This document discusses community-based social marketing (CBSM) as a sustainability gamechanger. CBSM uses principles of psychology and social marketing to promote sustainable behavior change. It works by addressing barriers to sustainable behaviors and incorporating strategies proven to make change easier, like social diffusion and norms. CBSM considers the community context and selects initiatives that fit. The document advocates for using CBSM ideas and provides contact information for further resources on CBSM presentations, workshops and consulting.