800,000-year Ice-Core Records of Atmospheric Methane (CH4)
This page introduces ice-core records of methane (CH4) extending back 800,000 years at Dome C, Antarctica and over 400,000 years at the Vostok site. Links are also provided to shorter records from other Antarctic locations. The 2000-year record from Law Dome, Antarctica, has been merged with modern records to create a long-term record to the present.
- Dome C 800,000-year record: European Project for Ice Coring in Antarctica (EPICA) members: D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T.F. Stocker.
- Vostok 400,000-plus-year record: J.R.Petit, Laboratoire de Glaciologie et Geophysique de l'Environnement , Grenoble, France.
Collective Period of Record
20th Century back to 795,000 years Before Present (B.P.) (Before 1950).
Antarctic Ice-Core Stations
Maps of Antarctica showing locations and elevations in meters above sea level (masl) of: Law Dome (66°44'S, 112°50'E, 1390 masl), Dome C (75°06'S, 123°24'E, 3233 masl), Taylor Dome (77°48'S, 158°43'E, 2365 masl), Vostok (78°28'S, 106°52'E, 3500 masl), Dome A (80°22'S, 77°22'E, 4084 masl), the South Pole station (90°S, 2810 masl), and Siple Station (75°55'S, 83°55'W, 1054 masl).
- Dome C "800,000-year" EPICA record,
- 400,000-year Vostok Record, and
- 2000-year record from Law Dome, Antarctica.
- Dome C "800,000-year" EPICA record (796,500 BCE-1813 CE)
- Vostok 400,000-plus-year record: http://www.ncdc.noaa.gov/paleo/icecore/antarctica/vostok/vostok.html
- Additional ice-core data found at the World Data Center ice-core gateway
- Law Dome (1- 2004 CE, merged with modern observational data) ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/law/law2006.txt
Air from polar ice-core samples of about 40 g (Bern) or 50 g (Grenoble) is extracted with a melt-refreezing method under vacuum, and the extracted gas is then analyzed for CH4 by gas chromatography followed by flame ionization detection. Two standard gases (408 ppb CH4 and 1050 ppb CH4) at Bern and one (499 ppb CH4) at the Laboratory of Glaciology, Geophysics and Environment, Grenoble, were used to calibrate the gas chromatographs.
Temporal uncertainty in the EPICA 800,000-year series increases with core depth, but estimates indicate that it is usually less than 5% of the true age and is frequently much less than that. Snow accumulation and mechanical flow models form the basis for estimating ages of the ice at a given place and depth. The most recent "EDC3" chronology is based on a snow accumulation and mechanical flow model combined with a set of independent age markers along the core, indicating either well-dated paleoclimatic records or insolation variations. See Parrenin et al. (2007) for more detail. The Vostok time scale is based on the "GT4" chronology, derived in a similar fashion to "EDC3" with age constraints at 110 thousand and at 390 thousand years ago which are assumed to match known events in marine sediments. See Petit et al. (1999) for more detail.
Cyclic changes in Earth’s orbital parameters are evident through 8 glacial cycles. EPICA and Vostok data are in close agreement over the period of the Vostok record (see Graphics). The earliest 4 glacial cycles appear to exhibit less influence of the precessional (22,000-year) component, which involves the time of year when the earth is closest to the sun. Pre-industrial methane fluctuations are between 300 and 800 ppb. Recent Southern Hemisphere concentrations of atmospheric methane are over 1700 ppb, and Northern Hemisphere methane concentrations are over 1800 ppb.
- Blunier, T., J Chappellaz, aJ. J. Schwander, A. Dallenbach, B Stauffer, T.F.Stocker, D. Raynaud, J. Jouzel, H.B. Claussen, C.U. Hammer and S.J. Johnsen. 1998. Asynchrony of Antarctic and Greenland Climate Change During the Last Glacial Period. Nature 394 739-743.
