Ecological Economics 47 (2003) 121 – 133 www.elsevier.com/locate/ecolecon METHODS Evolutionary policies for sustainable development: adaptive flexibility and risk minimising Christian Rammel a,*, Jeroen C.J.M. van den Bergh b,c a Department of Ecology and Conservation Biology, University of Vienna, Althanstraße 9, 1190 Vienna, Austria Department of Spatial Economics, Faculty of Economics and Business Administration, Free University, De Boelelaan 1105, 1081 HV Amsterdam, Netherlands c Faculty of Earth and Life Sciences, Institute for Environmental Studies, Free University, De Boelelaan 1105, 1081 HV Amsterdam, Netherlands b Received 15 October 2002; received in revised form 23 June 2003; accepted 25 June 2003 Abstract An evolutionary perspective on policies to foster sustainable development is presented. It is argued that policies suggested by the traditional economic theory of environmental policy can stimulate unsustainable socio-economic structures and patterns. In addition, they are unable to remove undesired locked-in systems and technologies. Drawing on evolutionary thinking, characterised by diversity, selection, innovation, path-dependence and bounded rationality, an alternative, partly complementary theory of environmental policy is suggested. Specific attention is given to the role of strategies that are aimed at increasing diversity and adaptive flexibility, and at reducing risk. D 2003 Elsevier B.V. All rights reserved. Keywords: Diversity; Evolution; Economic structure; Innovation; Lock-in; Selection; Stability; Uncertainty 1. Introduction Corresponding with an increasing awareness of global environmental problems and the need for a sustainable development is the realisation that traditional economic approaches may fall short in offering a complete perspective on the relevant issues, problem causes, and solutions. Nevertheless, the current debate about sustainable development is still dominated by neoclassical economic theory. Concepts like sustainable growth (Solow, 1992) and weak sustainability * Corresponding author. Tel.: +43-1-4277-54201; fax: +43-14277-9542. E-mail addresses: [email protected] (C. Rammel), [email protected] (J.C.J.M. van den Bergh). 0921-8009/$ - see front matter D 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0921-8009(03)00193-9 (Pearce and Atkinson, 1993) emphasise the fundamental role of markets in dealing with environmental problems, and reflect the deterministic and aggregate focus of neoclassical growth theory (Toman et al., 1995). In addition, the standard normative economic theory of environmental policy (Baumol and Oates, 1988) cannot do without the debatable assumptions of individual rationality and the Kaldor –Hicks potential Pareto improvement principle to arrive at conclusions about social optimality of policy instruments. Recently, a significant body of literature has discussed the shortcomings of traditional theories of environmental and resource economics, shedding light on the limitations of various concepts and methodologies. These include monetary valuation, substitution of natural by economic capital, traditional cost-benefit analysis and 122 C. Rammel, J.C.J.M. van den Bergh / Ecological Economics 47 (2003) 121–133 normative policy theory (e.g. Vatn and Bromley, 1994; Victor, 1991; Gute´s, 1996; Munda, 1996, 1997; van den Bergh et al., 2000; Gowdy, 2003). Within the mainstream the gap between normative and positive environmental policy theory has been identified (Dietz and Vollebergh, 1999; Oates and Portney, 2003). A possible reason for this gap is that assumptions about behaviour underlying normative policy theory are inconsistent with actual behaviour, which seems to characterised by bounded rationality—often expressed through habits and imitation—and the formation of interest groups. Nevertheless, traditional theory insufficiently recognises these fundamental problems, which may contribute to persistence of the gap. Despite these shortcomings, policy making strongly depends on economic advice derived within the neoclassical paradigm (Hall, 1993). This has initiated a tendency to ‘‘economise’’ politics by focusing the attention of decision-makers on efficiency and cost minimising. As the theory and models supporting the policy advice are founded on artificial planning-market systems that resemble closed mechanic systems that do not change over time, they are especially inappropriate to deal with the dynamics of structural and adaptive changes in economic systems. Such changes are either required for, or the result of, sustainable development (Georgescu-Roegen, 1971; Hodgson, 1993). In other words, the ‘‘mechanical corset’’ of neoclassical economics prevents a clear view on changes and adaptations stimulated by environmental policies. This calls for alternative approaches that might be better in coping with complex systems (Funtovicz and Ravetz, 1994). In the following we argue that a fruitful approach to study policies for sustainable development is offered by evolutionary thinking. Not only does it address the adaptive and structural elements of many economic changes, but also it is consistent with the view that economic behaviour of both firms and consumers is more in accordance with bounded than infinite rationality. Many authors have stressed the universal character of evolutionary phenomena, which has as a corollary that evolution applies equally to economic and biological phenomena (Dennett, 1995). Or better said, the fact that evolution was—somewhat coincidentally—taken more seriously early on in biology does not mean its relevance is restricted to this field. This is in line with a growing body of literature showing the potential of evolutionary thinking in economics in general (Dosi et al., 1988; Hodgson, 1993; Nelson, 