Abstract

The Mid-Pleistocene transition is a shift from 41-to 100-kyr ice age cycles that occurred

roughly 1,000,000 years ago. We revisit a simplification of the model of Quaternary climate

dynamics that was proposed by Saltzman and Maasch (1988). At parameters that

make the model bistable in the absence of forcing, the astronomical forcing can create a

peculiar type of transition from low-amplitude oscillations to high-amplitude relaxation

oscillations, which matches the palaeoclimate records well.

The talk will discuss the underlying mathematical mechanism behind this transition,

namely a non-smooth collision of invariant sets in quasi-periodically forced systems We

also show the consequences of this mathematical mechanism on early-warning signals.

This is joint work with Courtney Quinn (CSIRO Australia), Anna von der Heydt (Univ.

Utrecht, The Netherlands), and Tim Lenton (Exeter).

References

1. C. Quinn et al, Dynamics and Statistics of the Climate System 3(1), dzy005, 2018.

(https://doi.org/10.1093/climsys/dzy005)

2. C. Quinn et al. SIAM J. of Appl. Dyn. Sys. 18(2) pp. 1060-1077, 2019.

(https://doi.org/10.1137/18M1203079)