Mental models for sustainability

Mental models are a feature used by the human brain to handle complexity. In the environmental context, mental models are both useful to understand and to solve problems. The paper is specifically designed to address managerial thinking. To prove a conceptual skeleton for the notion of sustainability, a simple spreadsheet model is developed to show basic patterns of resource behaviour: constant stock, constant flow, regenerative stock and combinations thereof. Self-imposed limits are a means to manage sustainability. Uncertainty and competition are shown to be dangers to sustainability. The problems with current models in mainstream managerial thinking lie first in the limits of human perception itself. Second, in the economic theory, the issue of time is not handled adequately, for example, in discounting, the treatment of free goods and information provided by the market place. Similarly, the belief that technology might solve the problems does not include dynamic considerations. The fatalist view, that environmental problems cannot be solved at all, is a self-fulfilling prophecy. It can be overcome by managing both ecology and economy in a coherent way. Improved thinking tools may be derived from a systemic consideration of the environmental situation of a company or from the second law of thermodynamics. Challenges for science are the development of measurements for sustainability and an extension of economic theory to appropriate consideration of the issues ‘dynamic behaviour’ and ‘future’.