1995). Moreover, a small literature has developed around the idea that evolutionary theories and models can be usefully employed to study sustainable development and environmental policies that foster it (Norgaard, 1994; Clark et al. 1995; Ring, 1997; Allen, 1997; Norton et al. 1998; van den Bergh and Gowdy, 2000; Mulder and van den Bergh, 2001; van den Bergh, 2003a,b; Rammel, 2003). Given the context of sustainable development, the evolutionary perspective outlined in this article will be based on an integration of elements from evolutionary biology, evolutionary economics and technology studies. The analysis of sustainable development as an (set of) evolutionary process(es) allows us to address elementary issues like diversity, risk minimising, path-dependency and lock-in, which are ignored by conventional policy and growth theories in the context of environmental economics. The structure of this paper is as follows: Section 2 presents a short overview of evolutionary notions in biology, economics and technology studies, highlighting their common background and their potential relevance for sustainable development policies. Section 3 deals with an evolutionary foundation of sustainable development policies, emphasising adaptive flexibility, evolutionary potential, variability, risk minimising, and path-dependence and lock-in. Section 4 presents conclusions. 2. Evolutionary perspectives 2.1. Evolution in biology Systematic thought about evolution has its starting point in the last century, when Charles Darwin and Alfred Russel Wallace initiated a major transition in the discipline of biology. After an initially hesitant development of theory and empirical methods, biology became the dominant domain of evolutionary thinking after the 1930s. Not surprisingly, it has served as a rich source for possible evolutionary analogies in other fields, notably economics (see Hodgson, 1993; Eldredge, 1997). It is important to realise that economic development and technological C. Rammel, J.C.J.M. van den Bergh / Ecological Economics 47 (2003) 121–133 change are driven by evolutionary dynamics that not only share many similarities with biological evolution but also differ in many respects (Hodgson, 1993; van den Bergh, 2003a). In an appendix in the sixth edition of his ‘‘Origin of Species’’, in which he discusses the people that influenced his thinking, Charles Darwin acknowledged that he received a critical influence through the work of Thomas Malthus on (human) population growth. This only illustrates that the fact that biology was the first science to elaborate the idea of evolution can be regarded as a ‘‘historical accident’’, to use the jargon of evolutionary thinking. This is supported by the idea that Malthus and Darwin were both directly affected by the rapid changes in England during the Industrial Revolution, Darwin especially through his family’s connections with various industrialists. The Industrial Revolution possessed many evolutionary features, starting with changes in diversity caused by the interplay of innovation and selection. This underlines the multidisciplinary nature of evolutionary thinking. In biology, the essential role played by evolutionary theory is no longer open for discussion. The most famous statement that reflects this view is ‘‘. . . nothing makes sense in biology without an evolutionary perspective . . .’’ (Dobzhansky, 1973: 1). In general, Darwinian biological evolution is defined as a gradual and continuous adaptation through natural selection. The key elements of biological evolution are genetic variation, heredity and individual selection, which are facilitating a structure-building process with no predefined functionality (Mayr, 1988; Maynard Smith and Szathma´ry, 1996). Variation and diversity are caused by mutation and sexual recombination, and can be seen as the fundamental base upon which natural selection acts. Dependent on abiotic and biotic conditions— which are inevitably changing—selection ‘‘chooses’’ between alternative variants—alleles at a genetic level. Selective advantage is expressed by a greater fitness, i.e. the number or quality of offspring of an individual. Heredity is strictly bounded to a vertical transfer of information through genes within a single species. Going from one to the next generation, one can thus identify a chain of gradual adaptations. Each generation of a species thus can be seen to reflect the cumulative genetic effect of past selective conditions. A much debated cornerstone of biological evolution is the notion of adaptation, which can be seen as a 123 temporary feature providing a benefit over its alternatives under specific environmental conditions, or as the process by which this feature arises. The Darwinian understanding of gradual adaptation is expressed figuratively in Wright’s image of populations walking up the side of an adaptive ‘‘fitness peak’’ (Wright, 1964). If a population wants to find the highest position in an adaptive landscape—where foresight and prediction are impossible—the best guess is just to walk uphill step by step. Note that this routine is very common in algorithms designed to solve nonlinear optimisation problems in mathematical form. Like evolution, these will at best lead to local optima; global optima are not guaranteed. In other words, ultimately, a population may reach a very high point in the landscape, but it is unlikely that this will be the highest point. Furthermore, changes in the adaptive landscape, due to ‘‘coevolution’’, can cause a current state of the respective population to become less well adapted or even maladapted. Since the early 1970s, this understanding of gradual evolution and the concept of strong ‘‘adaptationism’’ were opposed—or perhaps it is better to say: extended—by the