Simulating horizon curvature

I am making a game where the character is running around and the world is being created procedurally. I want to add a curvature to the ground where it gives the impression that the world is spherical and not flat while you look at the horizon. What would be best way to do that? Some sort of distortion shader? Using mesh modifiers like Mega-Fiers (I did talk to the developer and Mega-Fiers and he said it might be too expensive to warp the visible scene on mobile)? Any other clever solution? Thanks in advance for your answer(s).

Cheers!