When we think about who is shaping the future of sustainable cities, the conversation often centres on national governments and large international agencies. But some of the most consequential climate leadership has come from city halls – and in particular, from women mayors who used local governance as a powerful platform for green transformation. Hanna Gronkiewicz-Waltz, Warsaw’s first female mayor, is one of the most compelling examples of this. Elected in 2006 and serving until 2018, she transformed a coal-dependent Central European capital into a recognised model of sustainable urban development – one whose lessons extend well beyond Poland’s borders.
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The climate protection committee: building institutional foundations
One of Gronkiewicz-Waltz’s earliest and most structurally important moves was establishing a formal institutional mechanism for climate governance. In 2008, she set up the Climate Protection Team – a body she chaired personally – bringing together directors from city departments alongside representatives from non-governmental organisations. This wasn’t a symbolic committee. It was a coordination engine that monitored and guided climate initiatives across the entire city administration.
The committee’s work fed directly into Warsaw’s Sustainable Energy Action Plan (SEAP), adopted by the City Council in 2011. The plan set three headline targets for 2020 compared to a 2007 baseline: a 20% reduction in CO₂ emissions, a 20% cut in energy consumption, and a 20% increase in the share of renewable energy. These were not soft aspirations – they were binding commitments made under the EU Covenant of Mayors, an initiative Warsaw was one of the first Polish cities to join in 2009.
What made this institutional design effective was its cross-sectoral scope. Rather than treating climate action as an environment department issue, the SEAP covered transport, buildings, heating, waste, and citizen behaviour – with each sector assigned concrete actions and timelines. By 2014, Warsaw had already reached the halfway point in its investment targets, with €2 billion committed to emissions reduction programmes across all those sectors.
Sustainable transport: buses, trams, and the Veturilo network
Transport was both Warsaw’s biggest challenge and one of its most visible successes under Gronkiewicz-Waltz. Private cars accounted for 80% of all transport-related emissions, even though public transport already handled 60% of all journeys in the city. The goal was not simply to reduce emissions from existing vehicles, but to make public and active transport so attractive that residents would choose to leave their cars behind.
The city invested heavily in modernising its fleet. This included the purchase of 186 new trams equipped with energy recovery systems, 273 modern buses, and 35 six-coach underground train units. Crucially, diesel buses were phased out in favour of electric and natural-gas models, directly cutting particulate emissions in a city already grappling with serious air quality problems. A second metro line – the single largest urban infrastructure investment of the era – was also constructed and extended.
Alongside mass transit, Gronkiewicz-Waltz launched the Veturilo public bicycle-sharing system in August 2012. Starting with 55 stations and 1,000 bicycles, the network expanded into one of the largest urban bike systems in Europe, eventually reaching over 400 stations and 6,000 bicycles spread across all of Warsaw’s districts. By the time the system had been running for eight years, it had recorded over 11 million individual bike rentals. The programme also helped normalise cycling as everyday urban transport, not just recreation – a cultural shift that complemented the infrastructure investments.
Efficient public utilities for a greener city
Heating is central to urban sustainability in Central European cities, where winters are long and coal has historically been the default fuel. Warsaw operates what is the largest district heating network in the European Union – approximately 1,800 kilometres of pipelines serving around 19,000 facilities and covering roughly 80% of the capital’s heating needs. Under Gronkiewicz-Waltz, modernising this network was treated as a climate imperative, not just a utility management issue.
Ten thousand additional homes were connected to the district heating system during her tenure, reducing reliance on individual coal or gas boilers which are far less efficient and far more polluting. Plans were also developed to switch one of Warsaw’s two main combined heat and power plants from coal to natural gas – a transition that, while not a final destination for decarbonisation, represented a significant near-term reduction in carbon dioxide and particulate matter emissions.
Wastewater management received equally serious attention. Warsaw’s treatment facilities were upgraded to use treated wastewater within their own processes, reducing municipal water demand. More significantly, biogas generated during the wastewater treatment process was captured and used to meet the facilities’ own energy needs – covering both heat production and, at the major Czajka plant, around 40% of its electricity demand. This kind of resource loop – where a waste product becomes an energy input – is precisely the logic of circular urban infrastructure.
