Cooperating on mass timber: How bio-based construction can build a greener future 

To make progress on decarbonizing the built environment, currently responsible for approximately 35-40% of all global greenhouse gas (GHG) emissions, we need to understand a few key figures. The first is that addressing embodied carbon is vital.

Embodied carbon – the emissions associated with constructing a building, as opposed to operating it – represents about half of all building-related emissions. Once the building is standing adjustments cannot be made, unlike operational emissions that can be improved with new technologies, standards and retrofits.

The second figure is that the vast majority of built environment emissions will occur in cities, which see the highest growth via new and retrofit construction. This proportion is multiplied because city construction currently has a much higher carbon footprint per square metre. That is due to the materials (such as concrete, steel and aluminium) with which urban buildings are most often constructed.

Finally, around 60-70% of embodied emissions come from the structural framework of urban buildings: steel beams and columns, reinforced concrete foundations, slabs and elevator cores. That is the case for a four-story apartment as much as a high-rise commercial or residential building.

These levels are the foundation – and the imperative – for the mass timber and bio-based materials movement worldwide. Mass timber and other bio-based structural materials can potentially displace most emissions from the structural frames of urban buildings from Zanzibar to Stockholm. Hundreds of bio-based urban structures are standing examples of this alternative.

But the devil is in the details.

How we grow, harvest and process bio-based fibres (whether timber, bamboo or date palm leaves) into viable structures has a range of impacts. Recent scientific reports show conflicting emissions associated with timber and bio-based building materials. The “worst-case scenario” of whole-life carbon from bio-based materials is nearly equivalent to using concrete and steel.

Other credible reports show much lower emissions than conventional materials, with the best-managed bio-based materials offering a significant net storage of carbon. In these scenarios, buildings can store more carbon dioxide than is emitted in production, creating carbon sinks that offset operational emissions and displace emissions from conventional materials – a powerful weapon against global warming.

The disparity in the science mirrors the complexity of the sourcing systems. Natural resources and land use, management protocols, production technologies, skills and knowledge vary widely between countries, as does the demand for new urban buildings.

This value system complexity, multiplied by the asymmetry of supply and demand from region to region, calls for global systems thinking and a tremendous amount of systemic collaboration. That is why we need – and why we are proposing – to co-create a global Forest-Positive Buildings Resource Platform, which will be advocated for at the upcoming UN Buildings and Climate Global Forum in Paris, France between 7 and 8 March.

The global nature of climate change has created an even greater need for common language and culture, alongside renewed commitments to local knowledge, languages, histories and practices.

While this ambitious collaboration platform will be co-created by dozens and ultimately thousands of organizations from government, industry, academic and non-profit sectors, we are currently working with governments to implement best practices, policies and pilot projects that will help us work together more effectively.

Within this two-day event in Paris, a coalition leading the discourse on the use of bio-based and timber solutions will present to government ministers from around the world. Pilot projects and partners in our community of practice are presenting the climate case for bio-based alternatives to “business as usual” construction.

To help attending leaders take action now and align with the transboundary flows of materials, data and knowledge, we have created a menu of recommendations that can be implemented today, focusing on building in-house capacity, skills, knowledge and infrastructure for action. Each recommendation implies some degree of collaboration between various types of public, private and third-sector expertise.

Summary of global actions for policy and industry leaders on bio-based low-carbon construction (see detailed list here):

Urban development cannot continue without incorporating climate action, which means the move towards mass timber and bio-based construction materials in an intentional and conscious way is more than a choice—it is imperative for a sustainable future.

Learn more about global actions and join the Forest-Positive Building Resource Platform here.