I've been flying up in Greenland over the last days, and I decided what I really need here is some ice. So I used the packice texture to make a shader effect with an adjustable amount of drift ice:
It isn't very sophisticated (has some rough edges, has tiling, isn't very high resolution...) but then again, you don't need it that often. But I don't really know what to do with it - of course it's one more slider to clutter the GUI, and that has drawn some critique already. And of course it is possible to adjust the sliders to get desert sand on the terrain and ice in the water, it's too complicated to run a model to drop implausible conditions.