idea that natural history consists of punctuated equilibria (Eldredge and Gould, 1972). This was mainly based on fossil records, which suggested the existence of long periods of stasis interrupted by sudden bursts of rapid change. The interpretation by the inventors of this theory is that ‘‘higher level’’ selection processes, known as sorting, emphasise that in biological evolution not every state can be interpreted as adaptive or caused only by natural selection (Gould and Lewontin, 1979; Gould, 1985). This idea of punctuated equilibrium has stimulated some debate in social science, and has, for instance, been related to Schumpeter’s long waves (Somit and Peterson, 1989; Gowdy, 1992). Recently, approaches using insights from biological evolution have started to influence the analysis of policies and (ecosystem) management for sustainable development. Much of the research on biodiversity loss, ecosystem resilience and exotic species falls under this heading, even if the link with evolution is not often made explicit. The relation between biodiversity and resilience has been stressed by ecologists and economists alike (Holling et al., 1994; Perrings, 1998; Common and Perrings, 1992). Whereas stability emerges at the level of biological populations, resil- 124 C. Rammel, J.C.J.M. van den Bergh / Ecological Economics 47 (2003) 121–133 ience is defined at the level of ecosystems and refers to the ability to maintain structure and self-organisation of a system in the face of external stress (Holling, 1992). The linkages between biodiversity, stability and resilience are still under discussion, but it is likely that they will be translated into implications for policies aiming at sustainable development (van den Bergh and Gowdy, 2000; Common and Perrings, 1992). Natural resource management is an area where environmental policies have to reckon with implications of evolutionary biology. Due to the selective pressure caused by human activities, irreversible evolutionary patterns occur. As a result, management systems could initiate negative changes in the quality of the resource base, making future utilisation more expensive or even impossible. In the context of fisheries, this phenomena has been addressed by authors like MacGlade and Allen (1987) and Heino et al. (2000), who emphasise that the selection pressure created by small fishing net mazes tends to increase the proportions of relative small fishes in the fished population and affects the viability of the population in the future. Munro (1997) has developed an elegant model of pesticide use in agriculture. This mixes a formulation of the traditional renewable resource management problem with an evolutionary model that reflects a positive correlation between selective pressure on pests and the number of pesticides-resistant individuals in the treated population. This allows to compare policies based on understanding the evolutionary impacts of resource use with those that do not understand these, using both economic and biological indicators. 2.2. Evolution of technology In the field of technology studies, there is a growing awareness that a complete understanding of technological change requires that it is seen as an evolutionary process (Hughes, 1983; Vicenti, 1990; Mokyr, 1990). Focusing on the individual level, technology can be understood as an ‘‘adaptive answer’’ to a priori defined problems. According to Dosi (1988), the context for this is given by ‘‘technological and scientific paradigms’’, which pre-define the patterns of solution and point the whole innovative process in particular directions. Engineers and inventors always face different possibilities and competing solutions. In other words, there is a high level of uncertainty, which is only resolved through ex post competition—i.e. selection—towards a better ability to solve the particular problem (Nelson, 1995). The latter is determined by technological criteria, costs, cultural values, life style, etc. (Vicenti, 1990; Hughes, 1983). Evolutionary thinking stresses another aspect of technological development, namely path-dependence, and the related notion of pre-adaptation. Technological systems are never created independently of their selective context or evolving out of nothing. In human history, most of the major technological innovations were built on prior inventions and required further innovations to become really effective (Kranzberg, 1997; Diamond, 1997). Due to this kind of required historical sequence or path-dependence, any technology can be understood as an intermediate element in a causal chain of undetermined evolutionary developments. The functionality and final purpose of the particular element need not emerge immediately. As authors like Diamond (1997), Hughes (1983, 1978) and Sigmund (1995) emphasise, many technological innovations were the result of pure curiosity and creative ‘‘inventing around’’ (Hughes, 1983), rather than driven by scarcity and real life problems. Without the focus on problem solving, the final purpose and need of these pre-adaptive innovations emerged only later—sometimes much later. Sudden advantages of ‘‘useless’’ innovations resulted from altered selective conditions. It is thus possible that technological innovations, that fail to develop successfully in one cultural context expand and flourish in another (Reynolds and Cutcliffe, 1997). On the societal level, evolutionary thinking is opposing the traditional approach to deal with technological systems through isolated analyses focused exclusively on technological criteria. In contrast, David Nye (1992) concept of ‘‘technological landscapes’’ describes technological evolution through the relations between economic, political, technological and environmental processes. Technology is adapted