With contributions from C40 Chair, Mayor of London Sadiq Khan, and C40 Executive Director Mark Watts

Foreword by C40 Chair, Mayor of London Sadiq Khan

As Mayor of London and Chair of C40, it’s been inspiring to see cities again leading the way in taking climate action in 2022. In recent years, the seriousness with which cities have treated this issue has been in sharp contrast to many of their national counterparts. Indeed, the difference between cities and national governments has been like the difference between night and day, with the former acting as the climate doers and many of the latter the climate delayers. In fact, three-quarters of C40 cities are decreasing their per capita emissions at a faster rate than their own countries.

From São Paulo to Seoul, Accra to Dhaka, Buenos Aires to Bogotá, and Milan to Montréal, C40 cities are stepping up and showing that ambitious climate action is possible. Mumbai, for example, is building on the pioneering work of Oslo by introducing climate budgeting. Tokyo is collaborating with Kuala Lumpur to develop low-carbon building standards. Lagos is decarbonising its energy supply by installing solar panels on schools and health centres. And in London, we’ve announced that we will expand our world-leading Ultra Low Emission Zone – to cover all of Greater London – ensuring that almost five million more Londoners will breathe cleaner air.

The example set by C40 cities shows that we can rise to meet the challenge of the climate crisis. Thanks to our track record of bold climate action, there has also been an on-average 5 per cent improvement in air quality – that’s 150 million residents all over the world benefitting from cleaner air. 

In October, C40 hosted the World Mayors Summit in Buenos Aires – it was the largest-ever gathering of mayors to date convened by C40, with 75 C40 mayors and 143 non-C40 cities taking part. At the summit, mayors united to drive the creation of 50 million good, green jobs by 2030 and announced record investment in C40 cities in the Global South, which are now projected to be able to access over $1 billion to tackle the climate emergency.

However, COP27 was a missed opportunity for national governments to meet the scale of the challenge we are facing. While the establishment of the fund for the countries that are most severely affected by the climate crisis was welcome, we need the money in place and flowing to help those who often have contributed the least to climate change. We must also accelerate climate action and stop investing in fossil fuels in order to limit global temperature rises to no more than 1.5 degrees. C40 research shows we can create six times as many jobs and far less pollution by doing this and investing in renovating buildings and solar power rather than fossil gas-powered electricity.

The continued commitment from C40 cities to the delivery of high-impact climate actions has put our network on track to halve their emissions by 2030. This is in sharp contrast to the expected 14 per cent rise in global emissions by the same date. As we progress through the decade, C40 is committed not only to ensuring that cities play their full part in addressing the climate crisis but maintaining pressure on national governments so we can secure a fairer, more sustainable and more prosperous future for all.

C40 World Mayors Summit

This year was also home to C40’s triennial C40 World Mayors Summit, which took place from 19–21 October 2022 in the host city of Buenos Aires, Argentina. 

The summit was C40’s largest-ever gathering of Mayors to date, with 75 C40 Mayors and 143 non-C40 cities participating.

Mayors of global and regional cities, alongside business leaders, philanthropists, campaigners, youth leaders, scientists and residents, convened to share bold ideas, showcase innovative solutions and stand together to create a sustainable, prosperous and equitable future.

© C40 / Franco Fafasuli

Over 100 businesses, charities, activists, and non-governmental organisations were present and witnessed a multitude of announcements across the three days of action.

Announcements at the C40 Summit

At the C40 World Mayors Summit, C40 announced action to drive the creation of 50 million good, green jobs by 2030 and a record investment in C40 cities in the Global South, projected to access over $1 billion to tackle the climate emergency.

Other announcements included: the recognition of the world’s best climate projects with the C40 Bloomberg Awards, the launch of C40 and Google’s new 24/7 Carbon-Free Energy for Cities programme (featuring London, Paris and Copenhagen), London joining the Global Mayors Task Force on Climate and Migration, and thirteen Global South cities signing up to C40’s Pathway Towards Zero Waste, which aims to slash waste emissions and set cities on a path to a cleaner, healthier, more resilient and inclusive future.

© C40 / Franco Fafasuli

An international delegation of over 60 young people from around the world attended the Summit, participating in events, keynotes, forums and masterclasses throughout the programme. Youth climate leaders and mayors also united to launch the first-ever global network of city-youth climate councils.

© C40

Inspiring words were shared in person and virtually, with moving addresses from leaders, such as the opening remarks by Global Youth and Mayors Forum member Hilda Flavia Nakabuye, a letter from His Holiness Pope Francis, and a personal video from the United Nations Secretary-General António Guterres commending the work of C40 and supporting the message of the C40 World Mayors Summit.

