On the Likelihood of Plate Tectonics on Super-Earths: Does Size Matter?

The operation of plate tectonics on Earth is essential to modulate its atmospheric composition over geological time and is thus commonly believed to be vital for planetary habitability at large. It has been suggested that plate tectonics is very likely for super-Earths, with or without surface water, because a planet with a larger mass tends to have sufficient convective stress to escape from the mode of stagnant-lid convection. Here, this suggestion is revisited on the basis of the recently developed scaling laws of plate-tectonic convection, which indicate that the planetary size plays a rather minor role and that the likelihood of plate tectonics is controlled largely by the presence of surface water.