Embodied CO2 Emissions Research Articles

Embodied CO2 emissions and efficiency of the service sector: Evidence from China

Numerous studies discuss energy consumption and carbon emissions in industrial sectors. However, studies of environmental problems caused indirectly by the development of the service sector have, until now, been rather limited. Using the input-output analysis and the three-stage data envelopment analysis (DEA) model, we propose an improved method for estimation of embodied CO2 emissions efficiency in the service sector, and apply it to provincial data in China. We observe that first, the service sector emitted a significant amount of embodied CO2; second, significant regional differences in CO2 emissions efficiency exist that, nevertheless, are consistent with the levels of regional economic development. Finally, we propose several policy implications for emissions reduction.

China’s aggregate embodied CO2 emission intensity from 2007 to 2012: A multi-region multiplicative structural decomposition analysis

The striking disparities among China’s provinces suggest the need for regionalized carbon emission intensity mitigation measures. This study extends the aggregate embodied energy/emission intensity measures proposed by Su and Ang (2017) to a national multi-region setting, defines the aggregate embodied CO2 emission intensity (AECI) indicators at the aggregate, provincial, and final demand category levels from the demand perspective, and adopts multiplicative structural decomposition analysis (SDA) to identify the driving factors of the historical changes over the 2007–2012 period in China. On the basis of China’s latest multiregion input-output tables, we find that (a) the AECIs show heterogeneities across the provinces and final demand categories, with the AECIs of inland provinces higher than those of coastal provinces and the AECIs of investment and export higher than those of consumption; (b) the generally downward trends of the AECIs hold at different levels, and the improvements in carbon emission performances are more pronounced in inland provinces, presenting a convergence toward the levels of developed coastal provinces; (c) according to the multiplicative SDA results, the input structure effect and the emission intensity effect generally contribute to the decline of AECIs. By providing a deeper understanding of carbon emission performance and its driving factors at the subnational level, our study finally proposes some policy recommendations.

Measuring the Impacts of International Trade on Carbon Emissions Intensity: A Global Value Chain Perspective

ABSTRACT Global international trade has had a tremendous impact on global economic development and carbon dioxide (CO2) emissions. By making the link between embodied CO2 emissions and the global value chain in the context of global multiregional input–output models, this study constructs a macro carbon trade intensity index to measure the carbon efficiency of international trade. Empirical results on 14 major economies from 1995 to 2009 are presented as follows: (1) The characteristics of the carbon trade vary between developing economies (or transition economies) and developed economies. On average, developing and transition economies have an export carbon intensity (ECI) 3.5 times that of their import carbon intensity (ICI), whereas the latter have an ICI 2.0 times that of their ECI; (2) The three carbon intensity indices in almost all economies decreased compared with 1995; however, the degree of reduction vary from 2% to 52%; (3) China’s ECIs showed little change compared with those of India. Russia’s ECIs were higher than those of China and India. In addition, countries with higher intensity are generally developing and transition economies.

Measuring embodied CO2 emission in construction materials in Kosovo apartments

Purpose The purpose of this paper is to quantify the carbon emissions emitted by two different typical apartment units representative of two different construction periods in Kosovo due to main construction materials as a consequence of embodied energy. Design/methodology/approach The present study uses a three-step (bottom-up) process-based life cycle analysis of the construction material set for two different apartment units. The current study uses material analysis. Embodied CO2 is estimated by multiplying material masses with the corresponding ECO2 coefficients (kg CO2/kg). Due to the lack of a comprehensive Kosovo database, data from an international database are utilized. The results provide practical baseline indicators for the contribution of each material in terms of mass and embodied CO2. Findings Results of quantitative research find that apartment unit representative of the old communist-era construction produces 50 percent more embodied CO2 emissions than an apartment unit that is representative of modern construction in Kosovo. The study finds that this difference comes mainly because of the utilization of larger quantities of steel, concrete, and precast fabricated concrete in the apartment unit that is representative of the old communist era. Research limitations/implications The calculation of embodied CO2 emissions for major construction materials in typical apartments in Kosovo can help in the development of national databases in the future. The availability of such databases could help the construction industry in Kosovo to open up to new sustainable design approaches since such databases and evaluations performed in the national context in Kosovo could help the builders in selecting, assessing and using environmentally friendly materials during the design or refurbishment stage of a building. Originality/value This paper is the first investigation of the embodied carbon emission in two different typical apartment building structures in Kosovo.

