n if these are not readily quantifiable.

As a result, even though the importance of sustainability is increasingly recognized, many software systems are unsustainable, and the broader impacts of most software systems on sustainability are unknown.\
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**Sustainability is systemic.** Sustainability is never an isolated property. Systems thinking has to be the starting point for the transdisciplinary common ground of sustainability.\
**Sustainability has multiple dimensions.** We have to include those dimensions into our analysis if we are to understand the nature of sustainability in any given situation.\
**Sustainability transcends multiple disciplines.** Working in sustainability means working with people from across many disciplines, addressing the challenges from multiple perspectives.\
**Sustainability is a concern independent of the purpose of the system.** Sustainability has to be considered even if the primary focus of the system under design is not sustainability.\
**Sustainability applies to both a system and its wider contexts** There are at least two spheres to consider in system design: the sustainability of the system itself and how it affects sustainability of the wider system of which it will be part.\
**Sustainability requires action on multiple levels.** Some interventions have more leverage on a system than others. Whenever we take action towards sustainability, we should consider opportunity costs: action at other levels may offer more effective forms of intervention.\
**System visibility is a necessary precondition and enabler for sustainability design.** The status of the system and its context should be visible at different levels of abstraction and perspectives to enable participation and informed responsible choice.\
**Sustainability requires long-term thinking.** We should assess benefits and impacts on multiple timescales, and include longer-term indicators in assessment and decisions.\
**It is possible to meet the needs of future generations without sacrificing the prosperity of the