Which of the following greenhouse gases trapped in permafrost and hydrates would be likely to be released due to global warming?

Methane is the greenhouse gas locked in permafrost and gas hydrates that warming can release.

Its escape as frozen ground thaws is a positive feedback that speeds up warming further.

Nitrous oxide comes mainly from soils and fertilisers, not from permafrost stores.

Chlorofluorocarbons are synthetic refrigerants, not gases trapped in frozen ground.

Hydrofluorocarbons are man-made cooling agents and are not stored in hydrates.

Methane traps far more heat per molecule than carbon dioxide over short spans.