How much should you worry about an Arctic methane bomb? It was a stunning figure: $60 trillion.
Such could be the cost, according to a recent commentary [PDF] in the journal Nature, of “the release of methane from thawing permafrost beneath the East Siberian Sea, off northern Russia … a figure comparable to the size of the world economy in 2012.” More specifically, the paper described a scenario in which rapid Arctic warming and sea ice retreat lead to a pulse of undersea methane being released into the atmosphere. How much methane? The paper modeled a release of 50 gigatons of this hard-hitting greenhouse gas (a gigaton is equal to a billion metric tons) between 2015 and 2025.
This, in turn, would trigger still more warming and gargantuan damage and adaptation costs. The $60 trillion figure went everywhere, and no wonder. According to the Nature commentary, that methane “is likely to be emitted as the seabed warms, either steadily over 50 years or suddenly.” Schmidt is hardly the only skeptic. Methane on ice A debate over hydrate depth. Les clathrates, énergie du futur ou bombe à retardement climatique ? Global Inventory of Natural Gas Hydrate Occurence - USGS PCMSC.
Natural gas hydrate occurs worldwide in oceanic sediment of continental and insular slopes and rises of active and passive margins, in deep-water sediment of inland lakes and seas, and in polar sediment on both continents and continental shelves.
In aquatic sediment, where water depths exceed about 300 m and bottom water temperatures approach 0° C, gas hydrate is found at the seafloor to sediment depths of about 1100 m. In polar continental regions, gas hydrate can be present in sediment at depths between about 150 and 2000 m. Thus, natural gas hydrate is restricted to the shallow geosphere where its presence affects the physical and chemical properties of near-surface sediment. This updated global inventory reports on natural gas hydrate recovered from 44 regions worldwide and includes 113 regions where the presence of gas hydrate has been inferred from geophysical, geochemical, and geological evidence. Energy resource, factor in global climate change, and geohazard. Hydrates de gaz : l'énergie des profondeurs. Hydrates de méthane : le nouveau gaz de schiste ? Les hydrates de méthane figurent parmi les ressources qui intéressent de près les industries pétrolières.
L'écorce terrestre en renferme de très grandes quantités, mais elles restent particulièrement difficiles à extraire et représentent une menace potentielle pour le climat. Après les gaz de schiste, voici les hydrates de méthane. Le 12 mars dernier, des scientifiques japonais ont réussi à extraire cette ressource énergétique présentée comme une opportunité à l’après pétrole.
Dans les eaux de la préfecture d’Aichi, à l’Ouest de l’Archipel, les forages conduits par la société JOGMEC (Japan Oil Gas & Metals National Corporation) ont réussi à remonter des hydrates de méthane piégés à 1000 m de profondeur et sous 300 m de sédiments océaniques. Voilà une nouvelle qui devrait satisfaire le Japon, qui souffre de sa dépendance énergétique. Aussi appelés « glaces qui brûlent », les hydrates de méthane appartiennent à la famille des gaz non conventionnels. L’engouement des industriels.