the routledge handbook of embodied carbon in the built environment

Manu-facturing of cement, steel, and aluminum used in building construction contributes 6% to global GHG emissions IEA, 2022b.While embodied carbon is not regulated by building codes in

This section will highlight the significance of embodied carbon and the urgency and need to address it in the context of national and international environmental goals, with a focus on policies and developments in North America and Europe, particularly in Scandinavia and Switzerland.

SECTION 2

Embodied decarbonization, approaches and policies

INTRODUCTION TO SECTION 2 National and international approaches

to and policies for decarbonisation

Alice Moncaster and Rahman Azari

Approaches and policies

This chapter introduces section 2, which discusses the current policy and industry initiatives for reducing embodied carbon in different regions of the world This is, we believe, a unique contribution to knowledge, revealing the real world transitions that are under way at this unique point in time across multiple different nations, as we collectively grow to realise the critical need to reduce emissions from construction

As identified in the first chapter of the section, this is indeed a ‘paradigm shift’ in our thinking – it remains to be seen whether the shift will be revolutionary enough to keep the climate from changing beyond recognition.

The first chapter in the section, Chapter 7 (Azari, 2023), considers what is happening in North America The author acknowledges that while the current changes in the construction sector may be centred on starting to measure and reduce embodied carbon from build-ing construction, they are part of a more complex system – a system which includes the need to optimise operational and embodied decarbonisation, and recognises the role that designers, green building rating schemes such as LEED, and material manufacturing and power sectors, have to play The second section of the chapter outlines what is currently happening across the US and Canada, starting by describing the impact of construction in these countries, responsible for 14% and 1.7% respectively of all global construction out-put Embodied carbon is still not regulated by federal (national) building codes in the US, but a number of states and an even larger number of cities have included, or are starting to include, legislation to reduce embodied carbon In Canada, there are similar initiatives at the city level in Toronto and Vancouver, while nationally there is a focus on reducing the embodied impacts of concrete.

The third section of the chapter discusses a case study of design proposals for building a museum in British Colombia in Canada, which was required to meet a target embodied carbon of 277 kg CO2e /m2 for the design life of 75 years The study discusses the percent-age results for different life cycle stages which were obtained through Tally, including and excluding biogenic carbon, as well as through the free-to-use Impact Estimator for Buildings

results from Tally including (275) and excluding (399) biogenic carbon, showing the current limitations of different approaches.

The chapter concludes that the current data-heavy tools need to be supported by more simple tools which can be applied in the early design stage, and that the social and health impacts of construction shouldn’t be forgotten in the drive to reduce carbon emissions.

The second chapter in this section, Chapter 8, comes from the Scandinavian countries of Finland, Sweden and Denmark, which would appear to be leading the way in implementing national regulations for measuring and reducing greenhouse gas impacts from the construction of buildings Written by authors who have been personally involved in the development and leadership of these regulations (Nygaard Rasmussen, Birgisdóttir, Malmqvist, Kuittinen, and Häkkinen, 2023), it is an interesting exploration of not just the resultant regulations, but also of the differences and similarities between the approaches of the three countries to developing and enforcing these regulations In each case described, the regulations were not a top-down diktat from the government, but were developed through extensive consultation with stake-holders The construction industries in each country also had previous experience of working towards green building rating systems, and so understood the concepts being proposed.

A detailed section describes the specific differences between the three sets of regulations, in terms of reference unit, reference study period, life cycle stages included, scope of inven-tory, and background data These issues will be of particular interest to all those involved in developing their own national regulations, where such issues are discussed at length The section also provides a discussion on the impact of ‘trade offs’ between scope and data, similar to the concern identified in the previous chapter – that is, the more detailed and accurate the scope, and the more specific the data requirements, the more difficult (and expensive) it is to apply This particular issue is being evaluated in Sweden and Denmark as the regulations are rolled out.

The final discussion section considers the application of the use of limit values, another issue of importance for those involved in developing such regulations Denmark, for ex-ample, has set a limit value of 12 kg CO2e/m2yr, which includes life cycle stages A1–3, B4, B6 and C3–4 This, therefore, combines the majority of embodied carbon impacts with the impact of operational carbon in B6 It could also be noted that comparison with the case study described in the previous chapter shows one of the difficulties of comparing different results In the Canadian case study, the limit was set to 277 kg CO2e/m2 which equates to just 3.7 kg CO2e/m2yr – however this excluded the operational carbon, while including the potential positive impacts of biogenic carbon, as well as ‘beyond life’ loads and benefits included in stage D Therefore it is almost impossible to compare with the Scandinavian limits, without re-analysis of the detailed results, and this is a common problem within as well as between different national case studies Between the three Scandinavian countries there are also differences, in terms of physical assemblies included and in terms of how the limits have been arrived at It is noted, too, that the differences in climate will result in differ-ent amounts of operational energy needed for comfortable conditions in otherwise identical buildings – an issue that will have a far bigger impact when applied to countries with more diverse temperatures Should operational carbon then be considered separate from embod-ied carbon, after all? An alternative approach which is gaining traction is also discussed in this chapter, which is whether limits should be set using ‘planetary boundaries’ – that is, rather than basing limits on current national construction practice and working out by how much and how fast we can realistically expect industries to improve on this, instead working out how much carbon ‘budget’ the planet can afford per person On this basis, the

budgets for A1–5 for Denmark and Finland are calculated as just 1.3 and 0.8 kg CO2e/m2yr respectively by 2030.

The chapter concludes by noting that, while there was considerable coordination tween the three countries in developing their regulations, nonetheless there are distinct na-tional differences in the results, due to pre-existing practices and stakeholders While there are pros and cons of each approach, as described here, maybe the main lesson is this: that even while construction companies often work across national boundaries and even across the globe, construction practice is nevertheless highly context-specific and contingent, and effective regulations are likely to need to be similarly diverse.

be-This chapter leads effectively onto Chapter 9, in which Priore, Habert and Jusselme (2023) offer a thoughtful development of a methodology through which we might meet planetary limits and keep to the Paris Agreement of 1.5 degrees of warming, as discussed briefly by the previous chapter This chapter is complex and extensive, but well worth read-ing in detail as it identifies and thoughtfully debates a number of important concerns around current approaches to carbon reduction from buildings.

Starting with a look at national inventories of greenhouse gas emissions the authors note the difference between production-based (‘territorial’) emissions as required report-ing under the IPCC guidelines, and consumption-based emissions The importance of the difference is explained by using Switzerland as an admittedly extreme example in which

production-based emissions of goods produced within the country’s boundaries (around 50

since around 2015, the former show no such clear pattern of reduction.

The next issue discussed is how the remaining ‘global carbon budget’ should be shared between nations Four alternative allocation principles which have been offered by other researchers are described: the Equality principle (or ‘Equal per capita’ – EPC), in which each person has an equal share of the remaining carbon budget to spend; the Responsibility principle, in which previous emissions are taken into account and subtracted from the share that is left for each nation; the Capability principle, in which richer nations who have more ability to pay have a higher level of responsibility to reduce their emissions; and the Sov-ereignty principle, in which the current percentage share of global emissions is continued

following the Equality principle for the EPC allocation, 0.400 Gt CO2 for the Grandfathering principle, retaining the same proportion of global emissions as Switzerland had in 2019,

to 1990 The chapter suggests that the last of these, while having some justification, is likely to be impossible in practice.

How Switzerland’s carbon budget, allocated through one of these principles, might then be shared between the different national sectors of building operation, transport, industry and ‘other’, is then discussed Embodied emissions fall under ‘industry’, and should include the imported emissions In order to reach the goals of the Paris Agreement, the operational emissions must reach zero by 2035, which will require embodied emissions to be spent in renovating existing buildings Alternative scenarios in which zero operational emissions are met by 2050, or in which new buildings are immediately required to meet zero operational emissions, are also discussed.

The chapter concludes that this approach, defining a national carbon budget and then allocating a portion to the building sector in order to set limits and targets in line with global

carbon reduction needs, is complex but possible It is also necessary While the energy tor is currently an international focus, the paper makes a strong case for the building sector to be given the same attention and urgency.

sec-Chapter 10 brings our focus back out from individual countries to consider what is pening across Europe as part of the Level(s) Framework Izaola (2023) starts by explain-ing the multitude of approaches and programmes towards sustainability that have been introduced across Europe up to 2023, before explaining the Level(s) Framework, which combines a common language and methodology for sustainability indicators for buildings, in further detail Focusing further, a specific project ‘LIFE Level(s)’ is then described The au-thor was the project coordinator for this ‘Governance and Information’ project, which was funded by the European Union between 2019 and 2022 and led by a consortium of eight national Green Building Councils The purpose was to encourage the understanding and use of LCA alongside life cycle costing (LCC) and indoor air quality (IAQ) for buildings, thereby covering environmental, economic and social (health) aspects of sustainability The chapter, and project, acknowledge that this does not incorporate all aspects therefore, but in offer-ing a reduced set of 16 indicators it aims to be more simple, usable and low cost than the majority of schemes The chapter then concentrates on one specific part of the project which considered the data available for LCA calculations across the eight participating countries, and particularly Croatia, Finland, Ireland, Italy and Spain The approaches taken by each has been quite different, and these, with the pros and cons, are described.

hap-This chapter, therefore, offers a unique perspective on what is happening in Europe from a source close to policy and practice rather than research It concludes with a discussion on progress, acknowledging increased ambition and still patchy changes, with a tendency across the sector and the globe to plan future carbon reductions rather than implement them now Nevertheless, the Level(s) Framework is undoubtedly changing behaviours in Europe, and the LIFE Level(s) project has had direct and measurable impacts on the construction industries of the participating countries; more such projects are needed.

The final chapter of this section, Chapter 11 (Houlihan Wiberg et al., 2023), looks cifically at the role of designers, and what they can do – particularly while and where there is still an absence of regulation – to reduce embodied carbon from their building designs Based on an analysis of 80 case studies collected and analysed by the International Energy Agency Energy (IEA EBC) Annex 57, the chapter first describes that project and its findings, and then presents the analysed case study results through a number of clear visuals aimed at practitioners Leading on from previously published papers on Annex 57 it develops a typology of approaches, starting with material substitution, then resource reduction, flexible designs, durability and re-use A further, shorter, section of the chapter then considers how impacts might be reduced from the specific life cycle stages of construction (A4–5) and end of life (C) Within each approach a number of specific strategies are proposed, alongside important design points to note.

spe-No numbers are offered as to how much emissions might be reduced by each of these strategies – however as has been noted in previous chapters, these are likely to be highly varied, or would need to be defined in considerable detail in order to be accurate The con-clusions also warn that some of the strategies in combination might have a negative impact, and that further research and detail is required in this area However what the chapter does offer is a starting point as to how designers and clients might consider reducing impacts at the start of the design stage, before investing the time and money in a full life cycle assessment.

