Constant energy molecular dynamics simulations are used to study the role of mass and heat transfer in the decomposition of methane hydrate. The rate of methane hydrate decomposition in a constant energy simulation is affected by heat and mass transfer arising from the breakup of the hydrate framework and release of the methane gas into the liquid phase. As the hydrate undergoes endothermic dissociation, temperature gradients are established between the remaining solid hydrate and the solution phases. Hydrate dissociation occurs in a concerted fashion with rows of sI cages parallel to the interface decomposing simultaneously. This leads to the release of large amounts of methane gas near the solid-liquid interface which can form bubbles that affect the rate of mass transfer between the phases. These phenomena can affect the rate of methane hydrate decomposition in natural methane hydrate reservoirs.