近日，美国俄亥俄州立大学Kara A. Lamantia团队分析了来自热带冰芯的全球大气甲烷记录。2026年8月19日出版的《自然》杂志发表了这项成果。

热带湿地被广泛认为是大气甲烷（CH₄）最大的自然源。然而，关于湿地范围及CH₄产量的不确定性，导致模型模拟的CH₄排放趋势存在较大差异。大多数历史重建依赖于极地冰芯数据，无法完全解析热带对CH₄收支的贡献。

研究组呈现了来自瓦斯卡兰山南峰顶（SCA；南纬9.122°，西经77.605°，海拔6,768米）钻取的冰芯所记录的两千年大气CH₄浓度序列。结果发现，该CH₄记录的趋势和幅度与极地记录大致一致。研究组的δ¹³C-CH₄测量结果（约公元1530年至1999年）与以热带为主要CH₄源的同位素特征值相符。

将该记录集成到一个大气四箱模型中，表明过去两千年间赤道地区的CH₄源强度持续占据主导地位。该研究结果表明，赤道CH₄排放量高于以往仅基于极地冰芯数据的估算，支持了长期以来的假说，即低纬度CH₄排放主导了工业化前（PI）时期的CH₄变化。这些结果证明了热带冰芯在重建CH₄变化及其纬度分布方面的重要性。

附：英文原文

Title: A global atmospheric methane record from a tropical ice core

Author: Lamantia, Kara A., Thompson, Lonnie G., Davis, Mary E., Riddell-Young, Ben, Strawson, Ivo, Beaudon, Emilie, Mosley-Thompson, Ellen, Nguyen, Newton, Brook, Edward J.

Issue&Volume: 2026-08-19

Abstract: Tropical wetlands are widely considered the largest natural source of atmospheric methane (CH4)1,2,3,4. However, uncertainties about wetland extent and CH4 production have led to large variations in modelled CH4 emission trends2,3. Most historical reconstructions rely on data from polar ice cores, which cannot fully resolve the tropical contribution5,6 to the CH4 budget. Here we present a 2,000-year record of atmospheric CH4 concentrations from ice cores drilled from the South Peak summit of Nevado Huascarán (Summit Core A, SCA; 9.122°S, 77.605°W; 6,768m asl). We find that the trends and magnitudes of our CH4 record are broadly consistent with polar records7. Our δ13C-CH4 measurements (from approximately 1530CE to 1999CE) align with isotope values8 consistent with a dominant tropical CH4 source. Integration of our record into an atmospheric four-box model suggests a sustained equatorial dominance of CH4 source strength over the past two millennia. Our findings indicate that equatorial CH4 emissions are higher than previous estimates based only on polar ice core data, supporting the long-standing hypothesis that low-latitude CH4 emissions dominated pre-industrial (PI) CH4 variability5,6. These results demonstrate the importance of tropical ice cores on the reconstruction of CH4 variability and latitudinal distribution.

DOI: 10.1038/s41586-026-10938-1

Source: https://www.nature.com/articles/s41586-026-10938-1