1 INTRODUCTION Futurists both outside and within geological engi- neering fields very rarely consider the requirements (and opportunities) for underground space (Hunt et al. 2009), even though its use has certain critical im- plications for a sustainable future above ground in urban areas (Sellberg 1996). Notwithstanding this shortfall it has been recognised for some time that the use of underground space would likely grow in- creasingly important with time (Sterling 2000). UF research can provide geological engineers with a better understanding of both current and fu- ture requirements (and opportunities) for under- ground space through the use of a toolkit for infra- structure provision (with a particular focus on sustainable use of underground space). The toolkit is being derived currently and ultimately will be used to help test the performance, resilience and robust- ness of current underground infrastructure solutions through the use of a range of possible urban future scenarios for 2050. Told in both numbers and words, future scenarios are plausible, challenging and relevant stories about the future (Raskin et al. 2005). They are a distinctly different from trend analysis tools in that they are devoid of the requirement to show exactly how we get there from here. This is vitally important because it moves ‘futures’ research far beyond current ob- servations and extrapolation of existing trends. In addition some might argue that this creative way of thinking helps us to better prepare for a future that may be distinctly different from what we know now. A fundamental challenge facing the UF team is selecting appropriate scenarios for 2050 and present- ing them to any given audience, i.e. unifying the richness of narrative with the clarity of quantifica- tion (Raskin 2005). [According to IPCC (2002), scenario-based research bridges the quantitative (i.e. models that give structure, discipline and academic rigor, see Raskin 2005) with the qualitative (i.e. sto- ries, or the ‘scenario narrative’, giving voice, tex- ture, richness and insight to those qualitative factors, see for example, Kahn et al. 1976, Kaplan 1994)]. An even bigger challenge is being able to convey quickly and concisely how each scenario both func- tions and performs when compared to each other and when compared to today. [It is akin to being para- chuted into a scenario and very quickly reporting back how they work.] The UF toolkit can overcome these challenges by using ‘key questions’, ‘sustainability indicators’ and Assessing the sustainability of underground space usage - A toolkit for testing possible urban futures D.V.L. Hunt The University of Birmingham, Birmingham, UK I. Jefferson The University of Birmingham, Birmingham, UK C.D.F. Rogers The University of Birmingham, Birmingham, UK ABSTRACT: A description of the future as it might be without forecasts, predictions and trend analysis can be referred to as a ‘future scenario’. An abundance of scenarios literature exists in which numerous pi c- tures have been painted of changed future worlds. However, upon closer inspection it becomes apparent that virtually all of this literature refers to changes occurring above ground, ignoring the inevitable consequences (or opportunities) for sustainable use of underground space, not least in densely populated urban areas, some of which may be underlain by complex geological conditions. This paper reports on the development (to date) of an ‘Urban Futures’ (UF) toolkit for sub-surface envi- ronments (including infrastructure and utilities) which, through use of ‘key’ questions ‘sustainable’ indicators and a ‘contextual’ narrative, allows for better definition and measured performance of underground space in the UK, both today and in the future. The toolkit explores possible uses for underground space within 4 plau- sible and well-cited future scenarios (i.e. New Sustainability Paradigm, Fortress World, Market Forces and Policy Reform). This forms part of a much larger generic toolkit which the UF research team are developing for exploring possible future scenarios over a range of UK urban regeneration case study areas.