GAP FUND TECHNICAL NOTES EMBODIED CARBON EMISSIONS MARCH 2024 © 2024 The World Bank 1818 H Street NW, Washington DC 20433 Telephone: 202-473-1000; Internet: www.worldbank.org Some rights reserved This work is a product of The World Bank. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of the Executive Directors of The World Bank or the governments they represent. The World Bank does not guarantee the accuracy, completeness, or currency of the data included in this work and does not assume responsibility for any errors, omissions, or discrepancies in the information, or liability with respect to the use of or failure to use the information, methods, processes, or conclusions set forth. The boundaries, colors, denominations, links/footnotes and other information shown in this work do not imply any judgment on the part of The World Bank concerning the legal status of any territory or the endorsement or acceptance of such boundaries. The citation of works authored by others does not mean the World Bank endorses the views expressed by those authors or the content of their works. Nothing herein shall constitute or be construed or considered to be a limitation upon or waiver of the privileges and immunities of The World Bank, all of which are specifically reserved. Rights and Permissions The material in this work is subject to copyright. Because The World Bank encourages dissemination of its knowledge, this work may be reproduced, in whole or in part, for noncommercial purposes as long as full attribution to this work is given. Attribution—Please cite the work as follows: “Chen, Tao, and Chandan Deuskar. 2024. Embodied Carbon Emissions. City Climate Finance Gap Fund Technical Note. © World Bank.” Any queries on rights and licenses, including subsidiary rights, should be addressed to World Bank Publications, The World Bank, 1818 H Street NW, Washington, DC 20433, USA; fax: 202-522-2625; e-mail: pubrights@worldbank.org. 1 Embodied Carbon Emissions1 Key Takeaways ● ‘Embodied’ carbon emissions are those associated with construction. This includes the emissions from materials such as cement and steel, including their manufacture, transportation, installation, maintenance, and disposal, along with other construction-related emissions. ● Embodied emissions from the manufacture of materials represent around 11% of all global carbon emissions today. This share is likely to increase as other sectors decarbonize and construction continues in low- and middle-income countries. ● Cement production alone emits 7% of global carbon emissions. It is projected to emit twice the amount of greenhouse gas over the rest of the 21st century as all passenger vehicles combined, in the absence of decarbonization. ● Changes to cement manufacturing processes can help reduce embodied emissions, along with the use of alternative construction materials including mass timber and bamboo to reduce the need for cement. ● Construction and design principles that support the mitigation of embodied emissions include prioritizing retrofitting over demolition and reconstruction, material efficiency in design, modular construction, fostering compact urban growth, optimizing building height, and transitioning to a circular economy for construction materials. ● More research is needed in order to fully understand embodied emissions in low- and middle-income countries, particularly those that are expected to see large amounts of new urban construction in coming years. Introduction The UN (2023) projects that 2.5 billion more people will live in cities by 2050, up from 4.4 billion today. Of the growing global population, most will come from the urban areas of low- and middle-income 1 Authored by Tao Chen and Chandan Deuskar for the City Climate Finance Gap Fund. Carina Lakovits, Augustin Maria, and Yan F. Zhang provided valuable feedback on drafts of this note. 2 countries in Sub-Saharan Africa and South Asia (ODNI 2021), with Sub-Saharan African cities currently already seeing a 4.1% growth in population annually (Makeka and Sharma 2022, 2). African cities need to construct an estimated 56 million additional housing units to meet demand (Makeka and Sharma 2022, 2). In 2015, the Indian government announced the ambition of building 20 million housing units by 2022 (livemint.com 2015). Globally, another 241 billion m2 of new floor area will need to be added to the global building stock, equivalent to building a new New York City every month until 2060 (Architecture2030 2023). The construction of this volume of new buildings and accompanying urban infrastructure involves significant embodied carbon emissions, i.e., emissions stemming from manufacturing, transportation, installation, maintenance, and disposal of building materials. 2 While public discourse often centers around curtailing operational emissions (Saint and Pomponi 2021, Cameron 2020), for example through energy efficiency and low-carbon energy supply, embodied emissions may surpass operational emissions, depending on the project. There has been limited research comparing operational and embodied emissions at the scale of entire cities, particularly in low- and middle-income countries. However, rough calculations suggest that in certain cases, embodied emissions may approach or even exceed the volume of operational emissions, for example in rapidly expanding cities with relatively low operational emissions due to mild climates, low household incomes, or renewable sources of grid electricity. According to the IFC (2023), construction accounts for around 40% of global energy and industrial- related CO2 emissions, with the production of construction materials (18.7% of global emissions) being responsible for nearly as much CO2 as the operation of buildings (20.4% of global emissions). This share is also likely to increase in coming years. Operational emissions from buildings are expected to decline in coming decades, along with emissions from energy production and transportation. However, industrial emissions, of which emissions from construction materials like cement, iron and steel make up one-third, are projected to increase in the absence of decarbonization solutions. Cement production alone may emit twice the amount of greenhouse gas over the rest of the 21st century as all passenger vehicles combined (Larsen, et al. 2023, 18). Low- and middle-income countries (LMICs) are responsible for around 83% percent of the global carbon emissions generated by the production of construction materials. China dominates these emissions, generating 68% of cement emissions and 62% of steel emissions globally. There are several reasons for the high share of construction emissions from LMICs. Their urbanization and income growth are usually associated with a large amount of new construction. LMICs are also 2 “Embodied emissions” are also referred to as “embodied carbon”, “embedded emissions”, or “upfront carbon”. This note avoids the term “embodied carbon” (which is “embodied” only in a figurative sense, but in a literal sense has already been released into the atmosphere) to avoid confusion with the carbon sequestered in certain materials such as wood (which is still physically located within the material). Some prefer the term “upfront emissions” as it emphasizes that most of it is released early in the construction life cycle and thus has an immediate impact on climate change, but this term is not widely used yet. 3 responsible for a large majority of material production: around 90% of global cement production and 70% of steel production. They also tend to use more carbon-intensive material production methods. For example, the production of an equivalent amount of cement is responsible for an average of 8.4 kg of CO2e in China and around 7.0 kg in other LMICs, compared to just 4.4 kg in high-income countries (IFC 2023). The accelerating urbanization in low- and middle-income countries is poised to consume a substantial portion of the world’s carbon budget. The emissions budget for building and infrastructure development to reach Western levels in LMICs with the current technologies alone is estimated to be 350 Gt CO2 (Akan, Dhavale and Sarkis 2017, 1196), which exceeds the entire remaining global carbon budget available to maintain a 50% probability of exceeding global warming of 1.5 °C above pre-industrial levels. 