Trans4Demo is an evidence-based and impact-driven set of actions to address contentious politics arising from climate change and sustainable transitions. These conflicts are seen as a critical challenge for democratic systems, and their importance is expected to grow in the future. Authoritarian tendencies and right-wing populism have weakened social cohesion, making large parts of EU populations less willing to change their practices and hindering responses to climate challenges. The main objective of the project is to investigate the role and evolution of diverse forms of opposition and contentious politics of sustainability transitions, and their impact on democracy. We aim at delivering the temporality-sensitive conceptual framework, practical understandings, and policy recommendations to assist in democracy reinvigoration. By exploring these intersections, we identify specific scientific, consensus-based, and politically normative goals that political communities in diverse European contexts could pursue. Empirically, throughout the project, we will (1) focus on practical understandings of the role of various bottom-up mobilizations against the populist backdrop, (2) identify novel sites of constructive democratic engagement, and (3) address the role of trust in the democratic process, including the validity of electoral processes. Building on this, (4) we will provide sound, research-based policy recommendations that balance bottom-up and top-down perspectives for democratic renewal. To achieve these targets, we will employ triangulated and participatory methodologies, including case studies and future-oriented methods, developed in collaboration with societal actors involved in the project—from the initial design of the research agenda to fieldwork and dissemination activities.