在米奥森晚期,北极的温暖和格陵兰岛北部记录的陆地气候被认为是主题
Gina E Moseley1, Gabriella Koltai1, Jonathan L Baker1
1Institute of Geology, University of Innsbruck, Innsbruck, Austria.
Nature geoscience
|December 11, 2025
概括
在格陵兰岛北部永久土缺失的证据表明,中期米奥森的北极变暖发生在温和的二氧化碳水平下. 这一时期出现了短暂的冰川和海冰扩张,突显了北极气候的敏感性.
科学领域:
- 古气候学 古气候学
- 北极气候动态 北极气候动态
- 新生气候气候演变的演变
背景情况:
- 中新世纪末期是理解过渡到全球气候变冷和北半球冰期的关键时期.
- 在此期间,陆地北极的气候敏感性仍然受到很小的约束.
- 了解永久土的动态是重建过去北极环境的关键.
研究的目的:
- 使用洞穴记录重建东北格陵兰的晚期米奥森陆地气候.
- 研究大气中的二氧化碳,温度和永久土的稳定性之间的关系.
- 为了确定气候变化和冰川活动的驱动因素,在中新世纪晚期.
主要方法:
- 来自格陵兰北部东部 (Kalaallit Nunaat) 的洞穴动物的分析.
- 测定洞穴长期的日期,以确定环境变化的时间表.
- 微量元素分析,以识别环态输入和推断冰川活动.
- 考古温度和大气二氧化碳水平的重建.
主要成果:
- 证据表明永久土在10-5万年之间没有存在,这表明平均年气温比现在高14°C.
- 永久土缺失发生在大气二氧化碳度高于~310 ppm和当地海面温度异常>2°C的情况下.
- 环状微量元素峰值在6.3和5.6万年前,表明格陵兰北部的短暂冰川.
- 气候变化主要是由斜率驱动的,在早期的中新世纪晚期与南极洲有潜在的反相.
- 在短暂的冰川 - 间冰川周期期间,海冰的峰值延伸度约为5.6亿年前.
结论:
- 北极气候系统,包括永久土,对温和的二氧化碳水平很敏感.
- 北格陵兰在中度二氧化碳条件下经历了显著的变暖和永久土融化,在中期米奥森时期.
- 轨道强迫在中新世纪晚期的气候变化和区域北极反应中发挥了关键作用.
- 这项研究为北半球冰川化前奏提供了关键的见解.
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