Climate change is becoming more real every day: around the world we are witnessing a sharp increase in climate disasters. Furthermore, the latest IPCC report warns us of possible “tipping points” from which the climate transition could become not gradual, but sudden and irrevocable.
Hélène Cartier is a speaker at the new LifeCycles festival, which will be held in Gent from 28 to 30 September 2022.
Spread over 3 days and 3 phases, LifeCycles will bring together over 40 leading speakers, who will discuss the future of our cities, architecture and the environment. More info and tickets on www.lifecycles.be
Over the past decade, little progress has been made to keep global warming below the 1.5 ° C target of the Paris Agreement. Leading climate scientists are now clear: 2020 will be a decisive decade for the survival of our environment. Global emissions must peak before 2025 and decline by 43% by 2030.
It is therefore an absolute priority to act and reduce emissions from the sectors most responsible for the climate crisis. The built environment industry in particular has a huge responsibility: buildings account for nearly 50% of annual global CO2 emissions and the global building surface is projected to double by 2060, which is the equivalent of ‘adding an entire New York City to the world, every month, for 40 years.
It is urgent to decarbonise buildings
Action to decarbonise new and existing buildings, making them more efficient so they use less energy and cleaning up the energy they use, is crucial. Construction operations are in fact responsible for nearly 30% of global annual CO2 emissions.
It is also the key to minimizing the carbon incorporated by the construction. Embedded carbon has been underestimated in the past. They are responsible for about an additional 20% of total emissions and are an important lever for rapidly reducing global greenhouse gas emissions. Indeed, unlike operational emissions that spread over the life of a building and can be reduced over time with building and energy system upgrades, embedded carbon generates an irreversible spike in emissions right at the start of a project.
To reduce embedded emissions, it is essential to slow down construction wherever possible by optimizing the use of existing buildings. For example, a recent study showed that in France the vacancy rate rises to 8.3% in 2021. This represents nearly 3 million housing units, compared to 1.85 million in 1982.
It is also essential to promote adaptive reuse projects and to prioritize the adaptation of buildings to limit the vicious circle of “demolition / reconstruction”. In this sense, when new construction is needed, it is essential to build in the long term – in fact, many buildings that are demolished do not present structural problems. In most cases, their demolition is due to their design and layout that no longer fit the needs and demands. The use of modularity / flexible design to allow the future adaptation of the building and extend its life is therefore of great importance.
Finally, it is crucial to use materials efficiently and to consider building materials with lower emissions such as wood and other bio-based materials. Several pioneering projects addressing embedded carbon emissions are being implemented around the world. The Porte Montreuil project, winner of the C40 Reinventing Cities competition in Paris, is an excellent example of this. This strategic site, which spans 35 hectares, will be the first Net zero neighborhood in the City. The constructions will be made with local materials, of biological origin, and 100% of the buildings will be reversible allowing to change uses and transform spaces over time, thus minimizing the need for demolition in the future.
Beyond the buildings, a new model of urban development is needed.
Architects, planners, developers, engineers – they don’t just build or transform individual buildings or blocks, they build a place where people will live. In this sense, they also contribute to shaping the overall model of the city.
The latest IPCC report highlights the importance of integrated urban planning to reduce emissions. It says urban emissions can be reduced by about 25% with more compact, mixed uses and resource-efficient cities.
Urban planning is not a separate emissions sector, but a cross enabling factor of emissions reductions and greater resilience. Once the urban fabric is built (roads, buildings, infrastructures as well as the mix of uses and people) it is very slow to change. Proper urban development is therefore essential to ensure the reduction of emissions in key sectors such as transport, buildings, as well as to reduce vulnerabilities to climate risks and social divisions.
But what is a good model of urban development?
- This is polycentric and made up of multiple, compact ‘complete neighborhoods’ integrating a mix of people and uses and the essential amenities and services promoted in the 15-minute city model.
- This is one that promotes people-centered streets and mobility, reclaiming city spaces from private vehicles and designing a public space that can act as a “neighborhood lounge” – a place where people can meet.
- This is one where every neighborhood is connected through quality public transport and digital infrastructure essential to avoid unnecessary travel and allow for more flexible working practices.
- This is one that takes advantage of urban nature to improve climate resilience and air quality, as well as promote physical and mental well-being.
- This is finally one that equips and empowers communities to adopt a low-carbon life by providing local facilities, such as compost for organic waste, bicycle parking, zero-waste shops, “return and recycling” centers and other shared services.
Many of these principles are based on the 15-minute city concept, on which the latest IPCC report places particular emphasis, and which allows everyone, in every neighborhood, to meet most of their daily needs with a short walk. or a bike ride from home.
These principles may seem sensible, but in reality they are in stark contrast to the urban paradigms that dominated the last century, which saw a monocentric urban development and a specialization of city neighborhoods: residential areas separated from commercial districts, commercial and industrial areas, and all connected by mainly automotive transport infrastructures. This situation has led to long commutes, poor air quality and lack of services in many neighborhoods, exacerbating feelings of isolation and inequity, as well as unsustainable lifestyles.
The past couple of years have seen an increase in interest in this 15-minute city concept, as the disruption of the pandemic and the development of hybrid work have emphasized the importance of the hyper-local environment to support quality of life and a more sustainable lifestyle. Many cities around the world have embraced this model. Leading examples include Paris’s 15-Minute City, Barcelona’s Superblock, Portland’s Complete Neighborhoods, Melbourne’s 20 Minute Neighborhoods, and Bogotá’s Barrios Vitales.
To address the climate crisis, cities and the built environment sector must work together to exploit these building and urban development models. Those that are not only low-carbon, but also resilient and thriving for the local community so they can be widely replicated, especially in fast-growing cities.
With the growth of urbanization, cities are our best opportunity to fight climate change.
The urban lifestyle is indeed the most sustainable because urban residents have smaller homes, which means fewer emissions from buildings and can have easier access to the infrastructure, services and facilities that make a lifestyle possible. sustainable.