The postfossilCities simulation game allows players to test climate mitigation measures in an experimental setting and to experience synergies and trade-offs of relevant societal actors. By playing the game, the players will get to know different mitigation options and learn how effective they are. Moreover, playing the game enables players to take on different and possibly unfamiliar perspectives, and it encourages thinking in strategic alliances. The time-lapse of the game allows players to feel the urgency of effective climate protection measures. The insights gained during a postfossilCities game workshop support participants in actively shaping the transformation to a post-fossil society in both their private and professional contexts.

postfossilCities includes seven roles of relevant societal actors, such as politicians, population, or investors, which are played by one to four people each. During the game, the roles pursue their own, role-specific interests, and at the same time work towards the common goal of reducing the CO₂-emissions of our society to net zero without exceeding the available carbon budget. To achieve this, each role receives a set of action cards with possible measures that can be implemented alone or in cooperation with other actors. As in real life, actors that implement measures on their own risk losing "strength", while those who collaborate with other roles gain strength. During the game, time is running relentlessly and simulation results from an integrated game model continuously show whether the actors are on course or not.

To ensure optimal outcomes, the postfossilCities simulation game is applied in facilitated workshops with 7-28 participants. A workshop lasts approximately four hours and is structured in three phases:

• During the introduction, the participants are introduced to the topic of a post-fossil city and are familiarized with the game's rules and procedures.
• During the simulation phase, the participants play the game by taking on roles, strategizing, interacting, negotiating, taking decisions and evaluating the results.
• After the game, a debriefing takes place for reflection and transfer purposes. First, the participants analyze and reflect on their experiences in the game. Based on this, they then identify ways in which the knowledge gained can be transferred and applied to their own professional and private context.

The debriefing phase is particularly important for the transfer of the game content to the participants' everyday contexts and can be adjusted according to the demands of the group playing the game.

The simulation game postfossilCities is suited for applications in different contexts and with different audiences, such as:

• Politicians and public administrations to design and implement climate strategies;
• Urban/spatial/transport planners to involve stakeholders and develop climate strategies;
• Economic actors to design climate strategies and explore alliances with strategic partners;
• Institutions of higher education to provide students with an interactive learning experience;
• Citizens to challenge mental models, develop a shared understanding, gain a sense of urgency and network.

Due to the generic nature of the game, thematic focus, debriefing and follow-up activities can be flexibly adapted to the respective target group and context. If you are interested in playing the game, co-organizing an application workshop, or have questions regarding the game, please !