Abstract <p>Since the formation of the Earth’s core, there has been a significant change in the thermal regime at the Earth’s surface and in the mantle. At the same time, according to palaeomagnetic observations, the dipole magnetic field has not undergone significant changes. Using a parametric model of core and mantle cooling, this paper discusses how this fact is consistent with the results of three-dimensional geodynamo modelling. It is shown that several-fold changes in the heat flux at the core–mantle boundary do not cause a transition from a dipole magnetic field to a multipole one.</p>