近日，中国科学院地质与地球物理研究所赵明宇团队揭示了脉冲生物甲烷排放与托瓦西安海洋缺氧事件期间的间歇性变暖相耦合。该项研究成果发表在2025年9月2日出版的《美国科学院院刊》杂志上。
重建古代气候变暖事件期间的碳释放通量对于改进未来人为变暖情景下的碳循环和气候动力学预测具有重要意义。
研究组分析了大约1.83亿年前的托阿利亚海洋缺氧事件（T-OAE）中生物甲烷释放的程度及其对气候变率的贡献。为此，研究组开发了一个全球生物地球化学模型，并应用了贝叶斯反演主题的马尔可夫链蒙特卡罗（MCMC）模拟。根据约克郡剖面的高分辨率碳同位素偏移记录，该结果表明，至少有4700 Gt碳从生物源CH4中释放出来 (碳同位素组成δ13C为50到70‰)，是准确再现δ13C明显的脉冲位移以及推断的大气pCO2和全球温度变化所必需的。
这种大规模的甲烷释放可能导致大气中pCH4的大幅增加，并导致全球表面进一步变暖，可能超过2°C。研究组进一步阐明，甲烷的释放可能是由甲烷生成的激增以及在富含有机物、硫酸盐枯竭的海洋环境中伴随的甲烷氧化的下降而促进的。活跃的CH4循环代表了一种正反馈机制，在气候变暖事件期间加剧了环境恶化，最终导致海洋生物的大规模灭绝。
附：英文原文
Title: Pulsed biogenic methane emissions coupled with episodic warming during the Toarcian Oceanic Anoxic Event
Author: Qiu, Ruoyuan, Yu, Zhichao, Mills, Benjamin J. W., Huang, Renda, Zhang, Wang, Isson, Terry, Wan, Bo, Zhang, Ruizhen, Zhao, Mingyu, Jin, Zhijun
Issue&Volume: 2025-9-2
Abstract: Reconstructing carbon release fluxes during ancient climatic warming events is important for improving predictions of carbon cycle and climate dynamics under future anthropogenic warming scenarios. We investigate the extent of biogenic methane release and its contribution to climate variability across the Toarcian Oceanic Anoxic Event (T-OAE) approximately 183 million years ago. To do this, we developed a global biogeochemical model and applied a Bayesian inversion using Markov Chain Monte Carlo (MCMC) simulations. Based on a high-resolution record of carbon isotope excursions from the Yorkshire section, our results indicate that a release of at least 4,700 Gt carbon from biogenic CH4 (with a carbon isotopic composition, δ13C of 50 to 70‰) is necessary to accurately reproduce the pronounced pulsed shift in the δ13C, as well as the inferred changes in atmospheric pCO2 and global temperature. This massive methane release may have led to a substantial increase in atmospheric pCH4 and contributed to additional global surface warming, perhaps by more than 2 °C. We further elucidate that the liberation of methane may have been facilitated by an upsurge in methanogenesis alongside a concomitant decline in methane oxidation within organic-rich, sulfate-depleted marine environments. An active CH4 cycle represents a positive feedback mechanism that exacerbates environmental deterioration during climatic warming events, ultimately contributing to mass extinction of marine life.
DOI: 10.1073/pnas.2423598122
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2423598122