Cryo-methane emissions - global consequences of permafrost and hydrate destabilization

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Earth's largest repositories of methane are in marine and terrestrial gas hydrates and within/beneath permafrost layers. Although estimates are uncertain, marine gas hydrates store ca. 1.5 x10^15 m^3 and terrestrial hydrates up to 0.06-0.7 x10^15 m^3. Combined they double conventional gas resources of ca. 0.4 x10^15 m^3. Our biogeochemical research of marine hydrates offshore Oregon and Vancouver Is. Margins, and onshore Arctic Mallik 2L-38 hydrate well, documented the character, environmental and economic aspects of hydrates. In concert, we investigated the rapid methane changes at Preboreal /Younger Dryas/Preboreal (YD/PB) transition and Late Glacial Maximum using methane stable C- and H-isotope ratios in Greenland ice. Our ice research indicates that marine gas hydrates and tropical wetlands are not responsible for the Late Pleistocene methane changes. My hypothesis for the YD/PB rise is the release of methane stored in near-surface permafrost soils. Warming causes permafrost layers in front of ice sheets to thaw and release trapped methane. Today, we are experiencing a similar retreat in permafrost. If my YD/PB hypothesis is correct, then in the coming decades we shall experience a similar rapid rise in atmospheric methane as the subArctic warms. This may be combined with the release of methane from shelf gas hydrates. The implications are dramatic shifts in present day global greenhouse gas budgets, impacts on current radiative budgets and influences on climate change. In my coming Discovery Grant period, I wish to intensely investigate the controls and rates of soil gas fluxes, especially methane, from changing discontinuous permafrost regions and shelf hydrates of Canada's Arctic. Using biogeochemical field measurements (including eddy flux correlation, gas composition, isotopes, biomarker compounds, and microbiological assays) coupled with modeling, I seek to determine if permafrost-and hydrate-derived methane: 1) is being influenced by changes in subArctic conditions, 2) is or can be released with sufficient quantity and isotope composition to be consistent with our YD/PB Canadian and Greenland ice signals, 3) will be of a magnitude that can significantly affect our future climate.