CO2 emissions embodied in trade: Evidence for Hong Kong SAR

Abstract Cities play an important role in carbon emissions reduction and climate change mitigation. In this study, we examine the CO2 emissions embodied in the imports and exports of the Hong Kong special administrative region (SAR) from 1990 to 2015 using the emissions embodied in bilateral trade (EEBT) method. The results show that Hong Kong SAR has been a net CO2 importer and Mainland China plays a dominating role in the embodied CO2 emissions of Hong Kong SAR. The sectors with high imported CO2 emissions are mainly the energy sectors, such as electricity, heat, gas and water production and supply. Population density, GDP per capita, and trade openness have significantly positive effects on net CO2 emissions increases in Hong Kong SAR, with population density taking the leading role. Population density increases by 1%, total net CO2 emissions increase by 4%. Population slowdown scenario simulation results show that net CO2 emissions of Hong Kong SAR could be reduced by 5.5%. Whereas, net CO2 emissions of Hong Kong SAR could increase by 8.7% in the accelerated economic development scenario. Therefore, to reduce CO2 emissions, Hong Kong SAR need control its population, develop the circular economy, and promote green lifestyle and consumption patterns.

Sustainable impact of adaptive reuse of communist style shopping malls in Kosovo

PurposeThe purpose of this paper is to study the sustainable impact of adaptive reuse of shopping malls built during communism in Kosovo.Design/methodology/approachThe present study uses qualitative research using semi-structured interviews with architects, civil engineers, real estate developers and facility managers.FindingsThe study found that it is the predominant opinion of respondents that the economic impact of adaptive reuse of old shopping malls in Kosovo is reflected through extension of useful life of the malls, lower cost of reuse vs demolition, economic and tourism development of the neighborhood, job creation and increase of property prices in the surrounding area. In addition, the study found that it is the predominant opinion of respondents that by adaptive reuse of old shopping malls, the revitalization and social dynamism of the surrounding area will be improved and collective memory and identity of these shopping malls will be extended, including the increased traffic, space utilization and security. The study concludes that operational CO2 emission of the old shopping malls will be reduced after their sustainable adaptation and also the embodied energy of the building materials will be reused.Research limitations/implicationsThe study has several implications. For real estate developers, it shows that is less costly to adapt and refurbish rather than redevelop. For authorities, it shows that by adapting old communist shopping malls, they would extend the collective memory of those locations, improve the social life and utilization of public spaces in the surrounding areas. The final implication is for municipal authorities and environmentalists that but allowing adaptation rather than demolition and redevelopment the embodied CO2 emission will be significantly reduced.Originality/valueThe study is the first qualitative study about the impact of adaptive reuse of old communist style commercial centers in Kosovo.

Imbalance of carbon emissions embodied in the US-Japan trade: temporal change and driving factors

Abstract In US-Japan trade, Japan ran both economic export surplus and export CO2 emission surplus with the US. Positive net monetary exports for Japan were actually a kind of economic losses of the US, while positive net export CO2 emissions, or net CO2 emissions embodied in US-Japan trade, were regarded as pollution transfer from U.S. to Japan. However, due to lack of unified measurement units and standards between the two research fields, it is difficult to directly assess whether positive effects of U.S. via carbon transfer outweigh negative effects caused by economic losses. The study transforms absolute values of net monetary exports and net export CO2 emissions from 2000 to 2011 in US-Japan trade into two ratios: the ratio of net monetary exports to GDP of U.S. and the ratio of net embodied CO2 emissions to total CO2 emissions of the US. By comparison, the result shows that on average, net monetary exports between U.S. and Japan accounted for 0.45% of American GDP, while ratio of net export emissions to aggregate consumption-based CO2 emissions of U.S. kept about 0.20% during the research period concerned, which indicated that negative effects of economic losses in U.S. outweighed positive effects via carbon transfer in US-Japan trade. Furthermore, a structural analysis of CO2 emissions embodied in US-Japan trade during the 11 years is given. The most significant driver was emission coefficients, defined as CO2 emissions per unit of energy consumption. The driving force of emission coefficients led to dramatic reduction in CO2 flows from Japan to the US and thus caused decrease of net export emissions, which also explained the major reason for the low ratio of export emissions to total CO2 emissions of the US. Finally, according to sectoral distributions of CO2 flows between Japan and the US, emission sources of two countries presented different characteristics.