to spatial and temporary conditions of cultural and environmental systems. Hence, development, transfer and diffusion of technology cannot be described only in terms of technological and economic efficiency, but are also strongly based on various other aspects of technological systems (Hughes, 1983; Bruland, 1994; Randall, 1994). C. Rammel, J.C.J.M. van den Bergh / Ecological Economics 47 (2003) 121–133 Seeing technological development as evolving, complex, multi-dimensional, culturally dependent and out-of-equilibrium leads to an entirely different perspective on sustainable development than one based, for instance, on endogenous growth theory, which focuses attention on the ‘‘optimal relationship’’ between technology and growth. Moreover, Nelson (1995): 64) points out that ‘‘(. . .) recent scholarship on the evolution of technology has proposed that there may be a number of different evolutionary tracks that go in quite different directions, and that movement down one may block movement down another’’. If one adds this to the discussion of ‘‘technological landscapes’’ and path-dependence, then it is very clear that there is no such notion as an ‘‘optimal technology’’. Perhaps optimality would makes sense if one would focus on a single criteria, reducing the value of alternative ones. However, policies for sustainable development cannot rely on the notion of optimal solutions based on a single measurement, the most likely being of course economic efficiency. The reason is that this denies the immense uncertainty surrounding any decision about long term growth and development. Uncertainty and keeping options is a theme that fits surprisingly well in an evolutionary setting. We will come back to this later. 2.3. Economic evolution Already since the end of the 19th century, economists have adopted concepts from evolutionary biology. It has been well documented what Marshall, Veblen and Schumpeter had to say on the subject (Hodgson, 1993). In the 1950s, even neoclassical economists showed an interest in evolution. However, this was reduced to (mis)regarding selection as optimisation (Alchian, 1950; Friedman, 1953). This incorrectly transferred the old idea of Herbert Spencer’s, ‘‘survival of the fittest’’, to economics. From a modern evolutionary perspective, however, the correct term would be ‘‘survival of the fitter or sufficiently fit one’’ (van den Bergh, 2003b) or ‘‘survival of the fitting’’ (Boulding, 1981). In general, the neoclassical understanding of evolution is synonymous with a determined process (Rostow, 1960) whereby progress is taken for granted (Hirshleifer, 1977), and a unique, optimal equilibrium is expected as the final result (Friedman, 1953; 125 Boulding, 1981). This is exemplified by evolutionary game theory, which tries to identify equilibria, and is sometimes more appropriately referred to as ‘‘equilibrium selection theory’’. The reason is that innovation is missing; and of course, if selection works long enough upon a given variety, in the absence of any innovation ultimately the system will end up in a situation with minimal variety, i.e. an equilibrium. Evidently, this does not represent a complete view of evolution, be it in economies, technological systems or natural systems. Typical of evolution, and the essence of its structure-forming character, is the interplay between selection and innovation forces. A number of approaches are more in line with evolution as it is generally regarded by natural scientists. Schumpeter (1934) work on innovative entrepreneurship and creative destruction was an initial starting point for further approaches. Subsequent theories, like the work of Nelson and Winter (1982) complemented the idea of pure economic selection with the concept of ‘‘routine’’, a concept similar to ‘‘gene’’. The evolutionary model of Silverberg et al. (1988) extends this with the notions of diversity, anticipation of firms and uncertainty. Opposing the non-historic view of conventional economics, authors like Arthur (1989) or David (1985) stress that ‘‘economic survival’’ is based on much more complex reasons than competitive selection towards economic efficiency. In their works they show that, due to pathdependence, non-predictable ‘‘historical small events’’ (Arthur, 1989) can cause inflexibility of current systems, followed by a lock-in of—possibly inferior or undesirable—technologies (see further Section 3.4). Gowdy (1992), starting from the biological theory of ‘‘punctuationism’’, argues that economic survival rates occur at several hierarchical levels. From this point of view, in the economic world, there is much more freedom in firm behaviour than pure maximisation, which gives room for differential success of firms, innovations or technologies. Opposed to equilibrium orientated concepts, evolutionary approaches in economics address the longterm effectiveness and stability of environmental policies (Ring, 1997). In this sense, evolutionary economics has the potential to integrate notions of non-optimised change, uncertainty and long-term development into sustainable development policies. The importance of this integration is underlined by find- 126 C. Rammel, J.C.J.M. van den Bergh / Ecological Economics 47 (2003) 121–133 ings in the field of adaptive environmental management, which emphasise that handling complex systems requires a balanced between flexible policy learning, monitoring and research (Walters, 1986). 