Crafting local climate action plans: An action prioritisation framework using multi-criteria decision analysis

The COP21 target to keep global warming to well below 2 (or 1.5) degrees Celsius cannot be met without massive transformation in cities. A major challenge on the road to nearly greenhouse gas (GHG) emissions-neutral cities is the successful development of a climate action plan (CAP) by the local authority, sometimes within the framework of its participation to different initiatives (e.g. the Global Covenant of Mayors). While the identification of the best actions for reaching their long-term GHG emission reduction target constitutes a common decision-making problem for local authorities, it is also an intricate one: conflicting and incommensurable aspects such as environmental, economic, social and technical issues, as well as conflicting stakeholder interests should be dealt with simultaneously when actions have to be programmed. Multi-Criteria Decision Analysis (MCDA) methods are well-known to cope with these complexities and have already been used for decades in several fields. However, they have not been systematically used within the context of local CAPs. The methodologies which are normally implemented to support the prioritisation of actions wholly or to a great extent rely on economic analyses and do not capture the potential co-impacts. In this context, this paper proposes a general participatory framework for guiding collaborative prioritisation of actions as a methodology to help local authorities with the development of more sustainable CAPs, while using MCDA. Finally, advantages, limitations and further steps in research regarding the proposed framework are discussed

The level of knowledge, use and acceptance of LCA among designers in Germany: A contribution to IEA EBC Annex 72

Architects and engineers have become more concerned about the environmental consequences of their design solutions. Knowledge about Life Cycle Assessment (LCA) is crucial for the necessary building sector decarbonisation, as well as for mitigating other negative environmental impacts. In Germany, designers\u27 attitudes towards LCA have not been analysed since 2005. However, since then, certain developments – such as the establishment of the sustainability assessment systems BNB and DGNB – have taken place. In 2019, as part of the project IEA EBC Annex 72, a survey was conducted amongst designers in Germany. The paper presents the current status to identify the progress being made since 2005 and provides recommendations to overcome barriers to LCA dissemination. The results show that although German designers are currently doing a lot with regard to environmental performance assessment, the most critical aspects are considered in a more qualitative way, except for the mandatory operational energy performance calculations. LCA-know-how and application still lags behind expectation. To support an increased use of LCA during building design, not only the provision of related data and design/assessment tools is necessary, but also the establishment of standards and regulations. The latter will drive the also necessary client demand

Principles and Tools for Designing Strategies for Sustainable Urban Development: A “Process-based” and “Action-oriented” Approach at Neighbourhood Level

Cities constitute essential parts of the solution to many of the current sustainable development challenges. They have a major role to play in sustainable development both as crucial “engines” of socio-economic growth and significant “originators” of environmental loads. The special significance of cities for sustainable development is also reflected in the Sustainable Development Goal (SDG) 11 “Make cities and human settlements inclusive, safe, resilient and sustainable” of the 2030 Agenda for Sustainable Development. To organize and to support a sustainable urban development is, however, a particularly complex task to accomplish for any local authority or stakeholder group. The reasons for this complexity are related to the amplitude of the sustainability concept, to the variety and changing nature of the factors to be taken into account, as well as to the challenge for balancing the needs and interests of different stakeholder groups involved in – or affected by – urban interventions. The neighbourhood, as a more manageable urban unit than the city, and as a promising level to test out new ideas and ways of achieving sustainable urban development, has increasingly been acknowledged by research, policy and industry. The thesis therefore investigates new approaches to support sustainable urban development at the neighbourhood scale, with a specific focus on the neighbourhoods in Europe. Existing literature indicates that prevailing approaches are traditionally prescriptive and outcomes-based and fail to acknowledge the process nature of sustainable urban development. Furthermore, their contribution commonly starts and ends with the measurement of indicators and the provision of assessment results in the form of static “snap-shots” without those being reflected in specific possibilities for action in the local area. This hardly solves the problem of the (further) development of existing neighbourhoods. Decoding these results into context-specific strategies and actions, as well as ways of managing these actions, remains a challenge and an area not much researched yet. To remediate these weaknesses and gaps, the thesis proposes a comprehensive and integrated conceptual “process-based” and “action-oriented” overall framework which combines three approaches: (1) a step-by-step structured workflow model that decomposes the process of SUD into manageable tasks and incorporates all necessary quality requirements that should accompany a transition to sustainability; the purpose is to support the preparation phase of sustainable urban development process; (2) a methodology for identifying problem areas, their respective tradeoffs, as well as selecting, organising and describing indicators in an action-oriented fashion; the purpose is to provide a new proposal for linking indicators to possibilities for action so that their use does not only focus on assessing but also guiding development; (3) a methodology for prioritising and selecting concrete strategies and actions for neighbourhoods. The usefulness of the latter is illustrated by the means of a hypothetical case, and with the help of a web-based tool built by the author specifically for the multi-criteria decision analysis (MCDA) method ELECTRE III. The originality of this research lies in that such a comprehensive framework, bringing all the above-mentioned elements together into one coherent solution, has not been available until now. The value of the research is that the proposed overall framework can be a helpful decision support tool for any neighbourhood in Europe which is developing a sustainable development plan

