Characterizing half-a-degree difference: a review of methods for identifying regional climate responses to global warming targets
Characterizing half-a-degree difference: a review of methods for identifying regional climate responses to global warming targets
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DOI：
10.1002/wcc.457
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发表时间：
2017-03-01
影响因子：
9.2
通讯作者：
Conway, Declan
中科院分区：
文献类型：
--
作者：
James, Rachel;Washington, Richard;Conway, Declan
《巴黎协定》的长期全球气温目标指的是两个全球变暖水平：远低于2摄氏度和高于工业化前1.5摄氏度。然而，特定全球变暖水平的区域气候信号，特别是1.5摄氏度和2摄氏度之间的差异，并没有得到很好的限制。特别是，与评估这些差异有关的方法学挑战受到的关注有限。本文回顾了识别与全球温度极限相关的区域气候信号的替代方法，并评估了它们在多大程度上构成影响分析的合理基础。概述了四种方法，包括比较来自不同温室气体情景的数据，根据全球温度响应选择气候模式，模式缩放，以及在每次全球温度增量时提取异常。这些方法很少用于比较2摄氏度和1.5摄氏度，但有些方法展示了有用研究的潜在途径。然而，在使用现有的气候模型实验方面存在着方法上的挑战，这些实验通常是为了模拟对不同水平的温室气体强迫的反应，而不是模拟对针对特定全球温度变化水平的特定强迫水平的气候反应。可能需要新的方法来解决政策问题，特别是：区分半度升温增量，同时考虑不同的不确定性来源;研究区域气候变化的机制，包括非线性反应的潜力;探索气候系统中时滞过程与排放量下降的相关性，以及由此产生的对替代缓解途径的敏感性。(C)2017作者WIREs Climate Change由Wiley Periodicals，Inc出版。
The Paris Agreement long-term global temperature goal refers to two global warming levels: well below 2 degrees C and 1.5 degrees C above preindustrial. Regional climate signals at specific global warming levels, and especially the differences between 1.5 degrees C and 2 degrees C, are not well constrained, however. In particular, methodological challenges related to the assessment of such differences have received limited attention. This article reviews alternative approaches for identifying regional climate signals associated with global temperature limits, and evaluates the extent to which they constitute a sound basis for impacts analysis. Four methods are outlined, including comparing data from different greenhouse gas scenarios, sub-selecting climate models based on global temperature response, pattern scaling, and extracting anomalies at the time of each global temperature increment. These methods have rarely been applied to compare 2 degrees C with 1.5 degrees C, but some demonstrate potential avenues for useful research. Nevertheless, there are methodological challenges associated with the use of existing climate model experiments, which are generally designed to model responses to different levels of greenhouse gas forcing, rather than to model climate responses to a specific level of forcing that targets a given level of global temperature change. Novel approaches may be required to address policy questions, in particular: to differentiate between half degree warming increments while accounting for different sources of uncertainty; to examine mechanisms of regional climate change including the potential for nonlinear responses; and to explore the relevance of time-lagged processes in the climate system and declining emissions, and the resulting sensitivity to alternative mitigation pathways. (C) 2017 The Authors. WIREs Climate Change published byWiley Periodicals, Inc.