Ricke K L, Millar R J, MacMartin D G
Scripps Institution of Oceanography, UC San Diego, La Jolla, USA.
School of Global Policy and Strategy, University of California, San Diego, La Jolla, USA.
Sci Rep. 2017 Nov 7;7(1):14743. doi: 10.1038/s41598-017-14503-9.
In the aftermath of the Paris Agreement, the climate science and policy communities are beginning to assess the feasibility and potential benefits of limiting global warming to 1.5 °C or 2 °C above preindustrial. Understanding the dependence of the magnitude and duration of possible temporary exceedance (i.e., "overshoot") of temperature targets on sustainable energy decarbonization futures and carbon dioxide (CO) removal rates will be an important contribution to this policy discussion. Drawing upon results from the mitigation literature and the IPCC Working Group 3 (WG3) scenario database, we examine the global mean temperature implications of differing, independent pathways for the decarbonization of global energy supply and the implementation of negative emissions technologies. We find that within the scope of scenarios broadly-consistent with the WG3 database, the magnitude of temperature overshoot is more sensitive to the rate of decarbonization. However, limiting the duration of overshoot to less than two centuries requires ambitious deployment of both decarbonization and negative emissions technology. The dependencies of temperature target overshoot's properties upon currently untested negative emissions technologies suggests that it will be important to consider how climate impacts depend on both the magnitude and duration of overshoot, not just long term residual warming.
在《巴黎协定》之后，气候科学和政策界开始评估将全球变暖限制在比工业化前水平高1.5摄氏度或2摄氏度的可行性和潜在益处。了解温度目标可能出现的暂时超标（即“超调”）的幅度和持续时间对可持续能源脱碳前景以及二氧化碳（CO）去除率的依赖性，将对这一政策讨论做出重要贡献。借鉴减缓文献和政府间气候变化专门委员会第三工作组（WG3）情景数据库的结果，我们研究了全球能源供应脱碳和负排放技术实施的不同独立路径对全球平均温度的影响。我们发现，在与WG3数据库大致一致的情景范围内，温度超调的幅度对脱碳速度更为敏感。然而，将超调持续时间限制在两个世纪以内需要大力部署脱碳和负排放技术。温度目标超调特性对目前未经测试的负排放技术的依赖性表明，重要的是要考虑气候影响如何既取决于超调的幅度又取决于超调的持续时间，而不仅仅是长期的残余变暖。
