If information and communication technologies (ICT) are to bring about a transformational change to a sustainable society, then we need to transform our thinking. Computer professionals already have a conceptual toolkit for problem solving, sometimes known as computational thinking. However, computational thinking tends to see the world in terms a series of problems (or problem types) that have computational solutions (or solution types). Sustainability, on the other hand, demands a more systemic approach, to avoid technological solutionism, and to acknowledge that technology, human behaviour and environmental impacts are tightly inter-related. In this paper, I argue that systems thinking provides the necessary bridge from computational thinking to sustainability practice, as it provides a domain ontology for reasoning about sustainability, a conceptual basis for reasoning about transformational change, and a set of methods for critical thinking about the social and environmental impacts of technology. I end the paper with a set of suggestions for how to build these ideas into the undergraduate curriculum for computer and information sciences.

In this paper, I argued that the societal transformations needed to achieve sustainability are more often hampered by ICT than they are helped. I identified computational thinking as an important factor, as it tends to push computer professionals towards overly simplistic formulations of complex societal problems, and fosters technological solutionism - a belief that solving these simplified problems will help build a more sustainable world.
Hence, we tend to look for solutions that automate and optimize existing ways of doing things, in preference to seeking more fundamental transformations towards sustainability. The reductionism of computational thinking offers an impoverished approach to dealing with systemic problems such as sustainability, and in the process blinds us to issues such as the social and environmental impacts of ICT.
In contrast, a fuller understanding of the role of ICT for sustainability requires a different kind of thinking, taking into account the emergent properties of complex systems, and the ways in which the dynamics of social systems shape our use of technology within them. I argued that systems thinking provides a useful antidote to the reductionism of computational thinking, and identified three specific contributions systems thinking can make to expanding the conceptual toolkit of computational thinkers, namely: a domain ontology for reasoning about sustainability, a set of theories of how transformational social change occurs, and a set of practices for critical thinking about the social and environmental impacts of technology.
While the techniques of systems thinking are not new, they have so far made little impact in most academic disciplines. I argued that this is partly because existing university structures do not encourage teaching and research into inter-disciplinary ideas, and partly because the ideas are often considered too abstract to be useful. To address this, we are exploring the introduction of systems thinking into computer science courses, via a collection of inter-disciplinary games that offer hands-on experience of the non-linear dynamics of complex systems. These games work well with variety of students, and are especially useful in mixed inter-disciplinary groups, as they overcome barriers that arise from mixing different levels of expertise within the same class. Response to the use of these games in the courses has so far been overwhelmingly positive, although a full evaluation of their effectiveness will be the subject of future work.