Kai Liebetanz, a sustainability expert in nature and resilience and guest speaker at the upcoming IGBC’s Build Green Now 2025 conference, speaks with ROBBIE COUSINS about why construction industry stakeholders should factor in embodied ecological impact when evaluating sustainability.
Kai Liebetanz, a sustainability expert in nature, resilience, and the circular economy, has recently been facilitating UK construction sector collaborative working groups at the UK Green Building Council (UKGBC) aimed at developing a better understanding of the embodied ecological impacts of the built environment and to tease out ways in which the sector can address the issue.
Embodied ecological impact concerns the built environment’s relationship with nature. According to the WWF Living Planet Report, there has been an alarming 73% decline in wildlife populations worldwide. “This ecological crisis”, Liebetanz warns, “necessitates understanding the construction sector’s contribution and identifying necessary actions that can be taken.”
He notes that when asked about construction’s impact on nature, responsible stakeholders often cite the necessity of human settlements and point to on-site measures like urban greening, biodiversity net gain, and green infrastructure. While acknowledging the importance of these local efforts for healthy, liveable cities, Kai Liebetanz argues they are insufficient to halt global biodiversity loss at the current enormous rate.
“The UKGBC urges the construction sector to adopt a more holistic perspective, moving beyond site-specific biodiversity impacts (like those within the development’s boundary or through urban planting) to consider the broader supply chain impacts and all ecological consequences occurring off-site. This wider view is what is termed embodied ecological impact.”
To illustrate the concept, Liebetanz compares embodied ecological impact to the journey of carbon emissions reduction. He points out that the carbon agenda initially centred on operational carbon, focusing on energy efficiency in buildings. However, the field has evolved to embrace a life-cycle perspective, encompassing both embodied and operational carbon.
The UKGBC seeks to apply this same comprehensive life-cycle thinking to nature and biodiversity, leading to the concept of embodied ecological impacts, a term deliberately echoing embodied carbon. By this, they mean impacts on nature and biodiversity that occur upstream, away from construction sites, during the extraction of raw materials.
He notes: “Whether it’s the ecological damage from mining iron ore for steel or quarrying sand and gravel for concrete, these off-site consequences constitute embodied ecological impacts. This approach directly supports compliance with CSRD reporting, which requires organisations to assess their impact on and reliance on nature. This is especially pertinent for the construction sector, which has a substantial impact through material sourcing yet fundamentally depends on these resources. Consequently, understanding embodied ecological impacts is inherently linked to fulfilling upcoming reporting duties, creating a beneficial alignment. However, we must go beyond just assessing and reporting and move towards meaningful action.”
EARLY DAYS
Two years ago, the UK Green Building Council (UKGBC) began this initiative. Central to the UKGBC’s methodology is the co-creation of guidance and reports through task groups. These groups consist of individuals from diverse organisations spanning the construction value chain, such as contractors, developers, architects, and financial institutions, ensuring industrywide input into the decisions made. To broaden understanding and engagement, the UKGBC has organised educational events, including webinars and public discussions, and hosted a conference on the topic last year.
Kai Liebetanz explains that there has been substantial industry involvement to date, but the concept remains relatively new to the wider construction sector, requiring ongoing awareness-raising. “The UKGBC is currently working with various stakeholders to collaboratively develop practical and effective strategies for implementation. So, I was delighted to get the invitation from the Irish Green Building Council (IGBC) to present on this topic in Dublin.”
QUANTIFYING EMBODIED ECOLOGICAL IMPACTS
He explains there are challenges: “The construction industry’s focus on carbon sustainability has led to expectations for similar quantification of embodied ecological impacts. However, unlike carbon, which is globally uniform and easily calculated, ecological impacts are highly location-specific. Reliable calculation is currently difficult. Therefore, supply chain transparency is crucial for assessing ecological impacts; knowing the source of materials is essential.
“Sand sourcing illustrates this complexity. Land quarries, potentially in already degraded areas, differ significantly from seabed dredging, where unknown biodiversity is at risk. Context drastically changes the impact, even for the same material.”
The IGBC will expand its work on embodied ecological impacts this year, engaging closely with its members. A workshop on the topic will held in May, and a dedicated case study on the subject will be published in the summer.
SUPPLY CHAIN TRANSPARENCY
According to Kai Liebetanz, a crucial step in addressing ecological impacts is for stakeholders to seek supply chain transparency from manufacturers, gaining a thorough understanding of material origins and the specific local impacts associated with extraction.
“Just as we’ve developed carbon reduction strategies, we must implement analogous solutions for ecological impacts. The circular economy, particularly reducing virgin material reliance, is key to mitigating extraction-related damage.”
While quantifying ecological impact is challenging, he explains that resource extraction significantly contributes to global biodiversity loss. “To mitigate this, we should prioritise circular economy principles, maximising material reuse and designing for disassembly.”
Liebetanz adds that prioritising refurbishment over new construction is another key strategy. “We must shift from defaulting to new builds with virgin materials to intelligently reusing existing structures.”
He continues: “Reducing virgin material use, particularly minerals and fossil fuels, is crucial. Shifting to sustainably sourced biogenic materials, such as timber and hemp, offers potential biodiversity benefits.”
CONTRACTOR ROLE
According to Liebetanz, contractors occupy a pivotal position within the supply chain, as they directly manage material sourcing, interacting with manufacturers and suppliers. He argues this gives them a crucial role in driving necessary changes.
“Their connections extend to demolition contractors, granting them unique insight into sourcing and reusing existing materials. Situated at the nexus of construction and demolition, contractors possess the right networks to identify reuse opportunities. This responsibility, however, also presents significant opportunities for them.”
MATERIAL CERTIFICATION
Over the past two years, the UKGBC has engaged with contractors to streamline material reuse. A key obstacle identified is the risk-averse nature of insurers and certifying bodies, who traditionally rely on historical data. Since material reuse is relatively novel, standard risk assessment methods are inadequate.
Kai Liebetanz comments that progress is being made around certifying materials for reuse.
“Certification is increasingly attainable, particularly when a transparent process is presented. This involves detailing material extraction, storage, risk mitigation, integration into new buildings, and adherence to testing requirements.
“Transparency is crucial. Insurers and authorities require a clear, documented process to assess risk. Conversely, a lack of transparency creates a ‘black box,’ hindering informed decision-making and increasing perceived risk, thus obstructing the process.
“If the contractor does groundwork, outlining step-by-step what measures are being taken and why they believe that there is no risk involved, this approach tends to lead to much better outcomes.”
BUILD GREEN NOW 2025
At its ‘Build Green Now’ conference on 15 May next, the IGBC will launch its ‘Building Circular Ireland’ Roadmap, which includes many recommendations and actions to support the reuse of buildings and materials in Ireland.
IN CONCLUSION
In a straightforward summation, Kai Liebetanz highlights the core problem as being that, ultimately, materials that are not renewable will run out, “A finite planet cannot indefinitely support a construction model based on virgin, non-renewable materials, so we need to start addressing this issue in a positive and meaningful way,” he concludes.
If you’re interested in exploring the links between biodiversity and resource efficiency—and hearing directly from expert Kai Liebetanz—the Irish Green Building Council (IGBC) invites you to join over 300 professionals at Build Green Now 2025.
Taking place on 15 May at the Mansion House, the conference will also mark the launch of the ‘Building a Circular Ireland’ roadmap. Learn more and register at www.igbc.ie/events