  The climate variability associated with the Pleistocene Ice Ages is one of
the most fascinating puzzles in the Earth Sciences still awaiting a
satisfactory explanation. In particular, the explanation of the dominant 100
kyr period of the glacial cycles over the last million years is a long-standing
problem. Based on bifurcation analyses of low-order models, many theories have
been suggested to explain these cycles and their frequency. The new aspect in
this contribution is that, for the first time, numerical bifurcation analysis
is applied to a two-dimensional marine ice sheet model with a dynamic grounding
line. In this model, we find Hopf bifurcations with an oscillation period of
about 100 kyr which may be relevant to glacial cycles.
