London, United Kingdom
Mayor Sadiq Khan

Sadiq Khan was elected for a second term as Mayor of London in May 2021. He was previously an MP for Tooting, South London for 11 years and served as Shadow Secretary of State for Justice from May 2010 and Shadow Minister for London from 2013.

Mayor Khan has declared a climate emergency and described it as one of the biggest threats we face today. In response, he has set an ambition for London to be net zero by 2030. He has also committed to a Green New Deal for London and to ensuring that there is a just transition in the capital from fossil fuel intensive industries to climate solutions.

Freetown, Sierra Leone

Yvonne Aki-Sawyerr OBE was Mayor of Freetown from May 2018 to February 2023 and was recently re-elected to serve for a second term. A finance professional with over 25 years of private sector experience in strategic planning, risk management consulting and project management, Mayor Aki-Sawyerr adopted an inclusive, data-driven approach to addressing challenges in the city. She championed the four-year Transform Freetown plan, which detailed 19 concrete targets across 11 sectors and covered issues ranging from tackling environmental degradation to facilitating the creation of jobs for youth. Annual Transform Freetown reports, which document progress made against targets, can be viewed here.

Mayor Aki-Sawyerr’s notable achievements include: the construction and operation of Freetown’s first-ever wastewater treatment plant; the digitalisation and expansion of the city’s property rate system, the creation of over 3,500 jobs for youth and women; the planting and tracking of over 800,000 trees as part of the #FreetownTheTreeTown 1 million trees target; and securing the ongoing feasibility study for the introduction of a cable car system for the city.

Mayor Aki-Sawyerr’s public sector engagement began with her work during the 2014-2015 Ebola epidemic and her subsequent role as Delivery Team Lead for the second phase of a multi-stakeholder programme to drive socio-economic recovery in Sierra Leone post-Ebola. Mayor Aki-Sawyerr was featured by Time Magazine in the Time100 Next 2021 List and by the BBC in the BBC 100 Women 2020 List. She is a Chartered Accountant with an MSc in Politics of the World Economy from the London School of Economics and a BSc Hons in Economics from Fourah Bay College. She is married with two children.

Phoenix, United States
Mayor Kate Gallego

Mayor Kate Gallego is the second elected female mayor in Phoenix history, and the youngest big city mayor in the United States. She graduated from Harvard University and earned an MBA from the Wharton School of Business at the University of Pennsylvania. Before being elected to Phoenix City Council, Mayor Gallego worked on Economic Development for local utility company, Salt River Project. 

Mayor Gallego has focused on three key policy areas during her time in office: diversifying the economy, strengthening infrastructure investment, and working to make Phoenix a leader in sustainability. Her record of proven results includes leading the campaign to pass Phoenix’s citywide transportation plan through 2050, which was the largest local government commitment to transportation infrastructure in the country when it passed in 2015.  She has led efforts on criminal justice reform and ensuring equal pay for equal work. Mayor Gallego is passionate about building a Phoenix that works for everyone and increasing the quality of life for all Phoenicians.

Phoenix is the fifth largest city in the United States and is currently the fastest growing city in the country.​

Medellín, Colombia
Mayor Federico Guiterrez Medellin

Federico Gutiérrez is serving as the Mayor of Medellín for the second time. and his recognition and popularity among the people of Medellín and many Colombians are the result of a life dedicated to public service. 

Politics as a way to find solutions to social problems and public service as a tool to help people has been Mayor Gutiérrez’s life project. He has never stopped walking the streets and studying the realities of the city and the country, listening to its citizens, gathering proposals from various social sectors, and thinking about how to contribute to the transformations demanded by today’s Colombia. He wants to continue working for Colombia and its regions to seek peace for families and opportunities for progress for everyone through a governance model based on citizen trust, institutional solidity, and teamwork among the public sector, private sector, academia, and civil society, without class antagonisms or hatred.

Copenhagen, Denmark
Foto, Sophie Hæstorp Andersen, credit Klaus Bo

Sophie Hæstorp Andersen has been the Lord Mayor of Copenhagen since 1 January, 2022, for the Social Democratic Party – the second woman to hold the office. She is working to further develop and improve Copenhagen as a city where healthy and meaningful lives go together with sustainable urban development and rapid carbon reductions. Under her leadership, the City of Copenhagen is developing a new climate plan for 2025–2035 with clear aspirations of becoming carbon-positive and strong ambitions to reduce consumption-based emissions. 

