Cities used to be designed from the bottom up to tame extreme temperatures, especially in warmer regions. In Yemen’s Old Walled City of Shibam, the “Manhattan of the Desert” combines narrow streets with tall buildings to trap cool air...vernacular architecture in the U.S. was often designed around natural climate control. In the humid Southeast, large windows and central corridors encouraged airflow. In the arid Southwest, thick facades and small windows kept cool air inside. In both cases, most houses were packed tightly together to cast shadows over streets, with awnings, balconies, and roof overhangs used to protect indoor spaces from direct sunlight.
Beginning in the 1910s, planners declared a war on shade as a means of responding to slum conditions and high-rises. As described by researcher Sonia Hirt, early land-use planners were inspired by the vision of the detached single-family house on a large lot—a development pattern that’s fine for cloudy Massachusetts, but spells trouble for sunny Florida. Assuming no shade as the ideal, the framers of modern zoning set out to design a system of regulations that make many naturally cooling design elements practically illegal.