3 This is particularly concerning when considering the “time value of carbon”, the concept that GHG emissions produced today are far more harmful than emissions produced in the future, since released greenhouse gases have a cumulative effect and continue to warm the planet after they are released (Alter 2022). This is not to mention that since embodied emissions are “upfront”, the opportunity to lower a building’s embodied emissions disappears once construction is complete, while a building’s operations can become cleaner over time with renewables and other efficiency-improving mechanisms. Since most embodied emissions – and in many cases the majority of a building’s combined lifetime embodied and operational emissions – come from the construction phase, significant upfront emissions are produced. By some estimates, these upfront emissions will be responsible for half of the entire carbon footprint of new construction between now and 2050 (World Green Building Council 2019). Therefore, the choice of technology, design, and materials used for constructing new housing and other associated infrastructure will have a significant impact on carbon emissions and must be carefully considered (Mastrucci and Rao 2019, 9). This note is intended as an introduction to the subject of embodied emissions, aimed at urban decision-makers in low- and middle-income countries, including government officials, urban planners, advisors from international organizations, and others. It assesses prevailing practices within the construction industry and delves into several options to mitigate embodied emissions associated with construction. The annex also provides an overview on tools that can aid in estimating the environmental impact of various construction standards and policies. While the note was written in the context of low- and middle-income countries, it often draws from literature from high-income countries, due to the relative lack of literature on the former group. Understanding Embodied Carbon Emissions Embodied emissions predominantly arise from building elements such as foundations, frames, and facades, due to the volume of materials required for these elements (World Green Building Council 3 Climate Change Tracker. Climatechangetracker.org/igcc/current-remaining-carbon-budget-and- trajectory-till-exhaustion. Accessed 30 January 2024. 4 2019, 22). Materials like steel, masonry, aluminum, glass, and especially concrete, contribute substantially to greenhouse gas emissions. Concrete, in particular, has gained prominence in global construction due to its strength, durability, and, crucially, the wide availability of its components (Olsson, Miller and Alexander 2023, 1). Cement manufacturing is estimated to contribute around 7% of global carbon emissions, while steel in construction contributes around 4% of the global total (World Green Building Council 2019, 24). The embodied emission profiles of the construction industry differ significantly between countries due to geographic differences in manufacturing methods, energy sources, transportation systems, suppliers, and more. Moreover, the levels of embodied emissions can vary substantially from one project to another based on the chosen building materials, systems, and technologies (Taffese and Abegaz 2019, 4). The discussions below touch on various specific topics related to embodied emissions – embodied emissions from infrastructure beyond buildings, emissions at the end of the life of a building or piece of infrastructure, and issues related to embodied emissions in informal construction – in order to further expand readers’ understanding of the subject. Infrastructure Construction While studies on embodied emissions have primarily centered around that of building construction, the construction of infrastructure, such as roads and pipes, also contribute significant emissions. Infrastructure construction practices vary globally, resulting in a spectrum of carbon emission magnitudes across countries. Even within a single country, there may be pronounced disparities in embodied emissions across different classifications of roads, considering the traffic needs, whether the road is elevated, the road width, and the construction methods (Yu, et al. 2022, 2). This variability is underscored in a report on the emissions of road construction in China by Chen et al. (2017, 1044), which indicates that a four-lane asphalt expressway produces around 1000 t CO2e per kilometer4, while a two-lane asphalt Class-II roadway5 produces around 250 t CO2e per kilometer. The material also matters, where the GHG emissions of cement-paved roads were approximately 64% greater than asphalt-paved roads (Chen, et al. 2017, 1044). The same variability is also observed in India, where a rural road in West Bengal involves 1,476 tons of CO2 per kilometer throughout the road’s lifetime, while a national highway in Uttar Pradesh involves 74,880 tons of CO2 per kilometer (ADB 2010, 18). As of 2016, Uttar Pradesh has 60 national highways totaling 8,483 km in length (Business Standard 2016), equating to 635 million tons, or 0.635 gigatons, of CO2, a significant number given that the remaining carbon budget is between 600 and 4 CO2e, or carbon dioxide equivalent, considers all GHG emissions using carbon dioxide as a reference standard, not just carbon dioxide. 5 A grade of road in China, approximately 12.0 meters wide and designed for speeds of 40-80 kilometers per hour (Asian Development Bank 2023) 5 1000 gigatons. For reference, the estimated average life cycle embodied carbon for buildings in a study of 769 buildings in Europe is 591 kg CO2e/m2 (Röck, et al. 2022, 11), and if the average home in Germany that is 94m2 is used as the example (Appolloni and D’Alessandro 2021, 11), then around 55.5 tons of CO2e is produced in the average home’s lifetime. Therefore, the lifetime embodied emissions of such a highway system exceed those of 11 million housing units in a high-income country. As such, it is imperative to broaden the focus on embodied emissions beyond building construction to include the significant impact of infrastructure development. End of Life The predominant approach to waste management in the construction industry follows a linear model, in which waste is simply disposed of at the end of its life, instead of being recycled and reused as in a circular economy (Sudarsan, Vaishampayan and Parija 2022, 1615). In many cases, construction and demolition waste disposal happens informally, whether it is in uncontrolled sites or along roadsides, contributing not only to wastage in materials, but also to contamination and pollution (Ferronato, et al. 2023, 24378). The recycling and reusage rate of construction and demolition waste varies around the world, ranging from under 10% in China and India to over 90% in Japan (Duan, et al. 2019). Recycled aggregate concrete (RAC) – or the concrete mix made with crushed old concrete – has the potential to be reused in road construction, noise barriers, and more (Portland Cement Association 2024). Transitioning towards a more circular economy approach necessitates incorporating disassembly planning into design before construction commences and utilizing materials like timber that facilitate the establishment of a circular economy. Informal