Sylvia Karlsson,Arthur Lyon Dahl, Reinette (Oonsie) Biggs, Ben J. E. ten Brink, Edgar Gutierrez-Espeleta, Mohd Nordin Hj. Hasan, Gregor Laumann, Bedrich Moldan,Ashbindu Singh, Joachim Spangenberg, and David Stanners
The concept of sustainability and its measurement with indicators may seem intuitively simple, but it is difficult to implement in practice. Over the past two decades some problems have been resolved and much progress made on others, but major challenges remain. This chapter summarizes the present conceptual challenges, illustrated by selected indicator approaches. The challenges are grouped in two clusters: measuring sustainability and sustainable development, and developing indicators through processes that ensure their universal applicability. These various conceptual challenges suggest future research agendas and approaches to indicator use.
Measuring Sustainability and Sustainable Development
The usefulness of any indicator intended to measure how sustainable (or unsustainable) the world is, or the progress society is making toward sustainable development, naturally depends on how these terms are defined. Although this was discussed briefly in chapter 1, it still provides the major conceptual challenges for indicator development. First, it is necessary to go beyond a sectoral approach to a system approach. Does sustainable development fit a linear model with three or four pillars? Are there alternative, system-based approaches to understanding and measuring sustainability? Second, the entity to be measured must be defined in temporal and spatial scales and related to some model for sustainable development. What does sustainability mean for a village, a country, or the planet? Over what time span should the world, its ecosystems, and humanity sustain themselves and in what form?
It has become common to consider sustainable development within a certain conceptual framework, and this also influences indicator development. In Agenda 21 and at the UN World Summit on Sustainable Development (WSSD), the international community refers to economic, social, and environmental dimensions or pillars of sustainable development (UNCED 1993; United Nations 2002). In some contexts a fourth institutional pillar is added, as in the framework for indicators adopted by the Commission on Sustainable Development (CSD).1 Alternatively, institutions are seen as providing the underlying enabling mechanism for effecting action and change in any of the pillars. Most of the present approaches to indicator development compile indicators for these pillars. There has been much progress in developing indicators within each pillar, and many such indicators are being implemented.2
Others prefer to see sustainable development as the interaction of the environmental and human systems in a two-part coupled framework (e.g., Prescott-Allen 2001). Many national and international bodies arrange their indicators in a "pressure-state-response framework" (sometimes expanded with "driving forces" and "impacts": DPSIR). Although this framework implies causal relationships between indicators, research has only recently begun to develop the data and models necessary to interrelate indicators in such a framework.3 Significant conceptual challenges remain even when we consider single indicators (and further challenges for aggregated indices). For example, there is limited understanding of how the complex properties of the social dimension reinforce or obstruct sustainable social development. Concepts such as social capital are emerging as aspects relevant to social cohesion but have not yet been captured in indicators, and more work is needed to evaluate their usefulness. There are similar challenges in the institutional pillar, as indicated by the very few institutional indicators included in the CSD list (UN Division for Sustainable Development 2001). Economic indicators are well established but do not include measures of long-term sustainability in the economic system.
All these approaches are limited in that they address isolated elements of sustain-ability. Sustainability and sustainable development are characteristics of integrated systems with multiple linkages, feedback loops, and interdependencies. Although political approaches to sustainable development often are narrowly sectoral, with little focus on integration in practice, decision makers are increasingly asking for indicators to help build mutually reinforcing links between pillars. The challenge of defining and quantifying links between the pillars has not been resolved, but some progress has been made in the last decade, and examples are available (Table 2.1).
The fundamental conceptual challenge is to go beyond a mere collection of parts and apply a more system science-oriented approach to consider the sustainability of whole systems composed of interacting subsystems with emergent system properties (Chapter 10, this volume). It is the underlying properties that determine the dynamics and behavior of these systems and ultimately how sustainable the systems are over long periods of time. Examples of such system properties are resilience, carrying capacity, energy and material flows, and intergenerational knowledge transfer.
