Construction must profoundly change if humanity is to halt global warming to an adaptable level. The non-renewable, high-emission conventional materials should be phased out fast and replaced with bio-based and renewable materials that can store carbon and convert the built environment into a long-term carbon storage. Biochar and mycelium are two very promising options.
Currently the built environment development is a huge source of emissions due to the synthetic materials highly used in construction. In 2020, the amount of total human-made mass, known as anthropogenic, exceed the weight of all living biomass – Earth’s total living biomass, which is currently about 1.1 teratonnes. Many indications exist that Earth is on the verge of an ecological collapse. Adjusting our use of resources is imperative to keep our goal of halting global warming to an adaptable level, and staying within the carrying capacity of the globe. Materials commonly used in construction such as concrete, steel, glass, and aluminum should be questioned because of their non-renewable nature and high emission intensities. Moreover, we should rapidly move towards materials that sequester and store carbon, and with them, convert the built environment into a long-term carbon storage.
This transition can make a huge difference in the fight to halt warming. In the Reykjavík Capital region alone, 20,000 new residential units will be built within 10 years. Even with a conservative estimation, with conventional construction materials this means greenhouses emissions of ~1,000,000 tons. With carbon negative materials this could alternatively mean creation of a sizeable long-term carbon storage. We, therefore, urgently need research about different alternative materials. Rather than through incremental improvements with the current construction methods and material reduce the harm the built environment development causes, the aim should be regenerative development, one that improves the state of the environment instead of destroying it.
One such development direction is biochar utilization in concrete and pavement materials to reduce the emission-intense non-renewable components. While the end-product is not fully renewable, such replacement can significantly reduce the emissions, and even convert these conventional materials into carbon storage. However, more research is needed to understand how biochar affects the material qualities. For example, we need to understand how much biochar can be added without losing the key properties of the material in question. 5, 10 or 20%, or even more? And where is the point after which the material becomes carbon negative?
In our project “Constructing Pavement with Carbon-Negative Materials”, funded by Vegagerðin, we are developing, in collaboration with Skógrækt, Icelandic biochar using bio waste from Icelandic wood, burned through pyrolysis. The result can be used as a natural additive, and added to the sand, cement and aggregates, where it acts as natural carbon sink as biochar absorbs CO2. Theoretically, this way all construction could be made carbon negative if the share of the biochar can be made high enough.
While biochar is a very interesting material, it is only one direction in the search for potential new sustainable and eco-friendly solutions. Another one derives from the long tradition of research with fungi, which already long ago have demonstrated their ability to provide powerful solutions across various industries and biotechnological applications. Fungi have given the world globally significant medicines such as penicillin and lovastatin, showcasing their immense potential in different fields however still understudied in all industries appliances. Previous research demonstrates how fungi represent great promise for their application in biotechnology and industry, specifically as plastic replacement material. Now the pressing need for alternative construction materials that can facilitate the transition to a sustainable circular economy has led to research on fungi-based solutions to entirely replace conventional non-renewable and high-emission materials. Mycelium-based bio-composites are an example of such materials. They have low embodied energy compared to concrete-based materials and commercial thermal insulators, and act as a net CO2 sink. Furthermore, mycelium is fast-growing and can be grown in controlled factory conditions to various shapes and sizes, and it has good qualities for further processing.
The adoption of mycelium-bound materials as replacements for current fossil fuel-derived materials would contribute to reducing greenhouse gas emissions and enhancing environmental sustainability. Previous findings presented in literature, robustly endorse the assertion that mycelium materials have the potential to significantly enhance both circular economy practices and the sustainability of the construction industry being a sustainable alternative to conventional materials.
Generally, mycelium and biocrete show promise as great alternatives to both indoor and outdoor conventional non-renewable, high-intensity pavement materials. Moving towards such materials in the quest for sustainable construction practices, and to utilization of other bio-based and carbon negative materials, would be an important step towards a regenerative economy, an economy improving the state of the environment instead of degenerating it.
Neuza Isabel Da Silva Valadas is an Architect and a PhD researcher at the University of Iceland, focusing on mycelium and biochar in her PhD research.
nid5@hi.is
Jukka Heinonen is a Professor at the University of Iceland in the field of sustainable built environment, and the supervisor of Neuza Valadas’ PhD work.
heinonen@hi.is
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