Research School of Earth Sciences, The Australian National University, Canberra 2601, Australia; email:
Ocean and Earth Science, University of Southampton, Southampton SO14 3ZH, United Kingdom; email:
Ann Rev Mar Sci. 2018 Jan 3;10:261-288. doi: 10.1146/annurev-marine-121916-063242. Epub 2017 Sep 22.
Climate sensitivity represents the global mean temperature change caused by changes in the radiative balance of climate; it is studied for both present/future (actuo) and past (paleo) climate variations, with the former based on instrumental records and/or various types of model simulations. Paleo-estimates are often considered informative for assessments of actuo-climate change caused by anthropogenic greenhouse forcing, but this utility remains debated because of concerns about the impacts of uncertainties, assumptions, and incomplete knowledge about controlling mechanisms in the dynamic climate system, with its multiple interacting feedbacks and their potential dependence on the climate background state. This is exacerbated by the need to assess actuo- and paleoclimate sensitivity over different timescales, with different drivers, and with different (data and/or model) limitations. Here, we visualize these impacts with idealized representations that graphically illustrate the nature of time-dependent actuo- and paleoclimate sensitivity estimates, evaluating the strengths, weaknesses, agreements, and differences of the two approaches. We also highlight priorities for future research to improve the use of paleo-estimates in evaluations of current climate change.
气候敏感性表示气候辐射平衡变化引起的全球平均温度变化；它既针对当前/未来（实测）气候变化，也针对过去（古气候）变化进行研究，前者基于仪器记录和/或各种类型的模型模拟。古气候估计通常被认为对评估人为温室气体强迫引起的当前气候变化有用，但由于对动态气候系统中控制机制的不确定性、假设和不完整知识的影响的担忧，这种效用仍然存在争议，该系统具有多个相互作用的反馈，其可能依赖于气候背景状态。由于需要评估不同时间尺度、不同驱动因素和不同（数据和/或模型）限制下的实测和古气候敏感性，这种情况更加严重。在这里，我们使用理想化的表示形式来直观地展示时变实测和古气候敏感性估计的性质，评估这两种方法的优缺点、一致性和差异。我们还强调了未来研究的重点，以提高古气候估计在评估当前气候变化中的应用。
