“By incorporating proximity into cities, the goal is to change the lifestyles of residents – freeing up time, increasing movement through active mobility, enhancing relationships with neighbours, reducing stress – and promote the development of the local economy.” – Prof Carlos Moreno

The clock is ticking: halving greenhouse gas emissions by 2030 is crucial to avoid catastrophic climate breakdown. As cities are expected to house over two-thirds of the world’s population by 2050, urban planning decisions made today are critical to our ability to meet climate goals and provide a good quality of life for urban residents. 

Ahead of C40’s participation at the UIA World Congress of Architects in Copenhagen from 2–6 July, we caught up with Carlos Moreno to get his expert insights on the urgent need to accelerate sustainable urban development.

Carlos Moreno is an Associate Professor at the Paris IAE – Panthéon Sorbonne University in France, and co-founder and Scientific Director of the Chair ETI. Specialising in complex systems and urban issues, Professor Moreno is internationally renowned for his pioneering works on sustainable cities.

Professor Moreno’s concepts focus on transforming our urban centres to provide solutions to the issues cities and their residents face – such as those caused and exacerbated by climate breakdown and rapid urbanisation – to help create more resilient cities, improve residents’ wellbeing and reduce cities’ carbon footprints.

What drew you to the field of sustainable design and urban planning, and why have cities been such an important feature of your work?

As a scientist specialising in complex systems, I initially focused on the study of the technical systems of cities. However, the increasingly obvious and tangible effects of climate change piqued my interest in cities, urban planning and their essential role in the environmental transition.  It’s the result of long-time observations, research and participation in complex systems studies and applying my methods to cities – a quintessentially complex system. 

The timeline of my reflections on cities has evolved in tandem with the increase in global awareness of the climate crisis. Indeed, I first worked on the “smart-city” concept and established some key guidelines to go from a tech city to a human and livable one, a “Human Smart City”, in 2012. 

Going forward, the process leads me to consider the key role of urban transformation in the transition to a liveable and sustainable world. According to UN-Habitat, cities account for 78% of the world’s energy consumption and produce over 60% of greenhouse gas emissions. Yet they cover less than 2% of the Earth’s surface. 

Logically, this led me to question how cities could be transformed to have a lower impact on the environment and the planet. What is wrong with how things are done? Why does it have such a high carbon impact?  How could we change that?

This process leads me to realise that modern cities are not only severely affecting biosystems, biodiversity and climate change, but are also adversely affecting inhabitants through lifestyles that depress and tire them. These observations led me to develop a new urban concept based on proximity, which aims to transform cities into more sustainable, lively and happy ones – the “15-minute city” or “30-minute territory” – the happy proximity way. 

Your sustainable city concepts have gained widespread recognition and influence. Can you give us some insight on how these concepts have evolved over time?

The 15-minute city has become very famous over the past three years. However, it began with an intuition that I developed into a concept and called the “15-minute city” in 2016; the result of research started in 2010, 13 years ago! Since then, several stages led to the current concept.

I started to share the idea of a sustainable, healthy and happy city through proximity in academic circles, but the concept really started to take off when the Mayor of Paris, Anne Hidalgo, saw it as an opportunity to transform Paris in 2019. The fact that the French capital, known and admired the world over, was transformed through proximity has been a milestone.

This resulted in two new dynamics; first, we entered a materialisation process, which sought to move from a theoretical concept to real urban planning; second, communication and interest in the “15-minute city” concept grew, especially thanks to C40. This international city forum really helped to build the strength of the concept by giving it visibility among the world’s mayors. The 21st Conference of the Parties (COP21) reinforced its pertinence to tackle climate change through urban transformation.

The COVID-19 pandemic made the 15-minute concept skyrocket. All over the world, cities and their inhabitants experienced the same situation, at the exact same moment: containment, telecommuting, homeschooling, local living, sanitary precautions, medical needs and problems, the opening of necessary shops only. On the other hand, nature, biodiversity, and animals benefited from this break in the world’s frenetic pace. COVID-19 made people and government realise a change was needed, and the 15-minute city concept was raised as a suitable solution for a sustainable, healthy and happy proximity. The pandemic prompted us to reflect on our habits and way of life and highlighted the urge to change them.

