Abstract: Despite the success of some environmental and sustainability initiatives and measures in policy-making, business and society, overall social, economic and ecological trends follow an unsustainable path. Next to existing strategies and policy instruments new approaches are needed. Recent debates and initiatives on new welfare measurements beyond GDP, sharing economy, transition towns, zero growth or degrowth reflect the search for more fundamental sustainability transitions. Within a pilot study for the German Environmental Protection Agency a new approach of participatory, qualitative modelling has been employed to identify drivers, blockages and fundamental leverage points for sustainability transitions. Next to the identification of interconnected key factors, explanations for collective stalement and requirements to rupture the vicious cycle of un-sustainability have been elaborated. Finally it is argued, that qualitative modelling has the potential to contribute to transformation research and practice regarding sustainability transitions.