This poster integrates the results of four different modules of the ClimPol project (Climate Policy Making for Enhanced Technological and Institutional Innovations). These modules deal with climate change mitigation behavior of individuals (ClimPol module B1), firms (D2), small rural/peri-urban communities (B2), and cities and counties (A2). The common topic of voluntary action for climate change mitigation links these modules. We define voluntary action as the action, when an individual, a firm, a community or a city have a negative impact on the natural environment and reduce it without being legally obliged to do so (Thalmann and Baranzini, 2004). Some selected findings of the four modules are presented and integrated with respect to the two guiding questions: Why do individuals, firms, small communities and cities take voluntary action to mitigate climate change? What is the advice for efficient voluntary action?