We know enough. The task now is aligning science, finance, and policy to deliver climate action where resilience is truly built: in our cities.

A personal reflection from Singapore stood out: long-term 15-year planning, continuously adapted, alongside a strong focus on developing workforce skills for the next phase of the economy. The pace of green development on the island nation is remarkable and offers lessons for cities everywhere.

With investors and policymakers, we focused on a persistent challenge: why capital still isn’t flowing into cities at the scale or speed required, and what exactly needs to change.

With @ipcc.bsky.social scientists and city leaders, we discussed how the latest IPCC cities report serves as a once-in-a-lifetime opportunity to translate science-backed climate evidence into real-world decisions that can benefit millions of people.

Resilience was the clear theme at the recent World Cities Summit I attended in Singapore 👇 One message stood out: urban nature is not a luxury – it is essential infrastructure for building liveable, resilient cities.

This morning, the Lord Mayor of Melbourne @nicholasreece.bsky.social & I spoke with @news.abc.net.au to discuss how cities around the world dealing with extreme heat and flooding. I’m looking forward to sharing more insights on how Sydney and Melbourne are protecting the people and places we love.

We spoke about how cities and other subnational leaders must be at the forefront of climate talks. On the frontline of the climate crisis, mayors and other local leaders are accepting accountability, showing collaborative leadership and delivering tangible action.

This week I’m in Australia, visiting the two C40 member cities: Sydney and Melbourne. I joined Lord Mayor @nicholasreece.bsky.social, Cathy Oke, and Jess Miller to discuss the role of cities in shaping the COP31 agenda as Australia prepares to take on the presidency of the climate negotiations.

In cities, resilience and nature can go hand in hand. Beijing transformed a former industrial site into a lush space that absorbs rainwater, reduces flood risk, and allows wildlife to thrive. Places like City Central Green Forest Park show what’s possible.

It’s amazing what the shift to renewables can look like. A theme park, a transport hub, and a library – all powered by clean energy. In Beijing, the transition is visible and practical, powering the places people use every day.

The best climate solutions do several things at once. At Shanghai's Luojing Port, ships plug in instead of burning fuel, cutting noise & cleaning the air for workers & nearby communities. The shift also helps push global shipping towards greener operations. That's the power of city climate action.

Beijing has cut PM2.5 pollution by nearly 70% since 2013, and you can feel and see the difference. More people outdoors, more cycling and running, more green spaces. Climate action woven into everyday life looks just like this.

Heidi Sørensen, who passed away on 25 April after living with cancer for years, was a pioneer in the global climate movement. At C40 Cities, we remember Heidi as a tenacious innovator who proved that cities must lead the way in solving the climate crisis.

It’s also been amazing to me that 24 hours after a major snowstorm, I could safely run along fully cleared sidewalks. Mamdani’s administration is building a city that is resilient to extreme weather - and offered $30 an hour to any New Yorkers who turned up to help the fire service clear the snow.

We discussed the new administration's climate priorities under Mayor Mamdani - including its clear understanding that tackling affordability means tackling the climate crisis. That means focusing on energy affordability and safe and healthy housing.

Great to meet with New York’s new Chief Climate Officer, Louise Yeung and other colleagues from across the NYC city government. New York has long been a climate leader. As one of the first members of C40 Cities, it has always set the pace for bold and practical action.

A standout moment at the #WMS25: youth activists declaring, "We do this for our today, we do this for our tomorrow, and we will do this together.” This new Hot Takes episode from the Cities 1.5 podcast brings the young voices we heard to even more people - an absolute must-listen: lnk.to/HotTakes2

How 2 people helped expose a $10B Exxon scandal. I highly recommend the latest episode of Cities 1.5, where Lindsey Gulden sheds light on how Exxon’s shocking overvaluation was protected by disinformation and silence. The fossil fuel industry’s culture of deception must be stopped. lnk.to/S6E3

“One city does something and a hundred of us then will take it to scale. I find hope in the fact that cities can make this work” - inspiring words for difficult times from the Mayor of Austin, Kirk Watson, in the latest episode of the Cities 1.5 podcast: lnk.to/S6E2

Privileged to accompany @london.gov.uk to welcome United Nations Secretary General, Antonio Guterres, to London today. Inspired by his leadership on climate & so much else & motivated by his message that we must up the pressure to shift off polluting fossil fuels

We must end the fossil fuel era. UN Secretary-General, António Guterres, knows this better than anyone. I want to thank him for his steadfast climate leadership and his commitment to phasing out fossil fuels. A pleasure to meet today together with C40 Cities Co-Chair, Mayor of London Sadiq Khan.

How are cities and subnational leaders turning negotiation into action? This #COP30 booklet captures the crucial role cities play in tackling the climate crisis, and lays out our COP30 asks. To deliver climate action at the speed required, subnational inclusion at COPs cannot be overlooked.

This week, I’m at @cop30brazil.bsky.social in Belém where cities are backing the COP30 Presidency's call in moving from negotiation to implementation. Here’s what to expect from C40 Cities over the next two weeks ⬇️

We were lucky to host many European mayors at #WMS25, part of the Local Leaders Forum, as well as @teresaribera.ec.europa.eu, who made the CHAMP announcement at the Local Climate Action Summit here in Rio today.

Brazil's biggest newspaper @oglobo.globo.com ran a series of articles on Cities of the Future - and the one just published features Rio, one of the finalists for the Local Leaders Climate Awards 2025, which will be presented later today. Good luck!

The World Mayors Summit 2025 opened with a powerful call: move negotiation to implementation. 20 years ago, a small group of forward-thinking mayors created this organisation because they feared no one else would act.

time.com/collections/...

Great to meet with the @cop30brazil.bsky.social High-Level Champion Dan Ioschpe who has made huge progress on consolidating the the action agenda to ensure it can deliver on the goals of the Paris Agreement. #ClimateWeekNYC

“We are united by a common purpose: to ensure that the energy systems of our cities are not just functional, but transformative, providing reliable power, fostering economic growth, and creating opportunities for every citizen.” - C40 Co-Chair, Mayor Aki-Sawyerr at Climate Week NYC.

At the opening ceremony, COP30 Brazil President André Corrêa do Lago said it best: “Subnational governments have an amazing role to play in climate action.” #ClimateWeekNYC