The construction industry has a great responsibility in the climate crisis
Climate change is becoming more real every day: we are witnessing a significant increase in climate catastrophes worldwide. Furthermore, the latest IPCC report warns us of possible “tipping points” from which climate change may become sudden and irreversible rather than gradual.
Hélène Cartier is a speaker at the new LifeCycles Festival taking place in Ghent from 28th to 30th September 2022.
Spread over 3 days and 3 stages, LifeCycles will gather over 40 leading speakers discussing the future of our cities, architecture and environment. More info and tickets at www.lifecycles.be
Over the past decade, little progress has been made to keep global warming below the 1.5 degree target set by the Paris Agreement. The leading climate researchers now agree: The 2020s will be a crucial decade for the survival of our environment. Global emissions must peak before 2025 and be reduced 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 major responsibility: buildings are responsible for nearly 50% of annual global CO2 emissions, and the global building footprint is expected to double by 2060, the equivalent of adding an entire New York City to the world. Every month for 40 years.
Buildings urgently need to be decarbonized
Action to decarbonize new and existing buildings – by making them more efficient so they use less energy and by cleaning the energy they use – is crucial. In fact, building operations are responsible for almost 30% of annual global CO2 emissions.
It is also key to minimize embodied carbon from construction. Embodied carbon has historically been underestimated. They are responsible for about another 20% of total emissions and represent an important lever to rapidly reduce global greenhouse gas emissions. Unlike operational emissions, which are spread over the life of a building and can be reduced over time through upgrades to buildings and energy systems, embodied carbon creates an irreversible spike in emissions right at the start of a project.
In order to reduce embodied emissions, it is crucial to slow construction as much as possible by optimizing the use of existing buildings. For example, a recent study has shown that in France the percentage of vacant dwellings will increase to 8.3% in 2021. 3 million dwelling units compared to 1.85 million in 1982.
It is also crucial to encourage adaptive reuse projects and prioritize building retrofits to limit the “demolition/rebuild” cycle. With that in mind, when new build is crucial to build for the long term – in fact, many buildings that are demolished have no structural problems. In most cases, their demolition is due to the fact that the design and layout no longer meet the needs and requirements. The use of modularity/flexible design to allow future adjustments to the building and extend its lifespan 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 embodied carbon emissions are being implemented around the world. The Porte Montreuil project, winner of the C40 Reinventing Cities competition in Paris, is a great example. This strategic location, spanning 35 hectares, will be the city’s first net zero district. Constructions will be made from locally sourced, organic materials and 100% of the buildings will be reversible, allowing uses to change and spaces to be transformed over time, minimizing the need for demolition in the future.
Beyond buildings, a new model of urban development is required.
Architects, town planners, developers, engineers – they don’t just build or transform individual buildings or blocks, they build a place for people to live. In this respect, they also contribute to the design of the overall city model.
The latest IPCC report underscores the importance of integrated urban planning to reduce emissions. According to this, urban emissions can be reduced by around 25% through more compact, mixed-use and more resource-efficient cities.
Urban planning is not a separate emissions sector, but a cross-cutting enabler for emissions reductions and increased resilience. Once built, the urban structure (streets, buildings, infrastructure and the mix of uses and people) only changes very slowly. Proper urban development is therefore crucial to ensure that emissions are reduced in key sectors such as transport and buildings, and to reduce vulnerability to climate risks and social inequality.
But what is a good urban development model?
- This is polycentric and consists of several “full neighborhoods” that are compact, integrating a mix of people and uses, and the essential amenities and services promoted in the 15-minute city model.
- It promotes human-centric streets and mobility by reclaiming urban spaces from private vehicles and designing public space that can act as a “neighborhood living room” – a place where people can come together.
- Here, every neighborhood is connected by quality public transportation, as well as digital infrastructure, essential to avoiding unnecessary travel and enabling more flexible working practices.
- This is one that uses 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 live low carbon lives by providing local facilities such as:
Many of these principles build on the 15-minute city concept, which the latest IPCC report emphasizes, and which allows everyone, in any neighborhood, to have most of their daily needs within a short walk or bike ride of their home out to fulfill .
These principles may seem sensible, but they are in stark contrast to the urban planning paradigms of a monocentric urban development and a specialization of city districts that dominated the past century: residential areas separated from commercial areas, commercial areas and industry, all connected by a predominantly car-oriented transport infrastructure. This situation resulted in long commutes, poor air quality, and a lack of amenities in many neighborhoods, compounding feelings of isolation and injustice and an unsustainable lifestyle.
Over the past two years, interest in this 15-minute city concept has surged as the pandemic disruption and the evolution of hybrid working have emphasized the importance of the hyper-local environment in supporting quality of life and a more sustainable lifestyle. Many cities around the world have adopted this model. Leading examples are the 15-minute city of Paris, the superblock of Barcelona, the complete neighborhoods of Portland, the 20-minute neighborhoods of Melbourne, and the Barrios Vitales of Bogotá.
To tackle the climate crisis, cities and the construction sector must work together to make such building and urban development models usable. Ones that are not only low-carbon, but also resilient and thriving for the local community, allowing them to be widely replicated, especially in fast-growing cities.
With increasing urbanization, cities are our best chance to fight climate change.
Indeed, urban living is the most sustainable because city dwellers have smaller homes – which means fewer building emissions and they have easier access to the infrastructure, services and facilities that enable sustainable living.