This week, wooden stakes displaying photos of young men were placed in the yellow sands of Copacabana beach, facing the upscale hotels on Avenida Atlântica in Rio de Janeiro. These hotels were hosting 300 mayors and their teams during the C40 World Mayors Summit.
The images showed four police officers who died in Brazil’s deadliest police raid just days before the summit. In that operation, which targeted two of Rio’s largest favela complexes, Alemão and Penha, 117 more people lost their lives. Police described it as a crackdown on organized crime.
The raid generated immediate media attention and even garnered support for regional governor Cláudio Castro, an ally of former president Jair Bolsonaro, who has denied climate change.
This protest cast a shadow over the start of a week when Rio was hosting not only the C40 summit on climate change—co-chaired by London’s Sadiq Khan and Rio’s mayor Eduardo Paes—but also Prince William’s Earthshot prize ceremony. Additionally, the COP30 climate talks are set to begin on Monday in Belém, a port city 2,000 miles to the north.
In a recent interview with the Guardian, UN Secretary-General António Guterres admitted that it’s now “inevitable” that humanity will exceed the Paris Agreement’s goal of limiting global warming to 1.5°C, which could have “devastating consequences” worldwide.
Despite extreme heat, floods, and wildfires, some populist leaders—ranging from skeptical to outright deniers of climate science—are emphasizing the costs of taking action rather than the risks of doing nothing.
Khan explains that the mayors’ summit aims to encourage regional politicians, often supported by progressive urban voters, to take stronger steps. He points out that cities produce 75% of global carbon emissions. It was also noted that the U.S. had the second-largest delegation at the summit, with about 100 mayors attending, despite the White House’s stance—no high-level Trump administration officials are expected at COP30.
Khan asserts, “Mayors worldwide, including in London, are leading by example and taking real action.” He adds that city leaders aren’t just making small changes; they’re striving to make a significant impact despite facing climate deniers like Donald Trump, widespread misinformation, public skepticism, and challenging local politics.
We spoke with six mayors about their efforts to address the climate crisis:
Yvonne Aki-Sawyerr, Mayor of Freetown, Sierra Leone (population 1.4 million), had a tough few days before flying to Brazil. A truck crashed into her parked car in Freetown, crushing the side where she usually sits, though she wasn’t in the vehicle at the time. Shortly after, her driver’s house caught fire for unknown reasons.
She reflects, “But there are a few things going on: I’m running for president, and I’ve been very vocal on narcotics,” calling it “a series of unfortunate events.” This isn’t her first encounter with such threats, but she says, “You can’t obsess about it or you wouldn’t get anything done.”
In Freetown, extreme weather, landslides, and flooding have led to a growingThe population in Aki-Sawyerr’s city is growing as subsistence farmers find they can no longer sustain a living from the land. In 2015, the city had just over a million residents, a number projected to double by 2028. This surge has led to an increase in informal settlements replacing forests on the hillsides around the capital and more logging for wood-burning stoves, which remain common and contribute to the city’s carbon emissions.
As mayor, Aki-Sawyerr’s authority is largely limited to sanitation. She dedicates much of her time to leveraging her position to secure international funding for initiatives like a cable car system to cut vehicle emissions and a goal to plant 5 million trees by 2030.
But how to prevent people from cutting down those trees? Her sanitation powers provide a solution. “We’re converting fecal sludge into briquettes as an alternative cooking fuel,” she explains. “It’s odorless, dried, and carbonized. By the end of December, we’ll have imported a machine that allows us to produce these briquettes on a large scale. We’ve tested them in homes and communities, and they’ve been well-received. The challenge has been scaling up production.”
Giuseppe Sala, a member of the Italian Green party and mayor of Milan for nearly a decade, expresses surprise at how rarely he sees Italy’s far-right Prime Minister Giorgia Meloni, who has visited the city only about three times in as many years. Meloni has voiced concerns about the “ideological” aspects of the European Green Deal, which aims to make Europe the first climate-neutral continent by 2050.
Sala highlights a project called “I don’t waste,” where primary school students are given reusable bags to take home uneaten food from school lunches. According to city hall estimates, this saves around 10,000 sandwiches, 9,000 pieces of fruit, and 1,000 desserts from being wasted each month. He also implemented a low-emission zone in Milan, the largest in the EU that restricts non-compliant vehicles. Although the city remains congested, air quality is improving, and the public has accepted the measure after a challenging first year.
Two months ago, Sala banned private vehicles from the roads around Via Monte Napoleone, Milan’s fashion district. “Always make step by step,” he advises, anticipating that the 2027 mayoral election will focus on this issue, with opponents arguing, “You have the right to drive your car where you want.” He sees this as an opportunity to gauge whether public attitudes can shift.
Nick Reece, serving as lord mayor of Melbourne for a year, began questioning the environmental impact when a planning application for a £100 million data center crossed his desk. “I asked the team: what’s the energy consumption going to be for this new data center?” he recalls. The response indicated that such facilities could account for a fifth of the city’s energy consumption by 2040.
Reece is now advocating for national and international regulations to govern data centers. “If we don’t establish a framework ensuring these new data centers are primarily powered by renewable energy, we won’t meet our carbon-reduction targets,” he warns. “We don’t want to see a race to the bottom in the pursuit of artificial intelligence and smart cities at the expense of the planet.”Reece also urges companies to think about how to best utilize the energy generated by data centers, for example, by using it to heat city swimming pools that typically depend on gas boilers. “In the push to develop smart cities, we must avoid overheating the planet,” he remarks. “That would be both ironic and tragic.”