Settlements and Self-Construction Addressing embodied emissions in owner-driven construction, particularly in informal settlements, holds significant potential for reducing the environmental impact of housing in low- and middle- income countries. In many of these countries, the majority of the population engages in self-driven construction. For instance, 93% of homes in Cameroon and 80% of the housing stock in Dakar, Senegal are products of owner-driven construction (Bah, Faye and Geh 2018, 160, Razwani and Nielsen 2021). To meet the escalating demand for housing and guide affordable, low-carbon construction, there is a critical need to focus on supply chains and embodied emissions. Currently, there is a lack of comprehensive research on the emissions associated with construction in informal settlements. While some settlements use recycled materials, potentially resulting in minimal embodied emissions, others rely on resource-inefficient manufacturing processes. For example, the production of burnt bricks, a common material in informal construction in Uganda, requires 1.6 to 5.7 times more energy than the more formalized generic fired clay brick (Hashemi, Cruickshank and Cheshmehzangi 2015, 7879). In contrast, hollow concrete bricks boast significantly lower energy requirements, approximately 90% less than artisan-burned brick. A study in India (Lall et al., 2017) found that the use of autoclaved aerated concrete, a lightweight concrete material, reduces 6 embodied energy6 by 10-20%. Understanding and addressing such variations is crucial for guiding construction practices toward lower embodied emissions. Moreover, when the manufacturing of materials in informal settlements depends on unregulated energy and water sources, disconnected from the centralized grid, it introduces inefficiencies, wastage, increased energy consumption, and heightened carbon emissions (Teferi and Newman 2018, 57). Therefore, there is an opportunity to make a substantial impact on reducing embodied emissions by improving supply chains and promoting sustainable construction practices in owner- driven construction projects. Further research is needed to quantify the volumes of emissions at stake in these contexts. Potential Mitigation Strategies Reducing Emissions from Cement Production Concrete is the second most-produced and consumed substance globally, second only to water. Approximately 3.8 tons of concrete are generated per individual globally (Akan, Dhavale and Sarkis 2017, 1). While the terms ‘concrete’ and ‘cement’ are often used interchangeably, cement is technically the binding agent that is added to other materials, such as gravel, crushed stone, and sand, to produce concrete. The first step of cement production involves the comminution (reduction in particle size by crushing or grinding) and amalgamation of an assortment of raw materials, including limestone, shale, clay, and iron ore (Rasheed, et al. 2022, 49430). This mixture subsequently undergoes heating at approximately 1,500°C in a kiln, where a chemical transformation engenders the formation of an intermediate product known as clinker. This process concurrently releases approximately 0.5 tons of carbon dioxide per ton of clinker produced, approximately 60% of the total emissions produced in the production process (Bizley 2023). Following this, the clinker is blended with gypsum and supplementary additives to yield cement. Upon the on-site mixing of this cement with water, the resulting amalgam solidifies to create concrete. The emissions produced per ton of cement have already decreased globally by around 20% since 1990, due to improved energy efficiency, the use of waste as fuel, and reducing the share of clinker in cement (IFC 2023). Some of these approaches are described briefly below. Reducing Emissions from Heating Cement Kilns Each phase within the cement production trajectory engenders significant carbon emissions. The electric power demand for both the material blending phase and the gypsum incorporation 6 Embodied energy refers to the energy consumed the manufacture, transportation, and disposal of construction materials. Its relationship with embodied emissions depends on the energy sources involved. It also does include embodied emissions that are not associated with energy consumption e.g., the release of carbon during chemical reactions in the manufacturing process of cement. 7 contributes to emissions. Around 40% of the total emissions throughout the production process stems come from the kiln’s heating process. The emissions from heating the kiln remain “notoriously difficult to decarbonize” due to the need for high temperatures (Bizley 2023). However, Olsson et al. (2023, 3) observes that the implementation of commonplace modifications in manufacturing could lead to substantial reductions in greenhouse gas emissions. These alterations include a potential 1% emission reduction through heightened kiln efficiency, approximately 15% with the substitution of higher-emission thermal energy sources with natural gas in kilns, and around 6% through the utilization of wind-generated electricity to fulfil all electricity requisites. A composite implementation of these strategies could translate into an approximate 20% reduction in carbon emissions. Reducing the Amount of Clinker in Cement Another oft-cited strategy to lowering carbon emissions in concrete production is to reduce the clinker-to-cement ratio by substituting it with other materials, or “supplementary cementitious materials” including waste materials such as fly ash from coal fired power plants, ground granulated blast furnace slag (GGBS) from steel production, micro silica, and more (Akan, Dhavale and Sarkis 2017, 1198). The industry standard Portland cement, used in over 98% of concrete globally (Timperley 2018), is heavily carbon intensive as explained above. Therefore, a range of alternative strategies could be used to mitigate this. The reduction of clinker-to-cement ratio is a relatively simple step that can be taken to reduce emissions, since clinker production is where the vast majority of emissions are produced. However, it is concerning to note that global clinker-to-cement ratios have surged since 2015, escalating from 0.66 in 2015 to 0.71 in 2022. This upsurge is largely attributed to heightened ratios in the low- and middle-income world, with China’s ratio increasing from 0.57 in 2015 to 0.65 in 2022. Nevertheless, one must contextualize this against standard industry practices in North America, where the United States boasts a ratio of 0.86 in 2022 (IEA 2023). Measures to reduce the clinker-to-cement ratio encompass the integration of material substitutes, such as fly ash (a particulate by-product of coal combustion), which is readily accessible in numerous low- and middle-income countries. Indonesia, for instance, sees roughly 5.5% of its total coal input manifest as ash, primarily in the form of fly ash. Experiments with incorporating fly ash in cement blends conducted in Cuba have yielded a noteworthy 30% reduction in CO2e (Berners-Lee 2022, 116). Should such blends be introduced in the Indonesian context, projections suggest that four major cement production facilities could mitigate their direct emissions by an estimated 1.9 million tons, or 0.002 gigatons of CO2 equivalent (GtCO2e) annually (Panjaitan, et al. 2021, 6). Notably, the selection of a specific supplementary material hinges on a country’s context, taking into account production costs and the availability of resources, which can fluctuate significantly from one region to another (Reed 2022). Other alternatives to Portland cement have been proposed, although their widespread commercial adoption remains constrained due to prohibitive costs. Noteworthy among these are metakaolin- 8 and calcium hydroxide-based cements, which