23 December 2025 – Cities, world expos and stakeholders driving sustainability
Cities are the defining form of human life in the 21st century. More than half of the world’s population already lives in urban areas, and by 2050 this figure will rise to nearly 70 percent. Cities concentrate people, resources, innovation and cultural expression—but also emissions, inequalities and systemic risks. For this reason, the future of sustainability will not be decided in abstract strategies alone. It will be decided where people live, move and interact every day: in cities.
This conviction shaped the Club of Rome Salon Building the City of the Future, a collaboration between the Arts & Nature Social Club and the German Association for the Club of Rome, held in Berlin in December. The Salon brought together political leadership, international institutions, urban practitioners, artists and civil society to explore how cities—and platforms such as world expos—can act as catalysts for sustainable transformation.
Speakers for the salon
Cities as engines of transformation
Urban areas account for the majority of global energy consumption, resource use and greenhouse gas emissions. Yet they are also places where change happens fastest. Since the adoption of Agenda 2030, cities around the world have demonstrated their capacity to translate global goals into local action—through sustainable infrastructure, inclusive planning, resilient systems and citizen participation.
At the salon, speakers emphasised that successful urban transformation depends on empowerment: cities must not be passive arenas of policy implementation, but active agents shaping their own futures. Sustainable cities are not built solely through technology or regulation; they emerge through dialogue, trust and shared responsibility between public institutions, businesses and citizens.
As highlighted by Eckart Würzner, Mayor of Heidelberg and Chair of the UN Forum of Mayors, long-term success requires participatory processes, ambitious climate targets and strong local ownership. Heidelberg’s experience illustrates how climate neutrality, social inclusion and economic vitality can be pursued together when citizens are involved and cities are given the mandate to lead.
World expos as platforms for collaboration and legacy
World expos have historically served as global stages for innovation, culture and progress. In recent decades, sustainability has become increasingly central to their mission. From Expo 2000 in Hanover—one of the first expos explicitly aligned with sustainability principles—to the current expo in Osaka, expos have evolved into collaborative platforms for education, dialogue, and experimentation.
Dimitri Kerkentzes, Secretary General of the Bureau International des Expositions (BIE), described expos as spaces where the world can “reimagine new possibilities.” Beyond showcasing ideas, they enable cooperation across borders and sectors, mobilise national and local actors and—when designed responsibly—leave lasting urban legacies. Expos are not ends in themselves; they are instruments to accelerate transformation and to ask what kind of future we want to build together.
In this context, discussions around Expo 2035 Berlin focused on its potential as a platform rather than a spectacle: a way to connect innovation with sustainability, global goals with local realities and visionary thinking with political responsibility. The emphasis was on long-term impact—on infrastructure, mobility, climate-neutral development and civic participation—rather than on the event alone.
Political responsibility and civic engagement
The political dimension of urban transformation was strongly articulated by Franziska Giffey, Mayor and Senator for Economy, Energy and Enterprise of Berlin. She underlined that sustainability must address concrete challenges—affordable housing, mobility, climate neutrality, economic innovation—while strengthening democracy, peace and social cohesion. Cities, she argued, are places where global questions become tangible and where solutions must prove themselves in everyday life.
A recurring theme throughout the evening was the importance of bottom-up processes. Transformation succeeds when citizens are not merely consulted, but actively involved; when cities have agency; and when different stakeholders are brought together across institutional and disciplinary boundaries.
Arts, culture and the human dimension of cities
Discussions on mobility and urban quality of life illustrated how global ambitions translate into everyday reality. Katrin Habenschaden, Head of Sustainability, Deutsche Bahn AG and former Deputy Mayor of the City of Munich, speaking from the audience, emphasised that major infrastructure such as central stations is necessary, but not transformative on its own. The real opportunity lies in developing these nodes into integrated mobility hubs that connect modes of transport and better serve people moving through—and living in—the city.
This functional perspective was complemented by a more human-centred view. Another voice from the audience, Heskel Nathaniel, Co-Founder & CEO, Trockland Management GmbH, reminded participants that the quality of urban life ultimately depends on the quality of relationships. Beyond environmental performance and technological innovation, cities and urban projects gain lasting value when they create spaces with soul—places that foster connection, trust and meaningful interaction between people.
Arts and culture are not optional add-ons to urban development, but essential components of the city of the future. They help create emotional connection, shared narratives and the capacity to imagine alternatives—without which transformation cannot succeed. This is a point I emphasised during the session as host and moderator.
Looking ahead
The Club of Rome Salon reaffirmed a central message: building the city of the future is a political, cultural and societal task. It requires courage, collaboration and imagination. Cities must be empowered to lead, citizens must be partners in change, and platforms for dialogue—such as world expos—must be designed with responsibility and legacy in mind.
The Arts & Nature Social Club will continue to create spaces where arts, nature, policy, and innovation intersect—spaces where complex challenges can be explored holistically, and where new narratives for a sustainable future can emerge.
