The nature and practice of sustainability is very complex, multi-dimensional and dynamic. Traditional and reductionist approaches have shown their inability to address sustainability issues. Increasing complex issues and challenges related to sustainability requires a fresh approach to address the multi-dimensional and multi-disciplinary nature of complexity. In this paper, systems thinking is used in a case study in a UNESCO designated Biosphere Reserve to demonstrate its application to effectively address complex and sustainability issues. A systems model has been developed, and various tools, processes and techniques of systems thinking have been used in the study. The systems model and its associated systems archetypes are qualitatively analysed to provide insights into potential system behaviour and to facilitate the identification of leverage points and systemic intervention strategies that are required for the sustainable development of the Biosphere. The unique approach used in this study has significant potential to apply globally considering the comprehensive network of Biosphere Reserves around the world, as well as the various sustainability and other complex issues that our society is facing. Copyright © 2012 John Wiley & Sons, Ltd.