مرور به سمت توسعه پایدار: یک رویکرد پویایی سیستم

Traditional fragmented and mechanistic science is unable to cope with issues about sustainability, as these are often related to complex, self-organizing systems. In the paper, sustainable development is seen as an unending process defined neither by fixed goals nor by specific means of achieving them. It is argued that, in order to understand the sources of and the solutions to modern problems, linear and mechanistic thinking must give way to non-linear and organic thinking, more commonly referred to as systems thinking. System Dynamics, which operates in a whole-system fashion, is put forward as a powerful methodology to deal with issues of sustainability. Examples of successful applications are given. Any system in which humans are involved is characterized by the following essential system properties: Bounded rationality, limited certainty, limited predictability, indeterminate causality, and evolutionary change. We need to resort to an adaptive approach, where we go through a learning process and modify our decision rules and our mental models of the real world as we go along. This will enable us to improve system performance by setting dynamic improvement goals (moving targets) for it. Finally, it is demonstrated how causal loop diagrams can be used to find the leverage points of a system.

We have long believed that science and technology can provide effective solutions to most, if not all, environmental problems facing modern society. However, the validity of this optimistic assumption has become increasingly questioned. The scientific system, thus, faces a crisis of confidence, of legitimacy, and ultimately of power, as there is a growing feeling from many quarters that science is not responding adequately to the challenges of our times, and particularly, those posed by the quest for sustainable development. Issues about sustainability are often related to complex, self-organizing systems, and although there has been a gradual fleshing-out of the meaning of sustainable development, most researchers still find it difficult to grasp the essence of the concept. For instance, most scientists still find it hard to accept that sustainability should not be perceived as a ‘project’ that has an end point, but as an ongoing process that needs to be regarded as part and parcel of everyday work. Modern science is characterized by ever-increasing specialization. As a result, it has delivered lots of knowledge but very little understanding. Basically, classical science, be it chemistry, biology, psychology, or the social sciences has focused on isolation of elements of the observed universe. The common belief has been that if we know everything about the parts, we will understand the whole. However, to create understanding, it is not enough to just study parts or processes in isolation. All this knowledge is, thus, in dire need of synthesis through some kind of multilevel and multi-dimensional graph of interconnections. There is a need to accept Leibniz's idea that within an entity of interacting parts, no part can be changed without triggering changes all over the whole. This means that we need to solve the decisive problem of how the order and organization unifying the parts affects the behavior of the whole system. Likewise, the engineering profession has to learn that arithmetic is a complement to, not a substitute for thought. As several scholars have pointed out, the very power of the computer to simulate complex systems by very high-speed arithmetic has prevented search for those unifying and simplified formulations that are the essence of progressive understanding. The uncertainties related to complex problems will not be resolved by mere growth in our data bases or computing power. Nonetheless, there is a need to try to bridge the gap between what is known and what is done. To this end, it is essential that research move beyond classical mono-disciplinary and even inter-disciplinary lines to one trans-disciplinary in nature, and fully integrates this approach in its problem solving efforts. There is an emerging understanding that the quality of the decision-making process is absolutely critical for the achievement of an effective product in the decision. This new understanding applies to the scientific aspect of decision-making as much as to any other. As Meadows et al. [23] point out, the world society is still trying to comprehend the concept of sustainability, a term that remains ambiguous and widely abused even more than one and a half decade after the Brundtland Commission coined it. Therefore, the aim of the present paper is to show how sustainable development can be dealt with by using the system dynamics approach—a feature of systems thinking that considers dynamic relations in a system holistically. Section 2 discusses the concept of sustainable development and some of the efforts made to make the concept operational. Then it goes on to argue that linear cause–effect mechanisms are unable to explain the complexity, which is inherent in issues of sustainability. Section 3 discusses systems thinking and, especially, one of its trans-disciplinary tools i.e. the system dynamics approach. In Section 4, it is stressed that fragmentation in the different branches of science should give way to holism where resources are viewed together, interacting with people and capital as well as interacting with each other. What is important is to understand changes, and to that end, we need to acknowledge the following essential system properties: Bounded rationality, limited certainty, limited predictability, indeterminate causality, and evolutionary change. In Section 5, it is stated that we need to adopt a learning approach to become able to cope with the self-organizing mechanisms active in complex systems. Then, Section 6 shows how system dynamics can be applied to issues of sustainable development. Hereby, it is shown how a system dynamics approach and its causal loop diagrams (CLD) can be used to identify different dynamic structures governing real world ecosystems. By recognizing the dynamic structures, we propose the idea of viability loops and describe sustainable development as a matter of keeping those viability loops functional. The paper ends with Section 7.

In spite of its simple definition, sustainable development risks to become a meaningless buzzword since most scientists are stuck in reductionist thinking. Many attempts have been made to put the concept into practice. However, rather than providing practical guidance, these attempts merely show that there are widely different perceptions of the concept of sustainable development. Many scientists look at sustainable development as a ‘project’ which has an ‘end state’. But it should be noted that sustainability is neither the state of the system nor is it a target to be achieved. Sustainability is an ideal to the system, which as an ongoing process, needs to be regarded as part and parcel of everyday work. It inter-relates different aspects of economy, environment and society. Classical science solves problems by breaking them down into elements and then focusing on the isolated elements. This paradigm which assumes that problems are limited and well defined is no more useful to face complex systems. Sustainable development is an issue of complex systems. Dealing with sustainable development requires moves across the boundaries of different branches of science and humanities. A shift of paradigm from fragmentation in science to holism is required. To achieve such a shift, linear and mechanistic thinking must give way to non-linear and organic thinking, more commonly referred to as systems thinking. Systems thinking is a way of understanding reality that emphasizes the relationships among a system's parts, rather than the parts themselves. System dynamics—one branch of systems thinking—is a thinking model and simulation methodology that was specifically developed to support the study of dynamic behavior in complex systems. It offers a powerful perspective, a specialized language, and a set of tools that one can use to address the most stubborn problems in one's everyday life and work. Thus, it provides us with potent tools for coping with sustainable development. Any natural system is run under the control of some balancing mechanisms, negative feedback loops, or Viability Loops, as we call them in this paper. The role of these viability loops is to keep the system working everlastingly. Hampering these balancing loops will result in domination by the reinforcing loops, which will finally destroy the system. Sustainable development—regarding the terminology of system dynamics approach—is therefore described in this paper as the process in which the viability loops are kept functional. Thus planning for a sustainable development would be to identify the viability loops in the system, and to direct efforts towards keeping these loops in a healthy state. Thus, if we base our analysis on a holistic vision of human and natural interactions, heterogeneity, and uncertainty, we arrive at the conclusion that, to be able to deal with sustainable development, we need to acknowledge the following essential system properties: Bounded rationality, limited certainty, limited predictability, indeterminate causality, and evolutionary change. The generic viability loops associated to Human needs, Economic, Environmental, and Life services structures have been shown and discussed using the CLD analysis. Sustainability is seen as an unending process of perceiving changes and keeping those loops active to adapt the system to changes. The System dynamics approach helps us to better understand the dynamic relations in the system and become aware of their changes through a learning process. This perception would be helpful to set moving targets for the system.