3. An evolutionary foundation of sustainable development policies 3.1. The lack of evolutionary elements in thinking about sustainable development and environmental policy Environmental policy instruments are usually classified into ‘‘command-and-control’’, ‘‘market based’’ or ‘‘economic incentives’’, and ‘‘moral suasion’’. Since environmental policy is moving from a curative and effect-oriented focus towards amore source-oriented approach, the latter two approaches may become increasingly important. There is a large body of literature on economic instruments of environmental policies, well-covered in the large number of textbooks on environmental economics. Economists have for long argued that market-based incentives are more efficient than the traditional approach based on direct policy regulations or command-and-control. This insight is, however, mainly dependent on static equilibrium analyses in which economic agents—consumers and producers—are individually efficient, due to rational behaviour (Baumol and Oates, 1988). It is certainly not evident that the same insight will be obtained when using theories and models that reflect a more complex, evolutionary systems approach in which agents act in accordance with bounded rationality. Indeed, a recent analysis of environmental policy using alternative theories of individual behaviour generates results that deviate from the standard ones (van den Bergh et al., 2000). Based on the assumptions that there exist ‘correct’ or ‘optimal’ prices for all environmental services as well as optimal equilibria, economic theory suggests that polluters should pay the full marginal costs of damages caused by their activity. Thus, an incentive to reduce the damage up to the socially optimal pollution or exploitation level is created. Various instruments like Pigouvian taxes, tradable permits and depositrefund systems are practicable applications of this approach. A number of disadvantages of such eco- nomic instruments have been mentioned: negative distributional effects, less certain environmental effects than direct regulations, and difficulties in measuring required tax levels due to marginal damage and abatement costs being related to hypothetical optimal equilibria (Cumberland, 1994; Dietz and van der Straaten, 1992; van den Bergh et al., 2000). From an evolutionary perspective, the major disadvantage of this approach is the assumed existence of optimality and stable equilibria. As a result, it is not focused at all on dealing with structural changes in environmental and economic systems that involve uncertainty, adaptations and path-dependence (Clark et al., 1995). Based on the assumption of optimal individual behaviour, the objective of social efficiency is the guiding principle in the traditional approach. Following this ‘‘ideology of efficiency’’ (Bromley, 1990), environmental policies aiming at market-based incentives and stable equilibrium ignore evolutionary characteristics like qualitative change that is irreversible and unpredictable and moving along non-equilibrium states. But the focus on efficiency—if realistic at all—is short term and feeble. Worse, environmental policies based on monetary cost-benefit analyses bear the risk of stimulating unsustainable socio-economic patterns and sacrificing long-term stability for shortterm ‘‘optimums’’ and gains of efficiency. This is currently most relevant for climate policy, where economic research is dominated by cost-benefit and optimisation approaches (van den Bergh, 2003c). 3.2. Stability versus optimality Evolutionary theory within the realm of biology, especially ecology, has devoted much attention to the issue of stability. The link between stability and diversity1 has been addressed by many authors. (e.g. Wagner and Altenberg, 1996; Holling, 1992; Perrings 1 In biology, diversity refers to the individual or species level, stressing primarily a high variety among individuals within a population or different species within an ecosystem (Hubbell, 1999). In contrast, variability is a term that describes the propensity of a genotype to vary. Whether this gives rise to a variety of phenotypic expressions depends highly on the hierarchical nature of the genotype – phenotype mapping (Wagner and Altenberg, 1996). Long-term stability depends both on variability and diversity. Given the multidisciplinary audience of this journal, we will simplify terminology by using the term diversity to cover also variability. C. Rammel, J.C.J.M. van den Bergh / Ecological Economics 47 (2003) 121–133 et al., 1995). Although stability is, or should, be a standard element of sustainability, it has received surprisingly little attention. Economists often resist too stringent environmental policies, feeling that these may create economic instability. This runs largely through expectations of economic agents, which are very much influenced by the general economic climate, as reflected by GDP growth, a country’s competitive international position and (un)employment. The link between expectations and these indicators is reinforced by financial markets. Nevertheless, these issues are seldomly approached from an explicit, theoretically well-founded perspective on stability. Traditional macroeconomics offers some perspective on stability, but has seen little influence on modern environmental economics and its policy theory. Evolutionary economics serves as another source of thinking about economic stability and the factors that contribute to it, but has seen equally little influence on environmental economics. In general, evolutionary systems do not relate to stability in a static sense as they are faced with moving equilibria and the dynamics of coevolutionary interactions which can not be foreseen ex ante. Given this permanent process of unpredictable change any kind of optimising must be understood as local and myopic (Nelson, 1995; Rammel and Staudinger, 2002; van den Bergh, 2003a). If optimality exists it will be temporary, because through evolution, selection and innovation, and environmental change, including coevolution, it is easily transformed into maladaptive traits (Vermeij, 1994; Norgaard, 1994). Under such conditions, diversity is a key elements of long term stability and even survival. This holds equally for biological and economic systems (Utterback and Sua´rez, 1993). This will be substantiated in the next section. 