C40 Cities

Water = life 💧 By introducing clean drinking water kiosks in underserved communities, C40 Co-Chair and Mayor of Freetown Yvonne Aki-Sawyerr is tackling climate challenges, creating new jobs and protecting people from unsafe water.

Episode 2 of the Oh Canada Podcast - Living with #fire in a warming world - is out now!🔥From restoring Indigenous #culturalburning practices to building #disaster-ready, #low-carbon homes, this episode explores what it will take to prepare for a future shaped by fire 🎧 lnk.to/OhCE2

More trees, cooler streets and a city better prepared for extreme heat. 🌳 Through ‘Freetown the Treetown’, C40 Co-Chair Mayor Yvonne Aki-Sawyerr is showing how a simple solution can make a big difference in the fight against rising temperatures in Freetown, Sierra Leone. Watch to see how.

Oh Canada: Solutions for the Climate Crisis is out now! Episode 1 explores the science, data & politics behind Canada’s #climate trajectory — and the #solutions we need. Featuring Ian J. Mauro, Amber Bennett & Steven Guilbeault. 🎧 lnk.to/OCE1 #cdnclimate #cdnpoli

Transforming the Seine River and making it clean and swimmable was one of the boldest moves Paris took to tackle the climate crisis. Hear from the Mayor of Paris, Emmanuel Gregoire, about how restoring the Seine is future-proofing the city for generations to come.

Cities are already feeling the impact of a hotter, more unforgiving climate. From opening public areas 24/7 for people to cool down to creating more shade and green spaces, cities like Paris are finding practical ways to protect residents from extreme heat. @egregoire.bsky.social

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Over the last 4 years, global emissions rose by 2%. Meanwhile, C40 cities cut emissions per person by 3.5% – proving that cities have the power to drive real change. Dive into the work mayors and cities are putting in every day to protect the people and places we love: bit.ly/C40AnnualReport2025

What if there are reasons to hope for a more #resilient #climate future right here in Canada? The Cities 1.5 podcast new miniseries, Oh Canada, features #elbowsupforclimate signatories who are leading on local climate solutions: buff.ly/RToT2VC @c40cities.bsky.social

36 cities in C40’s Cool Cities Accelerator are helping millions of people stay safe as temperatures rise. Lessons from pilot projects in cities such as New York City and Miami are now being shared across the C40 Cool Cities Accelerator to help these solutions reach more people.

Sessions during Climate Week NYC are looking at how cities can prepare for intensifying heat and unpredictable weather, with US mayors across the country already responding; Phoenix is expanding shade, Austin is making homes cooler, and NYC is improving access to essential cooling for tenants.

Governor of California @gavinnewsom.bsky.social speaking at the United Nations on the power of local climate action.

Mayor of Boston & C40 Vice-Chair @mayorwu.boston.gov speaking at the United Nations on the impact and importance of taking climate action every day.

Mayor of Freetown & C40 Co-Chair Yvonne Aki-Sawyerr speaking at the United Nations on why cities matter in the fight against climate breakdown.

"Before 2023, we only had about 14 days where the heat was over 105°. This August alone, we had 17 days in a row over 105°." - Mayor of Miami Eileen Higgins on the urgent need to act to help people stay safe as temperatures rise.

“Spaces like this provide incredible guidance. We’ve benefited so much from Climate Mayors and C40’s infrastructure.” - Mayor Wu speaks with Eric Garcetti at the @climatemayors.bsky.social Leadership Forum on the benefits of working with other city mayors.

With Ramboll, our new research shows how cities can expand affordable housing and protect people from climate risks: www.c40knowledgehub.org/s/article/Wh.... @sissemariewe.bsky.social, @annehidalgo.bsky.social & Anacláudia Rossbach examined how cities can deliver on housing in a changing climate.

