London, UK (22 June 2026) – The Mayor of London and co-chair of C40 Cities, Sir Sadiq Khan, will today open London Climate Action Week, promising to lead new coordinated action around the world to tackle the growing scourge of climate disinformation.
Key highlights
- City Climate Facts will equip mayors with the tools, evidence and support needed to lead climate action with confidence
- New global initiative from C40 Cities launched with the support of UN Special Adviser on Climate Action and Just Transition Selwin Hart
- Exclusive worldwide polling finds 84% of Londoners regularly encounter false or misleading information, while three-quarters of Melbourne residents say disinformation poses a serious risk to their community
- Cape Town to become first city to work with City Climate Facts, local polling finds nearly 90% of residents want their local governments to provide space to access the truth and assist in identifying false information
- Launch builds on the Mayor of London’s work leading the global fightback against disinformation
City Climate Facts launches at London Climate Action Week 2026
Today the mayor launches City Climate Facts (CCF), a major new global initiative designed to help city leaders tackle the growing threat of climate disinformation and rebuild public trust in an increasingly polluted online information environment.
The initiative has the support of Selwin Hart, UN Special Adviser on Climate Action and Just Transition. It will bring together data analysis, monitoring, rapid-response communications support, and practical guidance to help cities communicate clearly and confidently about climate policies and their benefits. It will work directly with cities around the world, starting with Cape Town, to provide practical, tailored advice, training and monitoring, while connecting cities with partners and experts.
The launch comes as new polling commissioned by C40 Cities reveals widespread worldwide concern about the scale of false and misleading information online, and strong public demand for trusted local leadership.
Climate disinformation is a growing threat to public trust worldwide
More than 8 in 10 (84%) report regularly encountering information they believe may be false or misleading
Three-quarters of London residents say misinformation and disinformation pose a serious risk to their community, while more than 8 in 10 (84%) report regularly encountering information they believe may be false or misleading.
The same is true in Santiago, where more than half of residents (58%) say they see disinformation ‘very often’. In Cape Town, nearly 90% of respondents called on their local governments to provide spaces to access the truth and to assist in identifying false information. And in Melbourne, only 45% of respondents said that they would be confident in spotting disinformation.
The polling also found that social media is now the most common place Londoners expect to encounter disinformation, with 76% identifying platforms as a key source of misleading content. Half of the respondents said manipulated or misleading photos were difficult to identify, while 47% said the same about written text.
What City Climate Facts does
CCF will work directly with cities around the world to provide practical, tailored advice, training, monitoring and rapid-response support, while connecting cities with partners, experts and peers. CCF’s first international project will be supporting the establishment of an anti-disinformation service in Cape Town, South Africa, where nearly 90% of residents polled wanted their local government to take a lead on tackling the issue.
London is on the frontline of increasingly coordinated online attacks surrounding climate action, air quality and a flood of disinformation being peddled online against the capital from all across the world.
The Mayor of London has previously warned of a ‘dark blizzard’ of disinformation targeting London, with City Hall research suggesting hostile actors, including foreign states and far-right groups, are portraying the capital as a city in decline. To fight back against this false narrative, earlier this month, the Mayor launched a major new international tourism and investment campaign to show the world the very best of London and fight back against this global scourge of online disinformation attacks.
CCF will be formally launched this evening when the Mayor delivers a keynote address to open London Climate Action Week at the Goals House reception at the Victoria and Albert Museum.
The Mayor of London, Sir Sadiq Khan, said:
“Climate change isn’t beyond politics – nothing is. The decisions we make about how to respond to our rapidly warming world will rightly provoke different opinions. In a healthy democracy, leaders shouldn’t just tolerate that debate – they should welcome it.
“What they shouldn’t welcome, however, are systematic attempts to subvert that debate by undermining the condition which makes it possible – the availability of reliable information. That is what climate wreckers and their propagandists are trying to do – rather than joining the conversation about how we respond to climate change, they want to destroy it by manufacturing doubt and denying the reality of the manmade crisis we face.”