Section 2 of the Handbook therefore moves full circle, with this last chapter of the section responding to the concluding point made in the first chapter of the section, in which Azari (2023) pointed out the need for simplified tools to be used at the early design stage Effec-tively that is what this chapter does, through a series of visualisations of approaches to low carbon Design practitioners looking to reduce the impact of their buildings are particularly encouraged to read this chapter.

The built environment, as we know, is responsible for around 38% of all energy-related greenhouse gas emissions How we reduce this, and the limits we aim for within individual countries and individual building projects, will depend on a number of complex factors The five chapters in this section discuss these issues from different viewpoints in the context of what is happening at the moment in various regions and nations Together they offer a thought-provoking and informative view of where we need to go now.

Azari, R (2023) Embodied decarbonization in North America; a paradigm shift In: Azari, R and

Mon-caster, A (eds) The Routledge Handbook of Embodied Carbon in the Built Environment Routledge.

Houlihan Wiberg, A., Moncaster, A., Birgisdottir, H., Nygaard Rasmussen, F., Malmqvist, T and James, B (2023) Embodied GHG emissions - knowledge building for industry In: Azari, R and Moncaster,

A (eds) The Routledge Handbook of Embodied Carbon in the Built Environment Routledge.

Izaola, B (2023) The level(s) framework and the life levels project: Developing common and national

approaches to embodied carbon in European countries In: Azari, R and Moncaster, A (eds) The Routledge Handbook of Embodied Carbon in the Built Environment Routledge.

Nygaard Rasmussen, F., Birgisdóttir, H., Malmqvist, T., Kuittinen, M and Häkkinen, T (2023) ied carbon in building regulation – Development and implementation in Finland, Sweden and

Embod-Denmark In: Azari, R and Moncaster, A (eds) The Routledge Handbook of Embodied Carbon in the Built Environment Routledge.

Priore, Y D., Habert, G and Jusselme, T (2023) Global carbon budgets for the built environment: How far are we to achieve a 1.5°C limit in global warming? A Swiss example In: Azari, R and Moncas-

ter, A (eds) The Routledge Handbook of Embodied Carbon in the Built Environment Routledge.

EMBODIED DECARBONIZATION IN NORTH AMERICA

A paradigm shift

Rahman Azari

Embodied carbon: the key component of a paradigm shift

The concept of ‘paradigm shift’ was introduced by the American science philosopher,

Thomas Kuhn In his 1962 book, The Structure of Scientific Revolutions, Kuhn (Kuhn, 1962)

depicted four stages of paradigm shifts in natural sciences including normal science, traordinary research, adoption of a new paradigm, and aftermath of the revolution Kuhn argued that the new paradigms in science emerge as the result of revolutions, rather than step-by-step changes in the thinking process of the professional communities (Kuhn, 1962) There is evidence that a form of paradigm shift has been taking place in all sectors including the construction industry that aims toward net-zero emission status by 2050 As a result, the dominant paradigms with a focus on energy efficiency are shifting to a new paradigm that is more holistic and considers the cross-sectoral synergies between construction, manufac-turing, transportation, and power generation sectors, as well as cross-component tradeoffs between energy efficiency and embodied carbon This paradigm shift may or may not rep-resent a revolutionary change of status in its current form and effects Or it could be argued that we might be just in the initial stages of adopting the new paradigm However, the scope of deviation from the ‘normal’ practice that needs to happen for limiting the contribution of building construction to climate change certainly needs urgent and radical changes in the way we design and construct the built environments to meet the rising demand of the global population, especially in urban areas.

ex-The construction industry, a sizable sector in the global economy, is undergoing creased demand due to factors such as rising population, improved living conditions, eco-nomic growth in developing countries, low-interest rates in developed countries, increased private and governmental spending on infrastructure and housing, and technological ad-vancements (NextMove, 2022) China, the United States, and India are the largest construc-tion markets in the world representing 45% of the global market (Carpenter, 2021) These countries also account for more than 51% of the growth in construction between 2020 and 2030 (Carpenter, 2021) The combined effects of the size and predicted growth of the construction sectors in these countries and other parts of the world and their reliance on flows of energy- and carbon-intensive materials such as cement and metals make embodied

in-carbon an important building environmental impact to worry about Embodied in-carbon is the construction-related global warming potential More specifically, it is the equivalent carbon dioxide of greenhouse gas emissions released over the complete life cycle of build-ings from raw material extraction, through manufacturing, construction, maintenance, to demolition, as well as all needed transportation Embodied carbon has been also receiving attention because of the tradeoffs between operational and embodied carbon components of building carbon emissions and the fact that as buildings become more energy-efficient in years to come, the share of embodied carbon in building cumulative carbon increases It is predicted that embodied carbon will account for about 50% of global emissions caused by new buildings constructed by 2050 (Architecture 2030, 2022).

The current paradigm shift taking place in the construction sector, in common with ers, has a holistic approach and concerns the following component:

oth-• It emphasizes the design for and mitigation of embodied carbon emissions in buildings In this paradigm shift, embodied carbon is expected to be measured and mitigated dur-ing the design process and reported along with energy use estimations Green building rating systems such as Leadership in Energy and Environmental Design (LEED) pioneered the efforts to mandate this expectation In 2017, LEED v4 Building Design and Construc-tion (BD+C) added a new credit to its requirement that concerned environmental impact reduction (Singh, 2017) Meeting this credit requires the design team to pursue reuse, renovation, or whole-building life cycle assessment to demonstrate the improvement of life cycle environmental impacts in at least three categories (such as global warming po-tential, acidification, and eutrophication) over a comparable baseline that has the same size, function, orientation, and energy performance (USGBC, 2017) Living Building Challenge (LBC), one of the most stringent frameworks for green building certification, requires 100% of embodied carbon emissions associated with a project construction to be measured, reported, and offset through Certified Emission Reduction (CER) and Verified Emission Reduction (VER) credits (ILFI, 2018) Achieving these goals requires architects and engineers to enhance their knowledge of material environmental impacts and develop analytical skills to measure them in a project.

• It acknowledges the tradeoffs between embodied and operational carbon avoidance and concerns that operational energy efficiency must not be achieved at the expense of embodied carbon expansion Hence, the architectural design process must have a system-based approach to decarbonization and aim for cumulative carbon mitigation by considering both operational and embodied carbon emissions The LBC framework ad-dresses this concern by enforcing strict net-zero-energy and net-zero embodied carbon requirements (ILFI, 2018).

• It also acknowledges cross-sectoral synergies and aims to create changes in non- construction infrastructure and processes (such as industrial and power sectors) to sup-port embodied decarbonization in the construction industry.

• More specifically, the production sector and material supply chains are expected to ply environmentally friendly technologies, responsible practices, and transparent report-ing of building environmental impacts and support low and net-zero embodied carbon construction Additionally, electrification of industrial and transportation sectors along with entirely clean power generation can ultimately eliminate the greenhouse gas emis-sions associated with building construction.

ap-• It also emphasizes non-carbon dioxide emissions Embodied carbon is the carbon- dioxide equivalent of GHG emissions released during building construction While car-bon dioxide is the dominant GHG emission and is used as the reference emission to communicate embodied carbon and global warming potential (GWP) of activities, it is not the only emission associated with building construction For example, HFC134a – a Hydrofluorocarbon (HFC) that is used as a blowing agent in the building insulation industry – is 1,430 times stronger than carbon dioxide in contributing to global warming and the U.S Environmental Protection Agency (EPA) aims to reduce HFC production and consumption by 85% in the next 15 years in line with the AIM ACT of 2020 (EPA, Final Rule – Phasedown of Hydrofluorocarbons: Establishing the Allowance Allocation and Trading Program under the AIM Act, 2022) According to the U.S EPA, the global phasedown of HFCs can avoid up to 0.5° Celsius of global warming by 2100 (EPA, Final Rule – Phasedown of Hydrofluorocarbons: Establishing the Allowance Allocation and Trading Program under the AIM Act, 2022).

Embodied Decarbonization: the case of the United States and Canada

The United States and Canada represent 14% and 1.7% of the global construction output and 11.1% and 1.7% of the construction output growth, respectively (Carpenter, 2021) Concrete, as the most consumed material globally (CGBC, 2021), is produced at the rate of 679 million tonnes (370 million cubic yards, 282 million cubic meters) per year in the United States (Margolies, 2020), and 60 million tonnes per year in Canada (Canada, 2021) Cement production is responsible for 1% (67MT) of the national GHG emissions in the U.S (EPA, U.S Cement Industry Carbon Intensities (2019), 2021) and 1.5% (10.8MT) in Canada (Canada, 2021).

The United States and Canada also annually produce 86 (USGS, 2018) and 13 (CGBC, 2021) million tonnes of cement, respectively Cement is the material that is used as a binder in concrete production The United States and Canada together are also responsible for 6% (0.03 Giga tonnes) of global steel demand for building construction (IEA, 2022a) Manu-facturing of cement, steel, and aluminum used in building construction contributes 6% to global GHG emissions (IEA, 2022b).

While embodied carbon is not regulated by building codes in the US, there have been various building embodied decarbonization policies and initiatives at federal, state, and local levels, developed in the past few years to limit the contribution of building construc-tion to greenhouse gas emissions At the federal level, President Biden’s executive order 14057 (President, 2021) and the Federal Sustainability Plan (House, 2021) call for all fed-eral buildings to achieve net-zero emission status by 2045, including a 50% reduction in building emissions by 2032, and for all federal procurement to reach net-zero emission status by 2050 The ‘Buy Clean’ initiative is part of the federal plan that aims to supply low-embodied carbon materials in federal projects, by also considering their social costs (House, 2021) In compliance with these requirements, the General Services Administra-tion (GSA) defines new standards for low-embodied carbon concrete and requires federal contractors to disclose greenhouse gas emissions of materials used in new building pro-jects (GSA, 2022).

