Late Carboniferous ice sheets in a coupled Earth-system model

The Late Paleozoic Ice Age (LPIA) was the latest phase of widespread glaciation on Earth before the current Late Cenozoic Ice Age. At its peak around 300 million years ago, ice sheets in southern Pangea reached their maximal extents. This knowledge comes from a plethora of geological evidence but has so far not been explored by fully three-dimensional coupled models of land ice and climate. Here we present results from the first peak-LPIA simulations with interactive ice sheets using CLIMBER-X, a fast coupled Earth-system model featuring a statistical–dynamical atmosphere and a frictional–geostrophic ocean. For a range of likely greenhouse-gas concentrations, we investigate how orbital geometry, topography, and the initialization of ice sheets affect the growth and distribution of land ice during the late Carboniferous. We find an especially distinct dependency on orbital geometry, with ice covering almost whole Gondwana in one case and being limited to the South American part in another, while keeping the greenhouse gases constant. We then plan to use the precipitation and ice-sheet cover output from the climate model to calibrate landscape evolution modeling with Fastscape and thereby obtain estimates of the global sediment flux during the LPIA.