Helama Samuli, Stoffel Markus, Hall Richard J, Jones Phil D, Arppe Laura, Matskovsky Vladimir V, Timonen Mauri, Nöjd Pekka, Mielikäinen Kari, Oinonen Markku
Natural Resources Institute Finland, Ounasjoentie 6, 96200 Rovaniemi, Finland.
Climate Change Impacts and Risks in the Anthropocene (C-CIA), Institute for Environmental Sciences, University of Geneva, Geneva, Switzerland.
Clim Dyn. 2021;56(11-12):3817-3833. doi: 10.1007/s00382-021-05669-0. Epub 2021 Feb 6.
Holocene climate variability is punctuated by episodic climatic events such as the Little Ice Age (LIA) predating the industrial-era warming. Their dating and forcing mechanisms have however remained controversial. Even more crucially, it is uncertain whether earlier events represent climatic regimes similar to the LIA. Here we produce and analyse a new 7500-year long palaeoclimate record tailored to detect LIA-like climatic regimes from northern European tree-ring data. In addition to the actual LIA, we identify LIA-like ca. 100-800 year periods with cold temperatures combined with clear sky conditions from 540 CE, 1670 BCE, 3240 BCE and 5450 BCE onwards, these LIA-like regimes covering 20% of the study period. Consistent with climate modelling, the LIA-like regimes originate from a coupled atmosphere-ocean-sea ice North Atlantic-Arctic system and were amplified by volcanic activity (multiple eruptions closely spaced in time), tree-ring evidence pointing to similarly enhanced LIA-like regimes starting after the eruptions recorded in 1627 BCE, 536/540 CE and 1809/1815 CE. Conversely, the ongoing decline in Arctic sea-ice extent is mirrored in our data which shows reversal of the LIA-like conditions since the late nineteenth century, our record also correlating highly with the instrumentally recorded Northern Hemisphere and global temperatures over the same period. Our results bridge the gaps between low- and high-resolution, precisely dated proxies and demonstrate the efficacy of slow and fast components of the climate system to generate LIA-like climate regimes.
The online version contains supplementary material available at 10.1007/s00382-021-05669-0.
全新世气候变率被诸如小冰期（LIA）等偶发性气候事件打断，小冰期早于工业时代的变暖。然而，它们的年代测定和驱动机制一直存在争议。更关键的是，尚不确定早期事件是否代表与小冰期类似的气候状态。在此，我们生成并分析了一个长达7500年的新古气候记录，该记录专门用于从北欧树木年轮数据中检测类似小冰期的气候状态。除了实际的小冰期，我们还识别出了类似小冰期的约100 - 800年时间段，这些时间段温度较低且天空晴朗，分别始于公元540年、公元前1670年、公元前3240年和公元前5450年，这些类似小冰期的状态覆盖了研究期的20%。与气候模型一致，类似小冰期的状态源自北大西洋 - 北极耦合的大气 - 海洋 - 海冰系统，并因火山活动（多次喷发在时间上紧密间隔）而被放大，树木年轮证据表明，在公元前1627年、公元536/540年和公元1809/1815年记录的喷发之后，类似小冰期的状态同样增强。相反，北极海冰范围的持续下降在我们的数据中得到反映，数据显示自19世纪后期以来类似小冰期的状况发生了逆转，我们的记录也与同期仪器记录的北半球和全球温度高度相关。我们的结果弥合了低分辨率和高分辨率、精确测年的代理数据之间的差距，并证明了气候系统的缓慢和快速成分产生类似小冰期气候状态的效力。
在线版本包含可在10.1007/s00382 - 021 - 05669 - 0获取的补充材料。
