Causal feedbacks in climate change
Causal feedbacks in climate change
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DOI：
10.1038/nclimate2568
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发表时间：
2015-05-01
影响因子：
30.7
通讯作者：
Sugihara, George
中科院分区：
文献类型：
--
作者：
van Nes, Egbert H.;Scheffer, Marten;Sugihara, George
冰川周期中温度和温室气体之间的统计关联已有很好的记录(1)，但这种关联背后的因果关系仍然很难直接从数据中提取出来。二氧化碳滞后于南极温度的时间滞后--最初被认为暗示温度(2，3)的驱动作用--在最后一次冰川消融时没有(4，5)，但最近在最后一次冰河时代开始(6)和较早的终止II(参考文献2)结束时证实了这一点。7)。我们表明，这种可变时滞对于复杂的非线性系统，如气候，是典型的，禁止直接使用相关滞后来推断原因。然而，动力系统理论的洞察力(8)现在允许我们绕过从多变量时间序列中解开因果关系的经典挑战。我们建立在这一认识的基础上，直接从冰芯数据中证明，在冰川-间冰期时间尺度上，气候动态在很大程度上是由地球系统内部机制驱动的，包括温度变化对温室气体浓度的显著正反馈效应。
The statistical association between temperature and greenhouse gases over glacial cycles is well documented(1), but causality behind this correlation remains difficult to extract directly from the data. A time lag of CO2 behind Antarctic temperature-originally thought to hint at a driving role for temperature(2,3)-is absent(4,5) at the last deglaciation, but recently confirmed at the last ice age inception(6) and the end of the earlier termination II (ref. 7). We show that such variable time lags are typical for complex nonlinear systems such as the climate, prohibiting straightforward use of correlation lags to infer causation. However, an insight from dynamical systems theory(8) now allows us to circumvent the classical challenges of unravelling causation from multivariate time series. We build on this insight to demonstrate directly from ice-core data that, over glacial-interglacial timescales, climate dynamics are largely driven by internal Earth system mechanisms, including a marked positive feedback effect from temperature variability on greenhouse-gas concentrations.