Eco-materials Alliance: a collective to accelerate the decarbonization of buildings

These minimally processed materials are still underutilized. Yet the supply chains are now operational and can significantly contribute to the decarbonization of the sector, while bringing multiple co-benefits to the community: public health, preservation of biodiversity and water resources, economic development of territories and local jobs.

Climate trajectory: urgent action is needed

Ten years after the Paris Agreement, the commitment to keep global warming below 2°C now seems unattainable. But avoiding 4°C of warming by 2100 is still possible, and above all necessary to limit adaptation efforts to the consequences of climate change (and its colossal inherent costs).

The French State, through the draft National Low Carbon Strategy 3 published in December 2025, plans to reduce greenhouse gas emissions by 5% per year by 2030, compared to 2% between 2017 and 2024. Such an acceleration requires mobilizing all available levers, particularly in the building sector, which is responsible for 23% of national greenhouse gas emissions.

Furthermore, the forest carbon sink is decreasing due to increased tree dieback and mortality, as well as the rise in fires linked to climate change. In response to this trend, the National Low-Carbon Strategy (SNBC) anticipates an increase in carbon storage in wood and bio-based products, particularly through construction materials.

Buildings: an immediately activatable decarbonization potential

The construction sector in France represents the first source of short-term decarbonization: it is a major emitter, and above all, the technical solutions for building, renovating or operating at a low carbon level are known and do not require a revolution in lifestyles, as may be the case for transport or food.

Renovate rather than build new

The first challenge is, of course, building renovation, which reduces energy consumption for heating and cooling buildings and has been the subject of ambitious public policies for many years. Another challenge lies in decarbonizing construction and/or renovation sites, linked in particular to the choice of building solutions, whose carbon footprint can vary from 1 to 10 depending on the materials chosen. Straw, hemp, wood, and earth are renewable materials, used raw or minimally processed, that rely neither on fossil fuels nor on energy-intensive manufacturing processes. They therefore emit very little carbon. Even better, they store it.

Store carbon now

Among the prospective scenarios for achieving carbon neutrality by 2050 developed by ADEME, scenario 4, "Repair Challenge," relies on the imminent development of technological carbon sinks, which remain uncertain at present. Conversely, scenario 1, "Frugal Generation," anticipates achieving carbon neutrality without relying on carbon capture and storage technologies. In this latter scenario, buildings can play a major role by becoming veritable "carbon banks."

We have known for centuries how to store carbon by building or renovating our buildings with eco-friendly materials. The plants from which bio-based materials are derived absorbed carbon during their growth, as did the soil that provides the earth used in construction. Building or renovating with wood, hemp, straw, or earth means storing this carbon in our buildings for 20, 30, 50 years or more, without waiting for the development of hypothetical technological devices. The wooden frames of our cathedrals have been storing carbon since the Middle Ages!

Real co-benefits for health and economic development

Finally, beyond their very low carbon impact, bio-based or geo-sourced materials have particularly interesting hygrothermal qualities for the renovation of old buildings, notably limiting the risks of humidity and mold, which are harmful to the durability of the building as well as to the health of the occupants.

An advantage for protecting oneself from heat waves

The thermal phase-shifting properties of bio-based and geo-sourced materials also provide real comfort during hot periods by delaying the heating of building interiors. This is yet another advantage for these materials in the current climate context and with the predicted increase in the number and intensity of heat waves.

A source of local economic development and jobs

Finally, eco-materials can provide territories, particularly rural areas, with real development opportunities. For example, the Gâtinais Regional Natural Park, in the southern Île-de-France region, has successfully developed a hemp industry. Initially initiated to preserve groundwater quality, hemp cultivation through crop rotation also allows farmers to regenerate the soil, as this hardy plant requires very little water and no inputs. The development of this crop, historically widespread in France, has enabled the Gâtinais region to structure an industry with the creation of a manufacturing facility that produces materials for textiles and construction, and to ensure the upskilling of local craftspeople in the application of concrete, plaster, and hemp wool on their construction sites.

More broadly, bio-based and geo-based construction materials, which are minimally processed and mostly produced in France, contribute to employment and local economic development, as well as to our sovereignty.

The Eco-Materials Alliance

Fifteen representative organizations of building stakeholders have decided to join forces to accelerate the development of eco-materials and, thus, contribute concretely to the ecological, social and health transition of the construction and renovation sector.

This Eco-materials Alliance brings together structures committed to the development and promotion of bio-based and geo-based materials, considered not only as robust technical solutions, but also as levers for societal transformation: relocation of sectors, resource efficiency, quality of life and responsibility towards future generations.

This alliance aims to:

• to unite stakeholders who share a demanding and responsible vision of eco-materials;
• to support professional practices that contribute to sustainable, healthy and accessible buildings;
• strengthen the eco-materials sectors that create value, jobs and skills;
• to deliver a credible message, based on actions and experience, not reduced to mere communication;
• To challenge public authorities on the role of eco-materials in territorial dynamics and social cohesion.

It is a space for work and dialogue, acting proactively and voluntarily to address contemporary challenges in a concrete, rapid and economically viable way.

Upcoming actions

The Eco-materials Alliance plans, as a second step, to advocate with public authorities and parliamentarians on the following topics:

• Reduced VAT rate on eco-materials
• A bonus-malus system that favors eco-materials and penalizes those derived from carbon-based industries.
• State or local government subsidies are conditional on the use of a significant percentage of eco-materials in buildings.

Members of the Alliance

• As Terre: National Association of Raw Earth Professionals
• AICB: Association of Manufacturers of Bio-based Construction Materials
• Robin.s Cluster: Burgundy-Franche-Comté Wood & Bio-based Construction Cluster
• National Council of the Order of Architects
• Build in hemp
• Echobat: a network of economic actors involved in eco-friendly and socially responsible construction
• Ecoconstruire Federation: federation of training organizations in eco-construction
• Ekopolis: the Ile-de-France resource center for sustainable building and development
• Fédécomat: Federation of Eco-Materials Traders
• Fibois France, the network of regional interprofessional organizations in the forestry and wood sector
• France Bois Forêt: the national interprofessional organization for the wood and forestry sector
• Movement for a happy and creative Frugality
• French Straw Bale Construction Network
• Permabita
• Interchanvre