Over the last thirty years, the concept of sustainability has become the central orientation framework for debates in politics, the economy, science, and the public all over the world on the future development of humankind. In order to be able to provide sufficient guidance for decisions within the framework of necessary social transformations, three things are particularly required: first, the concept must be translated into concrete goals at the conceptual level; second, instruments must be developed and applied to be able to analyze the most diverse subjects of observation in a context-adapted manner and to evaluate them against the background of the goals; third, the results of the application of these instruments to support decision-making processes must be provided in way that is appropriate for the addressees.

The central challenge is to realize this triad in such a way that, on the one hand, the complexity of the concept and the numerous subjects of observation are taken into consideration and, on the other hand, the analytical and practical implementation is guaranteed.

Against this background, the objectives of the cross-cutting activity are:

• Reflecting on the sustainability-related work of the last three decades in ITAS with the aim of evaluating the manifold experiences in realizing projects and providing advice to stakeholders and distilling the central “lessons learned” from them. This is supposed to contribute to the further specification of an “ITAS philosophy” on the topics of sustainability and sustainability assessment.
• Enhancing the Integrative Concept of Sustainable Development (ICoS), which has been mainly developed by ITAS, against the background of the wide range of application experience as well as advancing the instruments for integrative sustainability assessment, applied, for example, for energy scenarios.
• Realizing projects related to sustainability on different topics.
• Supporting ITAS colleagues during the application for and realization of sustainability-related projects.
• Fostering and accompanying the exchange between research groups on sustainability topics and methods.
• Strategically coordinating the ITAS sustainability research across the boundaries of research groups with the aim of pooling experience, improving learning processes, and providing the basis for further conceptual as well as methodological developments.