Cooler cities, transformed food systems, and climate-focused urban planning. At the 2025 World Mayors Summit, C40 Cities announced three new accelerators, all of which will help protect the people and places we love.
Cool Cities Accelerator
Extreme heat is a deadly and growing threat, killing an estimated 489,000 people each year. By 2050, the number of urban residents exposed to life-threatening temperatures is set to rise fivefold.
The C40 Cool Cities Accelerator will equip mayors with the tools and structure needed to deliver a strategic, coordinated and cross-departmental response and preparation for extreme heat. The cities who joined are committing to turning a climate crisis into an opportunity to build cooler, safer, and fairer cities for all. Every tree planted, every home cooled, and every life protected brings us closer to a more just and sustainable world.
Mayor of Freetown, Yvonne Aki-Sawyerr
Thriving Food Systems Accelerator
People living in cities consume over half of all food produced globally, and this is due to rise to 80% by 2050.
Through our new Thriving Food Systems Accelerator, mayors across Africa, Asia, and Latin America are committed to delivering a food system transformation by 2035. The initiative focuses on tackling hunger, improving livelihoods and building climate-aligned food economies.
From initiatives like universal school meals to better collaboration between cities and local producers, we can ensure every resident has access to affordable, healthy, and sustainable food.
Taking care of food is taking care of people
Mayor of Curitiba, Eduardo Pimentel
Curitiba offers three quality meals to 140,000 students every single day and has 35 public markets that sell nutritious food at lower prices for low-income families.
Now part of the Accelerator, Mayor Pimentel is excited to transform more spaces in Curitiba into urban farms that revitalise land, offer good food and become spaces for the community.
Urban Planning Accelerator
As cities face rapid expansion, shrinking green spaces and growing risks, future urban development must help cities grow in ways that are sustainable, equitable, and resilient.
C40 Cities and UN-Habitat today launched the Urban Planning Accelerator, an initiative designed to drive bold climate action in cities, placing people, planet, and prosperity at the centre of urban development. Through the accelerator, C40 and UN-Habitat will provide cities with technical, political, and policy support to put climate action at the heart of urban planning.
Hosting the World Mayors Summit here in Rio is a proud moment for our city and for Brazil. We know what it means to face climate risks, but also the opportunity that comes with action. Brazil’s hosting of COP30 will show that cities can deliver results now, not in the distant future.
“Our goal is to shift to a planning model that really puts people, planet and equity at its core. By adopting a better model of urban planning, cities could cut greenhouse gas emissions by up to 25% by 2050. The best climate activist might well be an urban planner,” – Cassie Sutherland, Managing Director for Climate Solutions and Networks, C40 Cities
Driving change
Freight transport keeps our economies moving, but it is also a rapidly growing source of climate emissions and a major contributor to air pollution in our cities.
Brazilian mayors joined freight businesses and partners from The Climate Pledge, Global Optimism and Amazon to showcase how cities and companies are joining forces to accelerate zero-emission freight.
We need to decarbonise urban logistics as a mandate for public health and urban equity. The solution is collaboration that bridges the public and private sectors.
Sally Fouts, The Climate Pledge
Cities leading the way to COP30
The Mutirão in Motion plenary brought together city and national leaders to show how cooperation across levels of government is helping accelerate climate action ahead of COP30.
Speakers, including Brazil’s Minister of Cities, Jader Filho, Mayor of Rio, Eduardo Paes, and Birgit S. Hansen, former mayor and current local government representative in Denmark, highlighted the importance of CHAMP – the Coalition for High Ambition Multilevel Partnerships – where 77 countries are now working with their cities and regions to shape stronger national climate plans.
As part of this progress, governments agreed to establish a new governance structure, including a Cities and Regions Advisory Group, to ensure local leadership has a permanent seat at the table.
Finance is key for multilevel collaboration. Things happen when mayors take responsibility. Hard work is not enough – we need money, and effective leadership is crucial.
Birgit S. Hansen
Mayors meeting to create change
C40 mayors from different regions met at the World Mayors Summit to share progress, exchange ideas, and strengthen their collective vision for climate leadership.
Facing rising heat, floods, and toxic air pollution, cities are on the frontline of the climate crisis – but are also driving solutions that deliver cleaner air, greener jobs, and more resilient communities.
Co-Chairs, Mayor of London, Sadiq Khan, and Mayor of Freetown, Yvonne Aki-Sawyerr, spent time with mayors from each region and discussed how their cities can shape the global climate agenda and ensure urban priorities are at its heart.
In the European convening, Governing Mayor of Oslo Eirik Lae Solberg spoke of the critical nature of the EU’s climate commitments: “Speaking from the perspective of a mayor from a country that is not part of the EU, I look at the EU for leadership. When we see national governments backtracking on their climate ambition, cities should push their national governments from below, while the EU should influence them from above.”
Disinformation threatening democracies
Later in the day, mayors came together for an honest discussion on one of the defining challenges of our time: disinformation.
Mayors heard how misinformation and disinformation threaten democratic engagement and climate progress. The conversation offered city leaders a rare opportunity to exchange insights on how cities can help rebuild trust through transparency, community dialogue, and collaboration with credible voices.
Together, mayors reaffirmed their commitment to driving hopeful, people-centred climate action.
Waste management: our emergency brake on climate change
Methane is one of our biggest opportunities to tackle global warming, as it contributes nearly half to recent temperature increases. If action is taken now, we could avoid 0.3 degrees of warming.
This is what the Waste Reduction: Cutting Methane and Creating Jobs panel at World Mayors Summit discussed today, with Executive Mayor of Ekurhuleni Nkosindiphile Xhakaza and Mayor of Helsinki Daniel Sazonov sharing experiences of managing methane in a way that assists their cities, reducing overall waste and creating good green jobs.
Port cities are where global trade and climate action meet.
This afternoon, Lord Mayor Lars Weiss, Mayor Karen Bass, Managing Co-Chair of America Is All In, Gina McCarthy, Deputy Mayor Nancy Sutley, WRI President and CEO Ani Dasgupta, and 68th US Secretary of State, John Kerry, joined industry and thought leaders, collectively emphasising that we cannot wait for global consensus on shipping. By transforming into clean energy hubs, cities can deliver a just maritime transition.
“Cities need to decarbonise shipping equitably, to demonstrate the clean energy opportunity to save lives and advance livelihoods. We need to push the International Maritime Organization for stronger climate action.”
We fight the good fight until we win
Managing Co-Chair of America Is All In, Gina McCarthy
Yearly offers of action
Throughout the World Mayors Summit, city leaders are unveiling their yearly offers of action – specific commitments to accelerate progress over the next 12 months.
Bringing greater urgency and accountability to local climate leadership, the actions support the Brazilian COP30 Presidency’s Global Mutirão and move from negotiation to implementation.
From Tokyo committing to install solar panels on new buildings to Seoul upgrading insulation in 1,500 low-income homes, C40 and GCoM mayors are taking action to protect the people and places we love.