Greenhouse gas emission reduction effect in the transportation sector by urban agriculture in Seoul, Korea

1. Background

Population concentration in cities is contributing to the speed of global warming through encroachment on natural environments and the excessive use of energy. With 91.1% of its people living in cities, Korea has a high urban population concentration ratio. Because of this high urban concentration rate, Korea produces a relatively high amount of CO₂ even in the process of transporting food to urban areas. Moreover, Korea depends on imports for 49.2% of the food consumed by the entire country, showing that the food mileage required for food imports is relatively high compared with other countries. Examined on a 2007 basis, food imports per capita in Korea were 543 kg, higher than the per-capita imports of England, France, and Japan. The food mileage per capita was 6,143 km in Korea, a figure that is 4.2 times that of France and twice that of England.

Food procured independently through urban farming could be an effective alternative to the environmental problems arising from urbanization. In particular, Korea is aggressively fostering urban agriculture as a method of solving environmental problems produced by urbanization. Numerous autonomous local entities have established the Urban Agriculture Ordinance, and the government has also enforced the Act on Fostering and Supporting Urban Agriculture of March 2013. Even socially, urban agriculture is being briskly developed based on the strength of the retirement activities of the baby boom generation, urban agriculture non-governmental organizations (NGOs), and social enterprises.

Urban agriculture enables us not only to supply food, but also to obtain several collateral effects. In particular, urban agriculture produces local food and reduces the mileage required to transport food to consumers. When urban agriculture is implemented, farm-product inflow decreases and GHG emissions also could decrease through the reduction in food mileage that occurs as traffic distances become shorter. When using building rooftops for urban farming, one possible effect is a decrease in energy use for air conditioning and heating because of the greening of a portion of the building. Another possible effect is the cultivation of social, emotional and community well-being through urban agricultural activities. Although numerous studies have examined the widely publicly understood concept of “food miles”, little research has analyzed GHG reduction linked to a decrease in the transport distances of farm products as a result of urban agriculture. This study aims to provide basic data for relevant political decision-making by analyzing the expected GHG reduction effect when urban agriculture is revitalized. In particular, this study focuses on the transportation sector by analyzing the reduction level of CO₂ emissions that primarily contributes to the GHG effect.

2. Methods

The main contributor (80%) to GHG is CO₂. The reduction of CO₂ generation through urban agriculture occur in two ways: first, a reduction in the energy content used for air conditioning and heating by reducing the surface temperature range; second, a reduction in the energy content required for transportation through a reduction in food miles by decreasing the amount of farm products flowing into urban areas. Of these ways, we analyzed the reduction effect in CO₂ emissions related to a reduction in food miles.