3.3. Diversity to enhance adaptive flexibility and evolutionary potential Since every successful adaptation is only a temporary ‘solution’ to changing selective conditions, maintained diversity represents a repertoire of alternative options and increases the possibility that altered conditions can be successfully met through pre-adaptations and further evolution. This is shortly referred to as ‘evolutionary potential’. It allows diversity to 127 contribute to long-term stability through adaptive flexibility. In evolutionary biology, adaptive flexibility is based on the ability to maintain genetic variability and a large amount of pre-adaptive evolutionary traits. The maintenance of diversity is mainly a passive process that relies on the imperfection of diversityreducing forces (Rosenzweig, 1995; Hubbell and Foster, 1986). In other words, adaptive flexibility is fostered by an evolutionary setting that is characterised by lax selection pressure. Evolutionary systems thus can be seen to express a sort of implicit trade-off between realising short-term local optima (like specific criteria of efficiency) and maintaining evolutionary potential to achieve adaptability and stable long-term developments. This holds equally for biological and social –economic systems (Schu¨tz 1999; Matutinuvic, 2001). In both, selection acts as a short-term adaptive force, which reduces diversity and optimises biological features to the narrow and specific environmental—biotic and abiotic— conditions of the moment. Hence, the selective process is strictly myopic and is by no means aimed at maintaining diversity or achieving survival in the long run. This trade-off between efficiency and diversity, or adaptability, was extensively described by authors such as Mayumi and Giampietro (2001), Giampietro (1997) and Giampietro et al., (1997). Recalling a general view on complex adaptive systems, Mayumi and Giampietro (2001): 13) state that a sound balance of this trade-off can be achieved when ‘‘increases in efficiency are obtained by amplifying the most performing activities, without eliminating completely the obsolete ones [emphasis by the authors]’’ (ibid.: 13). Consequently, as complex adaptive systems tend to move towards instability and new emerging sets of boundary conditions (Giampietro, 1997), diversity, in terms of a maintained repertoire of different meanings of efficiency, increases adaptive flexibility, i.e. the chances to cope with new socio-economical objectives and emerging properties. In line with Mayumi and Giampietro’s ‘‘different meanings of efficiency’’ it is useful to consider the perspective coming from ecosystem theory. As Ulanowicz (1997) shows, in dynamic ecosystems, efficiency also stands for a extended and improved use of resources by the diversity of species which are associated with different single-use efficiencies. From this ecological point of view, less efficient (and competi- 128 C. Rammel, J.C.J.M. van den Bergh / Ecological Economics 47 (2003) 121–133 tive) species are redundant, but for the stability and the development potential of ecosystems, functional redundancy represents a reservoir of adaptive responses and enhances the evolutionary potential (see also Rammel and Staudinger, 2002). Embedded in evolutionary system thinking, adaptive flexibility reflects a clear distinction between this higher level of systemic efficiency (based on functional diversity) and the standard economic understanding of efficiency explicable in terms of cost minimisation, factor endowments and the exclusion of ‘‘weak’’ performers. Given that the partial perspective of standard economic theory tends to decrease functional diversity in order to increase a specific and narrow meaning of efficiency, Schu¨tz (1999): 25) notes: ‘‘(. . .) the lower the diversity, the lower the efficiency of the system, the lower its potential to respond upon disturbances, and the lower its potential for innovative combinations’’ (Schu¨tz, 1999: 25). Using the notion of complex adaptive systems (Holland, 1995) to bridge ecosystem theory with socio-economic systems, Matutinuvic (2002) notes that resource-intensive socio-economic systems, characterised by reduced diversity and over-efficiency, may be too fragile to stand major perturbation. He concludes that diversity and a sound ‘‘balance between thermodynamic and maximum power efficiency’’ (Matutinuvic, 2002: 438) are the essential conditions for stable and sustainable economies and ecosystems. In the context of social–economic development, diversity related to a wide range of activities, including agricultural techniques, industrial production methods, means of communication, languages, institutions, legislation and informal rules (culture). Boyd and Richerson (1985) have argued that cultural diversity is the essential condition for the evolution and development of social systems. Schu¨tz (1999) extends this by arguing that functional diversity in both socioeconomic and biological spheres is a key element for any future sustainable economy. This interpretation of diversity is shared by Matutinuvic (2001), who understands diversity as functional and structural analogues of both socio-economic and biological systems. Notably, biological as well as cultural diversity relate to systemic coherence and integrity of the world socioeconomic system in terms of adaptations to changing environments, avoidance of head-to-head competi- tion, efficient use of resources and energy and the possible range of responses to new selective pressures (Matutinuvic, 2001). Emphasising the inevitable contradiction of valuing biodiversity or socio-diversity through a market-centred perspective, O’Hara (1995) defines diversity in socio-economic systems as different social and economic arrangements by which people organise their societies. This can be seen as institutional diversity, which coevolves with behavioural routines at the individual and group levels (van den Bergh and Stagl, 2003). Additionally various authors have emphasised the relevance of diversity in different socio-economic contexts, notably in resource based activities (Becker and Ostrom, 1995; Norgaard, 1994; Perrings, 1998; Rammel and Staudinger, 2002). As opposed to biological systems, socio-economic systems do not maintain diversity solely passively. They also devise active conservation policies—currently focusing on biodiversity, languages and cultural heritage (UNESCO, UNEP)—and diversity-generating activities (R&D) and institutions—think of universities and patenting legislation. These can be regarded as essential elements of policies aimed at promoting sustainable development. They are foster a sound balance between short-term efficiency goals and long-term stability based on a maintained evolutionary potential. Evolutionary potential and adaptive flexibility cannot be sufficiently realised through policies aimed at optimal equilibrium solutions, i.e. the traditional economic approach to environmental policy. The conventional cost-benefit approach emphasises the maintenance cost of variety or diversity, which subsequently is interpreted as a loss of efficiency or a lower profitability. As a result, cost-benefit criteria exclude options that try to maintain variety for the purpose of evolutionary potential, unless a descriptive underlying model explicitly accounts for evolutionary change and its impacts. Notions of option value and the Krutilla –Fisher algorithm are adaptations to the traditional cost-benefit paradigm that have tried to address the issue of irreversible changes. Gowdy (1992) notes the standard environmental economic theory of policy is indirectly influenced by the notion of ‘‘survival of the fittest’’. Evolutionary theory, however, instead supports a fundamentally different notion of ‘survival of the fitter or sufficiently C. Rammel, J.C.J.M. van den Bergh / Ecological Economics 47 (2003) 121–133 fit’ (see the discussion in Section 2.3). Survival of the fittest incorrectly suggests that there is no space for ‘excess baggage’ or diversity supporting evolutionary potential. Related is that present economic developments and policies that rely strongly on market selection tend to stimulate a decrease in diversity at national and global scales of human activity. This is reflected, among others, in a reduced genetic crop variability in agriculture, a focus on fossil fuel energy supply, a dominance of fuel-based transport, and dramatic losses of biodiversity and cultural diversity (including languages). Conventional policy instruments insufficiently recognise these trends, and even contribute to speed them up. They are not aimed at maintaining diversity. At best, they realise it as an unintended sideeffect (Shiva, 1995; Gowdy, 1997; O’Hara, 1995). 3.4. The problem of path-dependence and lock-in Evolutionary theory implies that future processes are influenced by their antecedents, in a very subtle way. Diversity in an evolving system changes in a certain ways that are unique and irreversible, just on probabilistic grounds, due to the large number of heterogeneous or diverse units in a system. A full understanding of such history or path-dependence can only be realised by studying mathematical illustrations of it. Policies for sustainable development need to tackle situations which are characterised by pathdependence and lock-in. In evolutionary economics, there is a growing body of literature that addresses these notions (Arthur, 1989; David, 1985; Katz and Shapiro, 1994; Silverberg et al., 1988). Mechanisms that contribute to lock-in create increasing returns to scale, which include economies of scale and scope, cumulative technological change, learning, network externalities, and complementary production factors. The general outcome of these studies shows that socio-economic systems can become locked-in through unpredictable historic events—historical accidents—in combination with the previous mechanisms. Chandler (1990) and Williamson (1985) point out that market selection tends to focus socio-economic developments in particular directions like economic efficiency and profitability, which means optimisation and innovation within a present development trajectory at the costs of alternative opportunities, which 129 might better meet other objectives. But path-dependence can also easily lead to outcomes that are not even efficient from a narrow private profit perspective. The well-known examples of lock-in given in the literature illustrate this: VHS video recorder, Qwerty keyboard and Windows operating system. Unsustainable—larger—systems like fossil-fuel cars, ‘‘industrialised agriculture’’ and fossil-based energy supply have become locked-in as well. Strategies aimed at creating a diversity of alternative options increase the possibility for future sustainable changes in these areas. In addition to some of the conventional regulatory instruments, notably ‘correct prices’, the lock-in and path-dependence perspective suggests a broad spectrum of interrelated strategies. These involve the creation of protected niches outside current market selection, stimulation of key-innovations and pathway technologies, and portfolio investment in different alternative innovations. These can prevent potential undesirable lock-ins, or unlock current locked-in systems and technologies. 