At the U.S state level, as of November 2022, eight states (Figure 7.1) have passed or are in the process of establishing procurement policies and Buy Clean initiatives that will re-quire environmental product declarations (EPD) and limiting of embodied carbon for major

construction materials including concrete, glass, and steel These states include California, Colorado, Connecticut, Minnesota, New York, New Jersey, Oregon, and Washington (CLF, 2022).

At the local level in the United States, more than 25 cities and authorities in the United States have introduced and implemented climate action plans with embodied carbon im-plications (CLF, 2022) For example, the New York state legislature has passed the Low Embodied Carbon Concrete Leadership Act (LECCLA) which calls for low-embodied carbon concrete procurement guidelines in state projects and designing a system for state agencies to award contracts based on climate performance, in addition to price (State of New York, 2021) The City of Los Angeles has also pledged that all new buildings in the city will be net-zero carbon emissions by 2030 and all buildings will be net-zero carbon emissions by 2050 (House, 2021).

Embodied Carbon reporting and improvement are also actively pursued through U.S green building rating systems such as LEED and Living Building Challenge, as discussed before An important next step would be for policymakers in the US to establish mandatory embodied carbon targets and thresholds in the building codes and institutionalize design for embodied carbon.

Canada is pursuing embodied carbon mitigation at national and local levels The ernment of Canada’s ‘Standard on Embodied Carbon in Construction’ aims to disclose and reduce the embodied carbon of ready-mix concrete by 10% (GOC, 2022) At the local level, the City of Vancouver (CoV) has defined the goal of a 40% reduction in embodied carbon by 2030 for all new construction projects, compared to 2018 levels (CoV, Climate action through buildings, 2022) Achieving this goal first requires reporting embodied carbon for all new buildings and making sure that it does not exceed twice the embodied carbon value

Gov-Figure 7.1 As of November 2022, eight states in the United States have passed or are in the process

of establishing procurement policies and Buy Clean initiatives.

of a standardized baseline building Starting in 2025, the CoV guidelines require a 10% embodied carbon reduction for all new buildings and 20% for new low-rise buildings (CoV, 2022) Toronto Green Standard (TGS) Version 4 defines mandatory (Tier 1) and voluntary performance metrics (Tiers 2 and 3) for development projects (TGS, 2022) The embodied carbon regulations in Toronto require city buildings to be designed and constructed to be net-zero emissions (TGS, 2022) In low-rise residential projects voluntarily pursuing a de-velopment charge refund program in Toronto, Tier 2 requirements call for the assessment and reporting of building material emissions (A1–A3), with a focus on structure, enclosure, and major finishes, and places a limit of 250 kgCO2e per square meter of heated floor area for emissions intensity Mid- to high-rise residential buildings and non-residential buildings can pursue material emissions assessment, based on A1–A5 for structure and enclosure, or conduct a full (A-C) life cycle assessment (LCA) and demonstrate 20% embodied carbon reduction (TGS, 2022).

Embodied carbon modeling – a case study

In 2021, the government of British Columbia (BC), Canada, shortlisted three bidding teams and invited them to participate in the request for proposals (RFP) for the design and con-struction of the Royal British Columbia museum’s new collections and research building (CRB) in Colwood, BC The RFP contained strict embodied carbon requirements including a target embodied carbon intensity of 277 kgCO2-eq per square meter of gross floor area The present section of this chapter reports the embodied carbon design and modeling ef-forts for the design proposal by the consortium of Kinetic Construction Ltd., Smith Bros & Wilson (B.C.) Ltd., Wright Holdings Inc., Diamond and Schmitt Architects, Inc., and Aspect Structural Engineers Canada Ltd., with BAS Carbon, Ltd as the project’s embodied carbon lead This design proposal ranked second in the bidding process and didn’t lead to the construction phase The author had the opportunity to serve as a consultant to the design team responsible for embodied carbon assessment and reporting of the proposed design’s embodied carbon performance It is important to note that the author has not designed this project, and was involved in the design-build bidding process for this specific proposal only as the embodied carbon consultant to the project’s team.

The proposed design reported here was a 15,703 square meter (m2) building proposal in two stories above ground, with a superstructure consisting of glulam, cross-laminated timber (CLT), and concrete (Figure 7.2) The primary exterior wall layers consist of metal cladding, the support system for cladding, air space, mineral wool insulation panels, air-vapor-moisture barriers, type X gypsum sheathing, steel studs with mineral wool insulation, and two layers of type X gypsum wallboard The roof and floor assemblies consist of CLT in addition to other layers of materials.

To mitigate embodied carbon in the proposed design and meet the embodied carbon intensity threshold of 277 kg CO2-eq/m2, as defined in the RFP, the design-build team pursued an integrated design and analytical process to design, estimate, redesign, and re-estimate the embodied carbon The objective of this process was to meet the client’s car-bon efficiency requirements while optimizing the project for cost efficiency This process involved close collaboration of structural engineers, architects, general contractors and suppliers, cost estimators, the project’s embodied carbon lead, and other stakeholders To achieve the embodied carbon intensity goals, the team employed multiple mitigation strate-gies including optimization of the building geometry, hybrid timber-concrete superstructure

for reduced material consumption while maintaining the structural integrity, low embodied carbon concrete with fly ash content, and mineral wool as the main insulation material in building enclosure The project was also designed to last longer than typical buildings with an assumed life span of 75 years for embodied carbon modeling.

Embodied carbon assessment in tally

The embodied carbon assessment of the design proposal was conducted in Autodesk vit and Tally (Tally, 2023), per requirements specified in project documents The analytical process used a central Revit-based Building Information Model (BIM) developed by the pro-ject team The central BIM model integrated architectural, structural, mechanical, and site sub-models The LCA and embodied carbon assessment used architectural and structural sub-models only, as mechanical and landscaping fell outside the scope of the RFP Project requirements prescribed the use of Tally as the LCA tool and defined the system boundaries For analysis in Tally, the user needs to define materials in detail For example, a reinforced concrete slab must be defined based on its compressive strength, concrete design mix, and rebar density While the detailed definition of materials is a time-consuming and labor- and data-intensive process, it helps reduce methodological assumptions and LCA result uncertainty.

Re-The scope of LCA analysis in this project, as reported in Table 7.1, included enclosure and structure, covering the entire life cycle of the project from product stage (A1–A3), con-struction stage (A4–A5), use stage (B2–B5), demolition (C2–C4), and beyond-life loads and benefits (D) Several stages including B1, B6, B7, and C1 was not included in the embodied carbon estimation The embodied carbon estimation included biogenic carbon and carbon sequestration based on the Tally methodology which assumed carbon sequestration as neg-ative emissions in its estimation More specifically, biogenic carbon enters the system in A1 and leaves the system partially in A2 and A3, and partially in module D (due to recycling) Tally reports only the biogenic carbon component of carbon sequestration.

Figure 7.2 The design proposal for the RBC CRB building by Diamond and Schmitt Architects met

the embodied carbon target of 277 kg CO2-e/m2, as a design phase requirement It is important to note that the architect’s design was not shortlisted as the finalist in the bid-ding process and did not proceed into the construction phase Rendering Diamond and Schmitt Architects.

Table 7.1 CRB building – scope of LCA assessment

Project name: RBC collections and research building

GFA: 15,702.99 m2 Uses: collection, research, labLocation: Colwood, British Columbia

Project description: The proposed design incorporates 15,702.99 m2 of gross floor area in one to

two floors above ground, and with a hybrid timber-concrete superstructure The primary exterior wall layers consist of metal cladding, support system for cladding, air space, mineral wool insulation panels, air-vapor-moisture barrier, type X gypsum sheathing, steel studs with mineral wool insulation, and two layers of type X gypsum wallboard The roof assembly consists of TPO membrane, overlayment board, two layers of polyisocyanurate rigid insulation, and vapor retarder over cross-laminated timber (CLT) structure.

Project documents used for assessment

Revit model

Project development stage at which

assessment was conducted ◻ Schematic design ☒ Design development◻ Construction documents ◻ Construction◻ Project completed

LCA Software Tally (Version 2021.11.01.01)

Life Cycle scenarios Scenarios used in this assessment come from databases maintained by Tally which are based on GaBi databases.

Life Cycle inventory (LCI) LCI data used in this assessment is from the Tally databases which are based on GaBi LCI databases and are compliant with ISO 14040–14044, ISO 21930:2017, ISO 21931:2010, EN 15804:2012, and EN 15978:2011.

Life Cycle impact assessment (LCIA) method

Pattern of use Typical for the functions provided

Required service life 75 years

Construction elements included in the assessment

☒ A1010 Standard foundations ☒ B2010 exterior walls ◻ C1020 Interior DOORS☒ A1020 Special foundations ☒ B2020 Exterior windows ☒ C2010 Stair construction☒ A1030 Slab on grade ☒ B2030 Exterior doors ☒ C2020 Stair finishes

Through an iterative design-analytical process, the team was able to yield an embodied carbon intensity of 275.07 kg CO2-e/m2 and meet the threshold defined by the project requirements The project’s total embodied carbon (A-D) including and excluding biogenic carbon are 4,319,421 and 6,270,999 kgCO2-e, respectively Figures 7.3 and 7.4 report the LCA results for this project.

The A-D embodied carbon in this design project was primarily caused by reinforced concrete components consisting of concrete and reinforcement rebars which accounted for 71% of the total life cycle mass of materials and 48% of the project’s embodied carbon Other contributors to embodied carbon included glazing systems consisting of double pane glazing with associated aluminum framing and fasteners (27%), thermal and moisture pro-tection consisting of different insulation materials, air barriers, vapor retarders, and water resistance barriers (20%), wall gypsum board finishes (3%), and steel structural components such as C-stud metal framing and wide flange shape sections (2%) Despite a relatively low 3% contribution to the total life cycle mass of materials in the project, aluminum-framed glazing systems in the design proposal contribute 27% to embodied carbon, 19% to acidi-fication potential, 20% to smog formation, and 25% to non-renewable energy demand The significant environmental impacts of the glazing systems are primarily caused by aluminum framing which can be reduced by using alternative framing materials However, windows’ notorious heat transfer liability and their contribution to energy use and operational carbon emissions require careful design and sizing in buildings On the other hand, wood-based materials (mainly glulam and CLT) in this design proposal contributed 17% to the total life cycle mass while leading to negative embodied carbon equivalent to 8% of the project’s A-D embodied carbon More specifically, the wood-based materials in the structure and enclosure of this proposal reduced the embodied carbon by 22.40 kgCO2-e per square me-ter of gross floor area Despite their negative embodied carbon contribution, it is important to note that the wood products in this timber-based design are responsible for 71% of its eutrophication potential, 46% of acidification potential, 30% of smog formation potential, and 14% of non-renewable energy demand.

