Gas can be produced from GH by inducing dissociation, which also releases large amounts of H2O (1). The three main methods of hydrate dissociation are (1) depres­surization, in which the pressure P is lowered to a level lower than the hydration pressure Pe at the prevailing temperature T, (2) thermal stimulation, in which T is raised above the hydration temperature Te at the prevailing P, and (3) the use of inhibitors (such as salts and alcohols), which shifts the Pe-Te equilibrium through competition for guest and host molecules [111] . Long-term production strategies often involve combinations of the three main dissociation methods [ 131, 132] . Another production method involves CH4 exchange with another hydrate-forming gas (e. g., CO2) through a thermodynamically favorable reaction [52, 213].

2 Occurrence, Research Activities and Priorities, and Prospective Production Targets