have only 50% of the carbon footprint of conventional Portland cement (Berners-Lee 2022, 116). Geopolymer-based cements advanced by companies like Zeobond and banahUK represent another avenue, eschewing calcium carbonate and emitting solely water in the production process (Timperley 2018). However, further exploration of alternatives is imperative, particularly those that are economically viable for pragmatic implementation in low- and middle-income countries. Use of Alternative Materials While contemporary construction practices predominantly rely on materials such as concrete, masonry, and steel, alternative construction materials embraced in “vernacular design,” including rammed earth, bamboo, and timber, can have lower carbon footprints (IPCC 2022, 975). However, the adoption of higher quality and low-carbon materials in the low- and middle-income world is constrained by two primary challenges: high costs and restricted accessibility. The deficiency in efficient transportation links and infrastructure, coupled with a scarcity of urban factories, leads to a dearth in supply to meet the burgeoning demand for housing (Hashemi, Cruickshank and Cheshmehzangi 2015, 7871). African countries, in particular, grapple with pronounced limitations within their construction industries, chiefly characterized by escalated costs and the restricted availability of superior quality materials, whether procured internationally or manufactured domestically. Furthermore, owing to the inadequacies in transportation infrastructure and the constrained access to urban factories, especially in rural locales, the supply of materials struggles to align with the heightened housing demand (Hashemi, Cruickshank and Cheshmehzangi 2015, 7871). Timber has been widely used in construction and manufacturing for centuries, and its popularity has gradually resurged over the past few decades, particularly in construction within high-income countries. This resurgence has garnered considerable attention both from the media and researchers, with extensive coverage by scholars such as Brasuell (2023), Fazzare (2023), and Hurley (2023) shedding light on the topic. Mass timber, represented by forms like glue-laminated timber (glulam) and cross-laminated timber (CLT), has gained prominence in Europe and North America. This type of timber involves stacking and gluing wood panels at perpendicular angles, negating the necessity for welding and thereby conserving energy. The efficacy of mass timber Is substantiated by its impressive strength-to-weight ratio, facilitating its application even in high-rise structures like the 18-story, 85.4-meter-tall multi-functional building Mjøstårnet in Norway (Van der Borght and Barbera 2023, 18). Rigorous testing has underscored the durability and fire-safety standards of mass timber (Van der Borght and Barbera 2023, 24-29), prompting building codes across various jurisdictions to progressively permit its utilization (Hurley 2023). Notably, timber buildings weigh approximately 20% of their concrete counterparts, reducing the demand for concrete foundation—substantially lowering construction and material emissions (Smedley 2019), including emissions coming from the transporting the materials. 9 Significantly, trees absorb and retain CO2 from the atmosphere as they grow, effectively sequestering carbon even after being harvested as lumber. On average, a cubic meter of wood holds approximately one ton of CO2, equivalent to the emissions from 350 liters of gasoline (Smedley 2019). It is paramount, however, that the wood originates from sustainably managed forests; otherwise, the emissions reduction objective is compromised. Mass timber should be sourced from young production forests rather than jeopardizing existing primary forests (van der Lugt, Martin and Dufourmont 2023, 76). To circumvent potential illegal harvesting, a substantial boost in mass timber production and the expansion of timber plantations is required (Pomponi, et al. 2020). The timber used in construction can store between 0.01 and 0.68 gigatons of carbon (GtC) annually, or 0.25 to 20 GtC within a 30-year span, contingent upon the extent to which timber construction is embraced and the building typology (Churkina, et al. 2020, 272). Notably, trees in tropical regions grow twice as fast as in other climates, presenting the possibility of job creation in low- and middle-income countries alongside greater mass timber production (IIED 2022). While machinery and adhesives utilized during the harvesting, transportation, and manufacturing of mass timber do contribute to CO2 emissions, their impact is negligible when juxtaposed with the carbon sequestration capacity of timber (van der Lugt, Martin and Dufourmont 2023, 52). Of course, the applicability of mass timber varies with geographic contexts. Other bio-based alternatives like bamboo and grasses merit exploration (Pomponi, et al. 2020, 160). Application of Low-Carbon Construction & Design Principles Retrofitting Over Reconstruction Owing to the prevailing emphasis on operational emissions in contrast to embodied emissions, a perception has emerged that new constructions inherently equate to reduced carbon emissions due to their higher energy efficiency. While newer constructions adhering to updated codes do tend to exhibit lower carbon emissions over their operational lifespan, the initial construction emissions are often overlooked (Cheshire and Burton 2023). The World Green Building Council elucidates this using the hypothetical example of the proposed demolition and reconstruction of the UN Headquarters in New York City, highlighting that it would be 35-70 years before the operational efficiencies accrued from the new construction would offset the initial outlay of embodied emissions (World Green Building Council 2019, 24). Even on a smaller scale, a theoretical scenario involving a detached house in the UK demonstrates that knocking down and rebuilding an outdated, inefficient building would result in emitting 80 tons of CO2e, whereas refurbishing would entail only 8 tons of CO2e. The upfront emissions from the demolition and reconstruction endeavor would only be recouped by the operational emissions of the more efficient new house in 15-20 years (Berners-Lee 2022, 169). It is important to acknowledge the substantial hurdles associated with retrofitting, especially concerning buildings constructed under older codes and lower standards. Nevertheless, if the costs remain reasonable and the structural integrity of the existing building permits retrofitting, prioritizing retrofitting is indeed imperative. Certain aspects of buildings have extended lifespans: facades typically endure around 50 years, structural elements persist for approximately 100 years, and foundations can last indefinitely (World Green Building Council 2019, 24). 10 Given the burgeoning urban population growth in low- and middle-income countries, existing buildings can only be expanded through retrofitting or upgrading up to a certain threshold before necessitating additional constructions. Nonetheless, a significant portion of the existing housing stock in the low- and middle-income world should undergo retrofitting to alleviate deficiencies. The Ellinikon Park Project, Athens The Ellinikon Park project in Athens, Greece, spearheaded by the design firm Sasaki Associates, aims to create Europe's largest coastal park in the former airport and Olympic venue (Bell 2023). The project works not only to reduce operational emissions, but also on reducing embodied emissions while maximizing carbon sequestration to achieve the goal of carbon neutrality by 2035 (Sasaki 2024). A range of techniques are used to reduce both embodied emissions and operational emissions, assisted by tools like Carbon Conscience and Pathfinder. 