The A-D embodied carbon assessment for the CRB design proposal also revealed that the end-of-life processes (C2–C4) (39%), maintenance and replacement (B2–B5) (32%), and product stage (A1–A3) (28%) are the largest contributors to embodied carbon The prod-uct stage in this project leads to a lesser share (i.e., 28%) in embodied carbon emissions, as compared with that of a typical building This happens mainly because of two factors

☒ A2 Transportation ☒ B2 Maintenance ☒ C2 Transportation

☒ A4 Transportation ☒ B4 Replacement ☒ C4 Disposal

☒ A5 Construction ☒ B5 Refurbishment ☒ D Beyond life loads and benefits

◻ B6 Operational energy◻ B7 Operational water

including a higher assumed life span of 75 years, as compared with a typical 50- or 60-year assumed life span in building LCA studies, and the use of wood products with negative product-stage emissions.

Embodied carbon assessment in Athena Impact Estimator for buildings (IE4B)

The LCA analyses are often time subject to various sources of uncertainty such as odological assumptions, data quality issues, and tool-related variations To understand the extent of tool-related variations, we conducted a life cycle assessment (LCA) in both Tally and Athena Impact Estimator for Buildings (IE4B) Athena IE4B is a free-of-charge LCA tool suitable for LCA studies focused on new construction and renovation projects in North

meth-Figure 7.3 LCA results – CRB building, based on data from Tally, A-D, including biogenic carbon.

Figure 7.4 LCA results generated in Tally – CRB building.

American locations (Athena, 2023) We used the most recent version (i.e., 5.4.01) of the software for this analysis.

To conduct LCA in Athena IE4B, the same bill of materials generated by Revit+Tally was used Working with IE4B or Tally, the main challenge that leads to a variation of results for the same project is database inconsistencies More specifically, the material definition in IE4B is a less-intensive process requiring lesser specification, as compared with Tally For example, the concrete definition in IE4B is based on compressive strength and the options of US or Canadian benchmarks only, and the user is not able to customize the concrete design mix based on typical local practices or the project’s unique design specifications A way to cover this deficiency would be to use a hybrid approach and combine the information in external Environmental Product Declarations (EPD) with those in IE4B Another form of database inconsistency is EPD source inconsistency which could lead to different impact results for the same material Another challenge in reducing uncertainty working with both tools is their black-box nature and undisclosed back-end calculations.

Table 7.3 lists A-C and A-D embodied carbon intensity results based on analysis with IE4B and Tally The Tally section of the table reports results for both including and excluding biogenic carbon cases Based on the results, embodied carbon intensity (A-D) of the design proposal is 215.86 kgCO2-e/m2 based on IE4B estimation while it is 275.07 and 399.35, based on the Tally estimation including and excluding biogenic, respectively The under-estimation of embodied carbon in IE4B is confirmed by other studies too (Cormick, 2017) Unfortunately, it is not clear if IE4B results include or exclude biogenic carbon.

As cities in North America enforce embodied carbon regulations, producing embodied carbon results with minimum uncertainty, consistent methodologies, assumptions, and data-bases, and transparent reporting for benchmarking purposes is more important than before Additionally, tool developers, researchers, and construction industry stakeholders must work together to develop more advanced tools that share material and EPD databases and are more transparent in their back-end calculations Also, more tools need to be developed to allow for coupling with energy simulation software and embodied-operational carbon tradeoff analysis.

Conclusion: the barriers to embodied carbon mitigation

Global concerns about climate change require radical changes in typical practices across sectors The current size and predicted growth of the construction industry both globally and in North America is a unique opportunity to mitigate global warming This chapter argues that significant interest in embodied carbon mitigation discussions in the past decade is part of a paradigm shift that characterizes a holistic approach to building carbon emissions

Table 7.2 Bill of materials

Aluminum extrusion (thermally improved mill-anodized in Tally) 231,487.2 kg

Concrete, lightweight, 3000 psi (PNW average in Tally) 656,214.9 kgConcrete, structural, 4000 psi (PNW average in Tally) 2,806,551.8 kgConcrete, structural, 5000 psi (PNW average in Tally) 4,979,664.3 kgDoor frame, aluminum (powder-coated, no door, in Tally) 308.4 kg

and environmental impacts, the focus on operation-embodied carbon tradeoffs, reducing both non-carbon dioxide and carbon dioxide emissions, and electrification of industrial and transportation sectors.

Despite the current elements of change in building decarbonization paradigms, a key question is if the new paradigm is going to be successful in its goal of yielding net-zero emis-sion status by 2050 and what the critical success factors are In his popular article, Leading Change: Why Transformation Efforts Fail, retired Harvard Business professor John P Kotter (Kotter, 1995) suggests that several critical factors are needed for successful transformations These factors include creating a sense of extraordinary urgency, forming powerful coali-tions, creating, and communicating a vision, removing obstacles, empowering others, cre-ating short-term wins, consolidating improvements, and institutionalizing new approaches (Kotter, 1995) Most importantly, embodied carbon researchers must translate their studies into accessible content for the public and policymakers to help create a sense of urgency to address embodied carbon Also, strong initiatives and coalitions must occur both horizon-tally and vertically to drive change in the construction sector.

To effectively mitigate embodied and cumulative carbon in the construction industry in North America, multiple barriers also need to be addressed Despite the current LCA benchmarking efforts, more research is needed to identify the status quo of building em-bodied carbon in the United States and Canada, for various building typologies The new benchmarking studies also need to account for variations in regional construction practices in both residential and commercial sectors The development of benchmarks to represent

Table 7.3 LCA results based on estimation using two tools

(including biogenic)Tally

(excluding biogenic)

Global warming potential

kg CFC-11 e 4.08E-06 4.08E-06 9.05E-06 9.01E-06 9.05E-06 9.01E-06

Smog potential

Total primary energy

MJ 7,128.18 6,489.96 8,130.25 6,234.59 8,130.25 6,234.59Non-renewable

MJ 6,522.78 5,888.61 5,725.82 4,580.55 5,725.82 4,580.55Fossil fuel

consumption

the status quo would help policymakers to define effective goals, targets, and action plans to reduce embodied carbon and track future improvements Also, more research is needed to develop more advanced future scenarios of building embodied carbon: The existing future scenario models for the building sector-related carbon emissions (Aabakken  & Short, 2003; North & Rufo, 2006; Amstalden, Kost, Nathani, & Imboden, 2007; Kannan & Strachan, 2009; Sartori, Wachenfeldt, & Hestnes, 2009; Urge-Vorsatz, et al., 2012; Boza-Kiss, Moles-Grueso, & Urge-Vorsatz, 2013; Urge-Vorsatz, Petrichenko, Staniec, & Eom, 2013; Østergaard, Andersen, & Kwon, 2015) are concerned with energy-related carbon emissions only and fail to account for the tradeoffs between energy-efficiency and embod-ied carbon This shortcoming limits the reliability of such models for providing insight into potential trends and paths toward achieving net-zero emission status by 2050.

Additionally, more holistic performance assessment approaches are needed to not only consider the operational-embodied carbon tradeoffs but also the social cost and health impacts of energy and carbon efficiency in buildings Social cost and health impacts are arguably the least quantified and understudied impacts of buildings during the architectural design process and are often not communicated by building performance modeling tools that architects and engineers use Therefore, we do not fully understand the scope and grav-ity of the life cycle impacts of buildings on population health in the U.S and how changes in construction practices could mitigate negative effects.

The current embodied carbon assessment tools are data- and labor-intensive that rely on carbon accounting-based techniques These tools need to be complemented with top-down data-driven tools that would help building professionals make the right decisions early in the design process where the information is most uncertain, and decisions are most impactful.

Finally, more rigorous building-embodied carbon policies, regulations, and codes must be developed in North America, particularly in the United States, to institutionalize the change These policies must aim for transparent reporting of embodied carbon and ambi-tious improvement of design and construction practices to mitigate it (Table 7.2).

2030, A (2022) Empowering the Building Sector Architecture 2030 Challenge.

Aabakken, J., & Short, W (2003) Domestic Energy Scenarios National Renewable Energy Laboratory

Amstalden, R., Kost, M., Nathani, C., & Imboden, D (2007) Economic potential of energy-efficient retrofitting in the Swiss residential building sector: The effects of policy instruments and energy

price expectations Energy Policy, 35(3), 1819–1829.

Athena (2023) Athena Impact Estimator for Buildings Athena Sustainable Materials Institute Retrieved

from http://www.athenasmi.org/our-software-data/impact-estimator/

Boza-Kiss, B., Moles-Grueso, S., & Urge-Vorsatz, D (2013) Evaluating policy instruments to foster

energy efficiency for the sustainable transformation of buildings Current Opinion in Environmental Sustainability, 5(2), 163–176.

Canada, G O (2021) Joint Statement: Canada’s Cement Industry and the Government of Canada Announce a Partnership to Establish Canada as a Global Leader in Low-Carbon Cement and to Achieve Net-Zero Carbon Concrete Retrieved from https://ised-isde.canada.ca/site/ised/en/

CLF (2022a) CLF Embodied Carbon Policy Toolkit Retrieved from https://carbonleadershipforum.org/

CoV (2022b) Climate Emergency – Bylaw and Policy Updates Applicable to New Buildings City of

Vancouver Retrieved from https://council.vancouver.ca/20220517/documents/R1a.pdf#page=34

EPA (2021) U.S Cement Industry Carbon Intensities (2019) Environmental Protection Agency.EPA (2022) Final Rule - Phasedown of Hydrofluorocarbons: Establishing the Allowance Allocation and

Trading Program under the AIM Act Environmental Protection Agency (EPA) Retrieved from https://

www.epa.gov/climate-hfcs-reduction/final-rule-phasedown-hydrofluorocarbons-establishing- allowance-allocation

GOC (2022) Standard on Embodied Carbon in Construction Government of Canada Retrieved from

GSA (2022) GSA Lightens the Environmental Footprint of its Building Materials U.S General

Services Administration Retrieved from https://www.gsa.gov/about-us/newsroom/news-releases/gsa-lightens-the-environmental-footprint-of-its-building-materials-03302022

House, T W (2021) Federal Sustainability Plan; Catalyzing America’s Clean Energy Industries and Jobs Retrieved from https://www.sustainability.gov/federalsustainabilityplan/

IEA (2022a) Global Steel Demand for Building Construction, 2000–2020, and in the Net Zero Scenario, 2025–2030 International Energy Agency Retrieved from https://www.iea.org/data-

and-statistics/charts/global-steel-demand-for-building-construction-2000-2020-and-in-the-net-IEA (2022b) Buildings, Sectorial Overview - Tracking Report International Energy Agency Retrieved

sis and Industry Forecast 2022–2030 Next Move Strategy Consulting.

