• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.155-156
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• 2023

This study aims to analyze the factors that cause differences in the evaluation results of the life cycle carbon emissions assessment of buildings in both Korea and China as part of the methodology research of building life cycle assessment for Chinese buildings to promote building life cycle assessment in China. Specifically, it examines the building LCA standards of Korea and the standard for building carbon emission calculation in China as mentioned in the green building certification systems of both countries. Based on the investigation of the two standards, the life cycle carbon emissions of the evaluation target building were evaluated using the building life cycle assessment methods of both countries, and the influencing factors that cause differences in the life cycle carbon emission assessment results of the two countries were analyzed.

• Journal of Environmental Science International
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• v.11 no.8
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• pp.773-781
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• 2002

The natural carbon cycle has been perturbed since the mid-19th century by anthropogenic CO$_2$emissions from fossil fuel combustion and deforestation due to population growth and industrialization. The current study simulated the global carbon cycle for the past 42 years using an eight-box carbon cycle model. The results showed that since the terrestrial biospheric carbon sink was roughly offset by the deforestation source, the fossil fuel emission source was partitioned between the atmospheric and oceanic sinks. However, the partitioning ratio between the atmosphere and the ocean exhibited a change, that is, the carbon accumulation rate was faster in the atmosphere than in the ocean, due to a decrease in the so-called ocean buffering capacity. It was found that the ocean buffering capacity to take up excess CO$_2$decreased by 50% in terms of the buffer factor over the past 42 years. Accordingly, these results indicate that if the current CO$_2$emission trend continues, the future rate of increase in the atmospheric CO$_2$concentration will accelerate.

• Journal of The Korean Association For Science Education
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• v.40 no.3
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• pp.237-251
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• 2020

Issues on climate change we are facing, such as global warming, are very important as it affects our lives directly. To overcome this, efforts to reduce greenhouse gases emissions (e.g., carbon dioxide) are necessary and these efforts should be based on our integrated understanding of carbon cycle. The purpose of this study is to examine the research trend on carbon cycle education and to suggest the value and direction of carbon cycle education for students who will be citizens of the future. We analyzed 52 carbon cycle education related studies collected from academic research databases (RISS, KCI, ERIC, Google Scholar, and others). As a result, we conclude that resources are still limited and more researches on verification and utilization of developed program, development of accurate and comprehensive tools for students' recognition and level assessment, developing educational model or teacher professional development, providing more appropriate curriculum resources, and the use of various topics or materials for carbon cycle education are necessary. Students' comprehensive understanding of the carbon cycle is important to actively react to the changes in the global environment. Therefore, to support such learning opportunities, resources that can be connected to students' daily experiences to improve students' understanding of carbon cycle and replace misconceptions based on the verification of existing programs should be provided in the classroom as well as the curriculum. In addition, sufficient exemplary cases in carbon cycle education including various materials and topics should be provided through professional development to support teachers teaching strategies with carbon cycle.

• KIEAE Journal
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• v.14 no.1
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• pp.49-57
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• 2014

Global warming has become a major issue all over the world. Noting the carbon dioxide emissions as a main contributor to global warming, we studied on the methods to reduce the life cycle building carbon emissions. Green Building Certification Criteria(GBCC) has been implemented since 2002 in Korea, but it doesn't estimate the quantities of the $CO_2$ emissions. Therefore, we studied the ways to implement the $CO_2$ emissions in quantity to GBCC. We select a government building which was rated excellent by the GBCC. This office building was regarded to excellent building by GBCC but not good for energy consumption. It was found energy glutton buildings for research by the Ministry of Public Administration and Security in 2010. This part of GBCC is need to be improved.. Also LCA (Life Cycle assessment) was carried out to estimate on carbon footprint on this office building. So we need to implementing quantitative evaluation on the amount of carbon emissions by GBCC. And it is possible to implementing quantitative evaluation on the amount of carbon emissions. Through this study, we expect that quantitative assessment of life cycle carbon emissions of buildings by the GBCC. Also expect to reduce the carbon emissions of the building by improving the GBCC.

