title: Ice record of delta13C for atmospheric CH4 across the Younger Dryas-Preboreal transition.
abstract: We report atmospheric methane carbon isotope ratios (delta13CH4) from the Western Greenland ice margin spanning the Younger Dryas-to-Preboreal (YD-PB) transition. Over the recorded approximately 800 years, delta13CH4 was around -46 per mil (per thousand); that is, approximately 1 per thousand higher than in the modern atmosphere and approximately 5.5 per thousand higher than would be expected from budgets without 13C-rich anthropogenic emissions. This requires higher natural 13C-rich emissions or stronger sink fractionation than conventionally assumed. Constant delta13CH4 during the rise in methane concentration at the YD-PB transition is consistent with additional emissions from tropical wetlands, or aerobic plant CH4 production, or with a multisource scenario. A marine clathrate source is unlikely.
authors.affiliation: School of Earth and Ocean Sciences, University of Victoria, Post Office Box 3055, V8W 3P6, Canada. schaefeh@geo.oregonstate.edu
authors.forename: Hinrich
authors.initials: H
authors.lastname: Schaefer
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Whiticar
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Brook
authors.forename: Vasilii V
authors.initials: VV
authors.lastname: Petrenko
authors.forename: Dominic F
authors.initials: DF
authors.lastname: Ferretti
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Severinghaus
mesh_terms: D000818:Animals; D001272:Atmosphere; D001419:Bacteria / Q000378:metabolism; D002247:Carbon Isotopes / Q000032:analysis; D002980:Climate; D017753:Ecosystem; D004777:Environment; D006116:Greenland; D007053:Ice / Q000032:analysis*; D008697:Methane / Q000032:analysis* / Q000378:metabolism; D010944:Plants / Q000378:metabolism; D013995:Time
chemical_list: D002247:Carbon Isotopes; D007053:Ice; D008697:Methane