千葉県銚子産キャベツのライフサイクルCO₂の試算

抄録

Objective. Displaying carbon footprint (CFP) of foods and daily goods is very important to “visualize” the environmental burden, especially life cycle CO₂ emission, of daily life. The objective in this study is to evoke people’s awareness to the environmental burden in daily life through the calculation of the cabbage’s life cycle CO₂ emission produced in Choshi city, Chiba prefecture. The main reason for selecting cabbage is that cabbage is produced in huge area which attains over 10% of the total land of Choshi city and therefore cabbage brings a great impact on regional environment.
Method. Functional unit is applied to the CO₂ emission per 1kg cabbage. The life cycle stages of cabbage are classified into 5 stages which are divided into 10 processes, and the CO₂ emission value is calculated as the total amount of CO₂ emission from each processes.
Results and Discussion. The calculation results of cabbage’s CO₂ emission was 360.0g-CO₂/kg calculated by standard cultivation method in Choshi area. The CO₂ emission from each life cycle stages are : raw materials procurement stage 36.1 g-CO₂ (component ratio: 10.0%), production stage 92.3 g-CO₂ (25.6%), distribution and selling stage 70.7 g-CO₂ (19.6%), operation and maintenance stage 156.2 g-CO₂ (43.4%), disposal and recycling stage 4.6g-CO₂ (1.3%). The most CO₂ is emitted from cooking process of the maintenance stage, which accounts for over one third of the total CO₂ emission. Therefore, it is very important to choose the cooking method with the least environmental burden.
Conclusions. The CO₂ emission is varies from the calculation conditions based on various producing methods of cabbages. In order to avoid having the varied CO₂ emission in different calculation methods, it is imperative to establish a “product category rule (PCR)” on the calculation method.