Analysis of carbon emission differences between Chinese and Japanese buildings based on qualitative and quantitative comparisons

Abstract

As the world's largest carbon emitter, China's building-related carbon emissions contributed to 50.9 % of the country's total carbon emissions in 2020, making it an important area for carbon reduction. In contrast, Japan, one of the world's most energy-efficient nations, has already achieved carbon peaking. To further clarify the current status of China's building carbon emissions and explore a reasonable path for reducing them, this study applied life cycle assessment to analyze the differences in carbon emissions from buildings in China and Japan. Firstly, the impact of five factors (climate environment, building structure, energy structure, population and economy) on the carbon emissions of buildings was assessed qualitatively. Secondly, example calculation and statistical analysis were used to quantitatively compare the carbon emissions of office buildings in China and Japan at the embodied carbon emission, operation, and demolition stages. In the example calculation, the total carbon emissions of the Chinese case are smaller than those of Japan, with the embodied carbon emissions, operation, and demolition carbon emissions are 1.23 times, 0.8 times, and 0.89 times higher than those of Japan respectively. And the statistical results show that the average value of carbon emissions in the Chinese case is larger than that of Japan, and the embodied carbon emissions, operation, and demolition carbon emissions are 1.54 times, 1.29 times, and 2.46 times of Japan respectively. The operation phase contributes 70 % of the difference in carbon emissions, with the nuclear shutdown leading to fluctuations in the carbon emission factor of electricity being the key to the opposite conclusion of the two comparisons. In addition, China has made a lot of efforts to save energy and develop clean energy, and Japan's operation energy consumption is 1.2–2.9 times higher than China's. Finally, recommendations are made in terms of energy saving, carbon reduction, and public awareness.