We prove lower bounds for the minimum distance of algebraic geometry codes over surfaces whose canonical divisor is either nef or anti-strictly nef and over surfaces without irreducible curves of small genus. These lower bounds are sharpened for surfaces whose arithmetic Picard number equals one, surfaces without curves with small self-intersection and fibered surfaces. What characterizes the bounds we obtain is that they involve a measure of closeness of the divisor defining the code to the ample cone in the Néron-Severi group.