Optimization of RC Structures with Regard to Amount of Embodied CO2 Emissions

The volume of CO2 emissions (and other greenhouse gases) has been rising almost continuously for several decades. Concrete is the most used man-made material in the world, thus the construction of reinforced concrete (RC) structures is associated with high environmental impact, mainly due to the consumption of cement as binder for concrete and steel as reinforcement. This article analyses the available options for the design of RC structure to reduce embodied CO2 emissions. The main part of the article is a case study demonstrating optimization of the load-bearing structure of multi-storey building. Emphasis was placed on achieving the optimal variant in terms of CO2 emissions, while maintaining a comparable cost of the construction. The results of this study show that in this particular case the use of concrete with a lower strength brings lower environmental impact than of concrete with higher strength. The reason is that the production of lower strength concrete allows the use of cements with a lower clinker content which is decisive for CO2 emissions. However, the use of concrete with higher strength allows more subtle structural members with lower content of concrete and potentially with higher durability.

CO2 emissions embodied in China’s export

ABSTRACTThe reduction of CO2 emissions embodied in export will have an important role for China to achieve its CO2 emissions peaking target. In this study, we use input–output analysis to examine the embodied CO2 emissions in China’s export to its top largest trading countries from 2008 to 2015. We find that China’s exported CO2 emissions peaked in 2008. More than 70% of embodied CO2 emission were exported to only 20 countries, and CO2 emissions exported to developing countries have been increasing. High-energy consumption sectors contribute to CO2 emissions embodied in export significantly, such as Electricity, Gas and Water. We conclude that structural adjustment could be considered alongside technological improvements to curb China’s growing CO2 emissions.

Potential of Circular Economy in Sustainable Buildings

The building industry contributes to resource scarcity by consuming vast amounts of natural resources and produces in addition large amounts of waste, both contributing to a considerable portion of the environmental impacts induced by the demands of a growing world population. Manufacturing of most building materials require large amounts of material and energy resources. These materials are nevertheless either down-cycled or ends up as waste after demolition. Consequently, the building industry only manages to exploit an insignificant percentage of the building materials’ inherent economic value and durability. Hence, the need for improved resource efficiency will increase parallel to the growing human demands to ensure that future needs. Circular economy principles can potentially facilitate minimising the aforementioned pending issues emanating from the building industry through recirculation of building materials. E.g. existing mechanical joint solutions can enable design for disassembly, thereby potentially prolonging the service life of building materials and components through reuse in subsequent building projects. The research presented in the paper at hand aims at identifying the main challenges of implementing circular economy principles, as well as potentials here-off, within the building industry through a literature review. Furthermore, a conventional Danish office building is used as case study to support the literature review by quantifying potential environmental and economic benefits of designing the buildings concrete structure for disassembly, with the purpose of reuse, as well as to exemplify how circular economy can be applied in future building projects. Moreover, the paper aims at suggesting a more industry focused approach towards circular economy in order to seize the inherent potentials. As a result, it was found that recycling and energy recovery are the most common circular economy practices in the building industry, even though the economic and environmental benefits of reuse are believed to be much higher. This observation is supported by the findings of the case study, which revealed that reuse of the concrete structure can potentially avoid a noteworthy portion of the building’s embodied CO2 emissions and provide a reasonable economic gain. Moreover, increased impact savings were exhibited when substituting concrete with alternative materials e.g. wood, steel and glass, thereby enabling easier disassembly for both reuse and recycling. However, main challenges preventing the industry from seizing these potentials are identified as: focus on short term goals, complex supply chains, lack of collaboration between stakeholders and absence of a commonly agreed definition of circular economy within the industry. In conclusion, the study demonstrates an improved environmental performance of the office building when designed for disassembly. Furthermore, the choice of building materials has a noteworthy influence on the building’s embodied environmental impacts. From the results obtained in this study it is estimated that the potential environmental impact savings as well as economic benefits can be further increased through a higher degree of design for disassembly.

