By Tove Lading, Associate Professor, and head of the continuing education program 'Master in Sustainable Construction,' offered by DTU in collaboration between the four technical universities: DTU, Aarhus University, Aalborg University, and the University of Southern Denmark. Published in Byrumsmonitor December 2023.
Environmental sustainability encompasses four challenges:
- Climate
- Biodiversity
- Resources
- Toxicity
The primary focus is on climate and CO2 emissions, both in the discussion of the green transition and in the construction industry. CO2 is the most crucial parameter in the building code and the most used life cycle assessments (LCA calculations).
Therefore, many in the construction industry lean towards using much more wood in new construction, which is positively regarded in terms of climate. Unfortunately, there is less emphasis on the other three aspects of sustainability.
Resources and Space are limited
Let's imagine that we replace almost all concrete in new buildings with wood in the future. This would require a significant part of our land to cultivate trees. This land use competes with other purposes - food production, recreational areas, infrastructure, housing, etc. We only have one planet. Is massive forestry the best way to use our limited land?
Moreover, growing trees takes time, so perhaps we should consider other solutions.
What about Biodiversity?
Biodiversity is not absent from the discussion, but for the construction industry, it often focuses on the local level. On grass roofs, wild gardens, and the immediate surroundings – commendable initiatives in themselves.
But I call for the larger picture - where it really matters. How will a significantly increased consumption of, for example, wood affect biodiversity at the national and global levels?
Not all wood is equally suitable for construction. At our latitudes, it is mainly coniferous trees that are suitable. Intensive coniferous forest management leads to monotonous landscapes, and increased forest management will affect biodiversity - just look at Sweden or Canada.
Forest management has long-term consequences and requires a perspective on biodiversity and land use that we currently lack.
Toxicity needs to be taken seriously
Finally, there is the issue of toxicity.We want to use more wood and other biogenic materials, which, however, have two undesirable properties: they can burn, and they can be broken down by fungi and mold. We can treat biogenic materials with fire retardants and fungicides ("wood protection"). These are substances with undesirable properties if released into the environment, and they can affect human health.
We may potentially risk having an environmental problem in a few years. There are substances we once praised and used for their good properties, such as PFAS, which we now know are highly problematic.
Greater insight and a long-term perspective are necessary
We have to think in the longterm and consider all aspects of environmental sustainability. Otherwise, we risk creating significant problems for future generations.
Let's acknowledge that sustainable construction is a complex field that requires good and broad knowledge to navigate - knowledge that we do not yet have in all aspects but still need to research.
Only through a synergy of better research, education, debate, and political initiatives can we prevent solving only one problem of environmental sustainability. We must view the future of sustainable construction as a whole, aiming to minimize the impact on climate, biodiversity, resources, and health."
