The simulation of glacial cycles with a complex Earth system model

What causes the sequence of ice ages and interglacials is one of the big unsolved questions of Earth system science. Interactions between atmosphere, ocean, ice, and oceanic and terrestrial biosphere are likely to be crucial. Here, we describe the fundamentals and first results of the most complex extant Earth system model for the simulation of long timescales. Interactive land vegetation enhances the climate change caused by variations in the Earth’s orbital parameters, and thus constitutes a positive feedback even in a complex Earth system model.