Building-integrated carbon storage

Fig 1. Timber used as construction material. Photo credits: UCSD Jacobs School of Engineering (CC 3.0).

Certain building materials, such as timber, straw, or hempcrete, are derived from biological sources and store carbon absorbed during the growth phase of the plants. These materials continue to store carbon throughout their lifespan within a building structure. Carbon can be stored in certain building materials through various processes: 

Photosynthesis

For example, bio-based building materials, such as harvested timber products, bamboo, and straw (Vallas and Courard, 2017)

Carbonation mechanisms

a process in which carbon dioxide reacts with calcium oxide in cement, resulting in the formation of calcium carbonates (Kuittinen et al., 2016). For example, through cementitious materials, such as concrete and mortar (Pacheco-Torgal et al., 2018)

Both carbonation and photosynthesis:

For example, hempcrete (Arehart et al., 2021)

Bio-mineralisation

a process by which living organisms produce minerals that biologically convert the sequestered carbon into carbonates (Heveran et al., 2020; Pedersen Zari, 2017). For example, employing cyanobacteria to produce building materials.

Name of NbS

Building-integrated carbon storage (BICS)

Location

BICS materials can be used in various settings, including urban, periurban or rural.  The applicability of these materials may vary depending on factors such as local climate, market availability, and technical expertise.

Type of NbS

Engineered interventions (not using vegetation)

Case Study:

The Living Pā

Fig 2. Hempcrete wall at CDL Green Gallery. Photo credits: Jnzl’s Photos, Flickr. CC BY 2.0 DEED.

Relationship to Indigenous knowledge

Traditional Oceania architecture typically utilises natural and renewable materials sourced from the local environment, such as timber, thatch, clay, palm fronds, and flax. Traditional architectural forms, ornamentation, and construction methods often carry symbolic meanings and narratives that reflect the history of the area and its people, cultural heritage and values. Traditionally, Karakia (prayers) were offered to Tanemahuta, God of the forest, before a tree was cut for human use in Aotearoa New Zealand for example (Whaanga, 2012).

Climate change benefits
  • Increased temperatures
  • Indirect health, social, cultural climate change impacts

by reducing the carbon footprint associated with the construction and operation of buildings and infrastructure. These materials help mitigate the concentration of CO2 in the atmosphere, which is a major contributor to global warming and has the potential for long-term carbon storage, particularly materials like timber that sequester carbon throughout their lifespan (Amiri et al., 2020). Bio-based materials, such as hempcrete, offer thermal insulation, improving the energy efficiency of buildings (Arehart et al., 2021). These materials also enhance the resilience of buildings and infrastructure to climate change impacts such as extreme weather events and rising temperatures (Arehart et al., 2021).  

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Societal / socio-cultural benefits
  • Climate change adaptation
  • Economic and social development
  • Rights / empowerment / equality / tino rangatiratanga

BICS materials store atmospheric carbon throughout their lifespan and therefore have the potential to achieve carbon-neutral or carbon-positive outcomes if manufactured from Forest Stewardship Council® (FSC®) certified forests, with Red List Free and/or Declare certifications (Maierhofer et al., 2023). Additionally, bio-based materials can replace traditional high-emission materials like concrete and steel, further reducing the embodied carbon of buildings (Grossi et al., 2023). Some BICS projects often involve community participation and engagement throughout the design and construction process, and therefore help empower communities, improve social cohesion, and build trust between residents, designers, and developers.  

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Ecological and biodiversity benefits
  • Climate regulation
  • Education and knowledge
  • Fixation of solar energy, Mana (pride)
  • whakamana (empowerment), tino rangatiratanga (sovereignty)
  • Social justice and equity

Incorporating BICS materials into buildings and infrastructure can enhance resilience to climate change impacts, such as extreme weather events and rising temperatures. BICS materials have the potential for long-term carbon storage, particularly materials like timber that store carbon throughout their lifespan, contributing to carbon mitigation and adaptation (Maierhofer et al., 2023). 

The adoption of BICS materials can raise awareness about sustainable building practices and climate change mitigation and adaptation strategies, serving as educational opportunities for architects, builders, and policymakers. BICS materials can indirectly support ecosystems by promoting sustainable land management practices. For example, using timber harvested from sustainably managed forests maintains the ecological functions of forests, such as soil stabilisation, water filtration, and nutrient cycling, which in turn support plant and animal life (Maierhofer et al., 2023).

Timber and bio-based insulation can be sourced locally or regionally, providing economic opportunities for local communities that can improve local economies, create jobs, and support small-scale industries (Arehart et al., 2021). Using locally sourced and renewable materials in affordable housing projects can help address housing affordability challenges while promoting environmental sustainability and social equity.  