Throughout the C40 World Mayors Summit, C40 received over 1.5 million live stream views from over 35 countries.


The 27th United Nations Climate Change Conference (COP27) took place in Sharm El Sheikh this year. The headline announcement from the conference was an agreement reached between participating countries to provide “loss and damage” funding to vulnerable countries hit hardest by the climate crisis. 

However, the agreement stopped short of detail on the source of the funds, which countries will be responsible for the provision of the funding and which vulnerable countries will stand to benefit. Estimates suggest that the cost of adaptation to climate breakdown, in the face of rising sea levels, drought and floods, could reach up to US$340 billion per year by 2030, rising to as much as US$565 billion by 2050 if climate breakdown continues at its current pace. 

On the issue of climate finance, more generally, an agreement was reached that acknowledged the need to invest US$4-6 trillion per year in renewable energy technologies and infrastructure.
Despite the progress made on these financial commitments, there was disappointment that the conference failed to deliver an agreement to slash the burning of fossil fuels. The final COP27 decision text omitted any mention of oil and gas and specifically any reference to a phase-out of fossil fuels that would bring national governments in line to limit global heating to 1.5°C. As research by C40 shows, investing in renewable energy and energy efficiency will cost less, create more jobs, and result in far less pollution than burning more gas, oil and coal. The number of good, new green jobs that can be created in C40 cities alone could reach 50 million if cities stick to their plans to halve emissions by 2030.

© C40 / Maurizio Martorana

More significant progress was made on several C40 priority areas in 2022, across air quality, climate finance and the green recovery.

Air quality

The scope of C40’s work on air quality expanded significantly this year, with half of all cities within our network committing to delivering cleaner air by signing our Clean Air Accelerator. In Bogotá, this resulted in the launch of Latin America’s largest air quality microsensor network, which will inform efforts to improve air quality in areas of high priority across the city. This was complemented by the introduction of a fleet of 1,485 electric buses, making it the biggest urban electric bus fleet in operation outside of China.

Meanwhile, the ports of Singapore, Los Angeles and Long Beach announced plans to establish a green and digital shipping corridor on trans-Pacific shipping lanes between Singapore and the San Pedro complex. This is a major step forward for green shipping, with the corridor benefitting from the use of low and zero-carbon fuels and digital tools that will help in the deployment of low-carbon ships.

  • Over 150 million residents in C40 cities are benefitting from cleaner air thanks to bold commitments by city leaders
  • Three-quarters of C40 cities are out-performing their respective nation-states in emission reductions
  • Air pollution has fallen by 5% across C40 cities in recent years

In London, C40 played a supporting role in the announcement of the expansion of the city’s ultra-low emission zone (ULEZ), by securing support from a number of city mayors, experts and youth leaders. The Mayor of Bogotá wrote a short blog outlining how the ULEZ inspired a similar project to reduce toxic emissions in the Colombian capital.

The actor and climate activist Leonardo DiCaprio also publicly supported the scheme.

© Leonardo DiCaprio / Facebook, Meta

Climate finance

Accelerating climate action in the Global South was a high priority for C40 Chair, Mayor of London Sadiq Khan this year. This resulted in the proportion of the C40 budget allocated to climate action in the region rising by two-thirds to around US$40 million. The funds will help cities across Africa, Latin America and parts of Asia to deliver on the high-priority elements of their climate action plans.

The creation of a new Inclusive Climate Action Fund, supported by the Open Society Foundation, will also help provide much-needed resources to cities in the Global South and Global North to pilot and drive fair and inclusive climate action in their cities.

Green recovery

The Global Green New Deal programme has also been the subject of a major expansion under the C40 Chair. Additional funding has been directed to cities to work with trade unions, youth groups and community organisations to ensure that climate action benefits everyone. Local green new deals are now being implemented in Accra, London, Seattle, Seoul, New York and Los Angeles.

At the C40 World Mayors Summit in Buenos Aires, scores of city mayors united to drive the creation of 50 million good, green jobs by the end of this decade. C40 research shows that 50 million green jobs are needed for C40 cities to deliver their share of halving emissions in line with the target of limiting global heating to 1.5°C.

Looking ahead to 2023: C40 Executive Director Mark Watts

As another COP ended without agreement to deliver urgent, science-based climate action from the world’s governments, it is clear that there is still much further to go. But we know what needs to be done – the best way to protect people everywhere from rising prices and extreme weather is to invest in a greener future for all, not fossil fuels. Three-quarters of C40 cities are cutting emissions faster than their respective nation-states. That’s great, but it’s not enough – now we need to ensure every city is on track to deliver its fair share of halving emissions this decade, ensuring that those who are currently most vulnerable gain most from that transition.

Here’s to a cleaner, greener, more peaceful 2023.
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