I don't have Civilization so I can't confirm this but holding the
fn key (bottom left of the keyboard on a MacBook Pro) causes the keys around the right hand home-row to work like a number pad. These keys have the numpad key they correspond to in the bottom right corner of the key. For example
I'm not familiar with keyboard shortcuts in Civ IV so there may be some negative overlap (
9 are the same key for the numpad and top row numbers) and pressing the
fn key can be a little awkward but this should at least let you use numpad controls.