Global Problems, Local Solutions: How housing can solve the climate crisis and promote biodiversity
Tackling the polycrisis with housing
Climate. Housing. Biodiversity. Three dimensions to a multi-dimensional polycrisis facing humanity in the 21st century. The list of interconnected challenges is endless, but what is common to many is a nexus, where the intersectionality of complex systems converge towards the shape and materiality of our built environment.
From a macro historical perspective, what has become commonplace today is an anomaly. A step change occurred around 200 years ago, when mainly local, regenerative building solutions began to be replaced with globalised supply chains, extractive materials and increasingly complex technologies. Fuelled by a super-abundance of fossil carbon and hydrocarbon energy, and more lately, petrochemical by-products, this trend has only gathered pace in recent years. But for so many reasons, that era is coming to an end.
How can that be? Because the way we currently make buildings is literally unsustainable, in every sense of the word. From how materials are extracted, processed and distributed, to the chronic under performance of the construction industry relative to other sectors. Poor quality, over-budget outcomes are endemic, and that’s before we consider biodiversity decline and credible strategies to maintain a habitable planet. With 39% of annual global emissions arising from the built environment, including 11% upfront in materials and construction, there is no realistic pathway for governments to meet their treaty obligations, while also delivering the homes we need.
In the UK for example, government policy targets between 300,000 to 370,000 new homes per year, though with conventional construction methods there’s not the remotest possibility that this can be achieved, because of labour skills shortages. But factor in the need to comply with legally binding emission reduction commitments, then the limit is more like 15,000, if built with conventional high embodied carbon materials.
The answer to this conundrum lies within the singularity of the housing nexus. Precisely because most mainstream construction solutions weigh so heavily on ecosystems, climate, human health and national economies, a systematic, focused intervention could have truly transformative potential.
The problem is the solution
Currently, on average, every new home in the UK built with conventional extractive materials emits roughly 50 tonnes of fossil carbon, prior to use. Construction activities consume 40-50% of all extracted raw materials globally each year and 20% of all plastic production. At the same time, demolition accounts for between 30-40% of waste going to landfill or incineration.
A widely promoted solution to tackle embodied emissions and avoid extractive materials, is to replace concrete and steel with timber in new buildings. Yet, timber construction, in the short term, is not carbon neutral. Long rotation cycles in forestry mean that a building made from timber alone simply transfers carbon from one carbon pool (the forest) to another (the built environment).
However, the arithmetic of carbon flux is very different when short-rotation biomass materials are incorporated into buildings. Together with re-use and circular economy strategies, utilising annual biomass crops means that emissions that would contribute towards climate change are instead permanently captured and stored in buildings.
Globally, plants absorb approximately 120 billion tonnes of atmospheric carbon annually, while human activities, such as burning fossil fuels, release approximately 41 billion tonnes. Some of the carbon captured in plants is stored in trees, but most is quickly released back into the atmosphere through decomposition or burning, so that every year the level of carbon dioxide in the atmosphere increases.
If even a small proportion of that short-cycle biomass were to be permanently stored in buildings, then there would be a robust and scalable means of stabilizing and ultimately reducing carbon dioxide in the atmosphere.
A recent study predicts that relatively minor changes to mainstream material composition used in construction would capture and store around 15 billion tonnes CO2 annually in buildings and infrastructure. This figure could be much higher with extensive use of annual biomass crops in housing.
Achieving fast carbon reduction
The difference for the climate between using fast-growing plants and wood is illustrated below. It shows the performance of 1 kg of each material with respect to global temperature change (GTP) as calculated by the methodology of Cooper et al. (2020). In such calculations the temporal effect of the GHGs is measured, which considers the direct effect due to carbon sequestration during plant growth as well as carbon emission during building material production. The biomass regrowth model considers a normal regrowth curve with all carbon removed starting at the year of construction and depending on the growth rate of the plant, which takes 90 years for sawn wood, 40 years for glulam, five years for bamboo and one year for straw.
The results show clearly that fast-growing materials achieve net-cooling impacts much faster due to their short crop rotation periods. This result illustrates how the carbon emission due to the production of building material is directly compensated by regrowth of the new plant and, overall, there is a cooling effect on the atmosphere. In contrast, materials that have longer rotation periods contribute in the short term to a warming of the atmosphere, and only achieve a cooling effect decades after implementation into a building. In that sense, the use of wood in construction is contributing to carbon removal from the atmosphere but a cooling effect on the climate is perceptible only decades after construction. In addition, the use of biobased construction products also avoids emissions by the replacement of a more polluting building material.
The scope for short rotation biomass
Industrial hemp has many remarkable characteristics when incorporated into a building, not the least of which is that it moderates relative humidity and indoor temperature, so that homes require less energy to heat (and to cool), as well as avoiding condensation and mould problems.
