Supporting cities in strengthening climate democracy: Lessons from Aachen and Barcelona

This article explores how two European cities strengthened climate action through democratic engagement. Supported by the NetZeroCities programme and Democratic Society, Aachen reframed climate narratives for public trust, while Barcelona bridged the gap between climate research and policymaking. Both cases demonstrate that thoughtful communication and scientific integration lead to more effective and democratic climate initiatives.

Cities across Europe face a double challenge – taking urgent climate action while maintaining public trust in an increasingly polarised environment. Two cases, in Aachen and Barcelona, show how, with good planning, climate action can deepen citizen engagement and create conditions for more bold action in the future.

The EU’s NetZeroCities programme supports the leading European non-profit Democratic Society (Demsoc) to work with both cities. In Aachen, Demsoc helped communicate climate policies in ways that avoid polarisation; in Barcelona, they supported efforts to map climate research and connect science with policymaking.

Both examples show how thoughtful support can lead to stronger, more democratic climate action. Cities can get greater long-term returns from participation than from broad-reach traditional communication – is the balance of spending right in your authority?

Reframing climate action narratives with the city of Aachen

When the City of Aachen approached our team at Democratic Society, their request was specific: help us communicate climate policies without triggering polarisation or resistance. Aachen faced a challenge familiar to many European municipalities – how to implement necessary environmental measures while maintaining public trust. What emerged became more than a communications strategy; it revealed how climate narratives can strengthen civic engagement.

The first crucial lesson was about framing. Climate policies succeed when framed around immediate human benefits, not emissions reduced, but lives improved. Pedestrian zones become opportunities for vibrant playgrounds and terraces. Cycling infrastructure means faster commutes and healthier families. Waste reduction translates to cleaner neighbourhoods and lower taxes for vulnerable groups. This shift from sacrifice to tangible benefit changes everything.

We emphasised that equitable implementation matters as much as the policies themselves. Low-emission zones must pair with affordable transit options. Green initiatives should first visibly improve life in underserved neighbourhoods. When climate action delivers clear advantages, such as expanded public spaces or reduced living costs, it builds trust rather than resistance. Also, economic concerns need to be addressed directly: nearly 40% of Germans worry climate action harms the economy; therefore, climate policies should always be paired with job creation numbers or cost savings.

Most crucially, we demonstrated the need for these approaches to be adaptable. There’s no one-size-fits-all solution, but rather a need for neighbourhood-by-neighbourhood dialogue. What works in Copenhagen’s cycling culture or Milan’s waste system must be reinterpreted for local contexts. The cities seeing most tremendous success are those treating climate communication not as publicity, but as ongoing democratic engagement – listening first, then co-creating solutions that address real community needs while advancing environmental goals.

As the workshop was very successful, we did it again, open to all Mission cities. Twenty-six cities joined, and currently we run this workshop with individual municipalities.

What began as a municipal consultation has evolved into something more significant: proof that thoughtful climate communication can be a powerful tool for democratic renewal. As other cities now apply these lessons, they’re discovering that the words we choose to describe change often determine whether communities fear it or embrace it. At the end of one of our recent workshops, a participant shared: “This was the single most useful online workshop I have attended—anywhere, on any platform—about communicating the net zero climate crisis.”

Bringing science and policy together: Mapping climate research in Barcelona

Like many cities worldwide, Barcelona is grappling with the intensifying impacts of climate change—rising temperatures, extreme weather events, heat islands and unequal access to green spaces. At the same time, it is home to a rich ecosystem of universities, research centres, and climate experts who produce high-quality studies on urban sustainability, decarbonisation, and environmental justice.

However, despite this wealth of knowledge, there had been limited structured interaction between scientists and the City Council. Policies were sometimes developed without fully integrating the latest research or consulting the broader scientific community. The city asked our team in Democratic Society to bridge this gap.

The Barcelona City Council requested that we develop a comprehensive research analysis and stakeholder engagement initiative in response to these challenges. The approach was multi-phased and focused on identifying existing knowledge, key players, and actionable insights.

The main objectives of the project were analysing all climate-related research carried out in the past 10 years related to urban contexts, decarbonisation, adaptation, climate justice, and citizen behaviour in Barcelona, identifying active researchers, research groups, and public or private institutions working in these fields and to extract key conclusions and recommendations from academic publications that could inform current or future public policies.

After that, the municipality asked us to organise a dedicated event that brought together researchers, policymakers, and other key stakeholders. This facilitated an open exchange of perspectives and laid the groundwork for ongoing collaboration. The event was not just a one-off meeting but the beginning of a process to build mutual trust and establish a structured model of governance that facilitates regular interaction between the scientific community and municipal decision-makers.

The results of the work we conducted for the municipality include improved visibility of climate research through mapping the landscape of climate-related studies and actors. The project created a valuable database that the City Council can use to consult experts and commission studies when developing new policies. Also, policymakers gained access to up-to-date research insights, which are now informing the city’s climate action plans and sustainability goals. Ultimately, a channel of communication has been established between local governments and academic institutions, fostering mutual understanding and collaboration.

This article was written in the context of the EU Cities Mission, as part of NetZeroCitiesEU, the project managing the EU Cities Mission Platform.

About Demsoc

Democratic Society is a membership organisation working across Europe to connect citizens with the decisions that shape their lives. We do this by building Democratic Infrastructure, driving structural change in local communities and putting together the relationships needed to shift systems. Since 2010, we have undertaken 150+ projects and worked with thousands of participants. In 2025, we were running 21 projects at local and European scale.