Lord Mayor Hæstorp Andersen is convinced that a climate-friendly city is also a healthy and livable city, which Copenhagen is a living proof of. Prior to her role as Lord Mayor of Copenhagen, she was a Member of the Danish Parliament (2001–2005; 2007–2013) and served as Chairperson of the Regional Council at the Capital Region of Denmark (2014–2021), where she was a driving force in developing a green partnership between Danish Regions and Municipalities working together towards more sustainable food production and procurement.

In her role as Vice Chair on the C40 Steering Committee, Lord Mayor Hæstorp Andersen will be a leading voice in promoting and advocating for bold and innovative climate action in cities worldwide and inspiring change for a better future for all people. 

Paris, France

Anne Hidalgo has been Mayor of Paris since 2014 – the first woman to hold that office. She was reelected in 2020 for a second term until 2026. During her period as mayor, her policies have put Paris at the vanguard of the fight against climate breakdown in urban areas.

These policies include the construction of hundreds of miles of bike lanes; the transformation of the Seine riverbank, now exclusively reserved for pedestrians and cyclists; banning traffic in certain areas of the capital on Sundays and holidays (“Paris Respire”); making the River Seine safe for swimming and bathing again by 2025; incorporating 15-minute city concepts into urban planning; greening Paris by planting 170,000 trees by the end of 2026; and her proposal to transform the Champs-Elysées by creating several gardens along the famous avenue. During her first term, the city of Paris won the bid to organise the 2024 Olympic and Paralympic Games, which have helped Paris to accelerate even further its ecological transformation. For its exceptional climate leadership, Paris received a Climate Action Award from the United Nations during COP26.

As Chair of C40 Cities between 2016 and 2019, Mayor Hidalgo championed city diplomacy worldwide and is currently engaged in several city networks, working relentlessly to raise the role of mayors in global affairs. As C40 Vice Chair for Europe, a key priority for Mayor Hidalgo will be cities’ leadership in urban climate innovation, including emphasising the importance of high-quality monitoring and reporting mechanisms that cities have introduced ahead of the COP28 Global Stocktake. Mayor Hidalgo is also committed to continuing her tireless campaign at the EU and global levels for cities to keep global heating below 1.5°C.

Dhaka North, Bangladesh
Mayor Mohammad Atiqul Islam

Mohammad Atiqul Islam’s leadership has become synonymous with dedication, honesty and generosity in Dhaka.

Mayor Atiqul Islam was born in 1961 in Comilla and raised in a large family by his high-ranking police officer father Momtaz Uddin Ahmed and his mother Mazeda Khatun. Having attended university, Mayor Atiqul Islam entered the business world with his older brother, establishing the Eminence of Islam Garments and employing 19,000 staff.

Mayor Atiqul Islam has been a member the Bangladesh Garment Manufacturers and Exporters Association (BGMEA) since 1990 where he abolished child labour, promoted gender equality, established hospitals for workers and managed the response to the Rana Plaza incident. His work helped to promote the badge of “Made In Bangladesh With Pride” to the world.

His dedication to transforming lives and bringing order to the chaos of rapid industrialisation led Mayor Atiqul Islam to politics. He was elected as the Mayor of Dhaka North City Corporation on 28 February 2019 and is well on his way to creating a lasting legacy of unparalleled service to this great city.

Nairobi, Kenya
GovernorJohnson Arthur Sakaja, Nairobi

H.E. Hon. Sakaja Arthur Johnson was elected the Governor of Nairobi City County, Kenya, in August 2022. Governor Johnson is working to realise a vision of Nairobi as the Green City in the Sun, a nickname derived from the city’s foliage and warm climate.

Johnson’s commitment is to put the city at the frontline for the implementation of the Climate Action Plan (2020-2050) with the support of C40, and focusing on developing a roadmap to get Nairobi to net zero, creating green jobs, and strengthening local resilience.