28,720 m2 of concrete from existing airport runways and tarmac is being repurposed to things like park benches and building foundations, significantly reducing the need for new carbon-intensive construction materials. The plant species that manage to “recolonize” the former airport and Olympic grounds are utilized, along with other local species, also form a major part of the project and assist in carbon sequestration (Sasaki 2024). The mixed-use residential and commercial sections of the project also abide by the “15-minute city” concept, where individuals can reach other parts of the park without private automobiles within 15 minutes (Bell 2023). Low-Carbon Design A buildin’'s design can profoundly influence the embodied emissions associated with its construction. A design approach centered on durability and constructability not only diminishes the necessity for frequent replacements but also enhances adaptability, extends the buildin ’'s utility, and facilitates effective end-of-life (Weir, Rempher and Esau 2023). Adhering to simple and efficient design principles substantially aids in curbing embodied emissions, as each architectural embellishment like recessed entrances, cantilevers, inset balconies, and façade steps incurs a carbon expenditure (Alter 2023). Notably, environmental considerations are frequently absent from the design codes of many countries (Olsson, Miller and Alexander 2023, 4). Buildings should also be designed with material efficiency in mind. Buildings often use more concrete and steel than required to meet safety standards. A recent estimate suggests that improving material efficiency in construction could cut embodied construction emissions by 2050 in half (IFC 2023). A design ethos that considers the eventual dismantling and reutilization of components upon a buildin’'s functional culmination also contributes to material recycling, attenuating the necessity for fresh material production (van der Lugt, Martin and Dufourmont 2023, 59). A study which modeled 11 the emissions from precast concrete multi-story buildings revealed that designing with disassembly in mind could lead to nearly a 10% reduction in deconstruction costs and a potential up to 40% decrease in deconstruction-related carbon emissions (Akbarnezhad, Ong and Chandra 2012). In cases involving mass timber, the carbon sequestered within the material can persist even longer if components are systematically reused. Broadly speaking, a more concerted effort is warranted from governing bodies to address the design of buildings and their anticipated embodied emissions. While carbon reduction at the design phase is garnering attention, particularly from international entities like the World Green Building Council, assessments of embodied impact remain voluntary in the global construction sphere (Saint and Pomponi 2021). Modular Construction Modular construction has witnessed a notable surge in popularity across North America since the mid-2010s, accounting for over 6% of all new construction starts—a threefold increase since 2015 (Modular Building Institute 2023). This burgeoning preference can be attributed to a multitude of advantages stemming from the precision manufacturing of modules within factories before their transportation to construction sites. Among these benefits are cost savings attributed to predictable scheduling, resistance to environmental conditions, and enhanced worker safety. In the context of embodied emissions, the utilization of prefabricated construction methodologies additionally fosters optimal material utilization. This stems from the advanced knowledge of the precise amount required for each module, leading to reduced wastage or“"offcut”" that would typically end up discarded in landfills (Weir, Rempher and Esau 2023). The ensuing reduction in embodied emissions varies contingent on various factors like materials employed and transportation distances, but the discrepancy could potentially reach as high as 45% of emissions (Engineering & Technology 2022, Pervez, Ali and Petrillo 2021). Nevertheless, i’'s important to acknowledge that the feasibility of factories depends on their proximity to the final construction destination. The modular construction industry in India, for instance, identifies a practical maximum distance of around 200 km for deliveries to remain financially viable (Gupta, Kamal and Brar 2021, 23). Mass production within this context necessitates a substantial degree of expertise and industrial integration. As a result, in regions where owner- driven construction predominates, the modular construction approach may encounter challenges in penetrating the market. Moreover, tailoring the modular units to match the local climate is imperative to ensure their durability. Optimizing Height and Density The relationship between urban density and building height is closely intertwined with the optimization of material strength. Generally, multi-story buildings exhibit lower energy intensity per unit of floor space across their lifecycle compared to single-family homes. This is primarily attributed to reduced material demands, as the foundation does’'t require excessive deepening, and the influence of roof construction on embodied emissions diminishes with increasing building heights (Gauch, et al. 2023, 8). Similarly, compact designs contribute to enhanced operational 12 energy efficiency by facilitating more effective resource transmission and heating (Mastrucci and Rao 2019, 14-15). However, there is a threshold beyond which building height significantly escalates embodied emissions. Approximately 20 to 50% of the concrete used in mid-rise and high-rise constructions lies below grade. Taller buildings need deeper foundations to accommodate their greater weight and the increased wind exposure at greater altitudes, rendering skyscrapers more resource- and carbon-intensive (Pomponi, et al. 2020, 1). According to one study that used buildings in the US as a reference (Bohne, et al. 2017, 1995), emissions escalate beyond a height of 12 stories, reducing the carbon advantage associated with taller structures. A study of eight buildings in India (Lall et al., 2017) found that embodied energy peaked slightly earlier, with a 12-story building consuming 40% more embodied energy than an 8-story building. Taller buildings also require greater spacing between them for structural stability and compliance with living quality standards, including ventilation and daylight (Pomponi, et al. 2020, 1). Moreover, many high-rises necessitate substantial underground parking facilities. An analysis of Toront’'s housing revealed that underground parking structures and other below-grade spaces exert a disproportionate impact on a projec’'s embodied emissions (Alter 2023). Consequently, it is estimated that a typical skyscrape’'s carbon footprint from embodied emissions is at least double that of a ten-story building with an equivalent total floor area (architectsdeclare.com 2022). The relationship between building height and timber-based structures is less straightforward, and the concept of a mid-rise“"sweet spo”" is not as pronounced in timber constructions as it is in concrete and steel developments (Bohne, et al. 2017, 1996). Also relevant to height is the factor of density. Compact and mixed-use urban planning strategies play pivotal roles in not only minimizing embodied and operational emissions but also maximizing overall resource efficiency. This approach aims to optimize urban spaces by reducing resource consumption. Carbon emissions associated with urban expansion involve a complex interplay of factors. However, studies have shown that, in the US context, every 1% increase in a city’s population density corresponds with a 0.79% reduction in its CO2 emissions per capita (Ribeiro, Rybski and Kropp 2019). In the Latin American context, a 1% increase in urban density can lead to a 0.58% reduction in total carbon dioxide emissions, while a 1% rise in suburban ratios contributes to a 0.41% increase in emissions, all else being equal (Van der Borght and Barbera 2023). This is due to the tendency for buildings to be higher in cities that are denser, which reduces the range in which roads, utility networks, and public services need to be served. At the same time, green spaces, farmland, and natural habitats are preserved when sprawl is minimized. 