Pliocene Warmth, Polar Amplification, and Stepped Pleistocene Cooling Recorded in NE Arctic Russia
Pliocene Warmth, Polar Amplification, and Stepped Pleistocene Cooling Recorded in NE Arctic Russia
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DOI：
10.1126/science.1233137
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发表时间：
2013-06-21
期刊：
影响因子：
56.9
通讯作者：
Herzschuh, Ulrike
中科院分区：
文献类型：
--
作者：
Brigham-Grette, Julie;Melles, Martin;Herzschuh, Ulrike
由于缺乏连续的、高分辨率的北极时间序列，理解北极极地气候从上新世中期的长期温暖到北半球最早的冰川旋回的演变一直受到阻碍。来自俄罗斯东北部的El‘gytgyn湖的证据表明，360万到340万年前，夏季的温度类似于比今天高8摄氏度，当时二氧化碳的分压类似于百万分之400。多指标证据表明，上新世中期的极端温暖和极地放大，上新世-更新世过渡期间的突然阶梯冷却事件，以及直到220万年前北半球冰川开始后的类似于现在的北极夏季，都比现在的夏季温暖。我们的数据与海平面记录和其他替代数据一致，表明北极的冷却不足以支撑大范围的冰盖，直到早更新世。
Understanding the evolution of Arctic polar climate from the protracted warmth of the middle Pliocene into the earliest glacial cycles in the Northern Hemisphere has been hindered by the lack of continuous, highly resolved Arctic time series. Evidence from Lake El'gygytgyn, in northeast (NE) Arctic Russia, shows that 3.6 to 3.4 million years ago, summer temperatures were similar to 8 degrees C warmer than today, when the partial pressure of CO2 was similar to 400 parts per million. Multiproxy evidence suggests extreme warmth and polar amplification during the middle Pliocene, sudden stepped cooling events during the Pliocene-Pleistocene transition, and warmer than present Arctic summers until similar to 2.2 million years ago, after the onset of Northern Hemispheric glaciation. Our data are consistent with sea-level records and other proxies indicating that Arctic cooling was insufficient to support large-scale ice sheets until the early Pleistocene.