UK's net zero policies: circular economy and embodied carbon

Circular economy is defined by the European Parliament as ‘a model of production and consumption that involves sharing, leasing, reusing, repairing, refurbishing, and recycling existing materials and products as long as possible. In this way, the life cycle of products is extended. Hence, the idea is to limit waste by extending products’ life cycles and promoting recycling and reuse. Therefore, we are moving away from a linear economy model, which involves disposing of natural capital way too quickly and inefficiently.

The life cycle of a product contains different stages. For instance, the construction of a building has a Beginning of Life (BoL) stage involving extracting raw materials, transporting them to be manufactured into usable material, and then transporting them again to the construction site and starting the construction process. A BoL stage in the construction sector is estimated to emit between 20% and 50% of ‘the whole life (embodied and operational) carbon emissions of a new building.’ Here, operational carbon emissions relate to the energy used in the building, and embodied emissions result from the construction process, such as during the BoL stage.

Consequently, the circular economy and embodied carbon are closely interlinked concepts. By using circular economy principles and closing the loop, product productivity can be improved, and recycling can reduce the extraction and use of raw materials, thus limiting BoL embodied carbon emissions and advancing towards net zero. Many actors are involved in the development of circularity. For instance, the Ellen MacArthur Foundation is a charity strongly involved in the research and development of our understanding of circularity.

Hereafter, we dive into the UK’s circular economy and embodied carbon policy strategies to understand how they attempt to close the loop. First, we review recent mentions of circular economy and embodied carbon in the UK net zero policies and the strategies announced. Then, we determine the tools available to implement and monitor a circular economy and embodied carbon emissions. We find that the UK is involved in the development of a circular economy nationally; however, consideration of embodied carbon emissions in policies is currently limited compared to other European countries.

Circular economy and embodied carbon in UK policies

The UK released in 2018 its 25-Year Environment Plan, setting the government’s long-term ambitions and action plan to achieve sustainability. In this plan, a circular economy is mentioned as a tool used to'maximize resource efficiency and minimise environmental impacts at the end of life, particularly in the Resource and Waste Strategy. However, while the circular economy is touched upon by the British government, embodied carbon is left out of its 25-Year Environment Plan and solely mentioned as a future consideration in the UK’s Net Zero Strategy, and the Resource and Waste Strategy report as a potential way to measure and monitor progress.

The resource and waste strategy

The Resource and Waste Strategy, released in 2018 in an attempt to build an understandable circular economy model for the UK, has two principal objectives:

To maximise the value of resource use; and,
To minimise waste and its impact on the environment.

The government aims to deliver this strategy through regulatory and/or economic incentives, enable information to citizens, and ensure good monitoring of waste to prevent it, manage it, and retain the ‘polluter pays’ principal. Five strategic ambitions are adopted, which are:

To work towards all plastic packaging placed on the market being recyclable, reusable, or compostable by 2025;
To work towards eliminating food waste from landfills by 2030;
To eliminate avoidable plastic waste over the lifetime of the 25-Year Environment Plan;
To double resource productivity by 2050; and
To eliminate avoidable waste of all kinds by 2050.

Over time, the British government aims to drastically limit product disposal and first encourage reuse of the product, then recycling, and finally other recoveries, such as ‘incineration with energy recovery’. They aim to implement strong monitoring to control:

The ‘value of resource use’ and ‘adverse environmental impacts’ and,
'Waste and its environmental impact’. However, as acknowledged by the government, the metrics used are weight-based (e.g., waste generation), thus flawing results by providing a lower estimation when it comes to light resources’ pollution, such as plastic.

Building on this, the Litter Strategy for England, released in 2017, encourages recycling in households and businesses. The British government aims to fight fly-tipping by educating the population on recycling, making recycling a cheap option for the population, and ensuring easy access to Household Waste Recycling Centres (HWRCs). To motivate businesses to recycle, the government considers opening HWRCs to small to medium-sized businesses for a small fee, giving them an easy access option to recycle, and increasing HWRCs funds and thus performance.

Embodied carbon in the UK’s strategies

Embodied carbon is lightly mentioned, with few references in the major UK plans for net zero. Nonetheless, it is paramount to understand its environmental impact, particularly in the construction sector, as mentioned previously, and consider it in the design stage of projects to limit embodied and operational emissions.

In April 2021, through the release of the Industrial Decarbonisation Strategy, the government recognised a lack of consideration for embodied carbon in its current definition of what constitutes a low-carbon product.

Following this, in October 2021, the Net Zero Strategy shared policy proposals under its Resource Efficiency and Energy Efficiency section. It suggests better product transparency, a transnational methodology, adding embodied carbon to the construction sectors’ carbon reporting requirements, and developing an embodied carbon emission ceiling for future new builds and the automotive sector.

