Atmospheric Methane: Comparison Between Methane's Record in 2006-2022 and During Glacial Terminations
Atmospheric Methane: Comparison Between Methane's Record in 2006-2022 and During Glacial Terminations
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DOI：
10.1029/2023gb007875
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发表时间：
2023-08-01
影响因子：
5.2
通讯作者：
Bromley，Tony
中科院分区：
文献类型：
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作者：
Nisbet，Euan G.;Manning，Martin R.;Bromley，Tony
从2006年底开始，大气甲烷的快速增长在观测记录中是前所未有的。对大气甲烷数据的评估将这种大气增长的很大一部分归因于热带地区自然排放的增加，这似乎是对人为气候强迫变化的反应。同位素较轻的测量是一致的，最近的大气甲烷增长主要是由微生物来源，特别是湿地的排放量增加。全球甲烷收支目前处于不平衡状态，新的投入尚未得到很好的量化。尽管2006年至2022年期间农业和废物来源的微生物排放量增加了35 Tg/年，但存在很大的不确定性，最近甲烷排放量净增长中约有35 - 45 Tg/年可能是由自然生物过程驱动的，特别是湿地对气候变化的反馈。模型比较表明，最近的变化可能是可比的或更大的规模和速度比甲烷的增长和同位素变化在过去的冰期/间冰期终止事件。甲烷目前的增长仍有可能在全新世变化的范围内，但甲烷最近的增长和同位素变化也可能表明自然气候和生物圈正在进行大规模重组。
Atmospheric methane's rapid growth from late 2006 is unprecedented in the observational record. Assessment of atmospheric methane data attributes a large fraction of this atmospheric growth to increased natural emissions over the tropics, which appear to be responding to changes in anthropogenic climate forcing. Isotopically lighter measurements of are consistent with the recent atmospheric methane growth being mainly driven by an increase in emissions from microbial sources, particularly wetlands. The global methane budget is currently in disequilibrium and new inputs are as yet poorly quantified. Although microbial emissions from agriculture and waste sources have increased between 2006 and 2022 by perhaps 35 Tg/yr, with wide uncertainty, approximately another 35–45 Tg/yr of the recent net growth in methane emissions may have been driven by natural biogenic processes, especially wetland feedbacks to climate change. A model comparison shows that recent changes may be comparable or greater in scale and speed than methane's growth and isotopic shift during past glacial/interglacial termination events. It remains possible that methane's current growth is within the range of Holocene variability, but it is also possible that methane's recent growth and isotopic shift may indicate a large‐scale reorganization of the natural climate and biosphere is under way.