For the next 40 years, the world will build over an area roughly the size of Paris every week. Given the contribution construction makes to material waste and climate change, how can we build more sustainably?
In 2022, the global population passed 8 billion – a fact not missed by headline writers around the world. And by 2050, it is forecast that we will be well on the way to a population of 10 billion. The world will need to house all these people, and while 80 per cent of buildings standing today will still be there in 2050, it will be impossible to avoid new building on a vast scale. Why does this matter, and what will it mean for our planet?
The construction sector is one of the most difficult to decarbonise. ‘Embodied carbon’ is a term used to describe the carbon dioxide emissions associated with materials and construction processes. And, globally, embodied carbon in construction is responsible for 15 per cent of world greenhouse gas emissions.
In addition to emissions, construction is a major source of waste. Astonishingly, roughly 15 per cent of the materials delivered to a construction site are not actually used. And construction alone uses half of all the non-renewable resources consumed by humanity.
While decarbonising construction is a difficult challenge, innovators around the world are showing that progress is possible, and that construction can help us to achieve the United Nations Sustainable Development Goals.
SDG 12: Responsible Consumption and Production
SDG 12 challenges the world to de-couple economic growth from resource consumption. This will require us to dramatically reduce waste and move to a more circular model of economic development. This is particularly relevant for the construction sector given that it accounts for one-third of all the waste produced on earth.
Innovators are tackling the problem in several ways. Dutch startup StoneCycling is re-using the waste that construction itself generates, turning construction debris into new bricks. And, in Australia, researchers are exploring using waste from a non-construction source, used PPE, to strengthen concrete. Meanwhile, in the UK, Pallet LOOP is incentivising builders to return the wooden pallets they use on-site, preventing them from going to landfill.
SDG 11: Sustainable cities and communities
Creating safe, resilient, and accessible human settlements is the focus of SDG 11, and construction naturally has an important role to play in this vision. Target 11.1 within SDG 11 calls for access to adequate, safe, and affordable housing. Based in France and the Netherlands, Cutwork Studios is tackling the housing crises plaguing many western cities with ‘lego-like’ stackable homes that are constructed off-site.
But SDG 11 is about more than simply providing housing – it also calls for access to green space within cities. In Spain, social enterprise Eixverd is taking a novel approach by creating community spaces in the form of ‘green roofs’ covered in vegetation. And in the US, a new housing development in the suburban Silicon Valley town of Santa Clara comes with its own on-site farm that produces low-cost food for residents.
SDG 7: Affordable and clean energy
SDG 7 focuses on the need for the world to transition away from fossil fuels towards, low-cost, clean energy. And while the energy systems of the past were concentrated around industrial-scale plants, the energy networks of the future will be more decentralised, with innovators exploring how energy generation can built into the fabric of buildings.
In the UK, researchers are exploring how perovskite solar cells can be ‘printed’ onto building steel. And in a domestic context, off-site construction company ilke Homes has teamed up with Octopus Energy to create a landmark development in the UK that consists of zero carbon homes equipped with air source heat pumps, solar panels, and battery storage. Meanwhile, in Canada, Mitrex has developed solar walls that look like a regular stone, brick, glass, or wood façade.
SDG 13: Climate action
Construction not only has a role to play in mitigating climate change by reducing fossil fuel consumption – it can also help our societies adapt to the new realities of climate change. Target 13.1 within SDG 13 calls for the world to build resilience to climate-related hazards, and construction innovators are rising to the challenge.
In Australia, insurer Suncorp has partnered with James Cook University, Csiro, and Room11 Architects to create an extreme-weather-proof home design that can resist rain, wind, and fire. Elsewhere, in the US, a startup has created flood-resistant pavers made from porous upcycled bricks, and, in Singapore, researchers have developed a film that makes wood a fire-resistant building material.
SDG 9: Industry, innovation, and infrastructure
SDG 9 calls for innovation to convert industries to environmentally sound processes. And, today, construction relies on several industries that are extremely emissions-intensive – notably cement production.
In the US, researchers are using a type of algae to ‘grow’ an alternative to limestone – one of the key ingredients in cement. They believe their process could be key to unlocking ‘carbon negative’ cement production. Further along the path to commercialisation, global materials company CEMEX has developed a process that reduces emissions by using solar technology to produce clinker for cement production.
Words: Matthew Hempstead
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29th November 2022