Table 2.1. Interlinkage indicators in the four-pillar sustainable development framework.
Environmental—economic Resource productivity (gross domestic product/total material input) (Eurostat 2001; OECD 2001). Transport intensity (Böge 1994; SDC 2004).
Socioeconomic Labor productivity (production per capita; see any national labor statistic).
Income distribution per decentile (see any national social statistic).
Socioenvironmental Environmental health problems (no clear definition so far; work under way by the World Health Organization, European Environment Agency, and others).
Access to common goods (to be specified regionally, available in Scandinavia under traditional law).
Economic—institutional Corruption rate (Transparency International Index I).
Share of taxes on labor, capital, and the environment in total tax revenues (not often calculated, but the basic data often are available from national statistical offices).
Socioinstitutional Co-decision rights of workers (e.g., according to the
European Works Council directive; in Europe, data are available from Eurostat labor market statistics, from the EU Commission, the trade unions, and others). Reliability of the health care and social security system (reliability is a subjective term and so far undefined).
Environmental—institutional Nongovernment organizations' right to file suit (data for this are collected under the Aarhus Convention demanding such access).
Freedom of information (in Europe, North America, and Central Asia regulated by an UN Economic Commission for Europe directive adopted in 1998 as a minimum standard).
Source: Spangenberg and Hinterberger (2002).
Only rudimentary efforts have been made to look at system properties and processes of integrated human, social, and economic systems. Many of the best-known indicators and indicator sets fail to include any such overall system properties, and they focus on more limited aspects of sustainable development (Chapter 11, this volume). For example, the CSD set assembles a large number of indicators but does not permit any judgment on the sustainable behavior of the system as a whole (Chapter 10, this volume). A more qualitative approach is to develop scenarios for alternative futures that span all the dimensions (e.g., Millennium Ecosystem Assessment 2005; UNEP 2002). These are sometimes generated by models (e.g., Meadows et al. 1992), in which case quantitative data and indicators can be both fed into and generated from the models. Modeling approaches provide tools to explore system behavior, identifying which factors are important and how sensitive the system is to variations in different indicators. Linking indicators with models will eventually provide more integrated perspectives on measuring progress toward sustainability.
Sustainability is a concept inherently related to time and space. What spatial unit should be sustained for how long? The approach to such questions differs between policymakers and scientists and depends on their focus on specific sectors or pillars of sustainable development.
With respect to the temporal dimension, each pillar is characterized predominantly by different time dynamics in, for example, lag times between cause and effect or the time horizon for policymaking. Sustainability in general is a long-term concept. Environmental issues have the longest range of temporal horizons, from floods or toxic emissions, to gradual changes over decades in the atmosphere, oceans, and climate caused by human action, to slow natural processes over millennia such as evolution and species formation, to the "death" of the sun. At the other extreme, economic issues involve very short-term decisions and impacts ranging from daily exchange figures to a few decades for infrastructure investments, with the future being discounted so that anything beyond that becomes irrelevant. Social issues generally fall between these two extremes, taking the length of a human life as an appropriate time frame, although negative effects on the social life of a generation, such as mass unemployment or poverty, can have impacts on the self-esteem and behavior of future generations (Arendt 1981).
The challenge for sustainability indicators is to anticipate such time lags and the trade-offs between the short and long terms. In developing highly aggregated indices, it may be worthwhile to consider weighting the time scales of the different pillars, giving higher weights to long-term or irreversible effects, for example, in order to improve their comparability.
For the spatial dimension, there are similar differences and specificities for each pillar. The relevant boundaries of a function or process may or may not correspond to the political boundaries of nation-states. Economic transactions increasingly span the globe, communities and cultures transcend national borders, and ecosystem boundaries range from puddles of water to biomes.4 Yet indicators for all three pillars are generally remapped onto political (usually national) boundaries. Indicators for local communities are also common, but there are almost no indicators measuring the sustainability of the planetary biogeochemical life support system or of humanity as a species at the global scale.5
A consequence of this spatial fragmentation is that trends and drivers are easily hidden when analyzed at one particular scale. A nation or local community can appear sustainable if it does not consider its impact on the sustainability of close and distant neighbors. Similarly, indicators portraying good average values, for example in income, can hide significant inequities between subregions and societal groups at smaller spatial scales.
