A reassessment of the heat transport by variable viscosity convection with plates and lids

The heat transport by a viscous fluid with temperature dependent viscosity has been studied numerically. As opposed to previous models, the top surface of the fluid clearly defines a tectonic plate with horizontally uniform velocity and subduction. Past studies failed to incorporate plates resulting in inefficient heat transport. With tectonic plates, the heat transport is as efficient as Rayleigh‐Benard convection with constant viscosity; there is a strong buffering between internal temperature and heat loss. Past studies of parameterized convection which incorporated parameters indicative of a strong buffering between internal temperature and total heat output still provide the most physically plausible representation of the Earth's thermal evolution.