High albedo is important because of its effect on the net reflectivity of the planet, not its effect of the radiation of the surface.
Emissivity is the material property involved in radiation loss, and ice is highly emissive, but so is almost anything non-conductive. Also radiation loss depends on T^4, so that 15-20% difference ends up being closer to one being double the other.
Emissivity is the material property involved in radiation loss, and ice is highly emissive, but so is almost anything non-conductive. Also radiation loss depends on T^4, so that 15-20% difference ends up being closer to one being double the other.