Lecture 9 Mechanisms and toy models of the glacial cycles

(Ghil [14]) Assume that higher elevation of the ice sheet surface results in colder ice-sheet surface temperature, therefore in less ablation, and therefore in more net accumulation (i.e. opposite of the elevation-desert effect). As the ice volume increases, the ice sheet sinks into the bedrock, moving more of the the glacier surface area into an elevation of less accumulation/ more ablation (or equivalently, moving the equilibrium line poleward). This results in a negative feedback between ice volume and net accumulation rate d p dt ∝−Vice which, together with the simple mass balance equation dVice dT ∝ p