With over 650,000 inhabitants, Nantes MĂ©tropole is the sixth-largest metropolitan area in France. It is the leading economic region in Western France, known for its cultural vibrancy, natural environment, and young demographics. Moreover, Nantes MĂ©tropole has been working on climate action since 2007. The city's long-term goal is to achieve climate neutrality by 2050. However, by joining the EU Mission: Climate-Neutral and Smart Cities and using the support of NetZeroCities, Nantes MĂ©tropole aims to accelerate its trajectory and reach climate neutrality by 2030.
As an EU Mission City, Nantes MĂ©tropole is committed to engaging citizens and promoting behavioural change towards more sustainable and climate-friendly lifestyles. The city has been using citizen challenges as an instrument to foster behavioural change since 2011. The approach showed positive results, with approximately 2,000 citizens participating in various thematic challenges, leading to real change, such as a 10% reduction in energy consumption and a 30% decrease in waste. Building on this experience, Nantes MĂ©tropole saw an opportunity to expand its ambition through the NetZeroCities Pilot Activity "Together Towards Climate Neutrality."
The objective of the Pilot was to mainstream citizen challenges and accelerate behavioural change by supporting 1,000 households annually in achieving a carbon-neutral lifestyle. The city also aimed to engage more diverse target groups (citizens, students, and companies) and broaden the scope of the challenges to include eight areas of daily life: energy, waste, food, digital, hobbies, consumption, mobility, and water.
To achieve such an ambitious goal, Nantes Métropole used a new application, LES DEFIS CLIMAT, developed by energy-related non-profits Alisée and Hespul. The app functions as a registration tool for Climate Challenge users, providing useful information, tips, resources, and a CO2 measurement tool.
The participants can join an individual or a collective challenge:
- A collective challenge allows citizens to join a team in the surrounding area, supported by a relay organisation. The challenge lasts three or six months and includes workshops, training and a festive event at the end of the challenge. For instance, in the challenge "Greening up my plate", participants discovered do's and don'ts of a vegetarian diet through cooking workshops led by a nutritionist, debated their views on summer barbecues, and reconnected food and production by visiting an organic farm. Among the 20 thematic challenges proposed, this was the participants' favourite!
- An individual challenge is designed for those who don't have the time or desire to join a collective challenge but would still like to participate in the initiative. The challenge is carried out in a guided manner on the app for four weeks. A participant can join one or more individual thematic challenges, choosing from four available topics: energy, food, waste and leisure.
Participants are also encouraged to measure their carbon footprint to gain an understanding of their current level of GHG emissions. Moreover, each challenge provides information on the CO2 reductions that can be achieved if completed, raising awareness about the impact of lifestyle choices.
Since the launch of the app in March 2024, Nantes MĂ©tropole has successfully engaged 52 collectives and 1,200 participants across 11 municipalities in the metropolitan area. The most popular challenge topics were (1) food, (2) digital, and (3) energy. Moreover, the measured carbon footprint of participants doesn't differ much from the average footprint in France or the Nantes area. It shows that the challenges have mobilised a population with an important CO2 reduction capacity.
What were the key drivers of the initiative?
Strategy: One of the strategic priorities of Nantes MĂ©tropole is social cohesion with a strong emphasis on community life. It informs much of the city's climate work, including climate challenges for citizens. Moreover, climate challenges are listed as one of the main actions of the new Climate Plan of Nantes MĂ©tropole and included in the Action Plan of the Climate City Contract.
Collaboration:
- The implementation of the Pilot Activity was a collaborative effort of six partner organisations led by Nantes MĂ©tropole. The city partnered with Nantes University, the employer association Dirigeants Responsables de l'Ouest, and SAMOA, the urban development public company for the Ăle de Nantes, to facilitate broader engagement among diverse target audiences. Nantes MĂ©tropole also engaged Gustave Eiffel University to support the analysis and evaluation of results while collaborating with non-profits AlisĂ©e and Hespul for app development.
- The initiative relies on the involvement of intermediary (relay) organisations that are the backbone of supporting collective challenges. The recruitment of relay structures enabled each partner organisation to establish new contacts and create a solid network with its structures. It also meant that the piloting team could mobilise more diverse audiences and increase their reach.
Shared concept & co-creation: The piloting team was guided by a shared concept reflected in the project roadmap. The objectives, processes, and roadmap were co-designed in a series of meetings to integrate past experiences, different approaches, and the needs of partner organisations.
Iterative work process: The app was designed, programmed, tested, and launched in under 8 months, a tight timeline. The project team utilised monthly feedback loops to gather and incorporate partner inputs and needs, ensuring that the resulting product met the expectations of all parties involved.
What were the challenges and barriers?
Diversification of target audiences: After one year of experimentation, results have shown a strong concentration of participants among young, educated adults with middle to high income, a higher participation rate among women and a low participation rate among elderly and working-class households. However, all groups, regardless of age and socio-economic background, have been represented. Working with a large network of relay structures from various fields (environment, education, church, culture, etc.) has been a key success factor in this regard, as it enabled diversification of the population reached.
User retention: On the participants' side, the app was not always used initially, prompting a need to collect feedback for improving its features and functionalities. Participation in climate challenges has varied significantly across different groups, primarily due to established group dynamics, facilitation, and the duration of the challenge. Six months were considered too long to maintain momentum; therefore, most challenges were scaled down to three months. Moreover, a tailor-made approach was employed (reduced duration, integration of challenge activities into curricula, etc.) to address the needs of specific target groups such as students.
Limited resources: Working against a tight timeline and with limited resources while accommodating the needs of a large network of actors required to establish clear priorities for app development. Nevertheless, the app development is being continued by Alisee and Hespul, with new functionalities to address the needs of different cities and territories in France (Angers, Lille, Lyon, etc.).
Potential for replication
Many cities in Europe are seeking new ways to promote behavioural change among their citizens. Therefore, the Nantes Pilot Activity can serve as a good example of mobilising and engaging a broader group of stakeholders to develop a solution for awareness-raising and participatory action, encouraging diverse groups of citizens to adopt more sustainable daily habits.
As mentioned earlier, the development of new functionalities is ongoing to enable the usage of the app in other French cities and regions. Additionally, an English beta version is in reflection with the support of NetZeroCities, as several other EU Mission Cities have expressed strong interest in testing the app. Moreover, Nantes Twin City KriĆŸevci (Croatia) aims to replicate and adapt the Climate Challenge app to their local context.
Key lessons learned:
- Imposing change doesn't work. Citizens and local organisations need to be empowered to take ownership of the change, which will ultimately lead to more successful outcomes.
- The relay structures, which are the backbone of the challenges, need a clear path, guidance, training and regular peer-to-peer exchanges along their journey. They also need to be provided with tailor-made solutions that best fit their needs, target groups, etc.
- The quality of content provided (workshops, training, conferences, visits, etc.) is essential for engaging participants in long-term reflection and adopting new lifestyles.
For more information, please contact the LES DEFIS CLIMAT team: lesdefisclimat@nantesmetropole.fr