13 Downtown Kingston Waterfront Improvement Project The Government of Jamaica with support of the World Bank are currently preparing the Kingston Waterfront Improvement Project, which envisions the redevelopment of the city’s waterfront into a resilient, low-carbon and iconic public space. To maximize mitigation (and adaptation) impacts of the project, local authorities worked with US-based sustainability design consultants Atelier Ten at the outset to identify ways to reduce both operational emissions and embodied emissions in the project. Critically, the team recognized the time value of emissions, in which embodied emissions happen upfront, rather than “diluted over the lifespan of a project” like operational emissions (Atelier Ten 2023, 17). The team identified a range of goals to reduce the embodied emissions of their design. This primarily involves reducing the use of concrete onsite since production of cement is the biggest source of embodied emissions. A range of methods are mentioned to achieve this, such as changing the concrete mix, repurposing existing waterfront materials, such as piers and pavers, and designing the waterfront such that concrete hardscape areas are reduced. At the same time, carbon sequestration is proposed as a method to offset emissions, with the planting palette used for the waterfront carefully chosen to sequester more carbon. More carbon-efficient methods of sourcing and using other materials used heavily in the waterfront project such as steel are also mentioned. It was recommended to design below-grade infrastructure such as piping and stormwater management with a view to limiting material use (Atelier Ten 2023, 17-18). The team assessed the reduction in embodied emissions from all these methods against a baseline scenario, showing that the combination of optimizing hardscape material, optimizing concrete use, and reusing existing on-site materials can reduce embodied emissions by 28%. Its recommendations also included working with local organizations and establishing a clear construction management apparatus to help achieve the stated goals (Atelier Ten 2023, 20-23). Areas for Future Research There remain significant gaps in our comprehension of the environmental impact of the construction industry, particularly in low- and middle-income countries. In the context of high- income countries, extensive research and meticulous data collection initiatives have been launched to scrutinize the environmental repercussions of the construction sector, encompassing its embodied emissions. This comprehensive understanding has allowed policymakers, researchers, and industry stakeholders to devise strategies aimed at curtailing the carbon footprint originating from construction activities within these countries. However, the scenario is notably distinct in low- and middle-income nations. The paucity of centralized and dependable information emanating from government sources in many of these regions poses a formidable obstacle for researchers and experts trying to evaluate the 14 environmental impact of construction. This dearth of data impedes the ability to quantify the scale of embodied emissions, identify the key drivers, and formulate effective measures for mitigation. In the absence of official data, researchers frequently resort to unofficial sources, estimations, and extrapolations to gauge the environmental impact of construction activities in low- and middle- income countries. While these methodologies aid in generating insights, they often lack the specificity and reliability of reports focused on high-income countries. Consequently, the overall comprehension of the extent and implications of embodied emissions within the construction sector of these countries remains circumscribed. This knowledge gap underscores the need for coordinated endeavors to enhance data collection, analysis, and collaborative initiatives aimed at fostering sustainable construction practices and ameliorating the industr’'s environmental imprint in these regions. Potential initiatives could concentrate on comparative data collection on construction practices and embodied emissions across building typologies and countries, mapping of construction material supply chains, and the dissemination of knowledge to facilitate informed decision-making and targeted interventions within the construction sector of low- and middle-income countries. 15 Annex: Tools Various tools are available for planners and policymakers to get a better understanding of the embodied emissions involved in a project and its potential alternatives. Sasaki’s Carbon Conscience Web App The design firm Sasaki released their Carbon Conscience Web App in 2021 and allows planners and designers to easily create scenarios and calculate the potential emissions. The tool can be accessed by creating a free account. Users set up a list of land use swatches with parameters that can be individually altered. These swatches can then be “painted” onto maps and images, where the total area covered by these different land uses will be calculated, and the associated carbon emissions can be estimated. For instance, if this lakefront golf course in Kisumu, Kenya is to be redeveloped, Sasaki’s application can be helpful. The materials involved can then be selected. 16 For this example, the concrete multi-family residential building with a masonry veneer is chosen. A cultivated gardens will be used as the green space in between the buildings. The estimated emissions and costs for each type of material is based on UNFAO datasets. Once the selected land uses are painted on, the carbon emissions and costs can be calculated. 17 https://carbon-conscience.web.app/ International Financial Corporation’s EDGE The IFC’s “Excellence in Design for Greater Efficiencies” (EDGE) works on a building-by-building basis, letting users predict the embodied emissions involved in a project’s construction and potential carbon-cutting measures. It also acts as a certification tool for individual projects in a similar manner to the US Green Building Council’s LEED certification. The application can be accessed without creating an account by logging in as a guest. Project options available on the EDGE tool include homes, hotels, retail, offices, and hospitals. Basic project details such as the country are entered, to which the tool will then make assumptions on the cost of electricity, water, and other fuels based on the location selected. The tool also lets users account for local climatic conditions. 18 Various energy, water, and operational measures can be tested and accounted for in the final calculations. 