To explain what I *think* he means:
If you can 'see' the whole globe, you can see terrain properly.
Here, by the way, is the reason for this: When you can see the whole world, nothing is selectively lit - the whole world is lit as if one big light (like the sun when behind clouds - this is a half truth, but it avoids problems of shadowing and directional light) were lighting it uniformly from all directions. When lighting the world in this way, no hardware transform and lighting is required, as the game isn't actually doing any 'real' lighting. Instead it's just applying an ambient brightness to the terrain. Hence why when the whole world is revealed, it renders properly.