Points at Issue for Assessing Contribution of Products on Avoided Greenhouse Gas Emissions

Abstract

While depressing greenhouse gas emissions has become a common target for human society to tackle climate change, it may not necessarily be efficient that all of the sectors aim to achieve the reduction of greenhouse gas emissions by only themselves from the aspect of investment efficiency. When an intermediate product（like a semi-conductor）is developed to achieve high performance, production of the intermediate product may emit more emissions than conventional ones. Meanwhile it may achieve to reduce emissions after being incorporated into final products due to its high performance. Thus, such efforts on technological development should be appropriately evaluated and life cycle thinking will play a very significant role in the assessment of the contribution to avoided emissions. At this point, the published “Guideline for assessing contribution of products on avoided greenhouse gas emissions” by the Institute of Life Cycle Assessment, Japan will be helpful for practitioners to understand the principle and framework for the assessment. On the other hand, there will be more specific points at issue for assessing contribution on avoided greenhouse gas emissions in practice because the targets of the assessment may be varied types of products not only final products but also intermediate materials/parts and services. In this article, important points to be discussed are raised and outlined by mainly focusing on the procedure of the assessment. Regarding intermediate products（materials/parts）, identifying final products and functional unit is very influential in the results of the assessment as same as the estimation of amounts of final products in use and contribution rate of the target. In the case of durable final products, the definition of base-line may particularly lead to high uncertainty of the results because of the diversity of final products for comparison. In terms of data collection, the fairness in collecting background and foreground data shall be completely assured for both of target products and base-line. In addition, these processes shall be transparently explained in reporting phase. Application in practice will be expected to deepen discussions about points raised in this article.