北极洞穴揭示了北半球近乎没有永久化的北半球在米奥生晚期
Anton Vaks1, Andrew Mason2, Sebastian F M Breitenbach3
1Geochemistry and Environmental Geology Division, Geological Survey of Israel, Jerusalem, Israel.
Nature communications
|July 2, 2025
概括
北极永久土在多特纪晚期 (大约870万年前) 基本上不存在,当时区域温度明显变暖. 这一发现表明,未来的变暖可能会消除北半球的永久土,并释放大量的碳.
科学领域:
- 古气候学 古气候学
- 永久土科学 永久土科学
- 地质化学 地质化学
背景情况:
- 北极的变暖速度是全球平均速度的近四倍.
- 估计长期永久土动态需要古气候代理数据超出当今的融化监测.
- 连续的永久土目前在西伯利亚北部防止洞穴碳酸盐 (洞穴) 的形成.
研究的目的:
- 为了重建北半球过去的永久土条件.
- 为了确定北半球何时主要没有永久土.
- 为预测永久土范围的气候模型提供经验数据.
主要方法:
- 来自西伯利亚北部一个洞穴的洞穴生物的分析.
- 洞穴物质的-年代测定,以确定生长周期.
- 使用洞穴地球化学重建古气温.
主要成果:
- 洞穴研究表明,在托尔顿晚期 (8.68±0.09亿年前) 阶段,永久土并不存在.
- 该地区的平均年气温 (MAAT) 在此期间为6.6°C至11.1°C.
- 这种变暖发生在全球MAAT大约比现代水平高4.5°C时.
结论:
- 升温到晚期的托尔顿气温将使北半球大部分永久土无冰.
- 这种变暖可能会从融化永久土中释放高达130百克的碳.
- 这种永久土的碳反可以显著提高全球变暖.
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