Is it too hot to walk around the block? Sure, blame global warming, but in many parts of the country there is also a noticeable absence of shade. Why? As Nolan Gray, a city planner in New York, argues one reason is that shade has been zoned out.
…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.
These design elements survive and thrive in cities built before air conditioning, like New Orleans, but are conspicuously absent from most modern Sun Belt metros. With houses sitting squat and far back from the street, and most commercial spaces sitting behind a veritable desert of parking, shade in cities like Phoenix and Atlanta is few and far between.
…The irony here is that the cities that most need shade are the least likely to have it…Older, urban cities with mild summers—think Boston—have shade in spades, while our newer Sun Belt cities —think Las Vegas—have virtually no shade at all, resulting in an unhealthy dependence on air conditioning.
Why did this happen? A big reason is the way we started planning cities in the twentieth century. 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.
…In most suburbs, for example, houses are legally prevented from sitting close to the lot line by setbacks, which prevent any shade from being cast on sidewalks or neighboring homes.
Strict rules surrounding building heights and density cap most suburban buildings at a standard height of 35 feet, well below what could potentially cast a cooling shadow. And shadows from high-rises are treated as an unambiguous evil in planning hearings, even in otherwise dense urban environments like San Francisco.
The criminalization of shade goes beyond land-use regulations; it extends to the way we design public spaces. Despite more and more cities encouraging street trees as a valuable source of shade, many state transportation offices continue to ban them, privileging ease of maintenance over outdoor comfort.
Trees in particular would not only create more shade but also reduce air pollution.