Ice-rich permafrost is estimated to underlie 20% of the Northern hemisphere’s permafrost region. It is particularly vulnerable to thawing processes referred to as “thermokarst”, which manifest in emerging characteristic landforms and rapidly changing landscapes. Prominent examples for theses processes are ground subsidence, thaw slumps, thermo-erosional valleys or the degradation of ice-wedge polygonal tundra. Altogether thermokarst poses risks to intact infrastructure and ecosystems in the Arctic, particularly in conjunction with a warming climate. To assess theses risks efficient prediction tools are demanded which are able to simulate the landscape changes due to thawing of ice-rich permafrost. We present a simple modeling approach based on the permafrost model CryoGrid3 which is able to simulate physical dynamics of thermokarst landforms. The landscape is partitioned into a set of distinct “tiles” which represent functionally different parts of it. Between adjacent tiles the lateral exchange of water, snow and heat is possible. We demonstrate the capability of our approach with showcasing the degradation of an ice-wedge polygonal tundra landscape. This landscape change involves a transition from an intact to an degraded permafrost landscape which can be considered as a regime shift between different stationary states. We further quantify the implications of this transition for cycling of water and energy in the landscape. We discuss the applicability of our model approach to other ice-rich permafrost landforms and its potential to a pan-Arctic risk assessment for infrastructure an ecosystems.