Johnson previously served as Senator of Nairobi. During his tenure in Parliament, he served as Chairman of the Standing Committee on Labour and Social Welfare and as Vice Chairman of the Standing Committee on National Security, Defence and Foreign Relations. He also served as the chairperson of the Kenya Young Parliamentarians Association.

Johnson has been nominated among the top 100 Future Leaders: The World’s Most Influential Young People in Government (2018) by Apolitica and awarded Change Maker of the year 2016 at the African Achievers Award, in recognition of his leadership skills and youth empowerment in Kenya. Johnson was elected to represent the 13 C40 cities in Africa.

Tokyo, Japan
Yuriko Koike

Yuriko Koike won Tokyo’s gubernatorial election in 2016 to become the city’s first female governor. She was re-elected in 2020 and is currently serving her second term.

In 2018, her third year of office, she hosted the Tokyo Forum for Clean City and Clear Sky, which focused on the common challenges facing large cities—waste management, sustainable resource management and air pollution. There, she and representatives of major cities around the world shared knowledge and information about their best practices, and confirmed that they will maintain and strengthen their global partnerships. At the same time, she also held the first C40 East, Southeast Asia and Oceania Regional Meeting as a C40 vice chair.

In May 2019, she hosted the U20 Mayors Summit. As an output of the summit, the views of the major cities of the world were prepared as a communiqué, which was delivered to the G20 by Governor Koike, representing the U20. At the U20 Mayors Summit, she also declared that Tokyo will become a “Zero Emission Tokyo” by 2050 to contribute to the world’s net zero carbon emissions.

Moreover, in January 2021, with a strong awareness of how crucial the actions taken over the next decade will be to achieve Zero Emission Tokyo, she announced that by 2030 Tokyo will reduce greenhouse gas emissions by 50 percent over year 2000 levels. This was followed by a kickoff meeting in February to roll out a global movement for climate action under the slogan “Time to Act,” with the aim to accelerate effective actions for decarbonization, and together with the participating mayors of major cities and experts, a joint message was sent out to the world.  

Governor Koike is also bringing changes to fields other than the environment. This includes empowering women, improving the parenting environment by resolving the issue of waitlists for daycare and introducing original programs to make daycare costs free, preventing secondhand smoke, and implementing administrative and fiscal reform. 

Calling for a sustainable recovery from the COVID-19 pandemic, she is currently launching and implementing numerous projects for the realization of a sustainable society by addressing the climate crisis in addition to working for recovery of the economy, society, and people’s spirits exhausted by the pandemic. 

A graduate of Cairo University, Egypt, after her return to Japan she worked as an Arabic interpreter and language instructor before becoming Japan’s first female economic news anchor for a television program reporting on the world’s economic issues.

She was elected to Japan’s House of Councillors in 1992, and to the House of Representatives in 1993, and has held key positions including the Minister of the Environment and Minister of Defense. She has always taken an active stance in addressing her concern for the environment. One leading example was her introduction of the Cool Biz campaign when she was the Minister of the Environment, which encouraged office workers to dress more casually during the summer to ensure comfort under higher room temperature settings.

Rio de Janeiro, Brazil
Mayor Eduardo Paes Rio De Janeiro

Eduardo Paes has been the Mayor of Rio de Janeiro since 2008 and is currently in his third term. As mayor, Mr. Paes oversaw a cycle of great events in Rio de Janeiro, from the Rio+20 Conference in 2012, through the 2014 FIFA World Cup to the 2016 Summer Olympic and Paralympic Games, which accelerated major transportation, infrastructure and urban renewal projects in the city.

Mayor Paes served as Chair of the C40 Cities between 2013-2016, succeeding Mayor Bloomberg of New York City. 

In 2023 he joined the Board of the Resilient Cities Network (R-Cities) and co-chairs the Urban SDG Finance Commission. He is currently the Vice-president of the Brazilian Conference of Mayors and its Special Envoy for Climate Change.

Montréal, Canada

First elected as a city councillor in the Sainte-Marie district in 2013, members of the Projet Montréal political party chose Valérie Plante to lead the party in 2016. Her contagious passion and energy have helped her rally people around her progressive vision, which is centred on increased access to public transit, better urban planning and public services, economic development, and protecting the environment.