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Technical requirements

BICS materials are required to meet performance and durability standards such as structural integrity, fire resistance, moisture resistance and longevity to ensure that buildings and infrastructure are safe, functional, and resilient over their lifespan. BICS materials should also be compatible with existing engineering and design standards and practices, such as load-bearing capacity, thermal performance, acoustic properties, and compatibility with other building materials and systems. A life cycle assessment could be conducted to evaluate the environmental impacts of BICS materials and technologies across their entire life cycle, from raw material extraction and production to use, maintenance, and disposal (Amiri et al., 2020). These materials may require ongoing monitoring and maintenance through regular inspections to identify and address issues such as degradation or wear and tear.

Issues and Barriers

Many stakeholders in Oceania, including architects, builders, developers, and policymakers, may have limited awareness and understanding of BICS practices and their potential benefits. Addressing this issue requires education to raise awareness, provide training, and disseminate information about BICS materials, technologies, and best practices (Arehart et al., 2021). The upfront costs associated with incorporating BICS materials and technologies into building projects can be higher than conventional construction methods. This cost barrier may deter some developers and clients from adopting BICS practices, particularly in regions where construction budgets are limited or where there is a focus on short-term economic considerations (Amiri et al., 2020).

Opportunities

Oceania is vulnerable to the impacts of climate change, including sea-level rise and extreme weather events. Using carbon-storing materials in construction can contribute to climate change mitigation by reducing greenhouse gas emissions and supporting sustainable development. Incorporating indigenous knowledge and cultural values into projects involving BICS materials in Oceania can promote cultural preservation, honour traditional building practices, and strengthen cultural identity. Collaborative efforts between researchers, industry stakeholders, and indigenous communities can lead to the development of innovative carbon-storing materials, technologies, and building practices tailored to the region’s needs and challenges.

Financial case

Assessing the cost-benefit analysis of building-integrated carbon storage materials involves considering both the upfront costs of implementing these materials and the long-term benefits they provide in terms of carbon mitigation, energy savings, and other environmental and societal benefits (Maierhofer et al., 2023). Energy-efficient materials such as bio-based insulation can lead to reduced energy consumption and lower operational costs for heating and cooling, resulting in long-term energy savings and cost reductions. Cost estimates can also vary depending on regional factors such as material availability, labour costs, market conditions, and climate considerations. For example, timber construction may be more cost-effective in regions with abundant forest resources (Ramage et al., 2017).

References
  • Amiri, A., Ottelin, J., Sorvari, J., & Junnila, S. (2020). Cities as carbon sinks—classification of wooden buildings. Environmental Research Letters15(9), 094076Arehart, J. H., Hart, J., Pomponi, F., & D’Amico, B. (2021). Carbon sequestration and storage in the built environment. Sustainable Production and Consumption27, 1047-1063.
  • Grossi, F., Ge, H., & Zmeureanu, R. (2023). Life Cycle Assessment of the Environmental Benefits of Using Wood Products and Planting Trees at an All-Electric University Laboratory. Buildings13(7), 1584.
  • Heveran, C. M., Williams, S. L., Qiu, J., Artier, J., Hubler, M. H., Cook, S. M., Cameron, J. C., and Srubar, W. V. (2020). Biomineralization and Successive Regeneration of Engineered Living Building Materials. Matter, 2(2), 481-494. https://doi.org/https://doi.org/10.1016/j.matt.2019.11.016.
  • Kuittinen, M., Moinel, C., and Adalgeirsdottir, K. (2016). Carbon sequestration through urban ecosystem services: A case study from Finland [Article]. Science of the Total Environment, 563-564, 623-632. https://doi.org/10.1016/j.scitotenv.2016.03.168
  • Maierhofer, D., Zögl, I., Saade, M. R. M., & Passer, A. (2023). The carbon dioxide storage potential of building materials: a systematic literature review. In Journal of Physics: Conference Series (Vol. 2600, No. 16, p. 162003). IOP Publishing.
  • Pacheco-Torgal, F., Shi, C., and Palomo, A. (2018). Carbon dioxide sequestration in cementitious construction materials. Woodhead Publishing.
  • Pedersen Zari, M. (2017). Utilizing relationships between ecosystem services, built environments, and building materials. Materials for a Healthy, Ecological and Sustainable Built Environment: Principles for Evaluation. Woodhead, 1-28.
  • Ramage, M. H., Burridge, H., Busse-Wicher, M., Fereday, G., Reynolds, T., Shah, D. U., … & Scherman, O. (2017). The wood from the trees: The use of timber in construction. Renewable and Sustainable Energy Reviews68, 333-359.
  • Whaanga, P. (2012). Maori values can reinvigorate a New Zealand philosophy (Doctoral dissertation, Open Access Te Herenga Waka-Victoria University of Wellington).Vallas, T., and Courard, L. (2017). Using nature in architecture: Building a living house with mycelium and trees. Frontiers of Architectural Research, 6(3), 318-328.