Methane concentration and delta deuterium of methane from the NGRIP ice core

• Main Authors: Bock, Michael, Schmitt, Jochen, Möller, Lars, Spahni, Renato, Blunier, Thomas, Fischer, Hubertus
• Format: Dataset
• Language: English
• Published: PANGAEA 2010
• Subjects: DEPTH; ice/snow; Gas age; Gas chromatography; Greenland; ICEDRILL; Ice drill; Mass spectrometry; Methane; NGRIP; North Greenland Ice Core Project; NorthGRIP; Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; Sample code/label; Sampling/drilling ice; SPP1158; δ Deuterium; Antarc*; Antarctic; Greenland ice core; Greenland Ice core Project; ice core; Methane hydrate; North Greenland; Sea ice
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.756715; https://doi.org/10.1594/PANGAEA.756715

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.