This article evaluates the synergies between circularity assessment and Life Cycle Assessment (LCA) by investigating their alignments, misalignments, and challenges in addressing sustainability. The analysis emphasizes the significance of a multi-level approach, positioning these methods at various levels, including philosophy, strategy, assessment, and communication. The findings demonstrate that both LCA and circularity assessment can serve as sustainability assessment methods for circularity strategies, despite existing gaps. However, neither approach can provide a complete picture of a system's environmental performance on its own. Data availability, diverse assumptions, spotlights and shadows (highlighted and neglected elements), multiple life cycles, products, functions, strategies, and as well as temporal aspects are identified as the main challenges in addressing sustainability. This article provides recommendations based on the lessons learned from each approach, suggesting the integration of their strengths and addressing challenges to achieve a comprehensive understanding of environmental sustainability and make informed decisions for a circular and sustainable future. These recommendations include using function-based models and the principles of prospective and dynamic LCAs for the development of future circularity assessments. Additionally, circularity assessment can be used to establish LCA models, aiding in identifying hotspots during the goal and scope definition, and determining allocation and weighting factors in both Life Cycle Inventory (LCI) and Life Cycle Impact Assessment (LCIA).

Lifecycle cost analysis (LCCA) is a tool to assess the costs associated with each phase of the building lifecycle. This study evaluated the lifecycle cost (LCC) of a prefabricated fiber-reinforced composite (FRC) building in comparison with a masonry one. The four lifecycle phases of construction, operation, maintenance, and demolition were taken into consideration, and buildings in the American cities of El Paso, Los Angeles, and San Francisco were analyzed. First, the contribution of different building components to construction cost was defined. Consequently, the operation costs to supply cooling and heating-energy demands and lighting and home appliances were calculated. After determining the maintenance and demolition costs, the total LCC of both building types were compared through net present value (NPV). Finally, sensitivity analyses were carried out to assess the impact of influential parameters. The results highlight the significance of construction cost for both structures and the higher maintenance and lower demolition costs of the prefabricated building. Moreover, the prefabricated building was found to have higher cooling costs despite its lower U-value. The prefabricated building had a higher total LCC in all locations. The results also demonstrate the importance of location by indicating substantial variations in construction, maintenance, and demolition costs among the studied cities. Furthermore, the prefabricated building was found to have lower operating costs in Los Angeles and San Francisco but higher costs in El Paso. The sensitivity analyses show significant impacts of the discount rate and lifetime, moderate influence of the inflation rates of maintenance and demolition costs, and limited impact of the inflation rate of electricity cost.

Non-technical summary: To decrease the negative impacts of the coronavirus outbreak on human health, governments have implemented wide-ranging control measures. Moreover, they were urged to tackle a new challenge in energy policies to supply a new form of demand derived from new lifestyles of citizens and different energy consumption patterns. This article investigates the impacts of these changes on climate change and human health (due to air pollution) as a challenge for both citizens and governments in four countries: Colombia, France, the Netherlands, and Portugal.Technical summary: The emergence of coronavirus disease 2019 (COVID-19) pandemic has been associated with global challenges in both energy supply and demand. Numerous articles have discussed the potential benefits of COVID-19 for our planet to mitigate greenhouse gas (GHG) emissions and air pollutants. By bringing the emissions from the energy production together with the air quality indicators, this article studies the impact on climate change and human health due to the COVID-19 pandemic, and the consequent changes in energy policies of governments as well as lifestyles in different societies. This study shows that in spite of having a reduction, the GHG emissions might go back to previous or higher levels if governments do not see this pandemic as an opportunity to promote the use of renewable energies, which are becoming cheaper than non-renewables. Additionally, lower energy demand and less anthropogenic activities do not necessarily result in lower GHG emissions from energy production. Our results highlight the need for revising the policies and decisions of both governments and citizens, as temporary reductions in the levels of energy demand and air pollutants can easily be counterbalanced by adverse effects, known as the ‘rebound effect.’Social media summary: How did the changes in energy consumption and production due to COVID-19 affect climate change and human health in different countries?