19 Of course, different materials used to build different parts of the building can be calculated too, giving a rather comprehensive account of embodied emissions too. In the example below, the default exterior walls were replaced with “Concrete Blocks | Hollow Blocks with Stone Cladding,” allowing an embodied emissions decrease of 18%. Lastly, the operational data can also be tracked in the “Operations” tab. 20 https://app.edgebuildings.com/ GCCA EPD Tool The Global Cement and Concrete Association (GCCA)’s Environmental Product Declarations tool helps users calculate the impact of clinker, cement, concrete, and more. It also provides a tool to calculate the emissions coming from all parts of the cement/concrete’s lifecycle, which can then be verified by a third-party verifier to become official public EPDs (GCCA 2023). The tool is not free for all users, but is free for GCCA members and available with a discount for GCCA Affiliates. https://gccassociation.org/our-story-cement-and-concrete/environmental-product- declarations/#tool Carbon Smart Materials Palette The Architecture 2030’s Carbon Smart Materials Palette is a useful website providing outlines on the embodied emissions of different materials in a manner similar to this report. Its associated page 2030palette.org/ also provides a detailed overview of different project types, acting as a bibliography for other resources too. https://materialspalette.org/ http://2030palette.org/ Bionova’s One Click LCA As the name suggests, the One Click LCA allows users to create Lifecycle Assessments with relatively ease. Building materials can be compared, along with overviews of a project’s energy and water consumptions, emissions from construction site operations, and more. Existing design tools and material databases are directly integrated in the One Click LCA. Credits can also be acquired for green building certifications by many organisations. Various pricing options are available. 21 https://www.oneclicklca.com/ Others Many more tools can be found here: https://carbonleadershipforum.org/tools-for-measuring- embodied-carbon/ many of which revolved around lifecycle assessments. 22 Works Cited ADB. 2010. Methodology for Estimating Carbon Footprint of Road Projects–- Case Study: India. Mandaluyong City: Asian Development Bank. Akan, Mahmure Övül Arıoglu, Dileep G. Dhavale, and Joseph Sarkis. 2017. “Greenhouse gas emissions in the construction industry: An analysis and evaluation of a concrete supply chain.” Journal of Cleaner Production 1195-1207. Akbarnezhad, A., K. Ong, and L. Chandra. 2012.“"Economic and environmental assessment of deconstruction strategies using building information modeling ”" Automation in Construction. Alter, Lloyd. 2022. Time Is as Important as Tech When Fighting Climate Change. May 12. Accessed November 17, 2023. https://www.treehugger.com/time-important-fighting-climate-crisis- 5271738. Alter, Lloyd. 2023. How tall should a building be: How not to build in a climate crisis. April 19. Accessed July 14, 2023. https://lloydalter.substack.com/p/how-tall-should-a-building-be- how?utm_medium=reader2. Appolloni, Letizia, and Daniela D’Alessandro. 2021. “Housing Spaces in Nine European Countries: A Comparisonof Dimensional Requirementss.” International Journal of Environmental Research and Public Health (International Journal of Environmental Research and Public Health). architectsdeclare.com. 2022. Open Letter to the Council on Tall Buildings and Urban Habitat. July. Accessed July 14, 2023. https://www.architectsdeclare.com/news/category/statements. Architecture2030. 2023. Why the Built Environment. Accessed October 4, 2023. https://architecture2030.org/why-the-built- environment/#:~:text=To%20accommodate%20the%20largest%20wave,every%20month %2C%20for%2040%20years. Asian Development Bank. 2023.“"People's Republic of China Road Classification Information”" Asian Development Bank. Accessed January 25, 2024. https://www.adb.org/sites/default/files/linked-documents/46040-003-sd-04.pdf. Atelier Ten. 2023.“"Downtown Kingston Waterfront Improvement Project”" Sustainability Report, New York City. Bah, El-hadj M., Issa Faye, and Zekebweliwai F. Geh. 2018.“"The Construction Cost Conundrum in Africa”" In Housing Market Dynamics in Africa, by El-hadj M. Bah, Issa Faye and Zekebweliwai F. Geh, 159-214. London: Palgrave Macmillan. 23 Bell, Katie Kelly. 2023. Greece Will Soon Be Home To Europe’s Largest Coastal Park. October 20. Accessed Jan 4, 2024. https://www.forbes.com/sites/katiebell/2023/10/20/greece-will- soon-be-home-to-europes-largest-coastal-park/?sh=3b3bf9192bda. Berners-Lee, Mike. 2022. The Carbon Footprint of Everything. Vancouver: Greystone. Bizley, David. 2023. An electrifying solution to decarbonising cement production. March 20. Accessed August 8, 2023. https://www.worldcement.com/special-reports/20032023/an- electrifying-solution-to-decarbonising-cement-production/. Bohne, Rolf André, Benedicte Kaspersen, Julie Lyso Skullestad, and Egil Ytrehus. 2017.“"Embodied Energy Versus Building Height, The “Premium” of Building Tall”" World Sustainable Environment Conference 2017 Hong Kong. Hong Kong: Construction Industry Council; Hong Kong Green Building Council. 1992-1997. Brasuell, James. 2023. Nashville Adopts New Mass Timber Building Standards. August 9. Accessed August 9, 2023. https://www.planetizen.com/news/2023/08/125054-nashville-adopts- new-mass-timber-building-standards. Business Standard. 2016. In the State of Uttar Pradesh there are 60 National Highways with total length of 8483 Kms. June 10. Accessed November 13, 2023. https://www.business- standard.com/article/news-cm/in-the-state-of-uttar-pradesh-there-are-60-national- highways-with-total-length-of-8483-kms-116061000394_1.html. Cameron, Lynelle. 2020. Data to the rescue: Embodied carbon in buildings and the urgency of now. September 15. Accessed October 16, 2023. https://www.mckinsey.com/capabilities/operations/our-insights/data-to-the-rescue- embodied-carbon-in-buildings-and-the-urgency-of-now. Chen, Jing, Fuquan Zhao, Zongwei Liu, Xunmin Ou, and Han Hao. 2017. “"Greenhouse gas emissions from road construction in China: A province-level analysis”" Journal of Cleaner Production 1039-1047. Cheshire, Dave, and Mike Burton. 2023. The carbon and business case for choosing refurbishment over new build. Accessed August 10, 2023. https://aecom.com/without- limits/article/refurbishment-vs-new-build-the-carbon-and-business-case/. Churkina, Galina, Alan Organschi, Christopher P. O. Reyer, Andrew Ruff, Kira Vinke, Zhu Liu, Barbara K. Reck, T. E. Graedel, and Hans Joachim Schellnhuber. 2020.“"Buildings as a global carbon sink”" Nature Sustainability 269-276. Duan, H, TR Miller, G Liu, and VWY Tam. 2019.“"Construction debris becomes growing concerns of growing cities”" Waste Mange 1-5. Engineering & Technology. 2022. Modular construction technique slashes carbon emissions from new buildings. June 6. Accessed June 8, 2023. 24 https://eandt.theiet.org/content/articles/2022/06/modular-construction-technique- slashes-carbon-emissions-from-new-buildings/. Fazzare, Elizabeth. 2023. Why naturally renewing ‘mass timber’ is the building block of the future. July 8. Accessed August 9, 2023. https://nypost.com/2023/07/08/why-timber-is-the-building- block-of-the-future/. Ferronato, Navarro, Rocio Clara Fuentes Sirpa, Edith Gabriela Guisbert Lizarazu, Fabio Conti, and Vincenzo Torretta. 2023.“"Construction and demolition waste recycling in developing cities: management and cost analysis”" Environmental Science and Pollution Research 24377-24397. Gauch, H.L., C.F. Dunant, W. Hawkins, and A. Cabrera Serrenho. 2023.“"What really matters in multi- storey building design? A simultaneous sensitivity study of embodied carbon, construction cost, and operational energy”" Applied Energy 1-14. GCCA. 2023.“"Environmental Products Declaration”" Global Cement and Concrete Association. Accessed August 16, 2023. https://gccassociation.org/wp- content/uploads/2023/07/GCCA_EPD_Tool_eBook_2023.pdf. Gupta, Neha, Mohammad Arif Kamal, and Tejwant Singh Brar. 2021.“"Exploration of prefabricated building system in housing construction”" Journal of Building Materials and Structures 19-31. Hashemi, Arman, Heather Cruickshank, and Ali Cheshmehzangi. 2015.“"Environmental Impacts and Embodied Energy of Construction Methods and Materials in Low-Income Tropical Housing”" Sustainability 7867-7883. Hurley, Amanda Kolson. 