Slowing down as an early warning signal for abrupt climate change
Slowing down as an early warning signal for abrupt climate change
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DOI：
10.1073/pnas.0802430105
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发表时间：
2008-09-23
影响因子：
11.1
通讯作者：
Held, Hermann
中科院分区：
文献类型：
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作者：
Dakos, Vasilis;Scheffer, Marten;Held, Hermann
在地球的历史上，相对稳定的气候时期经常被突然转变成一种对比鲜明的状态所打断。对这种突变事件的一种解释是，它们发生在地球系统达到临界点时。然而，这仍然很难证明遥远过去的事件，更难预测我们是否以及何时可能达到未来突然气候变化的临界点。在这里，我们分析了八个古代突然的气候变化，并表明它们都是在实际变化之前开始的波动特征减缓。这种减缓，以增加的自相关性来衡量，可以在数学上证明是临界点的标志。因此，我们的结果意味着独立的经验证据，证明过去的突然转变与临界阈值的通过有关。由于导致减速的机制是临界点所固有的，因此我们检测减速的方法可能被用作即将到来的灾难性变化的通用预警信号。众所周知，生态系统和其他复杂系统的临界点很难以其他方式预测，因此这是一个有希望的观点。
In the Earth's history, periods of relatively stable climate have often been interrupted by sharp transitions to a contrasting state. One explanation for such events of abrupt change is that they happened when the earth system reached a critical tipping point. However, this remains hard to prove for events in the remote past, and it is even more difficult to predict if and when we might reach a tipping point for abrupt climate change in the future. Here, we analyze eight ancient abrupt climate shifts and show that they were all preceded by a characteristic slowing down of the fluctuations starting well before the actual shift. Such slowing down, measured as increased autocorrelation, can be mathematically shown to be a hallmark of tipping points. Therefore, our results imply independent empirical evidence for the idea that past abrupt shifts were associated with the passing of critical thresholds. Because the mechanism causing slowing down is fundamentally inherent to tipping points, it follows that our way to detect slowing down might be used as a universal early warning signal for upcoming catastrophic change. Because tipping points in ecosystems and other complex systems are notoriously hard to predict in other ways, this is a promising perspective.