Greenhouse Gas Emission Reductions by Reusing and Recycling Used Clothing in Japan

According to the Ellen MacArthur Foundation, 73% of used clothing is landfilled or incinerated globally and greenhouse gas (GHG) emissions from fabric manufacturing in 2015 amounted to 1.2 billion tons. It must be reduced in the future, especially by reusing and recycling used clothing. Based on this perspective, researchers calculated the energy consumption and GHG emissions associated with reusing and recycling used clothing globally with a life cycle assessment (LCA). However, no study was conducted so far to estimate the total GHG emission reductions in Japan by reusing and recycling used clothing. In this study, the amount of used clothing currently discharged from households as combustible and noncombustible waste and their fiber types were estimated using literature. Then, the methods for reusing and recycling of used clothing were categorized into the following 5 types based on fiber type, that is, “reuse overseas,” “textile recycling to wipers,” “fiber recycling,” “chemical recycling” and “thermal recycling.” After that, by applying LCA, the GHG emission reductions by above 5 methods were estimated, based on the annual discharged weights of each fiber type. Consequently, the total GHG emissions reductions by reusing and recycling 6.03 × 10 8 kg of used clothing totally were estimated around 6.60 × 10 9 kg CO 2e , to range between 6.57 × 10 9 kg CO 2e and 6.64 × 10 9 kg CO 2e , which depended on the type of “chemical recycling.” The largest contribution was “reuse overseas,” which was 4.01 × 10 9 kg CO 2e corresponded to approximately 60% of the total reduction. Where, it was assumed that used clothing were exported from Japan to Malaysia which was currently the largest importing country. In this case, GHG emissions to manufacture new clothing in China, the largest country currently to export them to Japan, can be avoided, which are 29.4 kg CO 2e and 32.5 kg CO 2e respectively for 1 kg jeans and 1 kg T-shirts. Adding the GHG emissions for overseas transportation to this, on average, 32.0 kg CO 2e per kg of used clothing was reduced by “reuse overseas,” which was 19.6 times larger than GHG emissions by incineration, 1.63 kg CO 2e per kg, in which carbon neutrality for cotton was not counted. As the result, the total GHG emission reductions above mentioned, around 6.60 × 10 9 kg CO 2e , corresponds to 70% of the GHG emissions by incineration of total household garbage in Japan.