by Irene Domínguez Pérez
In the previous article of the series, we explored the main challenges that the building sector faces to decarbonise. Now, we take a look at the existing solutions from a technical perspective, and what needs to be done from the policy side to enable them.
The most sustainable building is the one that is already built – Carl Elefante, architect
There is a common saying among those who work in topics related with the environmental impact of the building sector, and that is that the greenest building is the one that is already built . This is not to say that many existing buildings do not need improvements, but that rather than demolishing and building anew, renovations are far better in most cases. Renovations allow to reduce the operational carbon emissions while minimising the embodied carbon impact (of the newly added materials), therefore optimising the overall footprint of the building, which is known as whole-life carbon (WLC).
The sooner, the better
The first step is to address the obvious need to improve the energy performance of buildings, by measures like insulating and electrifying heating systems (e.g., by phasing out fossil fuel-based systems and promoting the use of heat-pumps) . These types of measures, combined with the increasing penetration of renewable energy into the grid, will progressively reduce the operational carbon footprint of buildings.
However, new buildings are designed and constructed every day. In 2060, the number of buildings worldwide is expected to double, and approximately 70% of the global population is projected to reside in urban regions .
The earlier we tackle embodied carbon emissions, the sooner we avoid locking in emissions in buildings. This is true from a timeframe perspective, but also from a project management point of view: With embodied carbon in mind beginning at the design stage, the largest share of emissions can be avoided. The World Green Building Council presents a good rule of thumb to reduce carbon emissions at different stages of a development project, with the potential for reduction being higher at earlier stages .
Figure 1: Opportunities to reduce embodied carbon from the stage of the design process. Source: WorldGBC (2019) .
What is the policy around embodied carbon?
Embodied carbon policies are starting to take off in the Global North. Some regions in the US, Canada, and the UK have developed policies or financial incentives. In the case of the EU, its policy landscape is shifting towards prioritising embodied carbon reduction, driven by initiatives like the European Green Deal. The Renovation Wave and Fit for 55 are key measures within the Green Deal, focusing on energy efficiency, decarbonisation, and circularity in the building sector. Ongoing policy revisions target building regulations, product standards, and procurement practices, aiming to accelerate the transition to low-carbon materials and practices. The EU’s Circular Economy Action Plan and Taxonomy set criteria for sustainability and environmental performance, while the Carbon Border Adjustment Mechanism (CBAM) equalises carbon prices for imported goods, influencing material choices. Although the outcomes of these policy changes remain to be fully realised, they are expected to lead to increased renovation rates, higher costs for compliance, new business opportunities, and a greater emphasis on sustainable design, manufacturing, and construction practices across various stakeholder groups .
What else could be done?
Decarbonising construction materials is feasible from a technical point of view, but the necessary policies and incentives must be in place to enable the penetration of low-carbon products into the market.
To drive the adoption of sustainable and lower-carbon products, services, and technologies, creating lead markets is key. Lead markets, characterised by early adopters and innovators, play a pivotal role in reducing the “green premium” associated with environmentally friendly options. This premium refers to the higher cost of sustainable products due to increased production expenses and adherence to stricter standards. Lead markets contribute to technological advancements, economies of scale, and heightened consumer demand, which collectively make sustainable choices more accessible and cost-competitive .
Creating such markets involves strategies like green public procurement (GPP), green purchasing agreements, financial support, standards and regulations, and education and skill development, all of which foster a thriving ecosystem of sustainable solutions and contribute to realising lower-carbon buildings .
 Souza, E. (2022). The most sustainable building is the one that is already built: Multi-purpose and Healthy Spaces. https://www.archdaily.com/979371/the-most-sustainable-building-is-the-one-that-is-already-built-multi-purpose-and-healthy-spaces accessed on 16th Sept. 2023
 Bellona Europa (2023). https://bellona.org/news/cities-and-transport/2023-03-open-letter-call-to-vote-for-an-epbd-that-supports-a-fossil-fuel-and-gas-phase-out-from-buildings-this-decade accessed on 16th Sept. 2023
 IEA (2021). Empowering Cities for a Net Zero Future. https://www.iea.org/reports/empowering-cities-for-a-net-zero-future accessed on 31st Jul. 2023
 WorldGBC (2019). Bringing Embodied Carbon Upfront: Coordinated action for the buildingand construction sector to tackle embodied carbon. https://worldgbc.s3.eu-west-2.amazonaws.com/wp-content/uploads/2022/09/22123951/WorldGBC_Bringing_Embodied_Carbon_Upfront.pdf
 Council of the European Union (2023). https://www.consilium.europa.eu/en/policies/green-deal/fit-for-55-the-eu-plan-for-a-green-transition/ accessed on 16th Sept. 2023
 Bellona Europa. (2023). Lead Markets 101. https://bellona.org/news/industry/2023-01-lead-markets-101 accessed on 16th Sept. 2023