Late Quaternary Atmospheric CH4 Isotope Record Suggests Marine Clathrates Are Stable

  title={Late Quaternary Atmospheric CH4 Isotope Record Suggests Marine Clathrates Are Stable},
  author={Todd A. Sowers},
  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

Constant δ13CH4 during the rise in methane concentration at the YD-PB transition is consistent with additional emissions from tropical wetlands, or aerobic plant CH4 production, or with a multisource scenario.

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

Thermokarst Lakes as a Source of Atmospheric CH4 During the Last Deglaciation

It is found that CH4 bubbling from newly forming thermokarst lakes comprised 33 to 87% of the high-latitude increase in atmospheric methane concentration and, in turn, contributed to the climate warming at the Pleistocene-Holocene transition.

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



Atmospheric Methane and Nitrous Oxide of the Late Pleistocene from Antarctic Ice Cores

A combined record of CH4 measured along the Dome C and the Vostok ice cores demonstrates, within the resolution of the authors' measurements, that preindustrial concentrations over Antarctica have not exceeded 773 ± 15 ppbv during the past 650,000 years.

Synchronous changes in atmospheric CH4 and Greenland climate between 40 and 8 kyr BP

ICE-CORE reconstructions of atmospheric methane concentrations for the past 220 kyr have revealed large variations associated with different climatic periods1–4. But the phase relationship between

Timing of abrupt climate change at the end of the Younger Dryas interval from thermally fractionated gases in polar ice

Rapid temperature change fractionates gas isotopes in unconsolidated snow, producing a signal that is preserved in trapped air bubbles as the snow forms ice. The fractionation of nitrogen and argon

Rapid Variations in Atmospheric Methane Concentration During the Past 110,000 Years

A methane record from the GISP2 ice core reveals that millennial-scale variations in atmospheric methane concentration characterized much of the past 110,00 years, which suggests that insolation may have modulated the effects of interstadial climate change on the terrestrial biosphere.

Modeling glacial-interglacial changes in global fire regimes and trace gas emissions

Climate at the Last Glacial Maximum (LGM) together with low atmospheric CO2 concentration forced a shift in vegetation zones, generally favored grasses over woody plants and allowed the colonization

Comparison of oxygen isotope records from the GISP2 and GRIP Greenland ice cores

RECENT results1,2 from the Greenland Ice-core Project (GRIP) Summit ice core suggest that the climate in Greenland has been remarkably stable during the Holocene, but was extremely unstable for the

The isotopic composition of atmospheric methane

Measurements of the 13C/12C, D/H and 14C composition of atmospheric methane (CH4) between 1988 and 1995 are presented. The 13C/12C measurements represent the first global data set with time series