Please use this identifier to cite or link to this item: https://apo.ansto.gov.au/dspace/handle/10238/9501
Title: Ice core measurements of 14CH4 show no evidence of methane release to atmosphere from methane hydrates during a large warming event 11,600 years ago
Authors: Petrenko, VV
Severinghaus, JP
Smith, AM
Riedel, K
Brook, EJ
Schaefer, H
Baggenstos, D
Harth, CM
Hua, Q
Buizert, C
Schift, A
Fain, X
Mitchell, L
Bauska, TK
Orsi, A
Weiss, RF
Keywords: Pleistocene epoch
Glaciers
Greenhouse gases
Paleocclimatology
Climatic change
Antarticia
Greenland
Methane
Issue Date: 7-Mar-2016
Publisher: Antarctic Climate and Ecosystems Cooperative Research Centre
Citation: Petrenko, V.V., Severinghaus, J.P., Smith, A.M, Riedel, K., Brook, E., Schaefer, H.,Baggenstos, D., Harth, C. M., Hua, Q., Buizert, C., Schilt, A., Fain, X., Mitchell,L., Basuka, T.K., Orsi, A. J.,& Weiss, R. F. (2015). Ice core measurements of 14CH4 show no evidence of methane release to atmosphere from methane hydrates during a large warming event 11,600 years ago. Paper presented at the IPICS 2016, International Partnerships in Ice Core Sciences, Second Open Science Conference, 7-11 March 2016, Hobart, Tasmania.
Abstract: Thawing permafrost and marine methane hydrate destabilization have been proposed as large sources of methane to the atmosphere in response to both past and future warming. We present measurements of 14C of paleoatmospheric CH4 over the Younger Dryas – Preboreal (YD – PB) abrupt warming event (≈11,600 years ago) from ancient ice outcropping at Taylor Glacier, Antarctica. The YD – PB event was associated with a ≈ 50% increase in atmospheric CH4 concentrations. 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 nearsurface ice. In this new study, we have been able to accurately characterize and correct for the cosmogenic 14CH4 component. All samples from before, during and after the abrupt warming and associated CH4 increase yielded 14CH4 values that are consistent with 14C of atmospheric CO2 at that time, indicating a purely contemporaneous methane source. These new measurements rule out the possibility of large CH4 releases to the atmosphere from methane hydrates or old permafrost carbon in response to the large and rapid YD - PB warming, and confirm that wetlands were the main driver of the CH4 increase.
Gov't Doc #: 9605
URI: https://static1.squarespace.com/static/5459b25de4b00ee921cd006d/t/56dce081c2ea51eadac2f4e1/1457315995517/IPICS+2016+-+Abstracts.pdf
http://apo.ansto.gov.au/dspace/handle/10238/9501
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