Ice Record of δ 13 C for Atmospheric CH 4 Across the Younger Dryas-Preboreal Transition

We report atmospheric methane carbon isotope ratios (δ 13 CH 4 ) from the Western Greenland ice margin spanning the Younger Dryas–to–Preboreal (YD-PB) transition. Over the recorded ∼800 years, δ 13 CH 4 was around –46 per mil (‰); that is, ∼1‰ higher than in the modern atmosphere and ∼5.5‰ higher th...

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Bibliographic Details
Published in:Science
Main Authors: Schaefer, Hinrich, Whiticar, Michael J., Brook, Edward J., Petrenko, Vasilii V., Ferretti, Dominic F., Severinghaus, Jeffrey P.
Format: Article in Journal/Newspaper
Language:English
Published: American Association for the Advancement of Science (AAAS) 2006
Subjects:
Greenland
Online Access:http://dx.doi.org/10.1126/science.1126562
https://www.science.org/doi/pdf/10.1126/science.1126562
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Summary:We report atmospheric methane carbon isotope ratios (δ 13 CH 4 ) from the Western Greenland ice margin spanning the Younger Dryas–to–Preboreal (YD-PB) transition. Over the recorded ∼800 years, δ 13 CH 4 was around –46 per mil (‰); that is, ∼1‰ higher than in the modern atmosphere and ∼5.5‰ higher than would be expected from budgets without 13 C-rich anthropogenic emissions. This requires higher natural 13 C-rich emissions or stronger sink fractionation than conventionally assumed. Constant δ 13 CH 4 during the rise in methane concentration at the YD-PB transition is consistent with additional emissions from tropical wetlands, or aerobic plant CH 4 production, or with a multisource scenario. A marine clathrate source is unlikely.

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