Relationship between Self-sufficiency Rate of Food and CO₂ Emission in Japan

Abstract

LCA inventory data based on input-output tables was used to analyze the relationship between the self-sufficiency rate of food and CO₂ emission in Japan. For food item i with the total consumption C_i [M\] and self-sufficiency rate x_i, the total amount of CO₂ emission is composed of (1) domestic production of i, (2) production of industrial product j to be exported for the import of i, and (3) transportation to export j and import i. According to this model, an effective carbon emission coefficient, σ_eff, _{i, j}, was calculated for food item i by assuming the industrial item j to be exported. Then, σ_eff, _{i, j}was averaged among j proportionally to their amount of annual export statistics and the effective carbon emission coefficient σ_eff, ⁱ was calculated for each food item.
Because of the low self-sufficiency rate of food (-40%), the amount of carbon emission was proved to have substantially increased in Japan. The self-sufficiency rate of food based on C-emission is only 13.6% in Japan. The difference between the present C-emission and that by assuming 100% food self-sufficiency easily reached the goal to reduce CO₂ emission by COP3. This means that an increase in food self-sufficiency rate can be an effective option to reduce CO₂ emission in Japan.