However, national progress on embodied carbon policy remains stagnant whilst other European countries move faster at implementing whole-life carbon assessments to limit embodied carbon emissions, e.g., France under the RE2020.

Despite this, to improve embodied carbon emissions in the construction sector, local governments and even the built environment sector are taking action. They push for moving from a voluntary to a legally required Whole Life Carbon Assessment (WLCA) to motivate actors to limit their emissions. WLCAs improve the design stage of a building by providing a clear picture of carbon emissions throughout the product’s entire life cycle. An example is the GLA London Plan released in 2021, which includes WLCAs, referred to as Whole Life-Cycle Carbon Assessment, in its plan to make London a zero-carbon city by 2050.

In the recently published (March 2023) Carbon Budget Delivery Plan, the UK mentions looking for ways to agree on an international methodology to measure and report on embodied carbon emissions and explores ways to label low-carbon products with consideration of their embodied emissions. However, despite embodied carbon’s relevance to a circular economy, particularly in the construction sector, the UK government seems, so far, to consider them separately.

Implementing a circular economy and controlling embodied carbon emissions

Although the UK circular economy strategy and the embodied carbon one are developed separately and at different policy stages, a circular economy model and a consideration of embodied carbon emissions are crucial to reaching net zero by 2050. In practice, what kind of actions can be performed to ensure environmental, economic, and social success? Hereafter, we review Life Cycle Assessment, Design for X, and Industrial Symbiosis as processes to implement and monitor a circular economy whilst limiting embodied carbon emissions.

Life cycle assessments

A Life Cycle Assessment (LCA) is ‘a process for evaluating the environmental impacts of a product or service over the course of its entire life.’ The International Organisation of Standardisation, under ISO 14040:2006(en), explains that performing LCA results in making an inventory of the inputs and outputs of a product at a particular stage of life (e.g., BoL) and then conducting an impact assessment to determine the environmental impact of the product at this stage of life. For instance, LCAs can inform decisions at the design stage of a product to ensure that low-impact materials are favoured, such as choosing between two different packagings.

When performing an LCA on a building, companies should calculate carbon emissions throughout the building’s life, hence resulting in a WLCA. Therefore, LCAs can help control and limit embodied carbon emissions. As part of the Institution of Structural Engineers, Orr et al. (2020) explain the following: ‘an embodied carbon calculation is typically to multiply the quantity of each material or product by a carbon factor (normally measured in kgCO2 e per kg of material) for each lifecycle module being considered’, hence summing it up to ‘Embodied carbon = quantity × carbon factor’.

Nonetheless, LCAs have limitations. First, they do not typically include social and economic impacts. Therefore, another version of LCAs, called Social-LCA, assesses the direct impact on the public. Additionally, the Ellen MacArthur Foundation explains that when planning an LCA, it is paramount to choose a representative scope, justify the boundaries chosen, and feed the right data to the model to guarantee valid and reliable results. Further, it prioritises ‘short-term gain over systemic change’, underscoring the importance of using the right scope and data.

Design for X & industrial symbiosis

Other methods can be used to ensure the circularity of an economy, such as the Design for X method or industrial symbiosis. Design for X methods are defined as ‘design methods that ensure that a particular characteristic, function, or quality criteria is reflected in the final design. Different Design for X methods exist, such as the Multiple Life Cycle with Design for Disassembly and Reassembly, Design for Recycling, or even Design for Remanufacturing¹. These methods can contribute to a circular economy by extending the life cycle of a product and suppressing disposal at its end of life.

Industrial symbiosis aims at building a network between local actors to trade waste and resources to avoid product disposal. It positively impacts the environment by diminishing embodied carbon emissions, diminishing waste, and favouring recycling. An example of industrial symbiosis is Denmark's. The actors in the park, public and private, managed to close the loop by exchanging resources’ surplus and waste, such as water and energy. Nonetheless, scaling up a local industrial symbiosis project seems challenging as production could end up so intertwined that altering one process in one company or sector could negatively impact others.

Conclusion

To conclude, the UK's net zero policies strongly consider moving towards a circular economy in the next 20 to 30 years by first focusing on limiting waste, favouring recycling and reuse, and limiting the use of unsustainable and recycling materials. However, despite understanding the importance of managing and limiting embodied carbon emissions, particularly in the construction sector, the British government seems to fail to account for them in their current policies at a national level. Despite this, local governments and private companies have been active in pushing towards more regulations regarding WLCAs. We identified that LCAs, Design for X, or Industrial Symbiosis are methods that can be used to implement a circular economy and control embodied carbon emissions. It is paramount for the government to consider these methods but also understand and mitigate their weaknesses in policies.