North, A., & Rufo, M (2006) Using Scenario Analysis to Forecast Long-Term Residential Electric Energy

Consumption in California ACEEE Study on Energy Efficiency in Buildings, 7–201.

Østergaard, P., Andersen, M., & Kwon, P (2015) Energy Systems Scenario Modelling and Long Term

Forecasting of Hourly Electricity Demand International Journal of Sustainable Energy Planning and Management, 7, 99–116.

President, T (2021) Executive Order 14057 of December 8, 2021 Federal Register 86(236) Retrieved from https://www.govinfo.gov/content/pkg/FR-2021-12-13/pdf/2021-27114.pdf

Sartori, I., Wachenfeldt, B., & Hestnes, A (2009) Energy demand in the Norwegian building stock:

Scenarios on potential reduction Energy Policy, 37(5), 1614–1627.

Singh, R K (2017) Whole Building Life Cycle Assessment Through LEED v4 GBCI Retrieved from

State of New York (2021) Senate Bill S542A The New York State Senate Retrieved from https://www.

Tally (2023) Tally Retrieved from https://choosetally.com/

TGS (2022) Toronto Green Standard Version 4 Retrieved from https://www.toronto.ca/

city-government/planning-development/official-plan-guidelines/toronto-green-standard/toronto-green-standard-version-4/

Urge-Vorsatz, D., Eyre, N., Graham, P., Harvey, D., Hertwich, E., Jiang, Y., & Jochem, E (2012) Energy

end-use: Buildings Edited by the Global Energy Assessment (GEA) Council: In Global Energy Assessment: Toward a Sustainable Future (pp 649–760) Cambridge: Cambridge University Press.

Urge-Vorsatz, D., Petrichenko, K., Staniec, M., & Eom, J (2013) Energy use in buildings in a long-term

perspective Current Opinion in Environmental Sustainability, 5(2), 141–151.

USGBC (2017) Building Life-Cycle Impact Reduction Retrieved from https://www.usgbc.org/credits/

USGS (2018) 2018 Minerals Yearbook US Geological Survey.

EMBODIED CARBON IN BUILDING REGULATION – DEVELOPMENT

AND IMPLEMENTATION IN FINLAND, SWEDEN

The Dutch government was the first national body to introduce documentation ments on the environmental performance of residential and office buildings in 2012, with global warming potential being part of the single-indicator assessment method introduced (Scholten & van Ewik, 2013) However, several countries in Europe as well as New Zealand are currently preparing for, or implementing, limit values for either whole-life- or embodied-carbon of building construction In parallel with the development in individual countries, the European Parliament’s 2021 revision draft of the Energy Performance in Buildings Direc-tive introduced lifecycle carbon evaluations for all new constructions by 2030 Additionally, the Construction Products Regulation of the European Parliament was amended in early 2022, introducing the requirement for environmental declarations on a product level.

require-This chapter provides an account of how the introduction of LCA-based limit values for whole-life-carbon has been approached in the European Nordic region The content is specifically focused on Finland, Sweden and Denmark where the regulation has been de-veloped furthest However, Norway, Iceland and Estonia are also moving in this direction Norway has had the requirement of calculating whole-life-carbon in public construction

projects for years, and is preparing for legislation Iceland and Estonia are investigating assessment methods and potentials for regulation.

The chapter is based on official documents and articles published by national authorities and research bodies of the Nordic countries Furthermore, published material from Nordic workshops has been used as background for this chapter’s description of the development and implementation of regulation concerning embodied carbon.

Climate legislation in the countries

The United Nations’ International Panel on Climate Change (IPCC) has launched its updated reports on the state of climate change since 2006, and with increasing urgency, the IPPC calls for unprecedented changes to human lifestyles to mitigate global warming (Pörtner et al., 2022) The need for adjusting all human activities to a level of net-zero emissions by mid-century has caught on, also in international policy-making In 2020, the European Parliament adopted the proposal for a European Climate Law targeting climate neutrality by 2050 In parallel, several member states have set their own targets, aiming for more rapid transitions towards climate neutrality and carbon emissions reductions (Nash & Steurer, 2021) Although the notion of climate neutrality and zero-emission buildings is still defined by a multitude of different approaches, also for the construction activities (Lützkendorf & Frischknecht, 2020), the goal-setting has led to important progress towards emissions reduc-tions and specific policy initiatives.

In the geographical context of Finland, Sweden and Denmark, the policy goals and ways also differ slightly The climate act in Sweden was adopted in 2017 and set the goals for Sweden to be net-zero by 2045 and net-negative within the following decade (Klimatlag, 2017: 720) The climate act adopted in Finland in 2015, and recast in 2022, aims for the country to attain carbon-neutrality status by 2035 and carbon-negativity in 2040s (Climate Change Act, 2015) In Denmark, the climate act of 2020 outlines a 70% reduction of green-house gases from 1990 levels and climate-neutrality by 2050 (Lov Om Klima, 2020).

path-The interest in taking climate action is also present at the regional level path-The Nordic ministers responsible for construction and housing mandated the harmonisation of LCA for use in buildings in 2019 Based on the mandate, a working group with representatives from authorities, industry and research coordinate activities and share experiences as part of their cooperation (Nordic Council of Ministers for Sustainable Growth, 2019).

The regulation introduced for buildings

Having the national climate legislation in place, the road towards implementation in ing regulation followed different pathways in the three countries, as illustrated in Figure 8.1 The three national carbon footprint methods are all concerned with the emissions of green-

over a 100-year retention time in the atmosphere, and as specified by characterisation tors published by IPCC For now, none of the regulations cover any other environmental impact category than global warming potential.

fac-‘Reducing the carbon footprint of construction and housing’ constituted a specific mate objective in the Finnish Government’s programme for meeting the goals set out in the climate act (Kuittinen & Häkkinen, 2020) An official Finnish method for whole-life carbon assessment was then developed and published by the Finnish Ministry of the Environment

cli-in 2019, based on EU’s Level(s) method and the underlycli-ing European Standard EN 15978 The requirement on whole-life-carbon assessment is expected to become a binding part of the building regulation by 2025 The requirement applies for all building types with a few exceptions like industrial buildings, temporary buildings, and small residential buildings having a floor area of less than 50 square meters In other words, all buildings that need an energy declaration, will in the future also need a climate declaration In the Swedish case, the Swedish national board of Housing, Building and Planning suggested a method for a mandatory climate declaration in 2018 (Boverket, 2018) and the government an-nounced in 2019 the introduction of climate declaration requirements by 2022 In the years between 2019 and 2022 the regulation texts, guidelines for declarants, a declaration register, a climate database and administrative supervision, based on the method, were developed The new law about the declaration requirement was passed in 2021 (Lag, 2021: 787; Om  Klimatdeklaration För Byggnader, 2021) The requirement applies to all types of buildings with the exception of temporary buildings, buildings for farming/forestry opera-tions, industries, as well as some military and public buildings Furthermore, buildings with gross floor area of less than 100 m2 and single-family homes constructed by private persons are exempted from the regulation The reason for the latter is to reduce the administrative burden on private persons, and to put focus on the majority of total emissions from new construction Despite the fact that around half of the dwellings in Sweden are single-family homes, these are primarily constructed in timber.

The Danish authorities introduced a voluntary sustainability class to the building tion in 2020, including building-LCA as part of the requirements However, a year later, a majority in the parliament reached a political agreement about introducing requirements for climate declaration In the same agreement, it was decided to introduce LCA-based car-bon limit values for new buildings by 2023 The assessment method is based on an existing method used in DGNB Denmark and for research (Zimmermann et al., 2020) The method will be further developed in 2022 Adjustments of the initial limit values are scheduled for 2025, 2027 and 2029 The regulation applies to all new buildings for which a building

subject to compliance with the carbon limit values.

The requirements for a climate declaration in Sweden and Denmark are targeted at the stage of the commissioning permit, at building completion However, the Finnish regulation is targeted at the building permission stage The climate declaration is a requirement for

+ limit values + modules

Figure 8.1 Timeline with climate act targets (top) and targets for building regulations incorporating climate declarations (bottom).

getting the building permit In addition, staying below the whole-life-carbon limit values is a requirement except for detached buildings and large-scale renovation cases In Finland and Denmark, local building authorities are responsible for validating the climate declara-tions as part of the normal process of checking compliance with the building regulations In Sweden, the compliance check is not conducted at local level, but by the national building authority (i.e., the Swedish national board of Housing, Building and Planning) which is re-sponsible for random checks to ensure fulfilment of the requirements.

The Danish and Finnish adoptions of carbon limit values, as one of the first regulatory binding steps, stand in contrast to the approach taken in the Swedish system Swedish car-bon limit values are only expected to become an integrated part of the regulation after an initial test period of the regulation and assessment method Hence, the gradual approach in Sweden entails a suggested implementation of limit values in 2027 and further updates of these in 2035 and 2043 The Swedish approach was to start with a competence-building pe-riod and then introduce limit values in 2027 – meaning in practice that stakeholders would need to start planning for carbon reductions from 2022 The immediate introduction of limit values in the Danish regulation is partly related to the fact that a larger number of building-cases had already been used in Danish research to suggest reference, target and limit val-ues Furthermore, stakeholder networks within the building industry had been involved in a roadmap for carbon reductions as part of the climate act initiatives, and in this roadmap, the limit values from the Danish research were consistently referred to as an achievable limit value The advantage of immediate carbon limit value in place is that the industry supports and can adapt its practice to it However, the disadvantage is that the potential adjustments of the assessment method should, preferably, be in line with the binding limit value.

