Take a city with an usually large a) thirst for climate knowledge, b) passion for climate action, c) number of climate experts. e.g. Oxford. A potentially super-critical system. As a (PhD?) project, synthesise best data on climate impacts and solutions for individuals. Work with expert communicators (e.g. Climate Outreach in Cowley), social scientists, psychologists etc. to create the most impactful leaflet. Link to an associated website with more details, links to groups etc. Tap into networks of enthusiasts - student societies and representatives, diverse environmental groups - and deliver to every house in the city, within the smallest time window practicable. Anticipate non-linear benefits from everyone now knowing that their friends and neighbours know the same thing: a point of conversation, shared standards for assessing behaviour c.f. Martin Nowaks theoretical work on cooperative behaviour (reputation counts). Collect data on responses: energy usage, meat sales, switches to renewable energy providers, loft insulation uptake etc. Perform causal inference analysis for attribution e.g. could compare to matched time trends in another similar, famous, ancient British university town. Control for heavy access to the associated website from other locations (partially replicating the intervention elsewhere, reducing the estimated impact). Publish: "Measuring a public intervention for global health", destined for high-impact journal and media coverage. Coordinate with the University press office. Enthusiasts elsewhere will access the website, use it as a general resource, and re-implement the intervention locally: much easier once the leaflet and website have been designed. Allow user uploads of leaflets adapted to different settings, different languages etc. Ensure leaflet and website emphasise pressuring for system change too, with specific information on how: whom to write to, what to say. Important though with less measurable effect for the study.