IEA EBC Annex 72 - Assessing life cycle related environmental impacts caused by buildings - Targets and tasks

Investment decisions for buildings made today largely determine their environmental impacts over many future decades due to their long lifetimes. Such decisions involve a trade-off between additional investments today and potential savings during use and at end of life - in terms of economic costs, primary energy consumption, greenhouse gas emissions and other environmental impacts. Life cycle assessment (LCA) is suited to identify measures and action to increase the resource efficiency and the environmental performance of buildings and construction. This paper gives an overview of an ongoing international research project within the IEA EBC with the overall aim to harmonise LCA approaches on buildings and foster life cycle thinking in the real estate and construction sectors. The objectives of the project are i) to establish a common methodology guideline to assess the life cycle based environmental impacts caused by buildings, ii) to establish methods for the development of specific environmental benchmarks for different types of buildings, iii) to derive regionally differentiated guidelines and tools for the use of LCA in building design and tools such as BIM, and iv) to improve data availability by developing national or regional databases with regionally differentiated LCA data tailored to the construction sector. To ensure practical solutions a number of case studies will be used to test and illustrate the consensus approaches and research issues

Embodied GHG emissions of buildings – The hidden challenge for effective climate change mitigation

Buildings are major sources of greenhouse gas (GHG) emissions and contributors to the climate crisis. To meet climate-change mitigation needs, one must go beyond operational energy consumption and related GHG emissions of buildings and address their full life cycle. This study investigates the global trends of GHG emissions arising across the life cycle of buildings by systematically compiling and analysing more than 650 life cycle assessment (LCA) case studies. The results, presented for different energy performance classes based on a final sample of 238 cases, show a clear reduction trend in life cycle GHG emissions due to improved operational energy performance. However, the analysis reveals an increase in relative and absolute contributions of so‐called ‘embodied’ GHG emissions, i.e., emissions arising from manufacturing and processing of building materials. While the average share of embodied GHG emissions from buildings following current energy performance regulations is approximately 20–25% of life cycle GHG emissions, this figure escalates to 45–50% for highly energy-efficient buildings and surpasses 90% in extreme cases. Furthermore, this study analyses GHG emissions at time of occurrence, highlighting the ‘carbon spike’ from building production. Relating the results to existing benchmarks for buildings’ GHG emissions in the Swiss SIA energy efficiency path shows that most cases exceed the target of 11.0 kgCO$^{2}$eq/m$^{2}$a. Considering global GHG reduction targets, these results emphasize the urgent need to reduce GHG emissions of buildings by optimizing both operational and embodied impacts. The analysis further confirmed a need for improving transparency and comparability of LCA studies

Embodied GHG emissions of buildings - Critical reflection of benchmark comparison and in-depth analysis of drivers

In the face of the unfolding climate crisis, the role and importance of reducing Greenhouse gas (GHG) emissions from the building sector is increasing. This study investigates the global trends of GHG emissions occurring across the life cycle of buildings by systematically compiling life cycle assessment (LCA) studies and analysing more than 650 building cases. Based on the data extracted from these LCA studies, the influence of features related to LCA methodology and building design is analysed. Results show that embodied GHG emissions, which mainly arise from manufacturing and processing of building materials, are dominating life cycle emissions of new, advanced buildings. Analysis of GHG emissions at the time of occurrence, shows the upfront \u27carbon spike\u27 and emphasises the need to address and reduce the GHG \u27investment\u27 for new buildings. Comparing the results with existing life cycle-related benchmarks, we find only a small number of cases meeting the benchmark. Critically reflecting on the benchmark comparison, an in-depth analysis reveals different reasons for cases achieving the benchmark. While one would expect that different building design strategies and material choices lead to high or low embodied GHG emissions, the results mainly correlate with decisions related to LCA methodology, i.e. the scope of the assessments. The results emphasize the strong need for transparency in the reporting of LCA studies as well as need for consistency when applying environmental benchmarks. Furthermore, the paper opens up the discussion on the potential of utilizing big data and machine learning for analysis and prediction of environmental performance of buildings

Highly Dynamic Host Actin Reorganization around Developing Plasmodium Inside Hepatocytes

Plasmodium sporozoites are transmitted by Anopheles mosquitoes and infect hepatocytes, where a single sporozoite replicates into thousands of merozoites inside a parasitophorous vacuole. The nature of the Plasmodium-host cell interface, as well as the interactions occurring between these two organisms, remains largely unknown. Here we show that highly dynamic hepatocyte actin reorganization events occur around developing Plasmodium berghei parasites inside human hepatoma cells. Actin reorganization is most prominent between 10 to 16 hours post infection and depends on the actin severing and capping protein, gelsolin. Live cell imaging studies also suggest that the hepatocyte cytoskeleton may contribute to parasite elimination during Plasmodium development in the liver

