The Azimuth Project
Arctic methane deposits (Rev #2)

Arctic methane deposits

Idea

The cold Arctic regions contain large amounts of the greenhouse gas methane depostied in forms which are currently stable due to the low termperature. It is hypothesised that a small but signficant warming of the Arctic regions could destabilise these and lead to large releases of methane into the atmosphere.

Details

The Arctic currently (in geological time) has large “stores” of methane in three dominant forms:

  1. Conventional gas deposits (eg, trapped by shale rock, etc).

  2. Stored as methane clathrates (essentially methane molecules trapped in ice crystals) on the seabed.

  3. Locked in permafrost (essentially similar chemistry to methane clathrates above but stored several metres down into frozen soil).

The conventional gas deposits have the high stability of gas depsosits elsewhere.The last two are believed to be relatively stable at historical Arctic temperatures, but may be destabilised by a small but significant warming of the Arctic regions. It is believed that 0.5 Mt of methane is currently being released from the Arctic per year. However it is beleived plausible that up to 50 Gt of methane could be released into the atmoshpere very quickly should the storage become destabilised. (See Shakhova et al).

It should be noted that apparently modeling and measurements of methane in the atmosphere is less advanced than modeling carbon dixoide. In addition, there is debate about whether a sudden destabilisation of Arctic methane reserves is possible or only gradual release.

References

Wikipedia has information about general Arctic methane

and the chemistry of methane clathrates

category: carbon