The challenge is to develop indicators that capture issues of sustainability at different spatial scales, in a nested hierarchical structure that links the scales with some scientific consistency while reflecting what can be managed at each level. The same indicator may have different meanings for sustainability in different contexts or when applied at different scales, so each use is context specific. Some approaches such as material flow analysis and energy flow analysis with proper data and modifications can be scaled up and down.6
One approach that discusses and even measures degrees of sustainability is the notion of weak and strong sustainability (Turner 1993). It was derived from the economic concept of capital, defined as a stock of resources with the capacity to give rise to flows of goods and services.7 Ecological economists have expanded the concept to disaggregate the capital stock into four types (Ekins 1992) and linked them to the four dimensions of sustainability, including the institutional dimension (Spangenberg 2001):
• Manufactured capital: result of past material production (excess of output over immediate consumption)
• Human capital: people, skills, and knowledge
• Social and organizational capital: social networks and organization
• Natural capital: all features of nature providing resources for production and consumption, absorbing wastes, and furnishing amenities such as natural beauty
The issue is the substitutability of the different forms of capital in achieving sustain-ability of the whole system. Weak sustainability requires that the total capital stock (aggregated over the four types) does not decline. This presumes that all types of capital are sub-stitutable in their capacity to generate human welfare and maintain system functioning. Strong sustainability requires that the stock of natural capital be maintained above critical levels. This assumes that substitutability regarding welfare generation is limited, or it applies sustainability criteria broader than welfare maximization. It entails the physical protection of certain absolute levels of natural capital, which cannot be substituted without provoking major and unpredictable system perturbations. The challenge for indicator development is not to give the final answer to the question of whether weak sustainability is sufficient but rather to map out where on the scale of weak to strong sustainability current drivers and policies are heading regarding the fraction of human well-being that can be expressed in monetary values. The subjectivity of assigning such values to all dimensions, describing them as different types of capital, is controversial, but it does enable the integration of social and natural aspects with the economic indicators that usually dominate the political agenda.8 However, other elements of sustainability must be measured in other units, providing complementary but indispensable information.
A number of indicators and frameworks have been developed in the context of this discussion. For example, the "green" net national product has been proposed as a measure of the return on the aggregate of all capital types, but it requires reliable market values of all elements of the natural capital stock. On the other hand, the Critical Natural Capital (CRITINC) Framework recently introduced the concept of critical natural capital as those stocks of capital that cannot be substituted by other stocks of environmental or other capital to perform the same functions (Ekins et al. 2003). However, these indicators are very scale dependent, and evaluations of weak and strong sustain-ability must be considered at different temporal and spatial scales.
Carrying capacity is a familiar concept in ecology and refers to the population sizes of species that a particular ecosystem can sustain over time. In the context of measuring sustainability, it has been extended to the human species and refers to the numbers of people that can be maintained in the coupled human—environment system within planetary limits.
The difficulty in considering a species such as humans, who are able to raise the productivity of their own environment, is that carrying capacity, like sustainability itself, is a subjective and normative concept that depends on political choices of the spatial and temporal horizons considered and the preferred types of environmental, social, and economic systems. In environmental systems, for example, the carrying capacity depends on the limits set for the subsystem being analyzed and the acceptable level of degradation that can be tolerated in the system.
The only objective dimension to carrying capacity concerns the ultimate limits of maintaining conditions for life on the planet. Except for energy, the biosphere is essentially a closed system, and this imposes ultimate biophysical limits on growth in any material parameter at the planetary level. As resource limits are reached, further growth can come only from increases in efficiency.9 Human technological development allows us to reach those limits and has even given us the military capacity to exterminate ourselves, and our ignorance of biosphere systems can give us the illusion that there is no need to be precautionary. The difficulty is that the inertia in planetary systems produces long time lags between our impacts and the resulting consequences (Meadows et al. 1992). This again justifies efforts to develop global-scale indicators (Chapter 10, this volume).
