'Tis the season to watch some iconic films 🎄

300 mayors. 50 sessions. 1 shared purpose. To protect the people and places we love. At the World Mayors Summit in Rio, mayors shared how they are delivering results in their cities.

NEW: Cities 1.5 Podcast’s Hot Takes - Dispatches from the Frontlines of the Climate Crisis. Cities 1.5’s first Hot Take focuses on a major move in Canada’s energy future and what it means for climate, cities, and the promises made to hold fossil fuel giants accountable. lnk.to/HotTakes1

The latest Journal of City Climate Policy and Economy issue is here. Climate-neutral construction, just transition strategies, new finance models for urban resilience: see what cities are already putting into practice. utppublishing.com/toc/jccpe/4/3

From London hitting clean air targets nearly 200 years early to Bangkok strengthening its targets, here are our 5 top moments from 2025, where cities around the world showed how they are delivering cleaner air and safer futures.

Mayors are moving past talk and delivering real progress by committing to Yearly Offers of Action. Our Co-Chairs are joining other city leaders to turn climate pledges into results. @london.gov.uk

The year of the mayor 🎧

To continue driving climate action, cities need more than applause. While we saw progress in Belém, local leaders still lack the recognition, tools and direct finance to scale their impact. 🎧 Tune in to the Cities 1.5 Special for the definitive city-level analysis of COP30 outcomes. lnk.to/Summit2

“This hurricane season made one thing clear: resilience has become a core part of public health." - Dr Quinn Adams on the defining health challenges of the post-hurricane era. More insights and reflections via the C40 Centre's latest Substack: https://thecentre.substack.com/p/hurricanes-are-changing

#COP30 fell short - and missed the opportunity to truly shift from negotiation to implementation. But mayors will not slow down. We're delivering ambitious, inclusive climate action now. The world needs to follow the pace of cities.

From cooling centres in Phoenix to tree planting in Quezon City, mayors are fighting extreme heat. The new C40 Cool Cities Accelerator is scaling these life-saving actions, helping cities worldwide protect residents and build a more liveable urban future.

The final mutirão decision of the #COP30 negotiations falls short on several of its original goals.

My comment on the #COP30 outcome: Multilateralism needed a boost in Belém, and instead it got a bandage. The COP process needs to take a long, hard look at itself.

As we wait for the official outcome of #COP30, here’s a time capsule of its last day: the outrage, the optimism, the urgency, and the sheer human effort that goes into trying to land a deal. The latest episode of @outrageoptimism.bsky.social featuring C40’s Eric Garcetti & @mark--watts.bsky.social:

”On the brink of collapse, #COP30 needs cities to survive” Former LA Mayor Eric Garcetti warns a non-consensus COP30 would be a "worst message at the most urgent moment." The solution is to bring cities to the table: an “easy win” to prevent the conference from sinking.

Our reaction to the disappointing draft outcome of #COP30 is the lead story in Brazil’s biggest paper today. A COP30 declaration without any proposal to phase out fossil fuels would be a huge wasted opportunity - and could reduce the global mutirão to ashes.

🚨BREAKING: historic scenes at #COP30 as Colombia launches the Belém Declaration on fossil fuels, together with a first international conference on a just transition away from fossil fuels - and invites cities and subnationals.

‼️ #COP30 could miss a historic opportunity if it does not formally include cities and subnationals in its outcome text. Caterina Sarfatti, Head of the C40 Cities delegation at #COP30: “This will not be the COP of implementation without highlighting the implementers."

While @cop30brazil.bsky.social has been framed as a 'COP of implementation', @c40cities.bsky.social has argued that this will only be possible if #cities and other sub-nationals are recognised as critical partners in planning and delivery. 🏢 sustainabilityonline.net?p=16943

🚨BREAKING: C40 Cities reacts to the disappointing draft outcome of #COP30 @mark--watts.bsky.social, C40 Cities Executive Director, on the draft of the Belém Political Package: “The draft texts we've seen this morning in Belém suggest several parties are trying to leave the global mutirão in ashes.

The Yearly Offer of Action shows cities worldwide acting now — closing the gap between pledges and progress. Cities are calling on national governments to work closer with them to go further and faster in tackling the climate crisis. https://www.c40.org/news/yearly-offer-of-action/

At #COP30 youth are urging to put cities & local solutions at the heart of climate action. Global Youth is urging national govts to endorse & implement CHAMP to strengthen cooperation between national & local governments to ensure this becomes the COP of Implementation. @mayors4climate.bsky.social

🏙️ CITIES ARE DELIVERING. A new @mayors4climate.bsky.social – @c40cities.bsky.social assessment released at #COP30 shows that local climate action is accelerating faster in CHAMP countries - those that partner with cities.

❗NEW: a call for cooperative climate action at #COP30 Mayors delivered a crucial message to President @lulaoficialbluesky.bsky.social: the need for a strengthened formal dialogue between national, local, and regional governments to accelerate the delivery of the Paris Agreement.

🔴WATCH LIVE: local leaders conference at #COP30 Mayors and local leaders are the ‘climate doers’: this will not be a ‘COP of Implementation' without them. 📺 Live at 10am BRT/UTC-3: unfccc.int/event/c40-ci...

BREAKING: cities press @lulaoficialbluesky.bsky.social at #COP30 for a formal role in climate decisions An international coalition submits request for the final text to recognize the role of local governments. veja.abril.com.br/agenda-verde...

“Alongside hundreds of millions of city residents on the frontlines of the climate crisis, mayors are dealing with the causes and consequences of climate change every day.