The rapid growth of the hemp plant in a wide range of climate zones means it is a versatile break crop for farmers, improving soil quality, improving food crop yields and disrupting pest cycles. Herbicides and pesticides are unnecessary, so hemp enhances biodiversity. And because it’s ready to harvest in 3-4 months, hemp is up to 4-5 times more efficient than forestry at capturing carbon from the atmosphere.
All this makes hemp ideal from a farming and construction perspective, but there are many other biomass crops that are also suitable. For example, miscanthus composites can be formed into board materials, and engineered bamboo into beams and columns. Thus, it is possible now with existing and emergent technologies to make high performing, durable homes, almost entirely from short rotation biomass. Houses made in this way could last longer than conventional brick and block solutions, because of the moisture regulating properties of the materials; as well as providing better energy performance, thermal comfort and indoor air quality. Mandated performance requirements for fire resistance can be proven with testing and certification. And if deployed at scale, new homes would become net carbon sinks, combating climate change and reducing biodiversity loss, while delivering the homes we need.
Distributed manufacture
The principal obstacle to manufacturing housing at scale with regenerative materials is the relative cost when compared to mainstream extractive materials, and cultural perceptions of risk. The existing scale of extraction and production for inorganic materials (supported by historic and current fossil hydrocarbon inputs) dwarfs the production of biomass materials. Non-technical path dependencies relating to procurement and funding models impede widespread adoption. However, these obstacles can be overcome by systemising and de-risking construction products, using integrated digital design and manufacturing technologies to radically improve efficiencies.
As we transition towards a more energy and material constrained future, a bioregional economic model is increasingly likely. Globalised supply chains, predicated on limitless mineral extraction and fossil hydrocarbon resources, are no longer viable, even if we ignore the externalities of climate change and biodiversity loss. Growing and harvesting biomass crops to meet local housing needs, allows an alternative paradigm, where manufactured construction with rapid site assembly facilitates efficient localised production, powered by information technology innovation.
At Natural Building Systems we’ve developed interoperable construction products to harness the climate benefits and performance advantages of short rotation biomass materials, together with the cost efficiencies of integrated digital design and manufacturing tools. Housing needs are delivered with small, low cost, regional hubs responding to local needs with a versatile, standardised, pre-manufactured kit-of-parts, fully benefitting from economies of scale; avoiding the sunk costs and high overheads inherent in other off-site modular technologies.
The first of these production hubs will be operated by ADEPT® Modular, in the East of England near to where materials can be grown, harvested and processed; and close to where thousands of new homes are proposed. This distributed model of manufacture and construction can be replicated in any region of the UK and globally.
To make the houses we need requires policy makers to address the divergence of Net-Zero commitments and housing targets. In the meantime, we’re providing pragmatic bio-based solutions with immediate utility. Together with our design, product and material partners, Natural Building Systems meets multiple interconnected challenges with wide boundary systems thinking, designed for the real world and prepared for the future.
References
[1]‘We’re on the brink of a ‘polycrisis’ – how worried should we be?’ World Economic Forum Jan 2023
[2]The Farmer Review of the UK Construction Labour Model 2016
[3] ‘Bringing Embodied Carbon Upfront’ – World Green Building Council - 2019
[4] Planning overhaul to reach 1.5 million new homes - UK Govt. Press Release 12/12/24
[5] The 2025 Construction Market Outlook - Mark Farmer 01/02/25
[6] The Climate Change Act 2008 (2050 Target Amendment) Order 2019 - UK Government
[7] ‘A just transition of Europe’s built environment (Part 1)’ - Laudes x Dark Matter Labs 05/04/23
[8] ‘Mapping material use and embodied carbon in UK construction’ - Michał P. Drewniok et al - 06/01/23
[9]‘The circular economy: an opportunity for the buildings and construction sector’ – Price Waterhouse Coopers – White Paper 19/12/23
[10] ‘Why we must limit use of construction plastics’ – RICS Built Environment Journal 18/05/23
[11] ‘Current construction and demolition waste levels are unacceptable’ - PCB Today - 17/07/24
[12] ‘Barriers and opportunities of fast-growing biobased material use in buildings’ - Verena Göswein et al - 06/10/22
[13] ‘Carbon Capture is vital to fighting climate change…’ Carbon Technology Research Foundation 30/11/23
[14] ‘How much CO₂ does the world emit?’ - Our World in Data Jan 2024
[15] ‘Building materials could store more than 16 billion tonnes of CO2 annually’ - Elisabeth Van Roijen et al - Science - Jan 2025
[16] ‘Carbon Storage in Hemp and Wood raw materials for Construction Materials’ - Final report, Niels de Beus,et al - June 2023
[17] ‘Expanding Boundaries: Systems Thinking in the Built Environment’ 2016 edited by G. Habert and A. Schlueter