Neue Lerntechnologien für Umweltwissenschaften

Umweltwissenschaften/Ökologie sind durch ihren hohen Grad an Vernetzung, Inter- und Transdisziplinarität dazu prädestiniert, um umweltrelevantes Wissen mit "neuen Lerntechnologien" (E-Learning; internet-based learning; Multimedia-Unterricht) zu vermitteln. Dieser Beitrag stellt eine Auswahl von solchen Aktivitäten an den Universitäten Basel, Bern und Zürich sowie der ETH Zürich vor

Buildings LCA and digitalization: Designers\u27 toolbox based on a survey

In a context of digitalization and increasing quality requirements, the building sector is facing an increasing level of complexity regarding its design process. This results in a growing number of involved actors from different domains, a multitude of tasks to be completed and a higher degree of needed expertise. New buildings are also required to reach higher performances in terms of environmental quality. To that regard, the exploitation of the full potential of digital tools can facilitate the integration of environmental aspects in the planning process, limit productivity shortcomings and reduce environmental impacts, which can result from an unaware decision making. Building environmental assessment can be performed through several Life Cycle Assessment (LCA)-based tools. “Pure calculation” tools quantify final buildings\u27 environmental potential, while “complex tools” additionally support decision making during the planning process. It is often difficult to choose the best suitable tool, which strongly depends on the user\u27s needs. Within the IEA EBC Annex 72, a survey was realized with the main objective of creating a comprehensive overview of the existing tools dedicated to buildings LCA. The questionnaire included the usability, functionality, compliance, data reliability and interoperability of the analysed tools. Lastly, based on the survey outcomes and their critical assessment, a procedure for the identification and selection of a tool has been proposed based on user\u27s needs. As a result, this work outlines main features of currently available building LCA tools, for which there is a harmonized status in terms of usability and overall applied LCA methodology. Despite the need for more automatized workflows, tools\u27 embedding is mostly not yet applicable in system chains or limited to a restricted number of tools

Evolution and Nucleosynthesis of Very Massive Stars

In this chapter, after a brief introduction and overview of stellar evolution, we discuss the evolution and nucleosynthesis of very massive stars (VMS: M>100 solar masses) in the context of recent stellar evolution model calculations. This chapter covers the following aspects: general properties, evolution of surface properties, late central evolution, and nucleosynthesis including their dependence on metallicity, mass loss and rotation. Since very massive stars have very large convective cores during the main-sequence phase, their evolution is not so much affected by rotational mixing, but more by mass loss through stellar winds. Their evolution is never far from a homogeneous evolution even without rotational mixing. All VMS at metallicities close to solar end their life as WC(-WO) type Wolf-Rayet stars. Due to very important mass loss through stellar winds, these stars may have luminosities during the advanced phases of their evolution similar to stars with initial masses between 60 and 120 solar masses. A distinctive feature which may be used to disentangle Wolf-Rayet stars originating from VMS from those originating from lower initial masses is the enhanced abundances of neon and magnesium at the surface of WC stars. At solar metallicity, mass loss is so strong that even if a star is born with several hundred solar masses, it will end its life with less than 50 solar masses (using current mass loss prescriptions). At the metallicity of the LMC and lower, on the other hand, mass loss is weaker and might enable star to undergo pair-instability supernovae.Comment: 42 pages, 20 figures, Book Chapter in "Very Massive Stars in the Local Universe", Springer, Ed. Jorick S. Vin

Induced pseudoscalar coupling of the proton weak interaction

The induced pseudoscalar coupling $g_p$ is the least well known of the weak coupling constants of the proton's charged--current interaction. Its size is dictated by chiral symmetry arguments, and its measurement represents an important test of quantum chromodynamics at low energies. During the past decade a large body of new data relevant to the coupling $g_p$ has been accumulated. This data includes measurements of radiative and non radiative muon capture on targets ranging from hydrogen and few--nucleon systems to complex nuclei. Herein the authors review the theoretical underpinnings of $g_p$, the experimental studies of $g_p$, and the procedures and uncertainties in extracting the coupling from data. Current puzzles are highlighted and future opportunities are discussed.Comment: 58 pages, Latex, Revtex4, prepared for Reviews of Modern Physic

Existing benchmark systems for assessing global warming potential of buildings – Analysis of IEA EBC Annex 72 cases

Life cycle assessment (LCA) is increasingly being used as a tool by the building industry and actors to assess the global warming potential (GWP) of building activities. In several countries, life cycle based requirements on GWP are currently being incorporated into building regulations. After the establishment of general calculation rules for building LCA, a crucial next step is to evaluate the performance of the specific building design. For this, reference values or benchmarks are needed, but there are several approaches to defining these. This study presents an overview of existing benchmark systems documented in seventeen cases from the IEA EBC Annex 72 project on LCA of buildings. The study characterizes their different types of methodological background and displays the reported values. Full life cycle target values for residential and non-residential buildings are found around 10-20 kg CO$_2$e/m$^2$/y, whereas reference values are found between 20-80 kg CO$_2$e/m$^2$/y. Possible embodied target- and reference values are found between 1-12 kg CO$_2$e/m$^2$/y for both residential and non-residential buildings. Benchmark stakeholders can use the insights from this study to understand the justifications of the background methodological choices and to gain an overview of the level of GWP performance across benchmark systems