By 2023, the 15-minute city concept has reached worldwide recognition and become a transformation guideline for many cities. Many international organisations recognised its pertinence and support it, including UN-Habitat, the World Health Organization, C40, and others.

The impact of the climate crisis is a major concern for cities worldwide. How can sustainable urban planning help mitigate the effects of climate breakdown, and what are some stand-out approaches you have seen in this area?

As I have already said, cities and urbanised territories are at the core of the climate crisis because they concentrate activities and populations. In today’s world of the Anthropocene, they are therefore responsible for 60% of greenhouse gas emissions, mainly emitted by cars. They impose lifestyles that are disconnected from nature, time and circadian rhythms. In order to tackle the climate crisis, city transformation is undoubtedly part of the solution – and the emergency!

The 15-minute city concept has clearly been developed as a response to this challenge. It proposes an urban structure based on proximity; a compact and sustainable city of short distances. The goal is to improve the quality of urban life by focusing on the hyper-proximity of essential daily needs, reachable in 15 minutes on foot or by bike from home.

Children playing in a public playground. © World Resources Institute

By incorporating proximity into cities, the goal is to change the lifestyles of residents – freeing up time, increasing movement through active mobility, enhancing relationships with neighbours, reducing stress – and promote the development of the local economy.
As a result of these changes, the carbon impact of cities and their residents is reduced. The equation is simple: as distances are reduced, there is a corresponding decrease in reliance on long-distance transportation and individual cars. Meanwhile, as public spaces are transformed into greener spaces and vegetation is replanted in parks, streets, walls and roofs, the air is naturally filtered, and more carbon dioxide is absorbed. Cities become more pleasant places to live, with fresher air, and a calmer and healthier environment for residents.

Increased pedestrianisation of city streets makes them more appealing places to walk, and because inhabitants are walking more in their neighbourhood, they have more opportunities to buy local goods and thus participate in the transformation of consumption.

We know the impacts of the climate crisis are interconnected. How do you see urban planning impacting other critical areas?

Actually, urban planning and urban function are linked to so many different areas. Cities are host to a multitude of intertwined subjects and techniques, all of which need to respond to the climate crisis. 

The way we imagine and realise urban projects has changed now that sustainability is ubiquitous. Adapting cities to climate change means creating more resilient cities. This implies, for instance, managing water issues using more natural methods. 

City design should embody a sense of sobriety. This means focusing on efficient water distribution, innovation in water recovery and efficient waste management. It also means maximising energy efficiency and creating greener energy from natural resources. 

Renewable and circular approaches must play a key role. This entails the widespread adoption of waste sorting, the recovery and reuse of materials, as well as a prudent approach to land use. 

Adaptation to climate change has a huge impact on every sector – all areas of urban engineering, landscaping and housing are unavoidably changing. Employee skills, company operations, the world of work and education are also adapting to meet these new challenges. 

The UIA World Congress of Architects is the world’s largest event focused on sustainable architecture. How can architects, cities and the private sector collaborate to make sustainable urban development a reality?

The climate emergency needs strong and close collaboration between the entire urban production chain. The majority of urban sector actors are already working to create more sustainable cities, with new rules and new techniques that respond to requirements. 

Unfortunately, we need to be patient to see the results of this radical shift. Urban transformation takes a long time, given that big urban projects often involve eight to ten-year timescales. 

Of course, there is always more to do, but I think we need to be very pragmatic. The ideas are here, the knowledge is here (in part), but there is understandable urgency around the implementation.  The reduction in administrative obligations could be channelled towards speeding up innovation in the sector. For instance, let’s look at urban projects related to the 2024 Olympics in Paris; given its importance, all stakeholders have worked together to develop innovative large-scale projects with particularly sustainable and innovative construction methods in record time. 

What advice would you give to architects, urban planners and city leaders who are committed to ensuring cities develop sustainably and are designed for people?

Keep going! We need to focus on this objective, to engage and increase our involvement. Let’s talk about it, share it and participate in global change towards greener, safer and happier cities.

Prof Moreno joins C40 thought leaders, mayors, partners and urban planning and design experts in Copenhagen from 2–6 July for the UIA World Congress of Architects. In two key sessions, C40 and partners will lead vibrant discussions on designing and building resilient communities that prioritise sustainability, health and wellbeing.

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