On Earth Day, C40 makes the case for investing in our cities to build a sustainable future that works for everyone

C40 is a global network of nearly 100 mayors of the world’s leading cities that are united in action to confront the climate crisis. Our mayors aspire to create a sustainable future where everyone can thrive, but more green investment is urgently needed to accelerate ambitious city climate action.

Now is the time to harness the power and potential of our cities.

The challenge


For cities to deliver on 1.5°C they must collectively halve their emissions by 2030, while dealing with huge population increases as rapid urbanisation continues globally. This means investing in the right transportation systems, buildings and infrastructure to cut urban carbon footprints and ensure growth doesn’t lock cities into a high-carbon future.

At the same time, the impacts of climate breakdown are already hitting many cities. Immediate investment is needed to help cities adapt and protect residents with infrastructure that is resilient to extreme weather events and supports food and water security.

Why invest in cities?

1. With adequate investment, cities can significantly reduce emissions and create good, green jobs, simultaneously protecting the environment and our future.

According to C40 research, for C40 cities to contribute their fair share towards reducing emissions and limiting global heating to 1.5°C, 50 million green jobs are required. Green jobs will help create healthier, fairer communities with lower unemployment and rejuvenated economies that are no longer tied to fossil fuels that have long exacerbated energy poverty worldwide.

Our research shows that comprehensive climate action by C40 cities could result in over 30% more jobs compared to today’s “business-as-usual” economic approach. It could also reduce air pollution by up to 30% and deliver $280 billion in health-related economic benefits in C40 cities driven by reduced fossil fuel use.

A graphic by C40 Cities illustrating projected global greenhouse gas emissions from 2016 to 2030. The graphic includes a "business as usual" approach resulting in a line with a sharp upward trajectory, which indicates rapidly increasing emissions. Below that line is a less steep, but still trending upwards, line, which shows C40 cities' current projected emissions. Below that is a downward trending line, which reflects projected emissions if cities were to stick to a 1.5°C pathway.

New York City‘s Local Law 97, introduced in 2019 to reduce emissions from buildings over 25,000 square feet, cut nearly 6 million tonnes of CO2 equivalent emissions from large buildings – equal to removing 1.3 million cars from the road – and created 26,700 well-paid green jobs. This action resulted in an entirely new market for skilled and union labour, helping secure a just transition and new opportunities for workers.

Similarly, Johannesburg invested in a food resilience programme to tackle food insecurity and create local green jobs. The programme has established 50 cooperatives, four new farms, and an urban agri-zone, where farmers can grow and sell produce, expanding local food production and generating local revenue in line with Johannesburg’s Climate Action Plan. Increasing jobs in agriculture and food production results in numerous positive impacts, including increased self-reliance, more local produce, better nutrition, and healthier and more sustainable communities with greater social equality.

Investing in our cities is essential to investing in our planet. The benefits of such investments are clear: reducing emissions, creating good, green job opportunities, and building a healthier, more equitable and sustainable future for all.

2. Mayors are already united in action to create safer, more livable cities, but greater green urban investment will help accelerate action, benefiting climate resilience and residents’ quality of life.

C40 cities are showing the highest level of climate ambition; since 2011, cities have tripled the number of transformative climate actions implemented annually, showing that mayors are scaling up efforts to tackle the climate crisis and create resilient cities.

Transformative actions are science-based, politically ambitious, locally-relevant, and high-impact policies, programmes or projects that profoundly alter business-as-usual practices in the city they are implemented. These actions benefit frontline communities, have been co-created with relevant stakeholders, and are scalable and replicable across cities.

A graphic by C40 Cities illustrating the number of high-impact climate actions delivered annually in C40 cities from 2011 to 2021. The graph shows increasing actions each year, with actions trebling from 2011 to 2021. The specific number of actions delivered in each year is as follows: 2011 = 254; 2012 = 280; 2013 = 301; 2014 = 355; 2015 = 370; 2016 = 401; 2017 = 471; 2018 = 568; 2019 = 678; 2020 = 803; and 2021 = 872.

For example, Jalisco’s 2021 drought caused severe water shortages in the city, prompting the Metropolitan Area of Guadalajara to launch the Nidos de Lluvia (Rain Nests) programme to improve water security and boost resilience. The city installed rainwater collection and harvesting systems in the most water-vulnerable neighbourhoods. In 2021, 16 million litres of water were collected via 600 harvesting systems, providing water to over 2,000 residents. Metro Guadalajara estimates that by 2024, nearly 60,000 people will have improved water security, reducing the rates of critical water vulnerability by 67%.

In Pune, the city is taking action to clean the air for its 3.1 million residents through a public transport electrification programme. Since launching in 2019, 15% of the city’s buses have been electrified and used by 1.2 million passengers. By the end of 2023, the city’s e-bus network will comprise 950 e-buses, accounting for 40% of the city’s fleet. The city’s shift to electric buses will save ₹656 crores (USD $88 million) over the fleet’s lifetime and eliminate emissions equivalent to over 3,000 petrol and diesel-fuelled cars. The e-buses are designed to be accessible for people with disabilities, and a flat-fare policy capped at less than US 0.08 cents ensures lower-income residents are not excluded.

While C40 cities are progressing faster than most, they are not yet on track to halve emissions by 2030. The green investment gap impacts cities’ ability to accelerate and scale up transformative actions.

C40 Cities and our mayors are united in action to confront the climate crisis and create a sustainable future where everyone can thrive, but immediate investment is needed to help cities adapt and protect residents and our future.

Graphics: © C40 / Mistaker

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