New measurements of 14C provide constraints on sources of a large atmospheric methane increase during the Younger Dryas-Preboreal Abrupt Warming Event

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dc.contributor.authorPetrenko, VVen_AU
dc.contributor.authorSeveringhaus, JPen_AU
dc.contributor.authorSmith, AMen_AU
dc.contributor.authorRiedel, Ken_AU
dc.contributor.authorBrook, EJen_AU
dc.contributor.authorSchaefer, Hen_AU
dc.contributor.authorBaggenstos, Den_AU
dc.contributor.authorHarth, CMen_AU
dc.contributor.authorHua, Qen_AU
dc.contributor.authorBuizert, Cen_AU
dc.contributor.authorSchilt, Aen_AU
dc.contributor.authorFaïn, Xen_AU
dc.contributor.authorMitchell, Len_AU
dc.contributor.authorBauska, TKen_AU
dc.contributor.authorOrsi, AJen_AU
dc.contributor.authorWeiss, RFen_AU
dc.date.accessioned2021-07-28T01:02:17Zen_AU
dc.date.available2021-07-28T01:02:17Zen_AU
dc.date.issued2014-12-19en_AU
dc.date.statistics2021-07-12en_AU
dc.description.abstractThawing permafrost and marine methane hydrate destabilization have been proposed as large sources of methane to the atmosphere in the future warming world. To evaluate this hypothesis it is useful to ask whether such methane releases happened during past warming events. The two major abrupt warming events of the last deglaciation, Oldest Dryas – Bølling (OD–B) and Younger Dryas – Preboreal (YD-PB), were associated with large (up to 50%) increases in atmospheric methane (CH4) concentrations. The sources of these large warming-driven CH4 increases remain incompletely understood, with possible contributions from tropical and boreal wetlands, thawing permafrost as well as marine CH4 hydrates. We present new measurements of 14C of paleoatmospheric CH4 over the YD-PB transition from ancient ice outcropping at Taylor Glacier, Antarctica. 14C can unambiguously identify CH4 emissions from “old carbon” sources, such as permafrost and CH4 hydrates. The only prior study of paleoatmospheric 14CH4 (from Greenland ice) suggested that wetlands were the main driver of the YD-PB CH4 increase, but the results were weakened by an unexpected and poorly understood 14CH4 component from in situ cosmogenic production directly in near-surface ice. In this new study, we have been able to accurately characterize and correct for the cosmogenic 14CH4 component. Preliminary analysis of the results indicates that ≈10% of the overall CH4 source to the atmosphere during the nearly-constant climate of the YD was attributable to 14C-free sources. This 14C-free source fraction increased slightly over the YD-PB transition, however, wetlands were nonetheless the main driver of the CH4 increase. Final analysis and interpretation of the 14CH4 data are currently in progress. © AGU 2014en_AU
dc.identifier.citationPetrenko, V. V., Severinghaus, J. P., Smith, A., Riedel, K., Brook, E., Schaefer, H., Baggenstos, D., Harth, C. M., Hua, Q., Buizert, C., Schilt, A., Fain, X., Mitchell, L., Bauska, T. K., Orsi, A. & Weiss, R. F. (2014). New measurements of 14 C provide constraints on sources of a large atmospheric methane increase during the Younger Dryas-Preboreal abrupt warming event. Paper presented at the AGU Fall Meeting, San Francisco, California, 15 to 19 May 2014. Retrieved from: https://agu.confex.com/agu/fm14/meetingapp.cgi/Paper/17850en_AU
dc.identifier.conferenceenddate19 May 2014en_AU
dc.identifier.conferencenameAGU Fall Meeting 2014en_AU
dc.identifier.conferenceplaceSan Francisco, Californiaen_AU
dc.identifier.conferencestartdate15 May 2014en_AU
dc.identifier.otherPP51D-1154en_AU
dc.identifier.urihttps://agu.confex.com/agu/fm14/meetingapp.cgi/Paper/17850en_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/11116en_AU
dc.language.isoenen_AU
dc.publisherAmerican Geophysical Union (AGU)en_AU
dc.subjectPaleoclimatologyen_AU
dc.subjectClimatic changeen_AU
dc.subjectIceen_AU
dc.subjectGlaciersen_AU
dc.subjectCarbon 14en_AU
dc.subjectMethaneen_AU
dc.titleNew measurements of 14C provide constraints on sources of a large atmospheric methane increase during the Younger Dryas-Preboreal Abrupt Warming Eventen_AU
dc.typeConference Abstracten_AU
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