Records of the δ13C of atmospheric CH4 over the last 2 centuries as recorded in Antarctic snow and ice

Methane is one of the important greenhouse gases accumulating in the atmosphere today. The increased loading over the past 2 centuries is thought to be the result of increased anthropogenic emissions. Here we present records of the δ13C of CH4 in firn air from the South Pole and in trapped bubbles i...

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Bibliographic Details
Published in:Global Biogeochemical Cycles
Main Authors: Sowers, T., Bernard, S., Aballain, O., Chappellaz, J., Barnola, J. M., Marik, T.
Format: Text
Language:unknown
Published: Washington, American Geophysical Union (AGU) 2022
Subjects:
Antarctic
Siple
Siple Dome
South Pole
Antarc*
Antarctica
ice core
South pole
Online Access:https://doi.org/10.1029/2004GB002408
http://infoscience.epfl.ch/record/298371
Description
Summary:Methane is one of the important greenhouse gases accumulating in the atmosphere today. The increased loading over the past 2 centuries is thought to be the result of increased anthropogenic emissions. Here we present records of the δ13C of CH4 in firn air from the South Pole and in trapped bubbles in a short ice core from Siple Dome, Antarctica, that help constrain historical emissions of various sources throughout the last 2 centuries. Using two firn air samplings in 1995 and 2001 we calculate that δ 13CH4 has increased by an average of 0.06 ± 0.02‰/yr over the 6 years between samplings. Our ice core results suggest the δ13C of atmospheric CH4 has increased by 1.8 ± 0.2‰ between 1820 A.D. and 2001 A.D. The δ13CH4 changes in both data sets are the result of an increase in the relative proportion of CH4 sources with elevated 13C/12C isotope ratios. One explanation for observed trends involves a 16 Tg/yr increase in CH4 emissions associated with biomass burning over the past 2 centuries. Copyright 2005 by the American Geophysical Union.

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