Records of the δ13C of atmospheric CH4 over the last 2 centuries as recorded in Antarctic snow and ice
Article first published online: 2 APR 2005
Copyright 2005 by the American Geophysical Union.
Global Biogeochemical Cycles
Volume 19, Issue 2, June 2005
How to Cite
2005), Records of the δ13C of atmospheric CH4 over the last 2 centuries as recorded in Antarctic snow and ice, Global Biogeochem. Cycles, 19, GB2002, doi:10.1029/2004GB002408., , , , , and (
- Issue published online: 2 APR 2005
- Article first published online: 2 APR 2005
- Manuscript Accepted: 10 FEB 2005
- Manuscript Revised: 26 JAN 2005
- Manuscript Received: 9 NOV 2004
- atmospheric methane;
- ice cores;
- trace gas emissions
 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 δ13CH4 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 AD. 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.