Hydrogen isotopes preclude marine hydrate CH$_4$ emissions at the onset of Dansgaard-Oeschger events

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 [δD(CH...

Full description

Bibliographic Details
Published in:Science
Main Authors: Bock, Michael, Schmitt, Jochen, Möller, Lars, Spahni, Renato, Blunier, Thomas, Fischer, Hubertus
Format: Article in Journal/Newspaper
Language:English
Published: American Association for the Advancement of Science 2010
Subjects:
530 Physics
Dansgaard-Oeschger events
Greenland
Greenland ice core
Greenland Ice core Project
ice core
Methane hydrate
North Greenland
North Greenland Ice Core Project
Online Access:https://boris.unibe.ch/4605/1/1686.full.pdf
https://boris.unibe.ch/4605/
Description
Summary: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 [δD(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 δD(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.

Similar Items