Causes

Some societies build cities horizontally rather than vertically [Example: Southern California].

This is perceived to be convenient, but it is wasteful of energy [required for commute].

Effects

Air pollution [due to motor vehicle exhaust].

Encroachment on native ecosystems and wildlife habitats.

Negative impact on biodiversity.

Solution

Build better mass transportation [light rail, subways, more effective bus transportation].

Build cities vertically [more condominiums and apartments].

Discourage urban concentration.