Tracking the carbon from forests to the built environment with a scalable and geographically versatile model

Building cities with timber has been proposed as a feasible nature-based solution to balance the global carbon cycle and mitigate climate change. The transition to timber construction offers benefits, including enhanced on-site carbon storage and reduced carbon emissions from the construction sector. This transition also imposes pressure on forests, currently playing a crucial role in offsetting global warming. At the same time, this shift reshapes carbon pools not only in forests, but also in the built environment and fossil fuel reserves. The impacts of such a transition on all the carbon pools mentioned above are poorly understood. Here, the results of a new numerical model, which is scalable and geographically versatile, are presented, and the impacts of timber construction on carbon pools are assessed for three case studies located in Europe, Asia, and North America. The case studies had the highest impact on the carbon storage in forests (40%–46% of the potential stored carbon in each case study), followed by the impact on the carbon stored in the built environment (10%–23%) and preserved in fossil fuel deposits (9%–13%). All three projects created a temporary carbon pool in the form of scrap wood, whose size (22%–40%) exceeded the amount of carbon stored in the built environment or fossil fuel deposits. The presented model should provide guidance on optimizing and comparing the benefits of timber construction projects at different spatial scales and in different regions of the world for balancing the carbon cycle. The model offers a preliminary framework for guidance, pending evaluation. An open-access beta version of the model is available online.