2023. How a Seattle Architect Helped Make Timber Towers Legal in the US. March 23. Accessed August 9, 2023. https://www.bloomberg.com/news/articles/2023-03- 23/seattle-apartment-building-ushers-in-next-wave-of-wood-architecture. —. 2023. Why Wood Is the Breakout Architecture Star of the Early 21st Century. March 23. Accessed August 9, 2023. https://www.bloomberg.com/news/articles/2023-03-23/super-strong- wood-gains-on-concrete-and-steel-in-new-architecture. IEA. 2019. 2019 Global Status Report for Buildings and Construction. Status Report, Paris: Global Alliance for Buildings and Construction. IEA. 2023. Cement. August. Accessed August 8, 2023. https://www.iea.org/energy- system/industry/cement. IFC. 2023. Building Green: Sustainable Construction in Emerging Markets. Washington, DC: World Bank. http://hdl.handle.net/10986/40561 License: CC BY-NC-ND 3.0 IGO IIED. 2022. Building with wood in Africa could slash carbon emissions. April 27. Accessed June 12, 2023. https://www.iied.org/building-wood-africa-could-slash-carbon-emissions. 25 IPCC. 2022. Climate Change 2022: Impacts, Adaptation and Vulnerability . Working Group II Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, Geneva: Intergovernmental Panel on Climate Change. Jiang, Rui, Chengke Wu, Yongze Song, and Peng Wu. 2020.“"Estimating carbon emissions from road use, maintenance and rehabilitation through a hybrid life cycle assessment approach – A case study”" Journal of Cleaner Production 1-13. Lall, Ashok B., Divya Bansal, Salil Mohan, Sameer Maithel, Saswati Chetia. 2017. “Position paper on Low Carbon Resource- Efficient Affordable Housing.” https://www.capacitiesindia.org/position-paper-on-low-carbon-resource-efficient- affordable-housing/ Larsen, Kate, Hannah Pitt, Mahmoud Mobir, Shweta Movalia, Alfredo Rivera, Emma Rutkowski, Marie Tamba, Kelly McCusker, and Trevor Houser. 2023. Rhodium Climate Outlook: Probabilistic Projections of Energy, Emissions and Global Temperature Rise. Rhodium Group. livemint.com. 2015. Back Over 20 million units to be built under ‘Housing for All’ programme. January 21. Accessed August 14, 2023. https://www.livemint.com/Politics/rQOkJLXEasVLPQSXOsJckM/Over-20-million-units- to-be-built-under-Housing-for-All-pr.html. Makeka, Mokena, and Mudit Sharma. 2022. African timber cities: carbon sinks with development benefits? Brief, London: IIED. Mastrucci, Alessio, and Narasimha D. Rao. 2019. "Bridging India’s housing gap: lowering costs and CO2 emissions." Building Research & Information 8-23. Modular Building Institute. 2023. Modular Constrution Reports & Industry Analysis: Executive SUmmary. Accessed August 14, 2023. modular.org/industry- analysis/#:~:text=Executive%20Summary,market%20share%20was%202.14%20percent. ODNI. 2021. Global Trends 2040. March. Accessed August 7, 2023. https://www.dni.gov/index.php/gt2040-home/gt2040-structural-forces/demographics- and-human- development#:~:text=Relatively%20poor%20countries%20in%20Sub,necessary%20to% 20fully%20harness%20their. Olsson, Josefine A., Sabbie A. Miller, and Mark G. Alexander. 2023. "Near-term pathways for decarbonizing global concrete production." Nature 1-10. Panjaitan, Togar W.S., Paul Dargusch, David Wadley, and Ammar A. Aziz. 2021. "Meeting international standards of cleaner production in developing countries: Challenges and financial realities facing the Indonesian cement industry." Journal of Cleaner Production 1-21. 26 Pervez, Hamza, Yousaf Ali, and Antonella Petrillo. 2021. "A quantitative assessment of greenhouse gas (GHG) emissions from conventional and modular construction: A case of developing country." Journal of Cleaner Production 1-18. Pomponi, Francesco, Jim Hart, Jay H. Arehart, and Bernardino D’Amico. 2020. "Buildings as a Global Carbon Sink? A Reality Check on Feasibility Limits." One Earth 157-161. Portland Cement Association. 2024. Recycled Aggregates. Accessed January 25, 2024. https://www.cement.org/learn/concrete-technology/concrete-design- production/recycled-aggregates. Rasheed, Rizwan, Fizza Tahir, Muhammad Afzaal, and Sajid Rashid Ahmad. 2022. "Decomposition analytics of carbon emissions by cement manufacturing – a way forward towards carbon neutrality in a developing country." Environmental Science and Pollution Research 49429– 49438. Razwani, Naeem, and Olivia Nielsen. 2021. Why we need to start financing resilient housing in Africa. March 17. Accessed August 10, 2023. https://housingfinanceafrica.org/documents/why- we-need-to-start-financing-resilient-housing-in-africa/. Reed, Tristan. 2022. Why is the price of cement so high in Africa? June 16. Accessed June 8, 2023. https://blogs.worldbank.org/developmenttalk/why-price-cement-so-high-africa. Ribeiro, Haroldo V., Diego Rybski, and Jürgen P. Kropp. 2019. "Effects of changing population or density on urban carbon dioxide emissions." Nature 1-9. Röck, M, A Sørensen, B Tozan, J Steinmann, X Le Den, LH Horup, and H Birgisdottir. 2022. Towards EU embodied carbon benchmarks for buildings – Setting the baseline: A bottom-up approach. Brussels: Ramboll. Saint, Ruth, and Francesco Pomponi. 2021. Cities and climate change: Why low-rise buildings are the future, not skyscrapers. October 28. Accessed July 14, 2023. https://phys.org/news/2021- 10-cities-climate-low-rise-future-skyscrapers.html. Sasaki. 2024. The Ellinikon Park. Accessed January 4, 2024. https://www.sasaki.com/projects/the- ellinikon-park/. Smedley, Tim. 2019. Could wooden buildings be a solution to climate change? July 24. Accessed August 9, 2023. https://www.bbc.com/future/article/20190717-climate-change-wooden- architecture-concrete-global-warming. Sudarsan, J. S., Shruti Vaishampayan, and Padma Parija. 2022. "Making a case for sustainable building materials to promote carbon neutrality in Indian scenario." Clean Technologies and Environmental Policy 1609-1617. Taffese, Woubishet Zewdu, and Kassahun Admassu Abegaz. 2019. "Embodied Energy and CO2 Emissions of Widely Used Building Materials: The Ethiopian Context." Buildings 1-15. 27 Teferi, Zafu Assefa, and Peter Newman. 2018. “Slum Upgrading: Can the 1.5 °C Carbon Reduction Work with SDGs in these Settlements?” Urban Planning 52-63. Timperley, Jocelyn. 2018. Q&A: Why cement emissions matter for climate change. September 13. Accessed August 18, 2023. https://www.carbonbrief.org/qa-why-cement-emissions- matter-for-climate-change/. UN. 2023. Around 2.5 billion more people will be living in cities by 2050, projects new UN report. Accessed August 7, 2023. https://www.un.org/en/desa/around-25-billion-more-people- will-be-living-cities-2050-projects-new-un-report#:~:text=COVID%2D19- ,Around%202.5%20billion%20more%20people%20will%20be%20living%20in%20cities,ur ban%20planning%20and%20public%20services. Van der Borght, Rafael, and Montserrat Pallares Barbera. 2023. "How urban spatial expansion influences CO2 emissions in Latin American countries." Cities 1-14. van der Lugt, Pablo, Irene Luque Martin, and Joke Dufourmont. 2023. Discussing Timber Myths: A Dialogue Between Our Ambitions and the Facts. Amsterdam: Amsterdam Institute for Advanced Metropolitan Studies. Weir, Madeline, Audrey Rempher, and Rebecca Esau. 2023. Embodied Carbon 101: Building Materials. March 27. Accessed June 5, 2023. https://rmi.org/embodied-carbon- 101/#:~:text=Embodied%20carbon%20represents%20the%20millions,contribute%20to% 20embodied%20carbon%20emissions. World Green Building Council. 2019. Bringing embodied carbon upfront. London: World Green Building Council. World Green Building Council. 2019. Bringing embodied carbon upfront. Accessed October 16, 2023. https://worldgbc.org/advancing-net-zero/embodied-carbon/. Yu, Chao, Liu Wu, Yuyao Liu, Kunhui Ye, and Guibao Liang. 2022. "Estimating Greenhouse Gas Emissions from Road Construction by Considering the Regional Differences in Carbon Emission Factors of Cement: The Case of China." Buildings 12 (9). 28