Before entering the political arena in 2013, Valérie Plante obtained degrees in anthropology, museology, and in multiethnic intervention. She then became actively involved with numerous community groups, including the Fondation Filles d’action, which helps to build the skills and confidence of girls, young women and gender-diverse youth across Canada. On 5 November 2017, she became the first woman to be elected mayor of Montréal.

During Mayor Plante’s first term, major investments were made to increase access to green space, including creating what will be Canada’s largest urban park, the Grand parc de l’Ouest. The park will span 3,000 hectares and rehabilitate nearly 10 kilometres of river banks.

Milan, Italy

Giuseppe Sala is the Mayor of Milan. He is C40 Vice Chair for Europe, and chairs the Mayoral Task Force on a Green and Just Recovery.

Throughout his professional life, he has held positions of responsibility in both the private and public sectors, gaining important managerial experience.

He was the Government Commissioner and CEO of the World Expo held in Milan in 2015.

His love for Milan and his willingness to make it a more sustainable, more international and fairer city led him to commit himself to politics.

He was elected Mayor in June 2016 and re-elected in October 2021.

Giuseppe Sala holds a Degree in Economics and Business Administration from Bocconi University.

He is the author of four books, including Milano e il Secolo delle Città (Milan and the Century of Cities) and Lettere dalle città del futuro: Costruiamo oggi il mondo di domani (Letters from the cities of the future: Let’s build today the world of tomorrow).

Seoul, South Korea

Oh, who began an unprecedented fourth term as mayor of Seoul in July 2022, is well-known for his environmental leadership. He co-founded the Korea Federation for Environmental Movements and, as a lawyer, helped to establish the right to sunlight for the first time in South Korea’s history. 

As mayor, Oh has prioritised inclusive climate action to reach net-zero emissions by 2050, protect the safety of residents from the effects of climate change and improve equity. Among other measures, Oh has championed the Seoul Energy Welfare Civic Fund, which supports energy efficiency improvements among low-income households and other vulnerable populations, and connected young people hit hard by the COVID-19 pandemic to new climate and environmental jobs. 

Mayor Oh is committed to tackling air pollution, a major public health threat. In 2007, he developed the Clean Seoul 2010 initiative and in 2022, updated it as part of the Cleaner Seoul 2030, which includes various policy actions to cut air pollution emissions by 50% by 2030. Also high on Oh’s agenda is addressing emissions from waste. Under his leadership, Seoul is working towards a Zero Waste Seoul and striving to increase the plastic recycling rate to 80% by 2026. These efforts led to Seoul’s recycling earning the highest scores on the Global Power City Index ranked by the Mori Memorial Foundation in 2022.

Oslo, Norway
Eirik Lae Solberg Governing Mayor of Oslo

Eirik Lae Solberg represents the Conservative Party has been the Governing Mayor of Oslo since fall 2023.  Governing Mayor Solberg is strongly committed to Oslo’s adopted climate targets of 95% reduction in direct emissions by 2030, while ensuring that the city preserves nature and is resilient. International cooperation is essential in achieving this target. 

Governing Mayor Solberg has an education in economics, political science, and history. Prior to becoming Governing Mayor, Solberg’s career has been dedicated to leading positions in local and national politics and in the private sector.  

As a member of the C40 Steering Committee, representing the innovator cities, Governing Mayor Solberg will be a strong voice for using climate governance tools such as climate budgeting and public procurement to accelerate climate action. Oslo is committed to sharing solutions with other C40 cities and to advocating for city leadership at national and international levels.

Hong Kong, China

Mr Tse Chin-wan is the Secretary for Environment and Ecology of Hong Kong, China. Mr Tse joined the former Environmental Protection Agency of Hong Kong in 1985, which was subsequently reorganised in 1986 to become the current Environmental Protection Department (EPD). Throughout his service with EPD, he took up a wide range of duties at professional and senior managerial levels. He was appointed as a Deputy Director of Environmental Protection in 2013 and subsequently as the Under Secretary for the Environment in August 2017.

Mr Tse possesses a broad spectrum of experience in various areas of environmental protection, including law enforcement, computer modelling, environmental impact assessment and cross-boundary cooperation with the Mainland. During his tenure as the Under Secretary for the Environment, he helped spearhead the formulation of policies on air quality, waste management, climate actions and conservation.