NGRIP Ice Core 41-34 KYrBP dD(CH4) Data Bock, M.; Schmitt, J.; Möller, L.; Spahni, R.; Blunier, T.; Fischer, H. Bock, M. Schmitt, J. Möller, L. Spahni, R. Blunier, T. Fischer, H. Dansgaard-Oeschger cycles biogeochemical cycles earth science/paleoclimate/ice cores (sample identification,null,null,null,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (delta 2H,methane,null,per mil VSMOW,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (depth,null,null,meter,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (delta 2H,methane,null,per mil VSMOW,null,ice cores,corrected,null,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/climate forcing|ice cores (methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,null,null,N,null) earth science/paleoclimate/ice core earth science/paleoclimate/ice core (NGRIP>LATITUDE 75.1>LONGITUDE -42.33) The causes of past changes in the global methane cycle and especially the role of marine methane hydrate (clathrate) destabilization events are a matter of debate. Here we present evidence from the North Greenland Ice Core Project ice core based on the hydrogen isotopic composition of methane [dD(CH4)] that clathrates did not cause atmospheric methane concentration to rise at the onset of Dansgaard-Oeschger (DO) events 7 and 8. Box modeling supports boreal wetland emissions as the most likely explanation for the interstadial increase. Moreover, our data show that dD(CH4) dropped 500 years before the onset of DO 8, with CH4 concentration rising only slightly. This can be explained by an early climate response of boreal wetlands, which carry the strongly depleted isotopic signature of high-latitude precipitation at that time. STUDY NOTES: Deuterium isotope data of methane (dDCH4) from the NGRIP ice core, for 41-34 KYrBP. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Bock, M. Investigator : Schmitt, J. Investigator : Möller, L. Investigator : Spahni, R. Investigator : Blunier, T. Investigator : Fischer, H. 2011-02-02 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/10291 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/ngrip/isotopes/ngrip2010ddch4.xls https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/ngrip/isotopes/ngrip2010ddch4.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/ngrip/isotopes/ngrip2010ddch4.xls https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/ngrip/isotopes/ngrip2010ddch4.txt English https://www.ncdc.noaa.gov/paleo/study/10291 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/ngrip/isotopes/ngrip2010ddch4.xls https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/ngrip/isotopes/ngrip2010ddch4.txt Bock, M., J. Schmitt, L. Möller, R. Spahni, T. Blunier, and H. Fischer. 2010. Hydrogen Isotopes Preclude Marine Hydrate CH4 Emissions at the Onset of Dansgaard-Oeschger Events. Science, Vol. 328, pp. 1686. DOI: 10.1126/science.1187651 START YEAR: 40987 cal yr BP * END YEAR: 33678 cal yr BP -42.33 75.1 -42.33 75.1