近日，中国科学院青藏高原研究所刘建宝团队揭示了在末次冰消期变暖期间，北方湖泊中明显的甲烷循环与大气中CH4浓度的迅速上升同时发生。这一研究成果发表在2025年7月18日出版的《科学进展》杂志上。
大气甲烷浓度（AMC）在最后一次消冰期激增了约50%，其中北部（>30°N）地区占上升的约40%。然而，包括扩大湖泊、泥炭地和不稳定的永久冻土或水合物在内的假设原因无法解释这种快速增长。
研究组利用生物标志物、同位素和放射性碳数据来重建西藏热岩溶湖的温度变化、甲烷循环和永久冻土融化。放射性碳证据和异常δ13C值（- 80.3 / mil）表明，在新仙女木-前寒武纪过渡时期，古（~2500年）甲烷剧烈循环，与AMC激增和最迅速的增温同时发生。相比之下，在全新世气候最适期，尽管温度达到峰值，但甲烷循环较弱。
这些发现表明，异常高的变暖速率，而不仅仅是绝对温度，可能在触发增强的古甲烷循环中发挥重要作用。快速变暖可能加剧了北部现有湖泊的排放，助长了气候变化，但也明显加剧了北部甲烷的存在，这导致了冰川消融后AMC的突然上升。
附：英文原文
Title: Pronounced methane cycling in northern lakes coincided with a rapid rise in atmospheric CH4 during the last deglacial warming
Author: Xinwei Yan, Jianbao Liu, Wengang Kang, Xianyu Huang, Aifeng Zhou, Lin Chen, Jifeng Zhang, Haoran Dong, Zhitong Chen, Junjie Wu, Henry Holmstrand, Kathleen M. Rühland, John P. Smol, Fahu Chen, rjan Gustafsson
Issue&Volume: 2025-07-18
Abstract: Atmospheric methane concentration (AMC) surged by ~50% during the last deglaciation, with northern (>30°N) sources accounting for ~40% of the rise. However, hypothesized sources including expanding lakes, peatlands, and destabilized permafrost or hydrates fail to explain this rapid increase. We use biomarkers, isotopes, and radiocarbon data to reconstruct temperature change, methane cycling, and permafrost thaw from a Tibetan thermokarst lake. Radiocarbon evidence and ultradepleted δ13C values (80.3 per mil) of methane-diagnostic lipids indicate intense cycling of ancient (~2500-year-old) methane during the Younger Dryas–Preboreal transition, coeval with the AMC surge and the most rapid warming. By contrast, methane cycling was weak during the Holocene Climatic Optimum despite peak temperatures. These findings imply that anomalously high rates of warming, rather than absolute temperature alone, may play an important role in triggering enhanced paleo-methane cycling. Rapid warming likely intensified emissions from existing northern lakes, fueling the elusive yet clearly amplified northern methane source that contributed to the deglacial abrupt rise in AMC.
DOI: adt2561
Source: https://www.science.org/doi/10.1126/sciadv.adt2561