In Finland, according to the new proposal for the building act, the carbon footprint of a new building must not exceed the limit value set for each different use category The limit value requirement for the carbon footprint does not apply to new buildings exempted from the requirements of nearly zero-energy demand, nor for buildings to be renovated on a large scale The carbon footprint limits for a new building must be based on the use of energy and materials throughout the life cycle The legislation is based on the revised Building Act, and a decree on whole life carbon assessment of buildings Furthermore, there is guidance for the assessment as well as voluntary, more ambitious criteria for green public construction projects.

The assessment methods

The development of LCA-based methods for regulation was, in all three cases, characterised by a large degree of interaction with stakeholders and the industry This work did not start from scratch after the regulation was adopted by the parliaments In all three countries, the industry already had previous experience with different voluntary and market-based systems for ratings of green buildings, such as BREEAM, LEED, DGNB, Nordic Swan and Miljöbyggnad (Zimmermann et al., 2019) Although the green building rating systems in-clude LCA-based evaluations to different degrees, spanning from requirements for whole building LCAs to the mere documentation by EPDs, they provided the industry with a basic level of experience concerning LCA-related methods, tools and data This prior knowledge provided a stepping stone for the development of national methods in cooperation between research, authorities, and stakeholders from the industry Key information from the assess-ment methods in use in the three countries is shown in Table 8.1 and elaborated in the fol-lowing sections.

Reference unit

The methods differ already at the defining reference unit for the climate declaration Where the Finnish regulation refers the carbon footprint to the heated floor area of the building (as in energy declarations), the Swedish regulation uses the gross floor area, and the Danish regulation refers to a hybrid unit of floor area constructed partly on the basis of the floor area applied in the energy efficiency regulation.1 The hybrid unit has a clear disadvantage that it is difficult to communicate, and it will furthermore be difficult to put results in context to other

Table 8.1 Key information from the assessment methods

Reference unit Kg CO2eq/m2 heated floor area/year

Kg CO2eq/m2 gross floor area

Kg CO2eq/m2 hybrid unit area/year

Reference study period

B5 RefurbishmentB6 Operational

energy use

B7 Operational water use

C1 De-construction X

C3 Waste management

D Benefits/loads

Plans for life cycle

stages Suggested inclusion of B2, B4, B6, C1–C4 by 2027

Considering inclusion of A4-A5, D by 2025

(Continued)

Inventory scopeInventory – Building

parts to be included

Site/groundwork and pavings

Foundations and pilingLoad bearing structuresBuilding envelopeNon-load bearing

Fittings (e.g doors, windows)

Load bearing structuresBuilding envelopeNon-load bearing

Load bearing structuresFoundations

Building envelopeNon-load bearing

Plans for inventory Trees considered: loss of carbon as the site is cleared and uptake of carbon if trees are planted

Suggested inclusion by 2027 of site/ground work, Installations, Interior surfaceRoom fittings

Subject of evaluation during 2023

Background data National emissions database for

construction Average data can be replaced with product-specific data when known and available

Boverket’s climate database with conservatively set generic data and/or EPDs Average data can be replaced with product-specific data

Ökobaudat v 2021 Average data can be replaced with product- specific data when known and available

buildings, because information about the several types of floor area is needed to fully prehend which elements of the inventory may make a difference to results However, the introduction of limit values from the early stages of the regulation necessitates that potential loopholes, as well as unintended biases are sought to be covered A potential loophole for a reference unit based on gross floor area could be the installation of an integrated unheated

com-Table 8.1 (Continued)

garage with low carbon intensity per square meter The garage will ‘dilute’ the final carbon footprint for the building when calculating the results per square meter by use of a gross-floor reference unit An unintended bias for a reference unit based on a heated floor area could be the integration of an unheated parking basement The unheated basement will add to the total embodied carbon but not account for any square meter Thus, when reporting embodied carbon results per heated square meter, a building with an unheated basement will come off as worse than a building with a heated basement.

There are different approaches to counteract loopholes and biases In the Finnish case, the issues concerning an unheated parking basement are presumably balanced by including ‘car-bon footprint of the site’ as a separate inventory In this way, the parking service, also for the buildings having this as a separate lot-type installation, will be documented as a separate part of the building’s footprint The pilot phases for the Swedish and Finnish systems allow for eval-uation and adjustment of the reference unit by which the limit values shall eventually be met However, adjustments of method and limit value can be expected, also in the Danish system.

Reference study period

Both Finland and Denmark are applying 50 years as the reference study period for the larations It is important to notice that the reference study period is not directly associated with the expected service life of the building Hence, the building itself may (and should preferably) be in use for a much longer period The reference study period merely defines the time horizon for which the carbon footprint of all life cycle modules is calculated and distributed A 50-year reference study is applied in a range of national methods for the building industry and is also the time horizon applied for the European Commission’s re-porting initiative for sustainable buildings Level(s) as well as the draft for lifecycle carbon accounting in the forthcoming recast of Energy Performance of Buildings Directive.

dec-The choice of reference study period is widely disputed within the built environment research and practice Long reference study periods are more in line with the expected service life of the building However, there are large uncertainties associated with using a time horizon spanning up to, maybe, a century One of these uncertainties is related to the replacement of materials, and whether this follows the modelled replacement rates Another uncertainty is whether the building fulfils its expected service life.

Further, annualising results of longer reference study periods entail a fundamental ethical issue of effectively allocating environmental loads to future generations A reference study period of 50 years may thus be seen as a compromise between (1) ensuring that impacts from replacements of shorter-lived building materials will be reflected in the results, and (2) encouraging more emphasis on the more certain impacts associated with the preliminary life cycle stages within a one-generation perspective (Rasmussen et al., 2020).

Life cycle modules included

Due to its number of included life cycle modules, the Finnish method is the most extensively scoped method among the three methods presented here While the Swedish method has a deliberate focus on only the initial production and construction stages of the building life cycle, the Finnish cover all life cycle modules from A to D, albeit with only a selection of the use-stage modules B1–B7 The Danish method suggested for regulation follows, in this first version, the life cycle scope applied by the Danish DGNB certification system The scope is

thus well known to many stakeholders of the building industry For both the Danish and the Swedish systems, there are recommendations for the inclusion of more life cycle modules in later revisions of the regulation The later phase-in of additional life cycle modules can be seen as a way of attempting to gradually extend the scope in parallel with the increasing knowledge and acceptance within the industry Furthermore, an additional reason for hav-ing some elements introduced at a later stage follows the logic of awaiting more, and better, data to represent these modules.

The Finnish method requires separate documentation of results from the A, B, C and D modules Additionally, the Finnish method requires the documentation of the building’s handprint, which are climate benefits caused by the building as compared to a situation where the building was not constructed The handprint consists of elements usually as-sociated with module D, such as benefits from recycling and reuse as well as exported energy However, the handprint further includes the benefits of biogenic carbon storage and carbonation via cementitious carbon uptake after the demolition of concrete structures ( Kuittinen & Häkkinen, 2020).

Inventory scope

In terms of inventory, the Finnish method is again the most comprehensive of the three Both the Danish and the Finnish methods prescribe the inclusion of structure, envelope, non-loadbearing elements, surfaces and installations (HVAC, electrical systems and mechanical elements) However, in addition to this, the Finnish method also includes groundworks and external paved areas, such as parking spaces, and it includes fittings, such as doors and cabinets Fixtures are, for now, not included in any of the countries’ methods.

The Swedish method has, in its current version, a more limited scope of included ing parts Hence, only structure, envelope, and non-loadbearing elements are included The inventory scope will presumably be expanded as part of the evaluations of the first period of regulation, both in the Swedish and the Danish case.

build-Background data

All three methods are explicit about the type of data that can be used as a basis for climate declarations It is well known that data on carbon intensities of materials and energy conversion technologies vary widely depending on the source (Pomponi & Moncaster, 2018), so it is neces-sary to specify what type of data is allowed The most important distinction made for the carbon intensities of materials is whether or not the method follows the category rules stated in the Eu-ropean Standard 15804 about environmental product declarations (EPDs) for building materi-als Some level of harmonisation is ensured by adhering to the EPDs issued in accordance with the European Standard EN 15804, although research has shown very large deviations within product categories of concrete and wood (Anderson & Moncaster, 2020; Rasmussen et al., 2021) Hence, harmonisation efforts between stakeholders in the EPD development continue.

Compliance of data with the EN 15804 category rules is a requirement in all three national cases As a sub-criterion to this, the distinction between generic data and product- specific data is necessary The number of product-specific environmental product declarations fol-lowing EN 15804 are increasing rapidly, so for the individual building project, it will be possible to base a climate declaration on this specific data In all three cases, the use of product-specific data is encouraged, but not required This has to do with building authorities

of the three countries not being able to legally refer to product or producer-specific data as a requirement for the climate declaration Instead, the regulation must provide a pool of generic data that can be used as a default approach to the building modelling Figure 8.2 out-lines the connections between data in Regulation, EN Standard for EPDs and the building-specific Climate Declaration.

In the Finnish and Swedish cases, national climate databases with typical data were developed for this very purpose in the course of 2019–2021 The development was coordi-nated as part of the Nordic harmonisation effort The databases seek to cover the essential products and services on the national market for building construction The naming of the selected products was made by utilising the terms used in the harmonised standards and in the Construction 2000 classification system The values of carbon intensities of products are derived from the market representative EPDs, aiming for an average level An additional safety factor of 20% (Finnish database) and 25% (Swedish database) is added to the set values as a conservative approach to data representation The safety factor also serves to in-centivise the development and use of product-specific environmental product declarations The Finnish database also includes typical values for energy, transportation, construction, demolition and waste management services, and is being extended to include products used in infrastructure and landscaping works as well.

