The contribution of geologic emissions, thawing permafrost and methane hydrates to the global methane budget – perspective from ice core records

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dc.contributor.authorDynonisius, MNen_AU
dc.contributor.authorPetrenko, VVen_AU
dc.contributor.authorSmith, AMen_AU
dc.contributor.authorBeck, Jen_AU
dc.contributor.authorSchmitt, Jen_AU
dc.contributor.authorMenking, JAen_AU
dc.contributor.authorShackleton, SAen_AU
dc.contributor.authorHmiel, Ben_AU
dc.contributor.authorVimont, Ien_AU
dc.contributor.authorHua, Qen_AU
dc.contributor.authorYang, Ben_AU
dc.contributor.authorSeth, Ben_AU
dc.contributor.authorBock, Men_AU
dc.contributor.authorBeaudette, Ren_AU
dc.contributor.authorHarth, CMen_AU
dc.contributor.authorBaggenstos, Den_AU
dc.contributor.authorBauska, TKen_AU
dc.contributor.authorRhodes, RHen_AU
dc.contributor.authorBrook, EJen_AU
dc.contributor.authorFischer, Hen_AU
dc.contributor.authorSeveringhaus, JPen_AU
dc.contributor.authorWeiss, RFen_AU
dc.date.accessioned2023-12-08T00:58:47Zen_AU
dc.date.available2023-12-08T00:58:47Zen_AU
dc.date.issued2018-12-13en_AU
dc.date.statistics2023-02-23en_AU
dc.description.abstractStudies of methane (CH4) mole fraction and isotopes from trapped air in ice cores provide a long-term perspective on the natural CH4 budget. Among the CH4 isotopes, 14CH4 is unique in providing a definitive top-down constraint on the total fossil CH4 emissions from old carbon reservoirs (marine hydrates, permafrost, natural geologic seeps). We present new measurements of 14CH4 throughout most of the Last Deglaciation (≈15-8ka). Our 14CH4 data show that 14C-depleted CH4 sources (marine hydrates, geologic seeps and old permafrost) were not significant contributors to the deglacial CH4 rise. As the relatively large deglacial global warming (≈4oC, with warming further amplified at high latitudes) did not trigger CH4 emissions from old carbon reservoirs, such emissions in response to future warming also appear unlikely. Our results also strengthen the suggestion from an earlier study (Petrenko et al. 2017) that natural geologic emissions of CH4 are much lower (less than 15 Tg CH4 yr-1, 95% confidence) than recent bottom-up estimates (54-60 Tg CH4 yr-1) (Etiope 2015; Cias et al. 2013) and that, by extension, estimates of present-day total anthropogenic fossil CH4 emissions are likely too low.en_AU
dc.identifier.citationDyonisius, M., Petrenko, V. V., Smith, A. M., Beck, J., Schmitt, J., Menking, J., Shackleton, S., Hmiel, B., Vimont, I., Hua, Q., Yang., B., Seth, B., Bock, M., Beaudette, R., Harth, C. M., Baggenstos, D., Bauska, T. K., Rhodes, R., Brook, E. J., Fischer, H., Severinghaus, J. P., & Weiss, R. F. (2018). The contribution of geologic emissions, thawing permafrost and methane hydrates to the global methane budget – perspective from ice core records. Paper prestented to the AGU Fall Meeting, Washington, D. C., 10 to 14 December 2018. Retrieved from: https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/448986en_AU
dc.identifier.conferenceenddate2018-12-14en_AU
dc.identifier.conferencenameAGU Fall Meetingen_AU
dc.identifier.conferenceplaceWashington, D. C.en_AU
dc.identifier.conferencestartdate2018-12-10en_AU
dc.identifier.otherB43D-07en_AU
dc.identifier.urihttps://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/448986en_AU
dc.identifier.urihttps://apo.ansto.gov.au/handle/10238/15274en_AU
dc.language.isoenen_AU
dc.publisherAmerican Geophysical Unionen_AU
dc.subjectGeologic depositsen_AU
dc.subjectThawingen_AU
dc.subjectPermafrosten_AU
dc.subjectGas hydratesen_AU
dc.subjectDrill coresen_AU
dc.subjectIceen_AU
dc.subjectRecords managementen_AU
dc.subjectCarbon 14en_AU
dc.subjectSeepsen_AU
dc.titleThe contribution of geologic emissions, thawing permafrost and methane hydrates to the global methane budget – perspective from ice core recordsen_AU
dc.typeConference Paperen_AU
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