Kate Gallego, Mayor of Phoenix, US, with a population of 1.6 million, notes that financing projects has grown more complicated. Last year, Phoenix set a new temperature record with 113 days exceeding 100°F (38°C). “We reached 110°F in October for the first time ever,” she says. “Close to Halloween, my children’s pumpkins practically melted. It was a serious situation. During the first week of school this year, temperatures hit 118°F, and my eight-year-old couldn’t go outside.” She believes these extremes have helped build political consensus on climate action.
Even for a desert city like Phoenix, this was extreme, but it was part of a globally unusual year. Gallego mentions collaborating with the UK’s fire department on heat management and firefighter safety during heatwaves.
However, with Donald Trump in office, federal funding has dried up. “We greatly benefited from renewable energy tax credits, so losing them has made project financing much harder,” she explains. “We’re also losing a significant grant called Solar For All for low-income households, and our electric vehicle grants have been suspended. The change in administration has drastically reduced federal support.”
Although Arizona voted for Trump, Gallego says the extreme heat has fostered support for emission-reducing policies, such as investing in light rail, and mitigation measures like using cooling materials on pavements to lower street temperatures and reduce potholes from asphalt expansion.
Carolina Basualdo, Mayor of Despeñaderos, Argentina, a town of 9,000, faces uncertainty over whether Argentinian officials will attend the Cop30 climate talks in Belém. Like Trump, President Javier Milei rejects the scientific consensus on human-caused climate change, calling it a “socialist lie.”
For Basualdo, this means no government funding for climate mitigation efforts. “We get nada, nothing,” she states. The crisis’s impact is evident in her town, which now experiences three heatwaves a year and storms with tennis ball-sized hailstones.
In response, she has implemented solar panel installations, set municipal building temperatures to 24°C (75°F) to save on air conditioning, and repurposed park pruning waste as eco-friendly boiler fuel. Additionally, plastic polytunnels from fruit farms are recycled into bags and wallets by women at a local gender violence shelter. With support from Bloomberg Philanthropies, the community collected two tonnes of plastic bottle caps to replace a basketball club’s granite floor. “We’ve been working very hard,” Basualdo says.
Evandro LeitãoEvandro Leitão, the mayor of Fortaleza, Brazil—a city of 2.7 million people—emphasizes the importance of balance in leadership. He commented on former President Jair Bolsonaro, describing him as isolated and acting on his own whims. Bolsonaro was sentenced to 27 years in prison in September for conspiring to overturn his 2022 election loss to left-wing rival Luiz Inácio Lula da Silva, who, like Leitão, belongs to the Workers’ Party.
During his presidency, Bolsonaro weakened environmental protections and encouraged the clearing and settlement of the Amazon rainforest. Deforestation rates surged by 60% under his administration—the largest relative increase since satellite tracking began. In contrast, Lula aims to position Brazil as a climate leader by investing in renewable energy and forest conservation.
Since becoming mayor ten months ago, Leitão has overseen the construction of new micro-parks in Fortaleza, expanding the city’s green space by 40%. This expansion is equivalent to adding 4,100 football pitches over five years.
However, concerns have arisen following the Brazilian government’s decision to suspend the soy moratorium, which had acknowledged deforestation as a risk linked to clearing land for soy cultivation. Additionally, the state oil company Petrobras has received approval to drill for oil near the mouth of the Amazon River.
Leitão remarked, “You have to strike a balance between developing the country and preserving its green areas. That’s a challenge I also face.”
Travel expenses for the World Mayors Summit were covered by C40, a network of 97 cities committed to addressing the climate crisis.
Frequently Asked Questions
Of course Here is a list of helpful and clear FAQs about mayors taking action on climate change
General Beginner Questions
1 Whats the main point of this news
Six mayors from major cities around the world are implementing concrete policies to fight climate change directly opposing national leaders who downplay or deny the problem
2 Why are mayors doing this instead of national governments
Because cities are often on the front lines of climate impacts Mayors can act more quickly and directly on local issues like transport housing and waste creating a bottomup approach to a global problem
3 Who are these six mayors
While the specific six can vary they are typically leaders of major global cities like London Paris Los Angeles Tokyo Sydney and Rio de Janeiro They are part of international networks like C40 Cities
4 What are some simple examples of what these mayors are doing
Common actions include
Creating more bike lanes and pedestrianonly zones
Expanding and electrifying public bus and train systems
Installing more electric vehicle charging stations
Making buildings more energyefficient
Increasing green spaces and parks
Deeper Advanced Questions
5 How are they challenging populist leaders
They are challenging them by proving that climate action is popular practical and economically beneficial at the local level Their success creates a powerful counternarrative to the idea that climate action is a costly or unnecessary burden
6 What are the biggest challenges these mayors face
They often face a lack of funding from national governments political opposition from business interests tied to fossil fuels and the logistical difficulty of retrofitting old city infrastructure
7 Is this part of a larger movement
Yes This is a key part of the subnational climate action movement Networks like C40 Cities and the Global Covenant of Mayors allow cities to share strategies set collective goals and show that they represent a significant portion of the global economy and population
8 Do these local actions actually make a difference globally
Absolutely Cities are responsible for over 70 of global carbon emissions If the worlds major cities successfully decarbonize it would put a massive dent in global emissions and create new norms and
