An Adimensional Ice-Sheet-Climate Model for glacial cycles

Although the ultimate trigger of glacial cycles is Milankovitch insolation cycles, there are still uncertainties concerning their timing and transitions. These unknowns are believed to be due to intrinsic nonlinearities in the climate system, and there is a deep interest in their solution. However, the longer timescales involved make it infeasible to use comprehensive climate models because of the large computational cost involved. In this context, conceptual models are built to mimic complex processes in a simpler, computationally efficient way. Here we present an adimensional ice-sheet–climate model (AMOD), which aims to study these outstanding paleoclimatic topics. AMOD represents ice sheet dynamics by using common assumptions as in state-of-the-art ice-sheet models, adapted to its dimensionless nature, and it solves surface mass balance processes and the aging of snow and ice. In this way, AMOD is able to run several glacial cycles in seconds and produces results comparable to those of paleoclimatic proxies. Preliminary results indicate nonlinearities related to both ice dynamics and snow aging that determine the timing and shape of deglaciations.