As the Labour government heads into its second year a niggling worry is beginning to grow. To date no senior Labour figure has clearly and publicly articulated that the housing and climate crises are intertwined.
With 40 per cent of global climate emissions sourced from the built environment, the government needs to make it clear that it is alert to the danger that building 1.5 million new homes in the traditional way could make it impossible for the UK to reach net zero by 2050.
The good news is that the exact opposite is also possible: the completion of every desperately needed new home using different materials could also help to address positively the climate crisis.
Why is the built environment such a major cause of the climate crisis? Concrete, steel, bricks and breeze blocks can only be manufactured using large amounts of energy to generate heat, energy which is still predominately sourced from the burning of fossil fuels.
Concrete is an acute problem because, as well as the energy needed, the manufacturing process of extracting the lime from the limestone triggers a chemical reaction that releases CO2 into the atmosphere. In fact concrete is responsible for a staggering eight per cent of total global carbon emissions[2]. Steel is almost as problematic but is partly redeemed by its high recycling rates. Currently virtually everything we build has an unnecessarily large amount of embodied carbon i.e. our new buildings come with large carbon footprints.
The government, or at least parts of it, is aware of this significant climate problem hence the Ministry of Housing, Communities and Local Government commissioned a recently published external report The practical, technical and economic impacts of measuring and reducing embodied carbon in new buildings.[3]
It is not just the embodied carbon in a new build that is a climate problem. CO2 emissions continue after construction because buildings typically need to be heated. Again, this is mainly done using energy sourced from fossil fuels. In this case the solution is: much better insulation.
Is there then a material out there that we could use as a substitute for concrete, steel, brick and block? Yes: timber! Scotland, Canada, the USA and the Nordic countries build 80 per cent of their family homes with timber frames. But England builds less than 20 per cent. Does it matter? Yes. Timber’s carbon footprint is considerably lower than most construction materials, plus it also stores carbon – a virtue that will be of increasing importance in achieving net zero.
Recent developments with a material known as engineered timber or mass timber mean that it is now possible to build at height and at scale with timber in urban settings. Labour-led Hackney Council has the largest concentration of large engineered timber buildings in the world – including flats, offices, a cinema and a church.
Professor Michael Ramage of the University of Cambridge calculated that erecting a 300-square-metre, four-storey student residence in wood generated only 126 tonnes of CO2 emissions. If it had been made with concrete the tally would have risen to 310 tonnes. If steel had been used emissions would have topped 498 tonnes. Indeed the wood building can be viewed as ‘carbon negative’ as there is the equivalent of 540 tonnes of CO2 stored in the timber, resulting in a long-term removal of CO2 from the atmosphere.[4]
A switch to building more with wood rightly raises questions around the supply of sustainable timber. Reassurance here is provided by Sir David Attenborough speaking in a WWF video on forests in 2019.[5]
“… our growing global population will need to use more wood and that could be a good thing. Wood is an extraordinary renewable resource and taking it from well managed sources benefits forests and the planet. But on their own natural forests can’t provide all the wood we need so we also have to farm trees just like we do other crops and create a new generation of plantations.”
It’s these new plantations or new commercial forests that the government needs to ensure are planted. Currently the UK has amongst the lowest levels of forest cover in Europe. However we do have land on which we could plant new trees especially in the uplands.
Switching to more timber in construction would also store significantly more carbon. So much so that initial calculations point to carbon stored in timber in the built environment in future being able to match the government’s proposed Carbon Capture and Storage scheme under the North Sea and Irish Sea i.e. 8.5 Mt CO2e.[6] [7]
How then could the government speed up the use of timber in construction to the benefit of the climate?
1. Implement the Environmental Audit Committee’s 2022 proposal to legislate for mandatory whole-life carbon assessment of all new buildings, including the amount of stored carbon, as part of the planning permission process.[8]
2. Set maximum standards for the carbon footprints of new builds and their energy use which can then be tightened over time as we aim for net zero in 2050.
3. Incentivise the use of nature-based materials such as timber in construction, including insulation, in part by recognising that the storage of carbon in buildings is a climate benefit.
4. Facilitate education about the use of nature-based materials across the whole of the construction-value chain.
5. Increase the home-grown sustainable wood supply by increasing commercial forest planting.
6. Implement the Timber in Construction Roadmap 2025 which includes working with industry and academia to identify opportunities for and barriers to the use of timber in retrofit and promote best practice and innovation by 2027.[9]
Labour is right to state that there is no magic money tree. There is however – when it comes to tackling climate breakdown – a magic sustainable timber tree. This Labour government could deliver the homes the country desperately needs and at the same time could turn the built environment into a carbon sink rather than a carbon emitter. To do so would be a win-win for Labour, the country and the climate – time for Rayner and Miliband to hold a joint press conference.