Hydrogen Isotopes Preclude Marine Hydrate CH 4 Emissions at the Onset of Dansgaard-Oeschger Events

Abstract

Glacial Gas Intracellular bacterial pathogens, such as a series of sudden and large warming episodes, called Dansgaard-Oeschger events, interrupted the cold conditions of the last glacial period. Large increases in the concentration of atmospheric methane accompanied the events, whose causes have remained the object of much speculation. Bock et al. (p. 1686 ) report measurements of the hydrogen isotopic composition of methane recovered in the North Greenland Ice Core Project. The excess atmospheric methane accompanying two Dansgaard-Oeschger events did not come from marine clathrates; instead, the methane probably came from increased fluxes from boreal wetlands, another major source of methane.