector - whether it is moving in the right or the wrong direction, and at what speed. It is the direction and speed of the indicator vector as well as its location that really begin to define sustainability as a dynamic concept. They should be scaled or weighted in value according to the importance of the deviation. The critical points in these trajectories that will be of the greatest interest to policy makers, are the points where the indicator vector is changing (whether it is slowing down, speeding up, changing direction), as it is these changes that signal the effectiveness of whatever actions have been taken. Such trajectories and their vectors quickly show if management actions are sufficient.

Standard ways of expressing sustainability indicators should be agreed as far as possible, to make them easily understandable and widely recognizable. They could be developed not only as numbers and graphic representations, but also on scales and even colour codes. Indicators could be scaled as a percentage ranging from 100 for full sustainability to 0 for total unsustainability or collapse. Another measure could be the number of years to achieve sustainability (for positive trends) or absolute unsustainability (for negative ones). A colour scale could range from white for full sustainability through yellow and green for improvement and violet and red for degradation to black for collapse. Arrows or other symbols could communicate vector indicators. Sustainability may be a complex concept, but its indicators could still have a direct meaning for everyone.

Indicators of sustainable development are being pushed by political demand despite the hesitancy of experts and scholars to tackle questions that involve human values and political processes as much as or more than specific methodologies. We must rise to the challenge and work to develop indicators that can themselves become the driving forces towards a truly sustainable society.


Arthur Lyon Dahl is UNEP's Deputy Assistant Executive Director, Environmental Information and Assessment.


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