Cities are on the front lines of the climate crisis - and the solutions. @tainadepaularj.bsky.social, Rio's Deputy Mayor for Climate, and @mark--watts.bsky.social, C40 Cities' Executive Director, discuss how cities are leading the way with collaboration, innovation, and listening to communities.

It’s crunch time for negotiations at COP30. ⏰ For this to be the ‘COP of Implementation’, cities must be fully recognised as partners for multilevel cooperation.

A better food future is on the menu. 🍎 Through the new C40 Thriving Food Systems Accelerator, cities from São Paulo to Cape Town are building food systems that are healthy, sustainable, and create good green jobs.

Cities 1.5 is back with a podcast episode from the flagship gathering of the world’s urban climate leaders, the World Mayors Summit, which took place earlier this month. From London to Amman, hear from mayors about their vision for the future of city climate action: lnk.to/Summit1

Cities around the world are raising the bar on climate action. By committing to a Yearly Offer of Action, mayors are taking concrete steps to get the world on track to meet the goals of the Paris Agreement. https://www.c40.org/news/yearly-offer-of-action/

🇪🇺At a COP defined by action, Europe is backing the local climate agenda. The European Union has endorsed #CHAMP, reinforcing that cities & regions are indispensable for delivering the Paris Agreement: https://c40.me/4r6zIwE @ec.europa.eu | @mayors4climate.bsky.social | @teresaribera.ec.europa.eu#CHAMP

“I think this COP must be the ‘COP of cities’, must be the COP of local implementation, and must be the COP of dialogue between national governments and local governments.” - Mayor Mohamed Sefiani of Chefchaouen, Morocco & GCoM Regional Ambassador, speaking at #COP30 📽️: c40.me/4o27OiU

“If this is a COP of implementation, the absence of the urban and subnational agendas from the final decisions would be an adverse signal for the implementation of the agenda.” Strong call from Brazilian governors: #COP30 outcomes must leave a clear legacy for subnational governments.

What if cities could fight climate breakdown and improve the health of residents at the same time? @novonordisk.bsky.social and C40 Cities are helping cities like Bogotá and Rio de Janeiro transform neighbourhoods so everyone enjoys cleaner air and better health.

We start the final week of #COP30 with strong momentum behind our push for greater inclusion of cities as key partners in the delivery of these critical climate negotiations. A thread 👇 (1/7)

The climate crisis hits women, children & low-income communities hardest. C40 Cities' Caterina Sarfatti tells @cnn-brasil.bsky.social at #COP30 that a "just and orderly transition" isn't just possible, it's essential - and it's already starting in cities.

Half-time analysis at #COP30 ⚽️🕑🌎 Take a look at our mid-point assessment of city and subnational action and asks in Belém. c40.org/news/halftim...

When it comes to combating the climate crisis, cities like Paris, Tshwane, and Dalian are proving what’s possible. Through the Yearly Offer of Action, mayors commit to concrete steps over the next 12 months — turning ambition into implementation. https://www.c40.org/news/yearly-offer-of-action/

📣 At #COP30, the ICCT is partnering with @c40cities.bsky.social and the Climate and Clean Air Coalition (CCAC) to accelerate electrification of construction equipment globally. Construction equipment accounts for 40% of non-road emissions—a significant opportunity! 👉 theicct.org/pr-global-pa...

🚨 BREAKING: C40 Cities calls for #COP30 to raise ambition and progress plan to phase out fossil fuels ⚡ City leaders joined a coalition offering support for a fossil fuel transition roadmap. Cities are ready to contribute not only as partners in planning, but as essential drivers of delivery.

Cities are powering a cleaner, healthier future. ⚡ From Melbourne to Lagos, 15 cities in our Renewable Energy Accelerator are transitioning from fossil fuels. A third already powers their city operations with 100% renewable electricity, building a future where clean energy is available for all.

At #COP30 cities are ready to deliver on climate 🌍 They have the ideas, the action, and the people. Now they need predictable and accessible funding – for better transport, cleaner air, affordable housing, more resilient communities, and to create good green jobs.

From Rio to Rotterdam, cities are stepping up to help the world get back on track in combating climate breakdown. C40 mayors are standing together and delivering a Yearly Offer of Action - promising real results within their cities in the next 12 months.

📢 @c40cities.bsky.social and @un-habitat.bsky.social are joining forces to transform urban planning. Our Urban Planning Accelerator aims to help cities cut emissions by 25%. By providing cities with tools, expertise & technical guidance, we can create safer, more sustainable urban environments.

#Disinformation is a core topic at #COP30. C40's @mark--watts.bsky.social on how mayors are tackling it: "C40 supports the importance @lulaoficialbluesky.bsky.social has placed on information integrity and tackling disinformation. Cities can play a critical role in making this the ‘COP of Truth’.

🚨BREAKING: Ana Toni praised city leadership at #COP30 @cop30brazil.bsky.social CEO highlighted the just-announced Yearly Offers of Action: mayors' response plan to the NDC, adaptation & finance gap, and a concrete step to get the world on track to meet the Paris Agreement goals.

💥GOOD NEWS: multilevel climate governance milestones announced at #COP30 Brazil🇧🇷 & Germany🇩🇪 will co-chair the CHAMP coalition until 2027, accelerating national & local government collaboration. @marinasilva.bsky.social @mark--watts.bsky.social @meioambientegov.bsky.social @cop30brazil.bsky.social

Over 2000 attendees, 300 mayors, 50 sessions and 1 shared purpose: to protect the people and places we love. Thank you to the partners who made the C40 World Mayors Summit a success. Gold: Novo Nordisk Bronze: Uber, Carrier, @giz.de Exhibition: IBM #WMS25