Although science should determine the ultimate biophysical carrying capacity of the planet as the outer limit for long-term sustainability, only subjective choices can decide the second crucial dimension of human carrying capacity: the acceptable standard of living for the people within the system. A finite set of resources can provide abundance for a few or bare subsistence for many. This gives sustainable development an important dimension of redistributive justice both in space (relative wealth and poverty) and in time (intergenerational equity).
The environmental space concept and Ecological Footprint index effectively communicate the concept of planetary carrying capacity in one dimension, the spatial one, by calculating how much space is needed to meet the needs of an individual, community, or nation, as related to the space available (EEA 1997).
Vulnerability and resilience are two terms that are increasingly used in scientific analysis of sustainable development from a system perspective. Whereas many concepts focus on the outer limits to sustainability, these terms apply to the inner limits to sustainability in a particular system. Although there is still a need to clarify and consolidate how these concepts are defined and applied, resilience is the capacity of the coupled human-environment system to cope with internal or external disturbance and its ability to adjust and adapt (Gutierrez-Espeleta 1999). This applies to the social, economic, and environmental subsystems. Vulnerability is a characteristic of the lower end of the resilience spectrum. A system with high resilience has low vulnerability and vice versa. Systems need resilience not only to normal variations but also to extreme events, whether floods, droughts, or sudden drops in the stock market.
The increasing attention to these concepts has led to policy requests for indicators of resilience and vulnerability, such as in the UN Programme of Action for Small Island Developing States (United Nations 1994). Examples of responses are various economic vulnerability indices (Briguglio 1995) and the Environmental Vulnerability Index (EVI) (Pratt et al. 2004). The latter focuses on the environmental resources and ecosystems on which human society depends and profiles how vulnerable they are to further disturbance.
When a system is not resilient enough to absorb disturbance and is degraded, the changes often are irreversible. It is the irreversible changes that are critical to sustain-ability. Irreversibility defines an absolute limit beyond which reestablishing the status quo is not possible. The concept of irreversibility is inherent in any analysis of coevolving systems. However, so far it is used primarily for environmental systems, describing events such as species extinctions or permanent loss of vital ecosystem functions, and is an essential part of identifying reference values. The approach is very different in the social and economic sphere. Social systems are characterized by permanent change, and irreversible changes would be those that have impacts lasting more than two generations, for the better or for the worse. In economics, whereas more recently emerged subdisciplines such as evolutionary and ecological economics analyze irre-versibility and the resulting path dependency of system development as a characteristic of complex, nonlinear systems such as nature, society, and the economy, the neoclassical mainstream of economic thinking holds that everything in the economic system is reversible by definition, as reflected in the concept of weak sustainability.
The application of the concept of irreversibility in sustainability analysis depends on a number of factors:
• How critical the loss is to the overall system functions or productivity
• Whether substitutions for the loss are possible or desirable
• What compensations are needed to reduce the loss and the costs to the system
• What level of uncertainty is involved
The concept thus is not easily defined in scientific terms because it also depends on normative choices such as the social acceptance of compensation for degradation.
Defining irreversible limits to critical life support systems is a major conceptual challenge, as is the development of indicators providing early warning of the risk of irreversible damage. Setting such limits and predicting the risk for passing them are highly uncertain. Research has shown that the behavior of global systems such as biogeo-chemical cycles is characterized by thresholds and surprises (Steffen et al. 2002). Indeed, it was for situations with risk of irreversible damage that the precautionary principle was first formulated (EEA 2001). The Organisation for Economic Co-operation and Development (OECD) applies irreversibility only to ecosystems and the need to safeguard the natural processes capable of maintaining or restoring the integrity of ecosystems. Other areas of irreversibility may be difficult to define with the present state of knowledge and therefore are highly controversial.
Was this article helpful?