Harn Wei Kua
Department of Building, National University of Singapore
Harn-Wei KUA is Associate Professor at the Department of Building, School of Design & Environment (SDE), National University of Singapore. He is also the Assistant Dean (Academic) of the SDE. He is co-leading the newly established Smart Materials Laboratory in the department. His research interest is in life cycle sustainability assessment of buildings and bio-based building materials. He has about 100 academic articles and 3 patents to his credit.
It is widely agreed that there is a need to create a framework for life cycle sustainability assessment (LCSA) that broadens the scope of current life cycle assessment (LCA) to include all the three dimensions of sustainability (economy, environment and society/culture aspects). Current Life Cycle Sustainability Assessment frameworks do not adequately consider the role of stakeholders in the assessment process, Rebound Effects, and how the vulnerability, resilience and stakeholders’ risk aversion are linked to life cycle sustainability.
The framework of Life Cycle Sustainability Unified Analysis (LiCSUA) is proposed to address these four issues, while incorporating key features of the LCSA framework created by Klöpffer and Renner, and the Life Cycle Sustainability Analysis framework proposed under CALCAS.
Specifically, LiCSUA describes crosslinking indicators, inter- and intra-dimensional consequences when each crosslinking indicator is modified, Rebound Effects, and potential changes of these crosslinking indicators with time. Stakeholder involvement is incorporated into LiCSUA by applying a process supported by psychological and sociological theories. A mathematical model is then created to link the vulnerability of a life cycle system to factors such as stakeholders’ sense of vulnerability, Rebound Effects, life cycle stages' resilience, interactions between adjacent life cycle stages, and the adaptive capacity of the life cycle system.
To illustrate the capability of this framework, a theoretical example in which how certain policies will affect the life cycle impacts of the wood-plastic composite(WPC) sector was studied. Specifically, it was assumed that a series of policies aimed at reducing the total mass of discarded wood resulted in an increase in the waste-sorting behavior of residents and the amount of WPC made from recycled wood in the local market. Due to increased competition in the market, the average quality of the WPC in the market increased, which in turn led to more waste reduction.
However, after some time, the WPC market developed so well that local companies might face a shortage in supplies of recycled wood. As a result, some companies might resort to incentivizing consumers to dispose their wood products prematurely or using virgin wood as feed stock, so as to increase their source of waste wood. This is a kind of negative Rebound Effect.
Next, the interactions between the production, construction, use and recycling stages of WPC were defined in terms of production, construction and material utilization efficiency constants. Once these efficiency values, the aforementioned Rebound Effect and the adaptive capacities (or, level of resilience) of each of these stages are known, the framework estimates how the impact (which is defined as the changes made on certain crosslinking indicators of this life cycle system) caused by an environmental shock on the entire life cycle of the WPC system - such as the regular flash floods faced by many countries due to increased intensities of rainfall - can change with time, under different economic and social conditions. It was found that strongly negative Rebound Effects can potentially outweigh the other factors and drastically slow down the system’s ability to adapt to and assimilate the shock.
• Complexity, resilience and sustainability , • Life cycle sustainability assessment , • Advances in methods (e.g., life cycle assessment, social impact assessment, resilience a