In the Danish case, the regulation from 2023 will provide the option of using the neric database GenDK if product-specific data cannot be obtained The GenDK database consists mainly of datasets from Ökobaudat, a generic database for construction materials developed by the German Federal Ministry for Housing, Urban Development and Building The GenDK database has been in use for about a decade due to the lack of national data on carbon intensities of building products.

ge-Only the Finnish method includes an assessment of the data quality used for the building model The assessment is based on the method for data quality assessment introduced as part of the European Commission’s reporting framework for sustainable buildings Level(s) In the Finnish method, the assessment is made to determine the technological, geographical, and time-related representativeness of data, as well as the provision of uncertainty factors for the data This assessment is made on the level of each reported life cycle module (A-D,

Figure 8.2 Illustration of connections between data in Regulation, EN Standard for EPDs and the building-specific Climate Declaration.

see Table 8.1) In Level(s), the data quality assessment method is more comprehensive, based on a calculation formula and associated with hotspot analyses to identify main con-tributors to results across materials and life cycle stages However, the simplified Finnish approach ensures applicability for the building industry in these first stages of regulation and can potentially be expanded at a later stage.

The carbon intensities of energy conversion technologies are needed to properly model the use stage demand in buildings For use in the B6 module, the Finnish and Danish data for the carbon intensity of energy are based on projected future energy mixes, i.e with larger shares of renewable based technologies in electricity as well as district heating, as shown in Figure 8.3 The projection of these carbon intensities decreases the dominating role of operational impacts This approach is justified because of the foreseen rapid decrease of emissions of district heating and electricity, which is based on legislation that bans the use of fossil fuels by 2030 However, a similar approach will be necessary also for materials, although equally rapid emission development is not foreseen with regard to energy sources used by the most important building materials, such as concrete However, a proper pro-jection of material-related emissions regarding EPDs would require a profound control of the background data to ensure that aspects of fuel, transport and shift in technologies were modelled to a consistent scenario Currently, this is not possible, as long as the background data builds on more or less black-box impact data from industry via the EPDs However, consistency between the modelling of materials and energy data is desirable, and the cur-rent mismatch between these modelling approaches must be kept in mind when planning for policies based on results from the climate declarations.

Although there are requirements for the use of data in the three methods, none of the methods prescribe any specific tool for making the calculations However, there are some widely used tools among the industry in the different countries, for instance OneClick LCA in Finland (One Click LCA Ltd., 2022) and LCAbyg in Denmark (Birgisdóttir & Rasmussen, 2019) These tools have already prepared their interface and calculations to comply with the new regulations.

Figure 8.3 The projected carbon intensities of the Finnish (FI) and the Danish (DK) energy conversion technologies for use in the climate declaration.

Trade-offs in decisions about scope and data

There are important trade-offs in the decisions about scope and data that should be ered when developing the assessment method The greater the details in the building model, and the more life cycle modules included in the LCA analysis, the more accurate to scope the results can be However, the accuracy is also determined by the representativeness of the data applied to represent processes, scenarios and carbon intensities A higher level of representativeness and completeness usually comes with a trade-off for ease-of-application (schematically illustrated in Figure 8.4), because users of the method will have to collect more data themselves – or select from a wider array of datasets in the LCA software.

consid-There are practical concerns associated with the inclusion of many modules For instance, it can be difficult to establish a consistent data approach for some of the less investigated – and more scenario-based – modules, such as B1 use module and B2 maintenance module Specific data for these modules is difficult for the users to find and apply in a consistent manner If data are then pre-defined default scenarios and values applied to all projects, the inclusion of these additional modules may improve the overall accuracy of the pro-jects However, the generic data will be less representative than the specific data Hence, if generic data is used across all projects, the actual design related differences between the projects may be difficult to communicate In the Finnish, Swedish and Danish assessment methods, these choices about scope and data are being followed and evaluated closely as part of the ongoing development of the methods.

Limit values to assess the performance of buildings

Limit values can be put into use to quantitatively evaluate the performance of building projects, based on their respective climate declarations From a regulatory point of view, the building industry is well experienced in dealing with limit values in relation to different

ifpmiS

aspects of a building’s performance, for instance concerning heat losses, fire or tics However, the introduction of limit values necessitates knowledge about the typical performance of the building, to decide on the desirable levels for limit values Through a benchmarking exercise, reference values for representative buildings can be established The determination of limit values, as well as potential target values, is thereafter often a normative choice based on statistical analyses of the benchmark cases.

acous-Finland and Denmark introduced limit values in the regulation from the first enactment of the climate declaration For Finland, final limit values are yet not in place, but for Den-mark a limit value of 12 kg CO2eq/m2/year is set for buildings larger than 1000 m2 The limit value represents the scope of life cycle stages presented in Table 8.1, i.e A1–A3, B4, B6, C3–C4 A building owner can furthermore opt for compliance with the more ambitious limit value of 8 kg CO2eq/m2/year set in the voluntary CO2 class It is expected that the revision of the regulation in 2025 will lead to all buildings, regardless of size, having to comply with a limit value lower than the initial 12 kg CO2eq/m2/year The voluntary CO2 class will con-tinue to provide the option of striving for a more ambitious target.

Reference values for ‘typical’ buildings

The Swedish system is steering towards the introduction of limit values as well, but have oritised collecting experience and data from a test phase, before limit values are introduced Nevertheless, research in all three countries have investigated the reference levels for a range of building types Figure 8.5 present the reference levels for buildings as published by research in the three countries The Finnish research is based on an archetype approach, i.e defining one representative building for each selected use type and investigating results for this one The Swedish and the Danish research is based on collections of case buildings from practice, 68 Swedish buildings and 60 Danish buildings respectively.

pri-It is important to note that the research behind the figures does not entirely reflect the scope of life cycle stages and inventory as specified in Table 8.1 That is, for Figure 8.5, the Swedish values represent system boundaries as suggested for the 2027 update (i.e including surfaces and technical installations) Further, the Swedish values for this figure are normal-ised to a 50-year reference study period Note that the Danish method does not include A4–A5, B3, nor C1–C2 Note also that the Finnish results reported here are without the inclusion of parking spaces (outdoor and underground) as well as soil stabilisation.

Figure 8.5 illustrates the reference values related to the three methods However, it is not possible to make a meaningful comparison of the values themselves, because these are controlled partly by the background methodological choices, and partly by the building traditions they represent One example of methodological influence can be noticed by the Finnish reference values seemingly being at higher levels than the Danish reference values However, not only are the scopes of life cycle stages slightly different, but the normalisation of the Finnish values by use of the heated square meter of floor area will result in a higher car-bon footprint per square meter Furthermore, the Finnish climate is colder than in Denmark, hence there is more need for operational energy, accounted for in both methods (see Table 8.1) The difference in climatic conditions between the countries could additionally result in the need for more insulation and thermal mass, which would add to the embodied carbon An example of the differences caused by building tradition is seen in reference values for the Swedish single-family houses being notably lower than the Swedish multifamily houses, a pattern not present in the Danish numbers This is caused by the Swedish tradition of

building single-family houses primarily with wood-based construction The carbon sity of wooden materials most often is lower than functionally equivalent mineral materi-als, essentially due to the lighter weight of wooden structures compared to the functionally equivalent concrete or brick structures Thus, the single-family houses yield a low carbon footprint per square meter In the Danish case, both single-family and multifamily houses are primarily constructed by the use of mineral-based materials such as concrete and brick.

inten-What is also interesting to notice is the large variations found within, especially, the Swedish cases For the multifamily houses, the variation is substantial, a fact that can make it difficult to make a choice for a suitable limit value to introduce in regulation Primarily the reason is due to timber or concrete being the main material in structural solutions How-ever, there is also a large variation in the concrete group which displays the opportunities for emission reductions if considering optimisation of these solutions Another area with

Figure 8.5 Reference values of embodied (A1-A5, B3-B4, C1-C4) and operational carbon (B6) in new buildings, based on research from Finland, Sweden and Denmark (Bionova Ltd., 2021; Malmqvist et al., 2021; Zimmermann et al., 2020) Scopes of life cycle stages and inven-tory presented in legend (refer Table 8.1) The Swedish and Danish figures represent the reported median values of life cycle stages in the case samples Upper and lower bounds for these cases are marked with black lines.

large variability noted is the soil stabilisation in the Finnish cases These contributions are not shown in Figure 8.5, but the Finnish research report concludes that the soil stabilisation caused by unfavourable soil conditions (e.g on soft, coastal soils) may add considerably to the embodied carbon Again, this can prove difficult to include in a fixed limit value for all buildings, because building owners cannot always control which land they are permitted to develop On the other hand, the carbon footprint regulations should also guide land use and planning One option is to push the emissions accounting from soil stabilisation to the level of city planning, i.e where the choices about plots to develop are taken.

Even though the Danish and the Finnish method both include the operational impacts, it is worth noting that these are, de facto, regulated via the national implementations of the European Union’s Energy Performance in Buildings Directive Hence, the requirements about energy efficiency in buildings vary between the European Countries, and cannot be compared directly Future research could review embodied carbon limit values across the countries in the context of trade-offs with operational carbon.

Limit values based on planetary boundaries?

In parallel with the development of regulatory initiatives, a growing understanding of etary boundaries has emerged within research, a concept now seeping into the industry de-bates about low-carbon building design and practice The concept of planetary boundaries essentially moves the aim of improving, bit by bit, the existing practice, onto aims of evalu-ating initiatives in light of the carrying capacity of natural ecosystems The overall carrying capacity to keep global warming below 1.5 degrees celsius (66% likelihood) was estimated in 2018 to be approximately 400 gigatons CO2 (Rogelj et al., 2018) This carbon budget cor-responds to ten years of global emissions at current emissions levels.

plan-There are several approaches to divide the carbon budget onto the different activities of human society The partitioning of the budget follows normative choices concerning respon-sibility, capability and equality, on a geographical scale as well as on a time-related scale Actual budgets for building-related activities may therefore vary by at least one magnitude (Habert et al., 2020) Finnish and Danish buildings were recently used as cases for deriving budget-based benchmarks for new buildings (Horup et al., 2022) The global budgets were in that case divided into a global per capita budget, and then divided into national building-related impacts from principles of utility value Projections of future construction activities were further taken into account, generating a gradually regressive development of the emis-

Denmark and Finland respectively (illustrated in Figure 8.5) (Horup et al., 2022).

These examples of limit values based on planetary boundaries show the dramatic level of action actually needed from within industry and regulation However, the regulations in Finland, Sweden and Denmark start from a level more closely related to the current practice in the building industry As part of the gradual development of the regulation, the perspec-tives of planetary boundaries may still be introduced in some form at a later stage.