Growth potential for CO2 emissions transfer by tariff reduction

A reduction in tariff barriers facilitates the relocation of factories to countries with less stringent environmental regulations. There has been rapid growth in the transfer of emissions from developing to developed countries through international trade over the last 30 years. However, almost all countries still maintain their tariff barriers, and these tariffs limit the potential to increase carbon dioxide (CO2) emissions transfers. This paper aims to examine the impact of tariff reduction on the CO2 embodiment associated with the imports of the group of twenty (G20) countries. The econometric analysis uses disaggregated tariff data and CO2 embodied emissions data from 1990 to 2013. The findings reveal that a 1% tariff cut by G20 countries for mining gas, manufactured machinery, metal, and other mining imports would result in 2779, 1747, 1453, and 1018 tons of CO2 emissions, respectively. We show that a tariff cut would increase the embodied CO2 emissions significantly for most of the manufacturing and mining sectors. Here, we find there is a 3.5%–232.2% growth potential of CO2 emissions embodied in imports, depending on whether G20 countries abolish tariff barriers. This scenario makes it difficult to achieve national emissions reduction targets and to implement national environmental policy.

Effective use of ground waste expanded perlite as green supplementary cementitious material in eco-friendly alkali activated slag composites

The production of alkali activated slag composites (AASCs) generally requires a large amount of slag, and waste expanded perlite (WEP) is a type of industrial waste that can be used as green supplementary cementitious material (SCM) in the building industry. In this study, the feasibility of using ground WEP as a sustainable replacement for slag in AASCs was evaluated. The process of hydration, mechanical properties, and ecological and economic performance of the AASCs with ground WEP (WEP-AASCs) were investigated in this study. The results showed that the 28–day compressive strength of WEP-AASCs at 10, 30, and 50 vol% WEP decreased by 2.4 MPa (4%), 7.3 MPa (12%), and 9.4 MPa (16%), respectively, compared to AASCs without WEP. In addition, both the heat of reaction and reaction peak of WEP–AASCs by thermogravimetric analysis decreased with the increasing additions of ground WEP. Combined with the X-ray diffraction (XRD) and scanning electron microscope (SEM) of WEP–AASCs, it was found that the addition of ground WEP did not change the reaction products in the AASCs. Based on the economic and ecological analyses, reductions in cost (6–19%), embodied energy (5–24%), and embodied CO2 emissions (3.2–16%) can be achieved, compared to AASCs without ground WEP. Therefore, WEP is suitable for use as SCM in AASCs, and presents promising applications based on the identified performance and sustainability.

Integrating Dynamic Material Flow Analysis and Computable General Equilibrium Models for Both Mass and Monetary Balances in Prospective Modeling: A Case for the Chinese Building Sector.

Integrated Assessment Models based on Computable General Equilibrium (IAM/CGE) and dynamic Material Flow Analysis (dynamic MFA) are two most widely used prospective model families to assess large-scale and long-term socioeconomic metabolism (SEM) and inform sustainable SEM transition. The latter approach could complement the former by a more explicit understanding of service provision, in-use stocks, and material cycles in a mass balanced framework. In this paper, we demonstrated this by integrating the dynamic MFA and CGE model approaches for the Chinese building sector from 2012 to 2030. Our results revealed the impacts of building stock dynamics on sectoral and economy-wide CO2 emissions: lower service saturation levels and later saturation time of building stock development could free up investment on buildings and accumulatively save up to 25.4 Gt in embodied CO2 emissions of the building construction sector, representing a 2.7-fold of 2012 countrywide CO2 emissions. However, the save-ups are partly compensated by an increase of embodied CO2 emissions in the other sectors due to economy-wide rebound effect (ca. 18.8 Gt or about 74%). The integrated model we developed could help ensure both mass and monetary balances, explore rebound effects in prospective modeling, and thus better understand the economy-wide consequences of infrastructure development.

