Renouncing newbuilds in Ile-de-France to face planetary limits

Renouncing newbuilds to face planetary limits? A question motivated by the climate emergency

Climate emergency, the environmental weight of real estate, the importance of the renovation effort and the upcoming trade-off between renovation and construction are now broadly recognized. Against this observation, shouldn’t we stop new construction in Ile de France to face the planetary limits? What are the environmental impacts of new construction in Ile de France? Is it feasible to stop it? What shutdown protocol should be set in motion to take into account the economic and social aspects? The study answers these questions. It limits its perimeter to the shutdown of housing, offices and shops. It excludes the following assets: production buildings, logistics buildings and public facilities. However, it takes into account the 23 million m2 of housing, offices and shops already committed or remaining to be built in Greater Paris. The study is indeed considering stopping after Greater Paris.

The enquiry about the renouncing to newbuilds is based on authoritative scenarios and studies

This study combines elements established by recognized organizations and players in the field. For feasibility, it relies on 2 scenarios. Both are based on trajectories and assumptions defined by INSEE in terms of fertility, life expectancy and migratory balances. The first one, called “Business as Usual”, reflects the trends of recent years. The second one reflects INSEE’s low assumptions for these same indicators.

Newbuilds in Ile-de-France have a strong environmental impact

To begin with, the study reveals a strong environmental impact of new construction: major for artificialization and Greenhouse Gas (GHG) emissions and significant for material consumption and waste generation. Putting an end to it would halve the annual regional artificialization. It would also avoid committing 8 million tonnes of GHG emissions annually. This takes into account the construction products and equipment of buildings and the emissions due to their operation. This gain is equivalent to 20% of regional annual energy-related GHG emissions. In addition, the shutdown would save 8 million tonnes of material per year, or 8% of annual local imports and extractions. For waste, this would be an 8% gain per year in regional waste with 3.4 million tonnes of waste less per year. These impacts fully justify the question of renouncing construction.

Renouncing newbuilds is feasible for offices and shops, more problematic for housing

From this, the study then questions the feasibility of the shutdown. For offices, businesses and for all scenarios, this is doable. For many sub-scenarios, there is not even a need for the new shops and offices in Greater Paris. The answer is more nuanced for housing. In the trend scenario and with low urban recycling, stopping is not possible. However, with low demographic change assumptions and greater urban recycling it becomes feasible. In any case, urban regeneration can produce a large part of it.  Mainly by transformation of wastelands and by urban renovations. To a lesser extent by horizontal densification. More marginally by vertical densification or by recycling offices and shops. This is only possible by qualitatively adapting production to the real economic capacities of Ile-de-France residents, to changes in household size and to the needs linked to pendular effects. As for the issue of the single-family house, which is very politically sensitive,  despite the proven environmental impacts, it was not retained as a preponderant factor.

Flex-office, teleworking and the cost of offices significantly reduce the need for office space

For offices, the study examines various factors that may influence floor space requirement. Demography is taken into account through the 2 demographic scenarios of INSEE. We have not found any tangible signs that the share of the labor force, the share of the office labor force, may change. As a precaution, we have not ruled out the vacant office lever for stopping new construction. However, we have observed a strong trend in 3 phenomena: flex office, teleworking and the cost of offices which, when combined, make it possible to significantly reduce the required office space. So much so that today there is the problem of overproduction and over-supply of offices, amplified by Greater Paris, which provides for many offices.

The evolution of e-commerce is the most important factor for businesses

Then, concerning shops, in addition to the evolution of demography in Ile de France taken into account in the two scenarios, the evolution of commercial vacancies, commercial density (in m2 of shops per inhabitant) and tourism, due to its particular role in the Ile de France region, play on the need for retail space to be built. But it is the impact of the evolution of e-commerce that is the most important factor. This alone justifies that building new businesses is not necessary, in all scenarios.

Demographics and number of housing units built per household are the key factors in reducing the need for housing surface area.

The conclusions on housing are based first of all on the examination of levers that make it possible to reduce the surface area to be built. Demographics are the most important factor. But one factor seems key, much more than tourism, second homes, the size of housing, the aging of the population and the vacancy of housing. This is the number of dwellings built per new household. Today we are building almost twice as many additional households. Acting on this ratio would allow a significant reduction in the number of housing units to be built.

Urban regeneration offers also reduce the need for new housing construction

Finally, solutions exist to meet housing needs without building, and therefore through the urban regeneration mentioned above: recovery of wasteland, urban renewal, horizontal and vertical densification, recycling of offices and shops. The study also identified emerging offers such as co-living, intergenerational housing and so-called “invisible” land.

What to do with the 210,000 new construction jobs in Ile de France?

With the proven environmental impact and the feasibility of the shutdown verified, the study then examines the question of the social and economic feasibility of this transformation. Ecological redirection attaches major importance to these aspects. What to do with the 210,000 new construction jobs? How to shift the economy from the building industry from construction to renovation. The first is now split equally between construction and renovation. In the renovation economy, we would only have 20% of new construction activity and 80% of renovation activity. Three main avenues can be identified for this. First of all: the decarbonisation of energy linked to the existing fleet. Then: the energy renovation of the existing park. Finally, the urban renewal of cities, notably with renovations linked to changes in lifestyles, such as electric mobility.

Difficult political feasibility and worldviews hamper the process

Stopping new construction is politically difficult. For good reasons : the economic weight of the real estate sector, its diffuse nature, a high number of players. Without mentioning the delicate question of social housing and the importance of local participation in housing policy. Also, visions of the world hamper the process of stopping construction. For instance : the race for international attractiveness or the orientation towards newbuild in real estate professions.

But a well-engaged dynamic goes in the direction of stopping

Nevertheless, a dynamic already underway favors the switch to renovation. The more aggressive policy of zero net artificialization, changes in town planning rules, stricter supervision of mortgage loans are all effective tools for controlling and reducing new construction. We can fully imagine that these trends will continue. In addition, a good number of new approaches such as functional diversity, the reversibility of buildings, questioning of architecture and architects and reflections on new property regimes go in the direction of stopping in favor of profit. of the renovation.

The study on stopping new construction therefore highlights a fundamental trend that will now have to be organized.

To sum up, the study highlights underlying trends already at work and proposes recommendations. It thus shows that the Greater Paris project must be reviewed, that the development of office and retail space must be the subject of vigilance. If approaches to sobriety and circular town planning are already being developed and it remains to implement support for actors towards an economy of renovation and to specify the methods of defining low-key needs.

Background and authors of the study

This study was carried out as part of an ecological redirection commission by Arp Astrance at the Msc Design & Strategy for the Anthropocene. Hervé Moal (Loma Management on behalf of Arp Astrance) is at the origin of this visionary questioning. He and two master’s students: Philippe Bouteyre (Praxilience) and William van Gelderen Plannier are the authors.

The Msc Design & Strategy for the Anthropocene is the world’s first course in ecological redirection. Ecological redirection starts from the observation of the Anthropocene to land organizations within planetary limits. Even if it means closing certain deleterious activities or preventing others from happening. For this, the approach is based on the investigation and the design, making it possible to get as close as possible to the actors to make the redirection feasible and to come out “by the top (as little as possible)” (A.Monnin, 2021) of this situation. Finally, this approach intends to go beyond those, resolutely ineffective, of sustainable development, CSR and green growth.


The full summary of the study is available on request.

Leave a comment