GRIP Ice Core 40KYr Methane Data Blunier, T.; Chappellaz, J.A.; Schwander, J.; Stauffer, B.; Raynaud, D. Blunier, T. Chappellaz, J.A. Schwander, J. Stauffer, B. Raynaud, D. earth science/paleoclimate/climate forcing|ice cores (methane,bulk atmosphere,two standard deviations lower bound,parts per billion,null,climate forcing|ice cores,corrected,gas chromatography|wet extraction,N,null) earth science/paleoclimate/climate forcing|ice cores (methane,bulk atmosphere,two standard deviations upper bound,parts per billion,null,climate forcing|ice cores,corrected,gas chromatography|wet extraction,N,null) earth science/paleoclimate/climate forcing|ice cores (methane,bulk atmosphere,two standard deviations lower bound,parts per billion,null,climate forcing|ice cores,corrected,gas chromatography|mechanical dry extraction,N,null) earth science/paleoclimate/climate forcing|ice cores (methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,corrected,gas chromatography|wet extraction,N,null) earth science/paleoclimate/climate forcing|ice cores (methane,bulk atmosphere,two standard deviations upper bound,parts per billion,null,climate forcing|ice cores,corrected,gas chromatography|mechanical dry extraction,N,null) earth science/paleoclimate/ice cores (depth,null,null,meter,null,ice cores,null,null,N,null) earth science/paleoclimate/climate forcing|ice cores (methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,corrected,gas chromatography|mechanical dry extraction,N,null) earth science/paleoclimate/ice cores (gas age,null,null,calendar year before present,null,ice cores,null,null,N,null) earth science/paleoclimate/ice core (GRIP>LATITUDE 72.58>LONGITUDE -37.63) Records of the variation in atmospheric methane concentration have been obtained from ice cores for the past 1,000 years and for the period 8,000-220,000 yr BP, but data for the intervening period, spanning most of the present interglacial period (Holocene), are patchy. Here we present a continuous, high-resolution record of atmospheric methane from 8,000 to 1,000 yr BP, from the GRIP ice core in central Greenland. Unlike most other climate proxies from ice cores (such as oxygen isotope composition and electrical conductivity), methane concentrations show significant variations - up to 15% - during the Holocene. We have proposed that variations in the hydrological cycle at low latitudes are the dominant control on past levels of atmospheric methane. This is now supported by the observation that the lowest methane concentrations in our new record occur in the mid-Holocene, when many tropical lakes dried up. The concentration increases during the Late Holocene, probably owing to an increasing contribution from northern wetlands. STUDY NOTES: The measurements presented have been performed in Bern with a dry extraction technique and in Grenoble with a melting-refreezing method. In both laboratories the extracted air is analysed by gas chromatography. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Blunier, T. Investigator : Chappellaz, J.A. Investigator : Schwander, J. Investigator : Stauffer, B. Investigator : Raynaud, D. 1997-11-30 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/17879 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/gases/gripch4.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/gases/gripch4.txt English https://www.ncdc.noaa.gov/paleo/study/17879 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/gases/gripch4.txt T. Blunier, J. Chappellaz, J. Schwander, B. Stauffer and D. Raynaud 1995Variations in atmospheric methane concentration during the Holocene epochNature374651746-4910.1038/374046a0http://www.nature.com/nature/journal/v374/n6517/abs/374046a0.html START YEAR: 39408 cal yr BP * END YEAR: 175 cal yr BP -37.63 72.58 -37.63 72.58