“Research we’ve published today shows that Londoners are deeply worried. Three-quarters of them say that mis- and disinformation pose a serious risk to their community. That’s why, today, we’ve launched City Climate Facts – a new global initiative, coordinated by C40, designed to take on climate disinformation and rebuild public trust in our polluted online world.
“When we talk about disinformation, we’re not talking about well-intentioned attempts to challenge, criticise, or persuade. We’re talking about deliberate and coordinated attempts to deceive with deadly consequences, organised on online platforms where whipping up outrage and peddling conspiracy theories earns you a profit, not a punishment.
“In the fight against climate lies, the future of our planet isn’t the only thing at stake – the health of our citizens and the survival of our democracy are on the line, too. Taking a stand against disinformation is the only way to protect the welfare of our people and the freedoms they hold dear.”
Selwin Hart, UN Special Adviser on Climate Action and Just Transition, said:
“When climate science is undermined, people pay the price. Disinformation and misinformation do more than distort public debate — they delay action, weaken preparedness, and put lives and livelihoods at risk.
“At a time of escalating climate impacts, attacks on science and facts are attacks on our collective ability to protect people and communities. They also undermine confidence in the clean energy solutions that are essential to delivering energy security, economic opportunity and climate stability.
“Initiatives like City Climate Facts can help push back against this tide by equipping city leaders with credible information, strengthening public trust, and ensuring that facts and science – not falsehoods and vested interests – guide the choices that shape our future.”
Cities want better tools to fight climate disinformation
Nearly half of Londoners (47%), Melburnians (48%) and Santiaguinos (47%) said they wanted a trusted online space
The C40 Cities polling suggests urban residents are not only concerned about disinformation but are also actively seeking help navigating it.
Across the four cities polled, around a third of residents, when presented with true and false statements on issues including extreme heat, air quality and climate action, said the disinformation statements are closer to their beliefs.
In Cape Town, Santiago and London, more than four in five residents said it is important for local governments to provide information that helps people understand issues affecting their community.
When asked what support they wanted most, nearly half of Londoners (47%), Melburnians (48%) and Santiaguinos (47%) said they wanted a trusted online space where they could easily check whether something was true. Others called for simple guidance on identifying misleading claims and clearer explanations about how and why decisions are made.
There is growing evidence of coordinated online manipulation around climate policy debates. New analysis for C40 Cities using Valent’s disinformation intelligence software found that up to 48% of online engagement in some cities around air quality and low-emission policies is driven by bots.
At a time when cities are facing worsening climate impacts, including extreme heat, flooding, air pollution and rising energy costs, City Climate Facts aims to help mayors communicate clearly about both the risks communities face and the practical benefits climate action can deliver.
Yvonne Aki-Sawyerr OBE, Mayor of Freetown and Co-Chair of C40 Cities, said:
“Cities are on the frontlines of the climate crisis, but they are also at the forefront of delivering solutions. To act effectively, mayors need trusted, accessible information that helps us understand both the challenges our residents face and the actions that can improve their lives.
“City Climate Facts is an important step forward. By providing city leaders with clear, credible evidence and insights, it will help strengthen decision-making, counter false information, and support more effective climate action.
“At a time when trust and facts matter more than ever, initiatives like this can help ensure that cities are equipped to lead with confidence and deliver tangible benefits for the communities they serve.”
Mark Watts, Executive Director of C40 Cities, said:
“Whether the issue is clean air, extreme heat, renewable energy, or public transport, disinformation is making it harder for leaders to talk with residents about the challenges they face and the solutions that can improve their lives.
“City Climate Facts will change this. It will help cities access trusted information, share lessons from one another, and respond more effectively when climate action is misrepresented or distorted.
“It will mean that cities around the world will be better equipped to build trust, communicate with confidence, and deliver the climate action their residents expect and deserve.”