09/15/2011
Will Methane Buried in Shallow Arctic Ocean Sediments Be Released in Response to Warming Oceans?
Summary
Vast quantities of methane, a potent greenhouse gas, are trapped in oceanic hydrate deposits. There is concern that a rise in ocean temperatures will induce dissociation of these hydrate deposits, potentially releasing large amounts of carbon into the atmosphere. The recent discovery of active methane gas venting along the shallow continental slope west of Svalbard in northern Norway suggests that this process may already have begun, but the source of the methane has not yet been determined. DOE researchers have performed two-dimensional simulations of hydrate dissociation in conditions representative of the Arctic Ocean margin to assess whether such hydrates could contribute to the observed methane gas release. The results show that shallow hydrate deposits subjected to recently observed or future predicted temperature changes at the seafloor result in the release of methane at magnitudes and locations similar to what has been observed. Localized gas release is observed for most cases of gradual and rapid warming. These model results resemble recently published observations and strongly suggest that hydrate dissociation and methane release due to climate change may be real, that it could occur on decadal timescales, and that it may already be occurring.
References
Reagan, M. T., G. J. Moridis, S. M. Elliott, and M. Maltrud. 2011. “Contributions of Oceanic Gas Hydrate Dissociation to the Formation of Arctic Ocean Methane Plumes,” Journal of Geophysical Research Oceans 116, C09014. DOI: 10.1029/2011JC007189, 2011.