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The embodied carbon dilemma

Paul Maher

27/2/2023

Future Reference

The severity of the climate emergency cannot be understated. Embodied carbon and the reuse of existing buildings remain under-represented in policy, procurement, and the design of the built environment sector. This presents a dilemma: how can we harness, rather than squander, embodied carbon?

DIT Kevin Street under demolition. Photograph by Karl Matthews [1]

While government plans like Housing for All targets an upscaling in construction, the Climate Action Plan aims to halve the country’s emissions by 2030. It is impossible to square the circle without significant changes to how buildings will be designed, procured, and built. The mitigation of one crisis is likely to worsen another.

Many perceive climate change as a sort of moral and economic debt accumulated since the beginning of the industrial revolution. To the contrary, more than half of the carbon produced by the burning of fossil fuels has been emitted in just the past three decades [2]. To put this into context, since the premiere of Seinfeld there has been as much damage done to the fate of the planet and its ability to sustain life, as the rest of the centuries and millennia of human existence combined. The most perverse aspect of this fact is that during this period we have – unlike previous generations – been acutely aware of the impact of fossil fuels on the planet.

The world’s people will face untold suffering due to the climate crisis unless there are major transformations to global society. Yet, despite the continued unequivocal warnings, a kind of apocalyptic paralysis descends on even the most conscientious of us – as is the case with any sustained exposure to the subject of climate change. ‘Human kind, cannot bear very much reality’, as T.S. Eliot muses in The Four Quartets.

In modern history, there has been an inextricable link between economic growth and increased carbon emissions, of which a key component has been the construction industry [3]. The UN’s Intergovernmental Panel on Climate Change (IPCC) has made clear that the world has little over a decade to radically reduce its carbon emissions in order to avoid catastrophe [4]. Yet construction remains skewed towards energy-intensive, new-build development.

The Irish Green Building Council’s (IGBC) Building a Zero Carbon Ireland looks at the impact of Ireland’s built environment across its whole life cycle. It shows that the construction and built environment sectors account for 37% of Ireland’s carbon emissions – equalling that of the much-maligned agricultural sector. The IGBC have indicated that without significant changes to the carbon intensity of new construction and utilisation of existing building stock, not only will targets be missed but emissions may actually grow.

Whereas inroads are being made in the reduction of operational carbon (the energy used to heat, cool, and light our buildings), there appears to be little progress in the reduction of embodied carbon in the built environment in Ireland, which international studies indicate can result in damning consequences [5]. While government plans like Housing for All targets an upscaling in construction, the Climate Action Plan aims to halve the country’s emissions by 2030. It is impossible to square the circle without significant changes to how buildings will be designed, procured, and built. The mitigation of one crisis is likely to worsen another.

Currently the construction industry is based on a wasteful economic model which often involves tearing down existing structures and buildings, disposing of the resulting material, and rebuilding anew. Adaptive retrofit can account for substantial embodied energy savings by repurposing existing buildings – compared with the embodied energy costs of demolition and new build. The reuse of existing structures can appear to present creative limitations, however, such constraints can provide the basis for more imaginative responses. Innovative solutions can find value in the buildings that have been left behind, for example in Sala Beckett by Flores & Prats Architects, pictured below.

Spanish practice Flores & Prats’ illustrate with Sala Beckett, Barcelona, how creative retrofit of a derelict neighbourhood grocery store can produce a theatre and cultural institution deeply rooted in its architectural and historical context. Their winning competition entry stood out for being the only submission not to propose full demolition of the existing building.

Encouraging the imaginative reuse of buildings has importance beyond sustainability, such as retaining social, historical or cultural characteristics of the built environment and providing an alternative to help to alleviate the wave of corporate homogeneity sweeping over the urban realm in Ireland, which is particularly notable in Dublin. In the UK, proposals to demolish and rebuild the M&S flagship store on Oxford Street has sparked a debate on carbon footprints and building retrofits, ultimately resulting in a public enquiry. The conversation on embodied carbon needs to come to the fore in Ireland.

For example, in the Angel Building, by Alford Hall Monaghan Morris, the concrete frame of an existing 1980’s office building is re-used, extended, and re-wrapped with a highly energy-efficient, glazed skin. The resulting Stirling-Prize-nominated building bears little resemblance to the original tired 80s office block, however, much of the embodied carbon of the primary structure is retained. In recent months, the reinforced concrete frame of the former DIT Kevin Street building was demolished and disposed of with little concern evident for its environmental impact. Could such the approach applied to the Angel Building have been implemented on the DIT Kevin Street site?