Embodied carbon emissions in buildings: explanations, interpretations, recommendations

What is embodied carbon and why is it a significant challenge for clients and designers in the real estate and construction sector? It is the sum of greenhouse gas (GHG) emissions that arise in the life cycle of a building during manufacture and construction (upfront), maintenance and replacement of building components (recurrent), as well as dismantling and waste processing (end of life). Currently, the relative and absolute share of embodied carbon in the life cycle of a single building is growing and becoming a dominant factor in the case of energy-efficient buildings. For example, for new buildings, it can represent more than 50% of life-cycle carbon. Against this background, embodied carbon is becoming an object of assessment not just in research but also in design and decision-making. It also becomes a key action to reduce GHG emissions. Embodied carbon assessment and reduction are being increasingly mandated in national regulations. Clients and designers (as key actors in the supply chain) can harness new knowledge and tools to reduce embodied carbon as part of a strategy to reduce overall GHG emissions. Appropriate methods, data, benchmarks and tools are being further developed and operationalised to support the processes for specifying and designing low carbon buildings. An overview is presented of the state of knowledge and current developments. Constructive recommendations are provided for actions that clients and designers can take. 'Key findings' From the perspective of a single building’s life cycle, the proportion of embodied carbon is around 50% on average for new energy-efficient buildings. From a macro-economic perspective, approximately 10% of global energy-related CO2 emissions are attributable to the embodied emissions of buildings. Designers can influence and assess embodied carbon according to related design targets in the client’s brief and/or legal requirements. A trade-off between operational and embodied carbon is typical, but possibilities exist to optimise both sides. Embodied carbon can be reduced by selecting low carbon construction products and/or reused building components. Further possibilities are the revitalisation of existing buildings, the extension of their service life, the minimisation of useable areas (sufficiency), as well as the optimisation of buildings and their components. With good design, it is possible to construct low embodied carbon buildings with little or no additional costs, and even generate economic benefits

How to define (net) zero greenhouse gas emissions buildings: The results of an international survey as part of IEA EBC annex 72

The concept of (net) zero greenhouse gas (GHG) emission(s) buildings is gaining wide international attention and is considered to be the main pathway for achieving climate neutrality targets in the built environment. However, there is an increasing plethora of differing terms, definitions, and approaches emerging worldwide. To understand the current progress of the ongoing discussion, this study provides an overview of terms, definitions, and key features from a review of 35 building assessment approaches. The investigation identified that 13 voluntary frameworks from 11 countries are particularly characterised by net zero-carbon/GHG emissions performance targets, which are then subject to a more detailed analysis. The review was organised in the context of the project IEA EBC Annex 72 on “Assessing Life Cycle Related Environmental Impacts Caused by Buildings”, which involves researchers from over 25 countries worldwide. In the current dynamic political surroundings and ongoing scientific debate, only an initial overview of this topic can be presented. However, providing typologies and fostering transparency would be instrumental in delivering clarity, limiting misunderstanding, and avoiding potential greenwashing. To this end, this article categorises the most critical methodological options—i.e., system boundaries for both operational and embodied GHG emissions, the type of GHG emission factor for electricity use, the approach to the “time” aspect, and the possibilities of GHG emission compensation—into a comprehensive framework for clarifying or setting (net) zero GHG emission building definitions in a more systematic way. The article concludes that although variations in the existing approaches will continue to exist, certain minimum directions should be considered for the future development of harmonised (net) zero GHG emissions building frameworks. As a minimum, it is recommended to extend the usual scope of the operational energy use balance. At the same time, minimum requirements must also be set for embodied GHG emissions even if they are not considered in the carbon/GHG emissions balance

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 – The hidden challenge for effective climate change mitigation

ISSN:0306-2619ISSN:1872-911