Zero emission targets as long-term global goals for climate protection
Zero emission targets as long-term global goals for climate protection
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DOI：
10.1088/1748-9326/10/10/105007
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发表时间：
2015-10-01
影响因子：
6.7
通讯作者：
Hare, William
中科院分区：
文献类型：
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作者：
Rogelj, Joeri;Schaeffer, Michiel;Hare, William
最近的评估将全球平均气温上升的稳定与限制二氧化碳（CO2）排放总量的必要性紧密联系起来。因此，阻止全球变暖需要在某个时刻实现年度二氧化碳排放量几乎为零。政策制定者现已将这一概念纳入新的全球气候协议的谈判文本中，但对于碳中和、气候中和、完全脱碳以及净零碳或净零温室气体（GHG）排放等概念仍然存在困惑。在这里，我们澄清这些概念，讨论它们作为实现温度目标的长期全球基准的适当性，并提供详细的量化。我们发现，根据目前的承诺，以及保持在 2 摄氏度以下的可能性（>66%），情景文献表明 2060 年至 2070 年间二氧化碳净排放量为零，此后二氧化碳净排放量为负。由于残留的非二氧化碳排放，温室气体总排放量总是比二氧化碳排放晚达到净零排放。净零排放目标是政策的有用焦点，它将全球温度目标和社会经济路径与累积二氧化碳排放量的必要长期限制联系起来。
Recently, assessments have robustly linked stabilization of global-mean temperature rise to the necessity of limiting the total amount of emitted carbon-dioxide (CO2). Halting global warming thus requires virtually zero annual CO2 emissions at some point. Policymakers have now incorporated this concept in the negotiating text for a new global climate agreement, but confusion remains about concepts like carbon neutrality, climate neutrality, full decarbonization, and net zero carbon or net zero greenhouse gas (GHG) emissions. Here we clarify these concepts, discuss their appropriateness to serve as a long-term global benchmark for achieving temperature targets, and provide a detailed quantification. We find that with current pledges and for a likely (>66%) chance of staying below 2 degrees C, the scenario literature suggests net zero CO2 emissions between 2060 and 2070, with net negative CO2 emissions thereafter. Because of residual non-CO2 emissions, net zero is always reached later for total GHG emissions than for CO2. Net zero emissions targets are a useful focal point for policy, linking a global temperature target and socio-economic pathways to a necessary long-term limit on cumulative CO2 emissions.