Mayor of Freetown and C40 Co-Chair, Yvonne Aki-Swayerr, and New York City Chief Climate Officer Louise Yeung joined young leaders, including winners of C40’s Students Reinventing Cities competition. They explored how young people can shape urban planning for more inclusive, climate-resilient cities.

We heard from Simon Stiell, UNFCCC Executive Secretary, at New York Climate Week today. He spoke to the importance of continued climate action in the US and the power of sharing solutions that work.

Mayors, investors and industry leaders explored how cities can plan for the growth of data centres while protecting energy prices, water, and local communities.
The discussion focused on C40’s Global Urban Data Centre Pact, which sets out a vision for a more sustainable, affordable digital future.

Extreme heat is the deadliest climate risk cities face, and mayors are on the frontline of keeping people safe. C40 and @harvardsalata.bsky.social brought together Mayors Yvonne Aki-Sawyerr, @egregoire.bsky.social and Pramono Anung to see how cities can strengthen life-saving early warning systems.

“When a city succeeds, we know there is potential for all cities to succeed.” - Zohran Mamdani, @mayor.nyc.gov, speaking at U20. 📷: Scout Tufankjian

“We are more powerful when we work together. Climate change is borderless and unrelenting. In turn; we must be unrelenting in our response.” - NYC Chief Climate Officer, Louise Yeung, speaking at U20. 📷: Scout Tufankjian

“Working together is important; being here at U20, we can learn, benchmark, be inspired. We have all the solutions together.” - Mayor of The Hague, Jan Van Zanen, speaking at U20. 📷: Scout Tufankjian

“Climate action must benefit people in ways that they can see and feel in their daily lives. Jakarta is ready to serve what works, learn from other cities and turn the climate issues into practical solutions” - Governor of Jakarta, Pramono Anung, at U20. 📷: Scout Tufankjian

“We have a lot to do to face these challenges, and I’m sure the U20 will help us to succeed.” - Mayor of Paris @egregoire.bsky.social, speaking at U20. 📷: Scout Tufankjian

“We need to work side-by-side because whether it’s our neighbour across the street or across the ocean, this problem is our problem and the only viable solution is the one we developed and delivered together.” - Julia Kerson, NYC deputy mayor for operations, speaking at U20. 📷: Scout Tufankjian

“We need to work side-by-side because whether it’s our neighbour across the street or across the ocean, this problem is our problem and the only viable solution is the one we developed and delivered together.” - Julia Kerson, NYC deputy mayor for operations, speaking at U20. 📷: Scout Tufankjian

Climate Week NYC is here! 🇺🇸 🗽 💚 With city leadership more vital than ever, mayors are coming together at #ClimateWeekNYC to collaborate and share ideas on how to protect the people and places we love.

“We believe that we must march boldly into the future or we risk being dragged into it backwards. It calls for rigorous international collaboration.” - Elle Bisgaard-Church, Chief of Staff to @mayor.nyc.gov, speaking at U20. 📷: Scout Tufankjian

“We believe that cities have many of the answers.” - @zohrankmamdani.bsky.social @mayor.nyc.gov at U20.

C40 Co-Chair and Mayor of Freetown, Yvonne Aki-Sawyerr is sharing the work of fellow C40 mayors at U20 and highlighting where greater co-operation can help cities go further.

Nearly 1 billion people live in C40 cities, and over 30 of those cities have come together for this year’s Urban 20 (U20). Co-hosted by Los Angeles and New York, the summit will see mayors identifying shared priorities and opportunities for action on some of the world’s most pressing challenges.

⭐ U20 is here ⭐ At Urban20, mayors are discussing measures cities are already taking to build more affordable housing, protect tenants and make homes and neighbourhoods more resilient.

“Our cities are choosing cooperation.” - @mayor.nyc.gov, Zohran Mamdani Over the next two days, over 30 cities will come together for this year’s U20, co-hosted by Los Angeles and New York, to identify opportunities to act on some of the world’s most pressing challenges.