• International Journal of High-Rise Buildings
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• v.6 no.4
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• pp.333-343
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• 2017

Across the world, building energy codes are becoming stricter, demanding higher levels of energy performance with each issuance. Some locations have taken initiatives to eliminate operational emissions altogether by requiring buildings to be carbon neutral. However, while the objectives of carbon neutrality are without doubt statement worthy, we believe that once operational performance has been tackled to a reasonable level of performance the sights should be trained on a different objective-life; cycle carbon. This paper defines what we mean by life cycle carbon neutrality and presents an approach toward reducing it.

• Journal of Science Education
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• v.37 no.1
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• pp.157-169
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• 2013

The purpose of this study is to analyze carbon cycle concepts based on earth systems from the perspective of high school students. The subjects for this study were seven students who have completed Earth-science I curriculum. to analyze of carbon cycle concepts based on earth systems perspective, the methods of word association, casual map and drawing were used. The results of this study were as follows: first, 5 out of 7 students have suggested carbon cycle concepts less than three. Second, the carbon cycle concepts on the change of state were 2. Also, the carbon cycle concets on process were 8. Third, 2 out of 7 students present 2 feedback loops, 3 out of 7 students 1 feedback loops, but 2 out of 7 students couldn't present the feedback loops associated with carbon cycle. Finally, As for carbon cycle concepts through drawing, 1 out of 7 students drew 9 concepts, 3 out of 9 students drew 7 concepts and the rest of them drew 5, 4, 3 concepts respectively. These results suggest that concept and feedback loop thinking skills on carbon cycle are a low level. Therefore, It is suggested that more educational programs be developed on various topics in order for high school students to improve their system thinking skills as well as knowledge integration of earth systems.

• Journal of Ecology and Environment
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• v.42 no.1
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• pp.20-29
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• 2018

Background: For various reasons such as agricultural and economical purposes, land-use changes are rapidly increasing not only in Korea but also in the world, leading to shifts in the characteristics of local carbon cycle. Therefore, in order to understand the large-scale ecosystem carbon cycle, it is necessary first to understand vegetation on this local scale. As a result, it is essential to comprehend change of the carbon balance attributed by the land-use changes. In this study, we attempt to understand accumulated soil carbon (ASC) and soil respiration (Rs) related to carbon cycle in two ecosystems, artificially turned forest into pastureland from forest and a native deciduous temperate forest, resulted from different land-use in the same area. Results: Rs were shown typical seasonal changes in the alpine pastureland (AP) and temperate deciduous forest (TDF). The annual average Rs was $160.5mg\;CO_2\;m^{-2}h^{-1}$ in the AP, but it was $405.1mg\;CO_2\;m^{-2}h^{-1}$ in the TDF, indicating that the Rs in the AP was lower about 54% than that in the TDF. Also, ASC in the AP was $124.49Mg\;C\;ha^{-1}$ from litter layer to 30-cm soil depth. The ASC was about $88.9Mg\;C\;ha^{-1}$, and it was 71.5% of that of the AP. The temperature factors in the AP was high about $4^{\circ}C$ on average compared to the TDF. In AP, it was observed high amount of sunlight entering near the soil surface which is related to high soil temperature is due to low canopy structure. This tendency is due to the smaller emission of organic carbon that is accumulated in the soil, which means a higher ASC in the AP compared to the TDF. Conclusions: The artificial transformation of natural ecosystems into different ecosystems is proceeding widely in the world as well as Korea. The change in land-use type is caused to make the different characteristics of carbon cycle and storage in same region. For evaluating and predicting the carbon cycle in the vegetation modified by the human activity, it is necessary to understand the carbon cycle and storage characteristics of natural ecosystems and converted ecosystems. In this study, we studied the characteristics of ecosystem carbon cycle using different forms in the same region. The land-use changes from a TDF to AP leads to changes in dominant vegetation. Removal of canopy increased light and temperature conditions and slightly decreased SMC during the growing season. Also, land-use change led to an increase of ASC and decrease of Rs in AP. In terms of ecosystem carbon sequestration, AP showed a greater amount of carbon stored in the soil due to sustained supply of above-ground liters and lower degradation rate (soil respiration) than TDF in the high mountains. This shows that TDF and AP do not have much difference in terms of storage and circulation of carbon because the amount of carbon in the forest biomass is stored in the soil in the AP.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.47-48
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• 2022

