Alternative 鈥淕lobal Warming鈥?Metrics in Life Cycle Assessment: A Case Study with Existing Transportation Data

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• 作者：Glen P. Peters ; Borgar Aamaas ; Marianne T. Lund ; Christian Solli ; Jan S. Fuglestvedt
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：October 15, 2011
• 年：2011
• 卷：45
• 期：20
• 页码：8633-8641
• 全文大小：1186K
• 年卷期：v.45,no.20(October 15, 2011)
• ISSN：1520-5851

文摘

The Life Cycle Assessment (LCA) impact category 鈥済lobal warming鈥?compares emissions of long-lived greenhouse gases (LLGHGs) using Global Warming Potential (GWP) with a 100-year time-horizon as specified in the Kyoto Protocol. Two weaknesses of this approach are (1) the exclusion of short-lived climate forcers (SLCFs) and biophysical factors despite their established importance, and (2) the use of a particular emission metric (GWP) with a choice of specific time-horizons (20, 100, and 500 years). The GWP and the three time-horizons were based on an illustrative example with value judgments and vague interpretations. Here we illustrate, using LCA data of the transportation sector, the importance of SLCFs relative to LLGHGs, different emission metrics, and different treatments of time. We find that both the inclusion of SLCFs and the choice of emission metric can alter results and thereby change mitigation priorities. The explicit inclusion of time, both for emissions and impacts, can remove value-laden assumptions and provide additional information for impact assessments. We believe that our results show that a debate is needed in the LCA community on the impact category 鈥済lobal warming鈥?covering which emissions to include, the emission metric(s) to use, and the treatment of time.