Climatic Impact of Natural Gas Hydrate

Abstract

Gas hydrate occurrence in the sediments of the outer continental margins is sustained in place for relatively long periods by high hydrostatic pressure and low ambient temperature. Most naturally occurring hydrate is composed of molecules of methane trapped in an ice cage of water molecules. Thus, the breakdown of hydrate in response reduced hydrostatic pressure or increased bottom-water temperature can potentially introduce significant quantities of this potent greenhouse gas in the water column and atmosphere, encouraging accelerated warming. At higher latitudes hydrate also occurs in association with permafrost at depths ranging from 130 to 2000 m. Here methane is held captive in the clathrate enclosure by frigid temperatures. An increase in the mean temperature of the higher latitudes, therefore, also has the potential to dissociate the hydrate and emit methane directly into the atmosphere.