Where retention is impossible or unsustainable, the focus must immediately turn to low-carbon solutions. Paris-based office Barrault Pressacco are using sustainable materials as a primary element in the design of several low-carbon social housing projects. Ambitions to build with a lower carbon footprint have driven the practice towards construction with solid limestone as an alternative to concrete, and to building using biomaterials, including wood and hempcrete.

Barrault Pressacco’s apartments, Rue Oberkampf, Paris 11.  Photography by Maxime Delvaux

While there are some commendable low-carbon efforts internationally, the widespread favouring of carbon-intensive construction methods as the default is predictable; most systems mandate the use of concrete and steel. Typically, the pursuit of a low-carbon solution will require a monumental effort to appease and/or convince the client, building control, planning authority, fire officer, quantity surveyor, etc. The path of least resistance will be the tried-and-tested traditional methods of construction.

In order to promote the reuse of existing buildings and low-carbon construction, we need to address and remove the barriers that are currently in place. The Architects’ Journal Retrofirst campaign identifies three such barriers: taxation, policy, and procurement. Followig their suggestions, we could first cut the VAT rate on refurbishment to incentivise the reuse of existing buildings. Secondly, we could further promote the reuse of existing building stock and reclaimed construction material by introducing new clauses into planning guidance and building regulations. Thirdly, we could stimulate the circular economy and support a whole-life carbon approach in construction through publicly-financed projects [6].  

The built environment sector has a vital role to play in responding to the climate emergency. Because construction accounts for such a large percentage of Ireland’s emissions, it should be a cause for optimism; it means we have the power to significantly reduce the country’s carbon footprint by changing our approach to how we design, regulate, and construct the built environment. The solutions already exist, we now need to implement them.

Encouraging the imaginative reuse of buildings has importance beyond sustainability, such as retaining social, historical or cultural characteristics of the built environment and providing an alternative to help alleviate the wave of corporate homogeneity sweeping over the urban realm in Ireland, which is particularly notable in Dublin.

Future Reference is a time capsule. It features opinion-pieces that cover the current developments, debates, and trends in the built environment. Each article assesses its subject through a particular lens to offer a different perspective. For all enquiries and potential contributors, please contact cormac.murray@type.ie.

Future Reference is supported by the Arts Council through the Architecture Project Award Round 2 2022.

References

  1. K. Matthews, DIT Kevin Street Demolition, [online image], 15 October 2021, https://www.flickr.com/photos/turgidson/51635613291/, (accessed 22 February 2023).
  2. D. Wallace-Wells, The Uninhabitable Earth, Penguin Random House, 2019.
  3. W. Hurst, Introducing RetroFirst, [website], 2019, https://www.architectsjournal.co.uk/news/introducing-retrofirst-a-new-aj-campaign-championing-reuse-in-the-built-environment, (accessed 22 February 2023).
  4. Intergovernmental Panel on Climate Change, Climate Change2022: Mitigation of Climate Change [website], 2022, https://www.ipcc.ch/report/sixth-assessment-report-working-group-3/,(accessed 22 February 2023).
  5. In the UK the Royal Institute of Chartered Surveyors has found that, by practical completion stage, 35% of the whole-life carbon of a typical office development will already have been emitted, while the figure for residential is 51%. Royal Institute of Chartered Surveyors, Whole life carbon assessment for the built environment, [website], 2017, https://www.rics.org/profession-standards/rics-standards-and-guidance/sector-standards/building-surveying-standards/whole-life-carbon-assessment-for-the-built-environment, (accessed 22 February 2023).
  6. W. Hurst, Introducing RetroFirst, [website], 2019, https://www.architectsjournal.co.uk/news/introducing-retrofirst-a-new-aj-campaign-championing-reuse-in-the-built-environment, (accessed 22 February 2023).

Contributors

Paul Maher

Paul Maher is an architect based in Dublin. Paul studied at the Dublin School of Architecture, DIT, and the University of Westminster. He has since worked for award-winning practices in New York, Rotterdam, and London. Paul has worked on projects in the civic, residential, educational, and public realm sectors. His work has featured in publications such as The Architects' Journal, Casabella, Drawing Matter, and Architecture Today.

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