3.5. The concept of risk minimising Maintaining diversity to foster adaptive flexibility and evolutionary potential can be seen as a riskminimising strategy, much in line with the precautionary principle often mentioned in the context of environmental policy. The concept of risk minimising in an evolutionary setting originates from anthropology. Here it is argued that small-scale groups of nomadic hunters and gatherers often utilise and exploit their natural environment at a significantly lower level then would be possible. They invest a relatively small part of their time in actual working hours, devoting most of their time to social interactions with the purpose to strengthen reciprocal social relations (Groh, 1992; Sahlins, 1974; Smith and Wishnie, 2000). Such a strategy is capable of maintaining a safety buffer against inevitable fluctuations and changes in ecosystems, thus fostering long-term survival. The idea is that any short-term strategy of optimising the human – environment relation in revenue terms would raise the risk of dangerous breakdowns within small groups human populations (Groh, 1992). Hence, this strategy of conservation and ‘‘avoiding unused natural resources’’ supports socialecological stability and can be interpreted as an 130 C. Rammel, J.C.J.M. van den Bergh / Ecological Economics 47 (2003) 121–133 investment in long-term survival. As emphasised by Scott (1976) and Lipton (1968), such a societal strategy has also been essential for recent agricultural societies in Asia, where the traditional focus on risk minimising through the use of a large variety of less productive but rather invulnerable seeds is restricting the diffusion of high productive but vulnerable seeds. It resists the development of monocultures and contributes to combined biological –cultural diversity and adaptive flexibility. Given the objective of sustainable development, risk minimising is a necessary consequence of our ability to recognise complex systems driven by evolutionary dynamics. By addressing unpredictable changes and uncertain fluctuations typical of such systems, risk minimising helps to clarify and reduce potential problems of unstable and undesirable developments. Note that the concept of risk minimising has nothing to do with transforming uncertainties into calculated or insured risks, which is per definition strictly impossible for many natural phenomena, for pervasive and extreme uncertainty, and at a global scale (Dosi and Egidi, 1987). Authors such as Dosi (1988), Dosi and Egidi (1987) and Spash (2002) also distinguish between ‘‘weak’’ and ‘‘strong’’ uncertainty. While ‘‘weak’’ uncertainty is more familiar to imperfect information about the occurrence of known events, ‘‘strong’’ uncertainty refers to extreme uncertainty, i.e. unknown events and unknown consequences of particular actions. Risk minimising has to deal with three interrelated aspects: (1) adaptive flexibility and evolutionary potential; (2) pervasive and extreme uncertainty; and (3) path-dependence and lock-in. These were discussed in the previous sections. Risk minimising is based on the awareness that evolving systems are complex and can neither be understood nor controlled completely. Therefore, decentralised policies are attractive, notably ones based on self-organisation or self-regulation (Ostrom, 1990) and co-evolutionary mechanisms (Norgaard, 1984). Risk minimising strongly suggests to take the precautionary principle more seriously than is currently done. An original interpretation of this principle is in the statement of Ayres (1995): 99): ‘‘If it is impossible to know how far it is safe to perturb the system we live in without triggering a catastrophic collapse, then the only reasonable policy is not to perturb it more than it has been perturbed by natural phenomena in the past’’. A concrete elaboration is the safe minimum standard by Ciriacy-Wantrup (1968). From the perspective of path-dependence and lockin, risk minimising emphasises an adaptive design of environmental policies, which on one hand reduces the selective dominance of risky technologies and systems, and on the other hand supports alternative and sustainable trajectories by stimulating and fostering diversity. Specific instruments were already mentioned in the previous section. Finally, risk minimising can be linked to the notion of adaptive management (Walters, 1986). This says that any successful strategy for sustainability is characterised by a dynamic process of continuous adaptive learning. 4. Conclusion Sustainable development policies have to deal with uncertainty, unpredictable changes, and evolving properties of complex systems. An evolutionary perspective has been proposed here as the basis for developing a theoretical approach for studying such policies. It emphasises that economies are faced with a continuous process of adapting technologies, strategies, networks and structures to altered environmental conditions. The current economic focus on conventional policies is entirely based on optimum-andequilibrium oriented approaches that do not recognise the pivotal role of diversity. We have tried to shown that long-term sustainability calls for adaptive flexibility and evolutionary potential, which enables a continuous process of adaptive learning and a diversity of co-existing alternatives, at any level and in every subsystem of the economy. Implementing adaptive flexibility means shifting ones focus from a shortterm to a long-term horizon, where evolutionary potential and long-term stability can be linked to diversity. As a general policy approach, risk minimising was proposed. It is founded upon three pillars, namely evolutionary potential, uncertainty, and path-dependence. 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