末次盛冰期和消冰期大气甲烷变化主要受热带源控制，这一成果由美国俄勒冈州立大学 Riddell-Young, Ben 和 Rosen, Julia 研究团队经过不懈努力而取得。该项研究成果发表在2023年11月27日出版的《自然—地球科学》上。
该研究团队报告了一个涵盖末次盛冰期和消冰期，具有显著改善的时间分辨率，年代学和对格陵兰样品中甲烷产量的关键校正的冰芯衍生的极间差异记录。利用箱形模式推断纬度强度的变化，研究发现，热带来源主导了消冰期的甲烷突变，突出了它们对气候突变和热带降雨模式快速变化的敏感性。大约16,000年前，北方温带气体排放开始增加，可能是由于高纬度变暖导致的湿地扩张和/或永久冻土退化，并导致甲烷的突然上升，最多贡献了 25 Tg yr-1(占总排放量增加的45%)，这与 Bolling–Allerod 冰期区间开始时北方快速变暖相一致。这些对冰期气候—甲烷循环相互作用的限制，可以提高对当前和未来可能反馈的理解。
据了解，限制过去大气甲烷变化的原因，对于理解甲烷与气候之间的联系非常重要。为此目的，人们对末次消冰期间甲烷的突变进行了深入研究，但高纬度和热带来源的相对重要性仍然缺乏明确的认识。甲烷极间浓度差异反映了过去的地理排放变变化，但现有记录在分析过程中受到了细微但相当大的甲烷产量的影响。
附：英文原文
Title: Atmospheric methane variability through the Last Glacial Maximum and deglaciation mainly controlled by tropical sources
Author: Riddell-Young, Ben, Rosen, Julia, Brook, Edward, Buizert, Christo, Martin, Kaden, Lee, James, Edwards, Jon, Mhl, Michaela, Schmitt, Jochen, Fischer, Hubertus, Blunier, Thomas
Issue&Volume: 2023-11-27
Abstract: Constraining the causes of past atmospheric methane variability is important for understanding links between methane and climate. Abrupt methane changes during the last deglaciation have been intensely studied for this purpose, but the relative importance of high-latitude and tropical sources remains poorly constrained. The methane interpolar concentration difference reflects past geographic emission variability, but existing records suffered from subtle but considerable methane production during analysis. Here, we report an ice-core-derived interpolar difference record covering the Last Glacial Maximum and deglaciation, with substantially improved temporal resolution, chronology and a critical correction for methane production in samples from Greenland. Using box models to infer latitudinal source changes, we show that tropical sources dominated abrupt methane variability of the deglaciation, highlighting their sensitivity to abrupt climate change and rapidly shifting tropical rainfall patterns. Northern extratropical emissions began increasing ~16,000 years ago, probably through wetland expansion and/or permafrost degradation induced by high-latitude warming, and contributed at most 25 Tg yr-1 (45% of the total emission increase) to the abrupt methane rise that coincided with rapid northern warming at the onset of the Blling–Allerd interval. These constraints on deglacial climate–methane cycle interactions can improve the understanding of possible present and future feedbacks.
DOI: 10.1038/s41561-023-01332-x
Source: https://www.nature.com/articles/s41561-023-01332-x