FIGURE 3. The effect of ice dynamics on model results for an experiment with -5 W m-2 of infrared forcing.
From the following article:
Neoproterozoic 'snowball Earth' simulations with a coupled climate/ice-sheet model
William T. Hyde, Thomas J. Crowley, Steven K. Baum and W. Richard Peltier
Nature 405, 425-429(25 May 2000)
doi:10.1038/35013005
Without the ice sheet, the climate model predicts a climate in which only about one-quarter of the planetary surface is covered in snow or sea ice. If the ice sheets are allowed to grow, however, they flow into areas originally too warm for year-round snow, but the ice-sheet's thermal inertia and elevation prevent it from melting.