Approach to establish carbon emission benchmarking for construction materials

The construction industry will play a crucial rule in global carbon emission reduction as the embodied carbon of construction materials shares an increasing portion of a building’s life-cycle carbon dioxide (CO2) emissions. In order to reduce CO2 emissions by selecting low-carbon construction materials, it is inevitable that a proper benchmarking mechanism and severity representation of different emission levels should be established, as benchmarking is a useful tool for pursuing consumer purchasing habits toward selection of low-carbon materials. In addition, high variation of carbon emissions is observed among the large number of studies and databases, and there is no consensus on how these should be used in practice. Therefore, standardization and benchmarking of emissions for construction materials are essential. In this study, a novel benchmarking approach was developed for embodied carbon emissions of commonly used construction materials by applying a fuzzy set theory. Given that a reliable local database is lacking, the benchmark was developed by referring to the existing carbon inventories, linguistic variables of severity levels from a questionnaire survey, and the fuzzy set analysis. A six-step method was proposed based on a horizontal and graphical approach. This study offers an alternative approach in benchmarking where a database or a set of real data is not available. It is expected that the developed benchmarks will help practitioners and decision-makers compare the embodied CO2 emissions of a specific batch of construction materials and select low-carbon materials in construction projects.

Visualizing the change of embodied CO2 emissions along global production chains

Abstract Network analysis has become one of the most widely used tools for visualizing the major inter-country/inter-industry CO2 emission flows along the global production chains. Based on the World Input-Output Database (WIOD), we estimate worldwide CO2 emission flows across economies from 1995 to 2011, and visualize the major flows and their temporal changes through network analysis. More specifically, we adapt the recognition of crucial nodes in network, and present four types of networks: networks based on absolute size and relative size of CO2 emission flows for four individual years (1995, 2000, 2007, and 2011) and networks based on absolute change and relative change of CO2 emission flows for three sub-periods (1995–2000, 2000–2007, and 2007–2011). The results highlight the different roles economies play in worldwide CO2 trade networks and their temporary changes over time. While “large” economies such as the U.S. and China were often recognized as the major importers of worldwide CO2 emissions, the very rapid growth rates of a series of “medium” and “small” economies, such as Turkey, Mexico, and Cyprus, in CO2 imports throughout the entire period of 1995–2011 are not negligible. The global warming mitigation requires joint inputs from “large” economies as well as “medium” and “small” economies.

Seismic design of reinforced concrete frames for minimum embodied CO2 emissions

Optimum structural design of reinforced concrete (RC) frames has been the focus of extensive research. Typically, previous studies set economic cost as the main design objective despite the fact that RC structures are major contributors of CO2 emissions. The limited number of studies examining optimum design of RC frames for minimum CO2 emissions do not address seismic design considerations. However, in many countries around the world, including most of the top-10 countries in CO2 emissions from cement production, RC structures must be designed against earthquake threat. To bridge this gap, the present study develops optimum seismic designs of RC frames for minimum cradle to gate embodied CO2 emissions and compares them with optimum designs based on construction cost. The aim is to identify efficient design practices that minimize the environmental impact of earthquake-resistant RC frames and examine the trade-offs between their cost and CO2 footprint. To serve this goal, an RC frame is optimally designed according to all ductility classes of Eurocode 8 and for various design peak ground accelerations (PGAs), concrete classes and materials embodied CO2 footprint scenarios. It is found that the minimum feasible CO2 emissions of RC frames strongly depend on the adopted ductility class in regions of high seismicity, where low ductility seismic design can generate up to 60% more CO2 emissions than designs for medium and high ductility. The differences reduce, however, as the level of seismicity decreases. Furthermore, CO2 emissions increase significantly with the design PGA. On the other hand, they are less sensitive to the applied concrete class. It is also concluded that, for medium to high values of the ratio of the unit environmental impact of reinforcing steel to the respective impact of concrete, the minimum CO2 seismic designs are very closely related to the minimum cost designs. However, for low values of the same ratio, the minimum cost design solutions can generate up to 13% more emissions than the minimum CO2 designs.

