Significance of decarbonising the built environment

Decarbonising the built environment is widely acknowledged as critical to mitigating and adapting to global warming. Considering materials (13%) and operation (27%), buildings generate roughly 40% of emissions globally. Hence achieving the Net Zero CO2 2050 target set at the Paris COP meeting in 2015 to limit global warming to well below 2oC above pre-industrial levels will not be possible unless there is radical change towards sustainable building. Commercial and residential buildings and environment be built and perform more efficiently through material choices, waste minimisation, passive solar design, and electrification.  Also here is increasing realisation that reducing supply chain scope 3 emissions, such as those embedded in building materials, is essential and the new space for leadership in business and industry.


Building and Construction in Australia

The significance of their sector and sustainability principles are not news to architects, urban planners, building designers and sustainability professionals, and they have consistently demonstrated the possibilities and impacts of greener cities, precincts, and buildings. The move to mainstream the new Australian Building Standards towards a minimum 7-star rating as well as other initiatives such as the NatHERS Whole-of-Home assessments soon, shows that relevant stakeholders in Australia recognize the need for more resilient built living conditions in a continent projected to face increased climate change effects in the future. Despite these acknowledgements of change, sustainable building and construction is not yet mainstream, and the idea of circular building has been proposed as a way forward.


Circular Economy lands in Australia

In response to an ongoing waste and recycling crisis, exacerbated by waste export bans to Asia, Australia has recently joined a global move to promoting a circular economy. National, state and territory policies and business and industry circular initiatives in cities and regions have initially reframed the waste management and recycling crisis as an opportunity for close looped material and product production and consumption and diversion from landfill. The Ellen MacArthur Foundation has been a key voice in defining and visualization of the circular economy opportunity, and its core principle as designing out waste. However, while recycling and diversion of waste from landfill is part of the circular narrative, critics note that deeper circular change focused on so-called r-strategies at the beginning of the design and planning stage create a far larger impact.


The R-ladder for a sustainable circular economy

While depictions of the circular economy often refer to a range of so-called r-strategies, i.e., recycle, re-use, re-manufacture, the R-ladder includes at least ten (R0-R9) in order of priority (see below). Interestingly the first two terms – refuse and rethink – could signal a systems transition for any sector R2 – R7 are part of a standard circular narrative. The ladder shows in fact that the popular association of recycling waste with circularity is misleading, since the circular principle of designing out waste requires most importantly refusal, rethinking and reduction of material use and consumption. In some of my recent work with colleagues in Germany, we have redefined the r-ladder as shown below to reflect circular principles beyond eco-efficiency and towards systemic sustainability change.




















Rethink the system

R0 Refuse

Do not make, use or accept the product or materials, e.g., fast fashion, oversized ‘dream homes’

R1 Rethink

Redesign product or materials and rethink business models and purposes, e.g., thermal efficiency for rentals

Common circular economy principles

R2 Reduce

Use fewer resources, emissions, and materials, i.e., eco-efficiency

R3 Reuse

Product and spaces reused by another person, e.g., sharing economy initiatives

R4 Repair

Repair product to maintain its function, e.g., in repair café

R5 Refurbish

Restore a product to good working order, e.g., mobile phones, by repairing or replacing parts

R6 Remanufacture

Rebuild a product to specifications of the original manufactured product using a combination of reused, repaired, and new parts

R7 Repurpose

Use product discard or parts in new different product

Last resort strategies

R8 Recycle

Process materials for up or downcycling

R9 Recover

Incinerate material for energy recovery



Sustainable circular build

The relevant strategies from refusing new builds and certain materials to rethinking building and design and re-use of materials and spaces, demands new policies, standards, and political will to support building professionals in their active engagement with change. A sustainable circular economy is of course not only a more efficient decarbonized sector but one where inclusive and affordable design is possible.


In light of the long history of sustainable building and construction, a question that has arisen in my recent work is what is the difference between circular and sustainable building and design? In fact, the general principles of efficiency, material choices and generally minimizing resource use and emissions over the life of the building are common. The difference is in the articulation of circular building principles and its particular focus on r-strategies (as above) across the layers of the building fabric as well as hopefully a focus on social impact.


Australian responses to circular building

The building and construction industry is currently engaged in professional development around the new ABCB NCC 2022 seven-star standards, and the introduction of whole-of-Home Assessment and a range of other initiatives. Some organizations, including the GBCA and Design Matters National have begun to educate on circular build. These and other developments signal a changing building and design landscape in Australia. However, to date new standards and initiatives make no reference to the circular built environment opportunity. However, the situation may be changing


Recently, NSW Government has published Circular Design Guidelines for the Built Environment. Although not yet standards and regulations, this is a step in the right direction. The guidelines identify principles that increase the circularity of materials in projects through waste minimization and other efficiency measures. Beyond developing new circular build principles and practices, affordable and climate resilient housing is an issue of increasing relevance to Australia. A recent AHURI research report on a strategy for circular housing has identified the barriers to an inclusive circular housing for both new build and retrofit in Australia, including that current policy and standards are inadequate, and that greater collaboration among all civic, government and business stakeholders is required. They also argue for new design and build processes to meet their needs.


The Netherlands leads the way

As with other aspects of the circular economy and sustainability in the built environment, the Netherlands has been leafing the charge. On the broader city stage, the City Portrait of Amsterdam, which integrates Doughnut Economics principles about inclusion and circular economy material efficiencies has shown what a sustainable circular city can look like. On the academic front, TU Delft experts in Architecture and Industrial Design, have also been leading the way on circular building and design. The global architecture and construction firm Arup has developed a circular framework, which integrates upstream design and planning principles and exemplifies these in example buildings.


Insights for Australia

The idea of circular building and construction complements an increasing focus on sustainability considerations that have long been part of building design discourse and outcomes. International examples, especially in Europe are providing inspiration for developments in Australia. A truly sustainable circular economy must also address affordability and social equity, and this requires more than material efficiencies and technology developments. Notwithstanding the slow pace of the Australian response, the current global environment, concern with climate change and need for resilient housing looks set to impact building and design in Australia in the near future. The building design profession is well-placed to contribute to this agenda.