Renewable energy and citizen engagement
Gronkiewicz-Waltz understood that decarbonisation could not be achieved by infrastructure alone. The SEAP explicitly acknowledged that cultural change – shifting how residents thought about energy and climate – was as important as any technology investment. Warsaw’s approach to citizen engagement operated on several levels simultaneously.
At the household level, the city promoted individual-scale renewable energy installations, including solar panels, through awareness campaigns and alignment with national and EU subsidy frameworks. Warsaw’s geographic position – at a latitude where solar panels optimally tilted at around 43 degrees can generate meaningful output – made residential solar a genuinely viable option, and the city worked to make residents aware of both the technical and financial case for adopting it.
Educational programmes also brought climate literacy into schools, with students learning about energy systems as part of Warsaw’s broader push to create an informed, engaged citizenry. Events like Warsaw Energy Day brought public conversations about sustainability into civic life. The SEAP was explicitly designed as a plan that laid out what the local government needed to do – rather than vague aspirational language – making it legible and accountable to ordinary residents.
Internationally, Gronkiewicz-Waltz was equally active. Warsaw joined the C40 Large Cities Climate Leadership Group and became part of EUROCITIES, the network of major European cities – an organisation she would go on to lead as president from 2012 to 2014. In 2015, the city signed the Declaration of European Mayors for Climate Action ahead of COP21, committing to joint green public procurement including shared purchases of renewable energy for municipal use and natural-gas-powered municipal vehicles. These international connections helped Warsaw both benchmark its own progress and amplify its influence on European urban climate policy.
Legacy and impact: what Warsaw’s experience teaches us
Gronkiewicz-Waltz served as Warsaw’s mayor until 2018, and the foundations she laid continued to shape the city’s trajectory long after her departure. The Veturilo bike network kept growing. The district heating modernisation continued. The SEAP targets informed subsequent plans. Her work also elevated Warsaw’s international standing: the city was selected to host COP19 in 2013, a recognition of its commitment to climate action – a remarkable position for a capital city in a country still heavily dependent on coal at the national level.
After leaving the mayor’s office, her influence shifted to the European level. She served from 2019 to 2024 as Chair of the Mission Board for Climate-Neutral and Smart Cities, an initiative of the European Commission that she helped design – channelling the practical knowledge gained in Warsaw into policy frameworks that would apply to 100 European cities pursuing climate neutrality by 2030. In 2024, she joined the European Parliament, bringing that accumulated expertise into EU-level legislative work.
What Gronkiewicz-Waltz’s career demonstrates most clearly is the compound effect of sustained, systemic leadership at the city level. Individually, each initiative – bike sharing, bus electrification, heating network expansion, energy education – might look incremental. Taken together, they represent a coherent urban climate strategy delivered by a single accountable leader over more than a decade. Her approach also illustrates something broader: research consistently finds that women-led cities tend to prioritise long-term, systemic sustainability over short-term visibility – a governance orientation that urban climate challenges fundamentally require.
The OECD has noted that two-thirds of the global Sustainable Development Goals cannot be met without local governments. Warsaw under Gronkiewicz-Waltz is a demonstration of what local government can achieve when it treats sustainability not as an add-on but as a core function of city management – and when it is led by someone willing to build the institutions, make the investments, and bring citizens along in the process.
What do you think? Should city-level climate leadership carry more formal recognition and funding weight in national and EU policy frameworks – and does the gender of a city’s leader actually shape the sustainability ambitions it pursues?
References
- https://www.lincolninst.edu/publications/articles/mayors-desk-1
- https://www.climateaction.org/climate-leader-papers/the_warsaw_way_to_climate_protection/
- https://glcn-on-sp.org/cities/warsaw/
- http://www.climatescorecard.org/2016/11/poland-emissions-reduction-strategy/
- https://consortiumforsustainableurbanization.org/2020/07/the-transformation-of-the-cycling-culture-in-warsaw/
- https://link.springer.com/article/10.1007/s43937-023-00019-z
- https://profilesolar.com/locations/Poland/Warsaw/
- https://netzerocities.eu/2025/03/24/an-interview-with-hanna-gronkiewicz-waltz-the-cities-mission-is-transforming-our-cities-it-deserves-better-political-funding-support/
- https://corporateknights.com/rankings/sustainable-cities-rankings/2022-sustainable-cities-index/most-sustainable-cities-led-female-mayors/
- https://www.nachhaltigkeitsrat.de/en/sustainable-development/sustainable-development-in-city-and-country/
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