In Korea, construction and development has been continued rapidly since the 1970s, and the reconstruction and renovation market has recently been activated to improve old buildings. Most of the environmental evaluation of reconstruction and renovation projects is focused on the use of operating energy, and It is necessary to analyze carbon emissions throughout the life cycle for a comprehensive evaluation of reconstruction and remodeling projects. Therefore, this study quantitatively predicted carbon emissions from reconstruction and renovation based on ISO 14040s through case analysis for the purpose of evaluating the carbon emissions of renovated buildings from the perspective of the whole life cycle. In additional, the amount of carbon savings of each was analyzed through comparison with existing building.

• Plant Journal
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• v.15 no.2
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• pp.42-45
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• 2019

The molten carbonate fuel cell has a high temperature of waste heat and can constitute a bottoming cycle to increase the efficiency. Previous study used a bottoming cycle as steam turbine cycle. In this study, we are going to replace the bottoming cycle with a supercritical carbon dioxide power cycle. The system power was compared to consider replacing the bottoming cycle. As a result, the power of the supercritical carbon dioxide power cycle at the present development stage is lower than that of the steam turbine cycle, but theoretically, the power can be larger than the steam turbine cycle. If the supercritical carbon dioxide power cycle improves the isentropic efficiency of the turbine by 89%, the isentropic efficiency of the compressor by 83%, and the effectiveness of the recuperator by 0.9, the power can be same to the steam turbine cycle.

• Journal of Environmental Science International
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• v.27 no.12
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• pp.1169-1178
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• 2018

Two man-made carbon emissions, fossil fuel emissions and land use emissions, have been perturbing naturally occurring global carbon cycle. These emitted carbons will eventually be deposited into the atmosphere, the terrestrial biosphere, the soil, and the ocean. In this study, Simple Global Carbon Model (SGCM) was used to simulate global carbon cycle and to estimate global carbon budget. For the model input, fossil fuel emissions and land use emissions were taken from the literature. Unlike fossil fuel use, land use emissions were highly uncertain. Therefore land use emission inputs were adjusted within an uncertainty range suggested in the literature. Simulated atmospheric $CO_2$ concentrations were well fitted to observations with a standard error of 0.06 ppm. Moreover, simulated carbon budgets in the ocean and terrestrial biosphere were shown to be reasonable compared to the literature values, which have considerable uncertainties. Simulation results show that with increasing fossil fuel emissions, the ratios of carbon partitioning to the atmosphere and the terrestrial biosphere have increased from 42% and 24% in the year 1958 to 50% and 30% in the year 2016 respectively, while that to the ocean has decreased from 34% in the year 1958 to 20% in the year 2016. This finding indicates that if the current emission trend continues, the atmospheric carbon partitioning ratio might be continuously increasing and thereby the atmospheric $CO_2$ concentrations might be increasing much faster. Among the total emissions of 399 gigatons of carbon (GtC) from fossil fuel use and land use during the simulation period (between 1960 and 2016), 189 GtC were reallocated to the atmosphere (47%), 107 GtC to the terrestrial biosphere (27%), and 103GtC to the ocean (26%). The net terrestrial biospheric carbon accumulation (terrestrial biospheric allocations minus land use emissions) showed positive 46 GtC. In other words, the terrestrial biosphere has been accumulating carbon, although land use emission has been depleting carbon in the terrestrial biosphere.