Exploring the Characteristics of CO2 Emissions Embodied in International Trade and the Fair Share of Responsibility

This paper explores the characteristics of embodied CO2 emissions from the perspective of carbon inflows, carbon outflows, and the net effects, at both an aggregate and bilateral scale. We identify several important relationships in bilateral carbon flows, including China–EU, China–USA, Russia–EU, and China–Japan, which make China and Russia the largest carbon exporters and the EU and the USA the largest carbon importers. A further investigation of the sectors contributing to carbon flows shows that exports from the mineral, chemicals, metals, oil, transport, and other manufacturing sectors are the main cause of carbon outflows, while the intermediate inputs of the electricity and transport sectors are the primary cause of carbon outflows due to export production. Moreover, we propose an intensity-based shared responsibility strategy and find that China should take the most responsibility because it is responsible for nearly 32% of all embodied emissions, due to its less efficient and high carbon-intensive technologies. The USA and the EU follow China, with shares of 13.2% and 11.3%, respectively, owing to their heavy consumption. As a result, China and the USA contribute 31.8% and 20.6%, respectively, of the total global emissions, outweighing the aggregated contribution from all other countries/regions.

Are Developed Regions in China Achieving Their CO2 Emissions Reduction Targets on Their Own?—Case of Beijing

The extensive and close economic linkages among different regions of China have effects not only on regional economic growth, but also on CO2 emissions and carbon leakage among regions. Taking Beijing as a study case, we constructed MRIO models for China’s 30 provinces and municipalities for 2002, 2007 and 2010, to measure the embodied CO2 emissions in the interregional trade of China on regional and industrial levels to explore their changes over time, and to analyze the driving forces of the final demand-induced interregional CO2 emissions through an SDA model. Results showed that Beijing was a surplus region for embodied carbon and the net input embodied CO2 emissions were in industries with high CO2 emission coefficients, while the net output embodied carbon was in industries with low carbon-emission coefficients. Beijing’s trade with non-Beijing areas led to an increase in the total CO2 emissions in China and a composite effect of Beijing and the efficiency effect of non-Beijing areas were the main effects behind the reduction of Beijing’s input embodied carbon. The results have yielded important implications for China’s CO2 emissions control: first, the embodied CO2 need be taken into consideration when formulating CO2 emissions control measures; second, CO2 emission reduction requirements should be reasonably distributed across the provinces to reduce carbon leakage in interprovincial trade; third, the consumption structure in the production chain needs to be moderately adjusted; and last but not least, financial and technical support for CO2 emissions control in the central and western provinces should be strengthened.

Contribution to sustainable seismic design of reinforced concrete members through embodied CO2 emissions optimization

The embodied CO2 emissions of reinforced concrete (RC) structures can be significantly reduced by structural optimization that maximizes structural efficiency. Previous studies dealing with design of RC structures for minimum CO2 emissions do not address seismic design provisions. This is the case despite the fact that in many countries around the world, including most of the top 10 countries in CO2 emissions from cement production, RC structures have to be designed against earthquake hazard. To fill a part of this gap, this study, using exhaustive search, examines optimum designs of RC beam and column members for minimum embodied CO2 emissions according to Eurocode‐8 for all ductility classes and compares them with optimum designs based on material cost. It is shown that seismic designs for minimum CO2 footprint lead to less CO2 emissions but are more expensive than minimum cost designs. Their differences strongly depend on the assumed values of the environmental impact of reinforcing steel and concrete materials. Furthermore, it is concluded that seismic design for high ductility classes can drive to significant reductions in embodied CO2 emissions.

Sustainable energy and CO2 reduction policy in Thailand: An input–output approach from production- and consumption-based perspectives

Energy shortages and CO2 emissions reductions are critical contemporary challenges for Thailand. A consumption-based analysis provides crucial information that enables policymakers to more comprehensively understand the hidden contributors of energy demand and CO2 in the economy. The other manufacturing, construction and food and beverage sectors were amongst the five largest contributors to energy use and emissions in both 2000 and 2010, based on a consumption perspective. However, these sectors have been neglected by energy conservation and climate change mitigation policies in Thailand because they were the least energy-intensive sectors per government energy reports from 1995 to 2015. The CO2 emissions burden from exports was almost 50% of Thailand's national CO2 inventory in 2000 and 2010. The embodied CO2 emissions results revealed that Thailand could reduce its emissions inventory by 12% and 13% if embodied imports replaced exports in 2000 and 2010, respectively. Furthermore, the leading gross domestic product-generating industries in Thailand are seriously vulnerable to natural gas and crude oil shortages despite some sectors using them in small proportions in their production processes. Energy and emissions policies should better reflect consumption characteristics to increase the potential of energy-saving interventions and CO2 mitigation.