A lack of collective awareness negatively impacts perceived personal efficacy, which hampers efforts to address societal problems. DecarboNet is a multidisciplinary effort to tackle this problem by identifying determinants of collective awareness, translating awareness into behavioural change, and providing novel methods to analyse and visualise the underlying processes. The project's core innovations are built around a context-specific repository of carbon reduction strategies. This "decarbonisation methodology" will increase awareness not only of existing problems, but also of best-practice solutions and the impact of individual actions. To continuously refine this repository, the collective awareness platform of DecarboNet will utilise citizen-generated content in a societal feedback loop that enables an adaptive process of social innovation.Supporting and understanding this process at various levels of granularity requires significant technological advances, including (i) generic tools to co-create knowledge with on-the-fly recommendations of related content from multiple sources; (ii) a cross-platform social media application to provide eco-feedback and engage citizens in games with a purpose; and (iii) methods to measure and predict behavioural change, and to capture collective awareness in a quantitative framework based on diffusion models and resonance patterns in public discourse.To assess engagement strategies, two use cases will contrast the effectiveness of competition-based and cooperative approaches in a grassroots experiment to measure energy consumption (Energy Quest) and a large-scale awareness campaign (Earth Hour). Analysing the results on the individual and collective level will provide actionable knowledge for a wide range of stakeholders. Associate partners including EEA, NOAA and the World Bank will provide a rich stream of input data and amplify the impact by promoting the adoption of project technologies among large user communities.