Proposal of a design support method of backcasting scenarios for sustainable society

In the life cycle engineering, describing scenarios is considered a good approach to sustainability in manufacturing in terms of clarifying visions of future manufacturing industry. When envisioning sustainable futures, describing "backcasting" scenarios is especially hopeful, because in a backcasting scenario, ideal future visions are firstly developed apart from the present situation. Although many scenario development methods have been proposed, these methods are too abstract, especially have no specific procedure for designing backcasting scenarios. This paper proposes a method for supporting design of backcasting scenarios using logic trees. In this method, logic trees support determining the structure of a backcasting scenario and creating storylines, which are outlines of sub scenarios. The logic tree and the storylines support describing the scenario text. As a case study, we described a backcasting scenario on "breakdown" of Japanese manufacturing in 2050. The result of the case study revealed that the logic tree systematically supports determining the structure of this scenario and generating its storylines. And composing scenario text is successfully supported by detailing the logic tree and the storylines.