Decarbonisation requires circular economy practices

Although the UK Climate Change Committee, the UN and other leading bodies have demanded action to decrease greenhouse gas emissions to help limit global warming to 1.5°C, emissions are still increasing.

According to the UN environment programme Global Status Report for Buildings and Construction, there is a growing gap between the actual climate performance of the construction sector and the decarbonisation pathway required to achieve the necessary reduction in emissions.

To strengthen international collaboration on decarbonising the high-emitting sectors of the economy, the Breakthrough Agenda was launched at the UN's climate summit COP26 in Glasgow in 2021.

A subsequent Buildings Breakthrough initiative was officially launched at COP28 last November in Dubai, with a target of making near-zero emission and resilient buildings the new normal by 2030.

To coincide with the launch, the World Green Building Council (WGBC) and leading businesses in the buildings and construction industries made a unified call to political leaders, stressing the critical role of the built environment in climate action.

Their open letter was accompanied by a policy briefing that outlined how WGBC partners could work with policymakers, negotiators and governments at COP28 and beyond to support the creation of a decarbonised, circular and resilient society.

The key principles of a circular economy are to:

• design out pollution and waste
• to keep materials at their highest value for as long as possible
• to be regenerative and restorative, or in other words to be more good rather than less bad; for example cleaning up a river in addition to not polluting it.

For those of us in the construction industry, personal behaviours such as buying a reusable coffee cup, having meat-free Mondays or catching the train to work once a week just aren't enough to meet Buildings Breakthrough targets in the next six years.

To bring about the systemic change needed, we have to shift away from business as usual.

Changing mindsets, working from the bottom up and top down to achieve a decarbonised, circular and more resilient society requires collaboration, creativity and innovation, as well as supporting regulation and policy.

While current government policy may not be heading in the right direction, there are plenty of examples of circular business strategies and practices being implemented across the UK that could be replicated at scale.

• Cleveland Steel and Tubes supplies surplus and reclaimed steel to the construction industry, and contributed to the Olympic Stadium in London
• Engineering firm Max Fordham and main contractor ISG supported the reclamation and reuse of materials on the Entopia Building project in Cambridge.
  
• Contractor Morgan Sindall has developed its own Circular Twin carbon reduction project for public buildings.

Where we cannot redevelop or refurbish existing buildings and have to build new ones, those buildings need to be designed in layers, from fixtures and fittings through to the building's structure and skin.

These must be flexible, adaptable and easily maintained, and capable of being deconstructed for reuse.

To maximise the useful life of materials in existing buildings, a good starting point is to carry out a pre-refurbishment or pre-demolition audit.

It may be stating the obvious, but knowing what is in the building before strip-out and what could be reused in situ by another of the client's projects – or donated to others – is key to enabling the circular economy.

Other fundamental aspects of this process are the careful removal and storage of products and materials, and a marketplace system such as Reyooz and Excess Materials Exchange, among other examples, that enables donors to find recipients quickly and vice versa.

Beyond this, we should start to think of buildings as materials banks. This means that all materials and products are viewed as being deposited temporarily in a building until they are withdrawn or deconstructed, and then redeposited or reused in another building at a later date.

The client, design team, contractors and subcontractors all need to be on board to make reuse work. Equally, the whole value chain needs to collaborate to ensure that reuse becomes business as usual.

The foundations for a circular construction industry are already in place, though: clients are including key performance indicators about reuse in their procurement processes while architects are specifying reused materials and demolition contractors are turning to deconstruction full time.

We will continue to build on these foundations as the price of resources continues to increase and carbon targets become more significant.

Useful information and professional guidance on the topic includes the current edition of RICS' Whole life carbon assessment for the built environment, the Institution of Structural Engineers' Circular economy and reuse: Guidance for designers and the WGBC's Circular built environment playbook.

The services that a demolition contractor offers could well change over time, meaning they would become a consultant on designing for deconstruction with a possible role as a materials reuse wholesaler.

The stereotypically dirty and dangerous end of the construction process has never accurately represented the meticulous planning and expert knowledge required to demolish a building safely.

But as deconstruction and the reuse of materials increases, the role of the demolition – or deconstruction – contractor will become critical to the circular, whole-life process required to hit the 2030 Buildings Breakthrough target.

Under the measure, reused bricks or roof tiles – for instance – count as nominally having zero carbon emissions for modules A1–A3 of life-cycle assessment, covering raw materials, transport and manufacturing.

This is in line with existing practices in other Nordic countries such as Finland, Norway and Sweden, and is part of Denmark's ongoing efforts towards decarbonising its built environment.

Meanwhile, we at the Alliance for Sustainable Building Products (ASBP) are working with our members and the wider construction sector in the UK to increase the take-up of reused materials and products through initiatives such as the REUSE NOW campaign, which has demonstrated both carbon and cost savings, with further events planned.

For the Innovate UK-funded Delivering Innovative Steel ReUse Project (DISRUPT II), we have also partnered with the Institute of Demolition Engineers to explore how to reuse structural steel in construction and encourage adoption of new business models for the circular economy.

Do our current efforts mean we will be able to look back in 2030 and say that this year was a pivotal one for the construction industry?

A year where we made significant progress towards a decarbonised, circular and resilient society and contributed towards a downward trajectory in emissions?