Late Quaternary Atmospheric CH4 Isotope Record Suggests Marine Clathrates Are Stable

@article{Sowers2006LateQA,
  title={Late Quaternary Atmospheric CH4 Isotope Record Suggests Marine Clathrates Are Stable},
  author={Todd A. Sowers},
  journal={Science},
  year={2006},
  volume={311},
  pages={838 - 840}
}
  • T. Sowers
  • Published 10 February 2006
  • Environmental Science, Geography
  • Science
One explanation for the abrupt increases in atmospheric CH4, that occurred repeatedly during the last glacial cycle involves clathrate destabalization events. Because marine clathrates have a distinct deuterium/hydrogen (D/H) isotope ratio, any such destabilization event should cause the D/H ratio of atmospheric CH4 (δDCH4) to increase. Analyses of air trapped in the ice from the second Greenland ice sheet project show stable and/or decreasing δDCH4 values during the end of the Younger and… 

Ice Record of δ13C for Atmospheric CH4 Across the Younger Dryas-Preboreal Transition

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Enrichment in 13 C of atmospheric CH 4 during the Younger Dryas termination

The abrupt warming across the Younger Dryas termination (~11 600 yr before present) was marked by a large increase in the global atmospheric methane mixing ratio. The debate over sources responsible

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Hydrogen Isotopes Preclude Marine Hydrate CH4 Emissions at the Onset of Dansgaard-Oeschger Events

Evidence is presented from the North Greenland Ice Core Project ice core based on the hydrogen isotopic composition of methane that clathrates did not cause atmospheric methane concentration to rise at the onset of Dansgaard-Oeschger events 7 and 8, and box modeling supports boreal wetland emissions as the most likely explanation for the interstadial increase.

Methane and nitrous oxide in the ice core record

  • E. WolffR. Spahni
  • Environmental Science, Geography
    Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
  • 2007
Recent isotopic data appear to finally rule out any major impact of clathrate releases on methane at these time-scales, and the recent EPICA Dome C (Antarctica) record shows that methane tracked climate over the last 650 000 years, with lower methane concentrations in glacials than interglacials, and lower concentrations in cooler interglazials than in warmer ones.

Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH4 ice core records

Dual stable isotopic methane records from four Antarctic ice cores provide improved constraints on past changes in natural methane sources and show that tropical wetlands and seasonally inundated floodplains are most likely the controlling sources of atmospheric methane variations for the current and two older interglacials and their preceding glacial maxima.

Carbon isotope ratios suggest no additional methane from boreal wetlands during the rapid Greenland Interstadial 21.2

Samples from two Greenland ice cores (NEEM and NGRIP) have been measured for methane carbon isotope ratios (δ13C‐CH4) to investigate the CH4 mixing ratio anomaly during Greenland Interstadial (GI)

Abrupt changes in atmospheric methane at the MIS 5b–5a transition

New ice core analyses show that the prominent rise in atmospheric methane concentration at Dansgaard‐Oeschger event 21 was interrupted by a century‐long 20% decline, which was previously
...

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