You're not understanding how 3D graphics "works" - its not specific to OpenGL - its how ZBuffers work - and they work identically in OpenGL or D3D or anything else.
ZBuffers are used to store the depth of every pixel on the display relative to the viewer (NB Gaieus, this is why putting around the origin or in positive XY makes no difference whatsoever).
Graphics hardware generally limits the precision of the ZBuffer to 24 bits.
However, in order to display a 3D world on a 2D display, 3d software needs to perform a "Perspective Projection" which has the side effect of making a linear move away from the camera view in World space, a non-linear move in Projection space. What does all that mean?
Well, firstly what is actually stored in 1/depth, and what flows from that is that near to the viewer you get lots of precision and far away you get less and less. This is why a coplanar Picture on a wall might be fine close up but gradually degenerates into a buzzing mess as you recede.
In order to ensure you get maximum precision, most 3d software will control the ratio of near clipping to far clipping to ensure that it fits inside those 24 bits of precision.
So having a far clip of 10000.0 and a near clip of 1.0 gives a ratio of 10000:1 which can be represented by the 24 bit ZBuffer. Bringing the near clip in to 0.01 gives a ratio of 1000000:1 which its going to struggle.
SketchUp adjust the far clip to ensure you get maximum precision - but in the case of huge mountain range, you're going to have problems with this approach.
If you enable Fog, and use the cut-off slider to limit visibility, its possible SketchUp takes the minimum of Fog distance and Far clip which would give you manual control.
If it doesn't do this already, it should - and Adam should get a decent bottle of claret. 
Adam