Inconsistencies when applying novel metrics for emissions accounting to the Paris agreement
Inconsistencies when applying novel metrics for emissions accounting to the Paris agreement
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DOI：
10.1088/1748-9326/ab56e7
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发表时间：
2019-12-01
影响因子：
6.7
通讯作者：
Rogelj, Joeri
中科院分区：
文献类型：
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作者：
Schleussner, Carl-Friedrich;Nauels, Alexander;Rogelj, Joeri
应对非二氧化碳温室气体的排放是有效缓解气候变化的一个组成部分，因此也是气候政策的重要组成部分。衡量标准用于汇总和比较短期和长期温室气体的排放，并需要考虑到其气候影响的大小和持久性的差异。不同的衡量标准描述了不同的方法和视角，因此产生了不同的温室气体总排放量的数字估计。因此，在解释温室气体减排目标时，牢记基本的计量选择是至关重要的。在这里，我们介绍了最近提出的与二氧化碳强制当量排放概念有关的温室气体指标(称为GWP*)将对《巴黎协定》的内部一致性和环境完整性产生的影响。我们表明，用GWP*这样与IPCC第五次评估报告中使用的标准指标显著不同的指标来解释《巴黎协定》的目标，可能会导致该协定的缓解架构出现严重的不一致。它甚至可能完全破坏《协定》缓解目标的完整性，因为它无法实现净零二氧化碳排放，从而无法确保停止变暖。我们的结果表明，在应用科学上看似有利于预先存在的气候政策背景的新概念时，需要非常谨慎。
Addressing emissions of non-CO2 greenhouse gases (GHGs) is an integral part of efficient climate change mitigation and therefore an essential part of climate policy. Metrics are used to aggregate and compare emissions of short- and long-lived GHGs and need to account for the difference in both magnitude and persistence of their climatic effects. Different metrics describe different approaches and perspectives, and hence yield different numerical estimates for aggregated GHG emissions. When interpreting GHG emission reduction targets, being mindful of the underlying metrical choices thus proves to be essential. Here we present the impact a recently proposed GHG metric related to the concept of CO2 forcing-equivalent emissions (called GWP*) would have on the internal consistency and environmental integrity of the Paris Agreement. We show that interpreting the Paris Agreement goals in a metric like GWP* that is significantly different from the standard metric used in the IPCC Fifth Assessment Report can lead to profound inconsistencies in the mitigation architecture of the Agreement. It could even undermine the integrity of the Agreement's mitigation target altogether by failing to deliver net-zero CO2 emissions and therewith failing to ensure warming is halted. Our results indicate that great care needs to be taken when applying new concepts that appear scientifically favourable to a pre-existing climate policy context.