Summary of developments and future outlook

The Nordic countries are currently introducing carbon declarations in the national building regulations, following suit of the Netherlands and France as first-movers in the European

region There is limited experience to gain from other national contexts, since the Netherlands is the only other country with related regulation in place for a number of years The efforts in Finland, Sweden and Denmark have been closely coordinated between authorities as well as research and industry partners In spite of the Nordic coordination, the development shows that the national methods, in the end, take rather different shapes, for instance relating to reference units, scope and limit values These differences are the results of slightly differ-ent contextual situations concerning stakeholders involved as well as the political processes driving the regulation onwards, and also a consequence of differences in energy systems, existing regulation and, to some extent, building practice Table 8.2 presents a summary of the pros and cons of the methods introduced for regulation in the three countries.

Table 8.2 Summary of pros and cons of the methods in the three countries

Reference

unit (kg CO2eq/m

2 heated floor area/year)+ same reference area

as used in energy demand calculations

(kg CO2eq/m2 gross floor area)

+ the floor area found in analyses of Swedish cases to be able to handle the in-/exclusion of larger basements

(kg CO2eq/m2 hybrid unit area/year)

+ chosen to avoid loopholes about in-/exclusion of areas, such as balconies

+ same area as declared for the building permit application

− difficult to communicate to practitioners

Reference study period

+ same as in Level(s)+ ensuring more

emphasis on impacts accounted for in a one-generation perspective

+ same as in Level(s)+ ensuring more emphasis

on impacts accounted for in a one-generation perspective

Life cycle modules

+ comprehensive scope to align with Level(s)

− risk of data scarcity Practitioners will initially have to use standard values for several modules

+ focus on emissions taking place today that are possible to verify+ extending the scope in

parallel with increasing knowledge and acceptance within the industry

− initially not covering the use and end-of-life stages

+ in line with the scope of DGNB certification, familiar with the industry− initially not capturing

all upfront emissions (A4-A5)

(Continued)

Introducing climate declarations in the building regulation requires that method and data for the assessment method are unambiguously constructed and described Users of the method will need clear guidance on how to apply the method, especially since the majority will be unfamiliar with the basic concepts of life-cycle based evaluations In Sweden, users will have some years to practice and obtain knowledge about the documentation process as well as the types of designs that ensure lower levels of embodied and operational carbon

the building industry to a new type of process and practice.

Future directions

All three methods are expected to undergo some level of change within the coming years, especially as the recast Energy Performance of Buildings Directive will be nationally im-plemented in EU member states These changes can be method-related adjustments based on learnings from approved declarations, or they can be process-related adjustments based on learnings from the implementation and applicability perspective Clear communication

Table 8.2 (Continued)

Inventory scope

+ comprehensive scope

− more laborious for practitioners

+ extending the scope in parallel with increasing knowledge and acceptance within the industry

− initially limited scope underestimate the actual impact of buildings

+ comprehensive scope− more laborious for

Background

data + generic data for carbon intensities of products are available in a national database+ projected development

of carbon intensities of energy mix is used in calculations

− projected development of carbon intensities of products not yet integrated

+ generic data for carbon intensities of products are available in a national database

+ generic data for carbon intensities of products are available based on German data (Ökobaudat)

+ projected development of carbon intensities of energy mix is used in calculations

− projected development of carbon intensities of products not yet integrated

about this ‘evolutionary’ process of the assessment method will be needed to align tions with the users of the method However, the foreseen changes must not be a reason for delaying the implementation of life-cycle-based regulation of buildings To ensure rapid action against climate change and enforce the uptake of carbon metrics, it is advisable for authorities to start implementing a version of the life-cycle-based evaluations, and adjust accordingly in the years following.

expecta-The introduction of climate declarations can be seen as a big regulatory step in the Nordic building industry, where only a minor part of the stakeholders has experience with carrying out life-cycle-based footprint calculations However, the initiatives in regulation answer to the urgency of mitigation initiatives requested by the IPPC and promised by the governments involved Finnish, Swedish and Danish authorities are currently introducing the regulation aiming to contribute to reaching the climate goals set by parliaments Limit values to guide building design to the ‘right’ solutions for low-carbon built environment are needed as a next step in regulation However, recent knowledge about carbon budgets also makes it clear that additional giant leaps are needed for the building industry to operate within the planetary boundaries The actions needed to abide by the carbon budget per-spective may not just be an obligation for the building and construction industry Policies should also target the demand side, i.e the residents and users of the buildings – to ensure that existing and new buildings are used and maintained in an energy-efficient and low-carbon fashion.

1 The hybrid unit consists of heated floor area to account for the B6 operational carbon, and the gross floor area to account for embodied carbon However, some building elements such as bal-conies, external stairs and walkways contribute fully to the total embodied carbon results, but only contribute by 30–50% of their floor area to the gross floor area used as reference unit.

Anderson, J., & Moncaster, A (2020) Embodied carbon of concrete in buildings, Part 1: Analysis of

published EPD Buildings and Cities, 1(1), 198–217 https://doi.org/10.5334/bc.59

Bionova Ltd (2021) Carbon footprint limits for common building types https://www.oneclicklca.com/

Birgisdóttir, H., & Rasmussen, F N (2019) Development of LCAbyg: A national life cycle assessment

tool for buildings in Denmark IOP Conference Series: Earth and Environmental Science, accepted.Boverket (2018) Klimatdeklaration av byggnader https://www.boverket.se/sv/om-boverket/publicerat-

Climate Change Act (2015) https://www.finlex.fi/fi/laki/kaannokset/2015/en20150609.pdf

Habert, G., Röck, M., Steininger, K., Lupísek, A., Birgisdottir, H., Desing, H., Chandrakumar, C., Pittau, F., Passer, A., Rovers, R., Slavkovic, K., Hollberg, A., Hoxha, E., Jusselme, T., Nault, E., Allacker, K., & Lützkendorf, T (2020) Carbon budgets for buildings: Harmonising temporal, spatial and sectoral

dimensions Buildings and Cities, 1(1), 429–452 https://doi.org/10.5334/bc.47

Häkkinen, T., Nibel, Sylviane., Birgisdóttir, H (2021) Definition and methods for the carbon handprint of buildings Danish Housing and Planning Authorities and Finnish Ministry of the Environment https://ym.fi/documents

Horup, L., Steinmann, J., le Den, X., Röck, M., Birgisdóttir, H., Tozan, B., & Sørensen, A (2022) Towards EU embodied carbon benchmarks for buildings Defining budget-based targets: A top-down ap-proach https://doi.org/10.5281/zenodo.6120882

Klimatlag (2017:720), (2017) https://www.riksdagen.se/sv/dokument-lagar/dokument/svensk- forfattningssamling/klimatlag-2017720_sfs-2017-720

Kuittinen, M., & Häkkinen, T (2020) Reduced carbon footprints of buildings: New finnish standards

and assessments Buildings and Cities, 1(1), 182–197 https://doi.org/10.5334/BC.30

Lag (2021:787) om klimatdeklaration för byggnader, (2021) http://rkrattsbaser.gov.se/sfst?bet=2021:787Lov om klima (2020) https://www.retsinformation.dk/eli/lta/2020/965

Lützkendorf, T., & Frischknecht, R (2020) (Net-) zero-emission buildings: A typology of terms and

definitions Buildings and Cities, 1(1), 662–675 https://doi.org/10.5334/bc.66

Malmqvist, T., Borgström, S., Brismark, J., & Erlandsson, M (2021) Referensvärden för klimatpåverkan vid uppförande av byggnader Stockholm: KTH Skolan för Arkitektur och SamhällsbyggnadMatthew, A., Burrows, V., & Richardson, S (2019) Bringing embodied carbon upfront In Bringing

embodied carbon upfront London: World Green Building Council https://worldgbc.org/article/

Nash, S L., & Steurer, R (2021) Climate change acts in Scotland, Austria, Denmark and Sweden: The

role of discourse and deliberation Climate Policy, 21(9), 1120–1131 https://doi.org/10.1080/146

Nordic Council of Ministers for Sustainable Growth (2019) Nordic declaration on low carbon struction and circular principles in the construction sector https://www.norden.org/en/declaration/

One Click LCA Ltd (2022) One click LCA https://www.oneclicklca.com/

Pomponi, F., & Moncaster, A (2018) Scrutinising embodied carbon in buildings: The next

perfor-mance gap made manifest Renewable and Sustainable Energy Reviews, 81, 2431–2442 https://

Pörtner, H.-O., Roberts, D C., Tignor, M., Poloczanska, E S., Mintenbeck, K., Alegría, A., Craig, M.,

Langsdorf, S., Löschke, S., Möller, V., Okem, A., & Rama, B (2022) Climate change 2022: Impacts, adaptation, and vulnerability (contribution of working Group II to the sixth assessment report of IPCC) Intergovernmental Panel on Climate Change.

Rasmussen, F N., Andersen, C E., Wittchen, A., Hansen, R N., & Birgisdóttir, H (2021) tal product declarations of structural wood: A review of impacts and potential pitfalls for practice

Environmen-Buildings, 11(8), 362 https://doi.org/10.3390/buildings11080362

Rasmussen, F N., Zimmermann, R K., Kanafani, K., Andersen, C., & Birgisdóttir, H (2020) The choice

of reference study period in building LCA - case-based analysis and arguments IOP Conference Series: Earth and Environmental Science, 588(3), 032029 https://doi.org/10.1088/1755-1315/588/

Delmotte, V., P Zhai, H.-O Pörtner, D Roberts, J Skea, P.R Shukla, A Pirani, W Moufouma-Okia, C Péan, R Pidcock, S Connors, J.B.R Matthews, Y Chen, X Zhou, M.I Gomis, E Lonnoy, T May-cock, M Tignor, and T Waterfield (eds.) Cambridge and New York: Cambridge University Press, pp. 93–174 doi:10.1017/9781009157940.004.

Scholten, N., & van Ewik, H (2013) Environmental performance regulations in the Netherlands 4th International Conference Civil Engineering`13 Proceedings.

UN Environment Programme (2020) 2020 Global status report for buildings and construction Global

Status Report.

Zimmermann, R K., Andersen, C E., Kanafani, K., & Birgisdóttir, H (2020) Klimapåvirkning fra 60 bygninger - Muligheder for udformning af referenceværdier til LCA for bygninger [Climate impacts from 60 buildings - Potentials for deriving reference values for LCA of buildings] Copenhagen: