Abstract <p>A mathematical model has been formulated for the degradation of saline perennially frozen rocks (PFRs) containing ice, accumulations of metastable self-conserved gas hydrates, and free gas due to climate warming and under the influence of heat flow from below. In the simplest case, the model has yielded an analytical expression of the laws of reservoir degradation from above due to an increase in temperature at the upper boundary, and from below due to the effect of an increased heat flow. The degradation from below has been shown to occur mainly linearly in time, while degradation from above is slower, that is, following a square root law. The proposed model and the simplest formulas obtained can be used to study the fronts of the frozen layer degradation not only due to ice melting, but also to study the earlier and faster decomposition fronts of metastable gas hydrates without ice melting. The relevant thermodynamic points are close. A specific numerical variant is considered as an application of the model, and the curves of degradation fronts are illustrated.</p>