- Chappellaz, J., J.M. Barnola, D. Raynaud, Y.S. Korotkevich, and C. Lorius. 1990. Ice-core Record of Atmospheric Methane over the past 160,000 years. Nature 345, 127-131.
- Fluckiger, J. E. Monnin, B. Stauffer, J. Schwander, T.F. Stocker, J. Chappelaz, D. Raynoud and J.-M. Barnola. 2002. High Resolution Holocene N2O Record and its Relationship with CH4 and CO2. Global Biogeochemical Cycles 16, 1 (March). doi 10.1029/2001GB001417.
- Loulergue, L. F. Parrenin, T. Blunier, J.M. Barnola, R. Spahni, A Schilt, G. Raisbeck and J. Chappelaz. 2007. New Constraints on the Gas-ice Age Difference Among the EPICA ice cores, 0-50KYr. Climate of the Past 3, 3, 527-540.
- Loulergue, L., A. Schilt, R. Spahni, V. Masson-Delmotte, T. Blunier, B. Lemieux, J.-M. Barnola, D. Raynaud, T.F. Stocker, and J. Chappellaz. 2008. Orbital and millennial-scale features of atmospheric CH4 over the past 800,000 years. Nature 453, 383-386. doi:10.1038/nature06950
- Monnin E., A Indermuhle, A Dallenbach, J. Fluckiger, B Stauffer,T.F.Stocker, D. Raynoud, and J.M. Barnola. 2001. Atmospheric CO2 Concentrations over the Last Glacial Termination. Science 291, 112-114.
- Parrenin, F. J-M. Barnola, J. Beer, T. Blunier, E. Castellano, J. Chappelaz, G. Dreyfus, H. Fischer, S. Fujita, J. Jouzel, K. Kawamura, B. Lemieux-Dudon, L. Loulergue, V. Masson-Delmotte, B. Narcisi, J.-R. Petit, G. Raisbeck, D Raynaud, U. Ruth, J. Schwander, M. Severi, R. Spahni, J.P. Steffensen, A Svensson, R. Udisti, C. Waelbroeck and E. Wolff. 2007. The EDC3 Chronology for the EPICA Dome C Ice Core, Climate of the Past 3, 3, 485-497.
- Petit J.R., Jouzel J., Raynaud D., Barkov N.I., Barnola J.M., Basile I., Bender M., Chappellaz J., Davis J., Delaygue G., Delmotte M., Kotlyakov V.M., Legrand M., Lipenkov V., Lorius C., Pépin L., Ritz C., Saltzman E., Stievenard M., 1999, Climate and Atmospheric History of the Past 420,000 years from the Vostok Ice Core, Antarctica, Nature 399, pp.429-436.
- Spahni R., et al, 2003. The Attenuation of Fast Atmospheric CH4 Variations Recorded in Polar Ice Cores. Geophysical Research Letters 30, 1571.
- Spahni, R. J. Chappelaz, T.F. Stocker, L. Loulergue, G. Hausammann, K. Kamamura, J. Fluckiger, J Schwander, D. Raynoud, V. Masson-Delmotte and J. Jouzel. 2005. Atmospheric Methane and Nitrous Oxide of the Late Pleistocene from Antarctic Ice Cores. Science 310, 1317-1321.
Loulergue, L. et al. 2008. EPICA Dome C Ice Core, 800 KYyr Methane Data. IGBP PAGES, World Data Center for Paleoclimatology, Data Contribution Series # 2008 - 054. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. (If accessing the data from this CDIAC site, please add: "(accessed from the Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy).
Also cite the reference to Loulergue et al. 2008, given above if using the data in any published work.
Instructions are given at the beginning of the "description" file; ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/readme_petit1999.txt If using one of the shorter data sets, cite the Chappellaz (1990), or Blunier (1998) references, given above, as appropriate.
Other Data Sets
Instructions are given in the headers of the World Data Center data sets.