Several studies have demonstrated the far-reaching influence of the Antarctic climate. Here we present results from a space-borne study of the radiative properties of clouds and snow, which play a key role in the energy budget of Antarctica. A significant variability in snow-grain size is observed, apparantly in relation to regional meteorology. Remote sensing of clouds over snow can be significantly improved by taking this variability into account. The change in near-infrared albedo also results in large changes in absorbed solar radiation, suggesting a potentially important role in high latitude climate modelling.