Zhang Zhifeng, Huang Yongjian, Ma Chao, Yin Qiuzhen, Yang Hanfei, Lee Eun Young, Cheng Hai, Sames Benjamin, Wagreich Michael, Wang Tiantian, Liu Qingping, Wang Chengshan
State Key Laboratory of Geomicrobiology and Environmental Changes, China University of Geosciences, Beijing, China.
School of Earth Sciences and Resources, China University of Geosciences, Beijing, China.
Nat Commun. 2025 Aug 28;16(1):8043. doi: 10.1038/s41467-025-63403-4.
Earth's climate has been dominated by 100-kyr glacial cycles over the past ~800 ka, yet the mechanism remains debated. Here, we present correlation analyses of spectral power ratios of global records spanning the past 2.7 Ma, revealing a persistent anticorrelation between ~21-kyr and ~100-kyr power ratios, but no significant relationship between ~41-kyr and ~100-kyr power ratios. This suggests that ~100-kyr climate cycles are more related to eccentricity-modulated precession than to obliquity. Phase analyses of benthic δO/ice volume and δC (carbon cycle) since Antarctic glaciation onset (34 Ma) show that strong 100-kyr cycles emerged only when these proxies were phase-coupled. Such coupling recurred at ~2.4-Myr eccentricity maxima during the unipolar regime (before 7.5 Ma) and minima during the bipolar regime (after 4 Ma), explaining the persistent ~21-kyr/100-kyr anticorrelation because eccentricity modulates precession amplitude. We propose that internal carbon cycle dynamics and ~2.4-Myr eccentricity-modulated δ¹⁸O/ice volume-δ¹³C coupling amplified ~100-kyr climate cycles not only over the past ~800 ka but since 34 Ma. Given that eccentricity will remain low for the next 400 kyr, ~100-kyr periodicities may continue to dominate future climate variability, assuming Earth remains in a bipolar regime.
在过去约80万年里，地球气候一直受约10万年的冰川周期主导，但其机制仍存在争议。在此，我们展示了对过去270万年全球记录的谱功率比进行的相关性分析，结果显示约2.1万年与约10万年的功率比之间存在持续的反相关性，但约4.1万年与约10万年的功率比之间没有显著关系。这表明约10万年的气候周期与偏心率调制的岁差更相关，而非与倾角相关。自南极冰川作用开始（约3400万年前）以来，对底栖δO/冰量和δC（碳循环）的相位分析表明，只有当这些指标相位耦合时，强烈的约10万年周期才会出现。这种耦合在单极状态（750万年前之前）的约240万年偏心率最大值和约400万年后双极状态的最小值时反复出现，解释了持续的约2.1万年/约10万年反相关性，因为偏心率调制了岁差幅度。我们提出，内部碳循环动力学和约240万年偏心率调制的δ¹⁸O/冰量 - δ¹³C耦合不仅在过去约80万年里，而且自3400万年前以来放大了约10万年的气候周期。鉴于在接下来的40万年里偏心率将保持较低水平，假设地球仍处于双极状态，约10万年的周期性可能会继续主导未来的气候变化。
