Forecasting the need for AC
The heat index measures temperature and humidity to help assess how hot it feels outside. Days with index values above 65 degrees typically demand AC. In the early 1980s, the continental United States required AC for 61 days, or about 66 percent of July to September. Now about 71 percent of summer days requires AC. By 2060, the number of AC-required summer days is projected to rise even more, to 87 percent.
More fundamentally, air conditioning is evolving rapidly from an appliance that adds comfort and convenience to an ever-present life-support system. It’s no longer mentally associated with things such as toasters, refrigerators and televisions but instead with those often-invisible systems that we take for granted until they fail, such as the electrical grid or medical implants, pharmaceuticals and the blood supply.
It’s possible to see a future in which we are dependent on the perfect, continuous performance of air conditioning the way many people are dependent on lifesaving drugs, planes are dependent on air traffic control, and a colony on the moon or Mars would be dependent on perpetual sources of oxygen and water. It is a technology so deeply embedded in our daily lives, and so increasingly important to our survival, that when we think of it, it is not with pleasure, as a luxury, or with pride, as an exemplar of our technical ingenuity. Rather, it reminds us of our frailty. As the danger zone for excess heat creeps into once clement zones, the air conditioner joins the furnace as an essential system for ever more people.
We are now at about the century mark since air conditioning began its conquest of America — in movie theaters in the 1920s; in trains, hotels and other public places in the 1930s; and with astonishing speed and reach, in private homes and suburbia since the 1950s. The history is longer, messier and more complicated than that shorthand, but AC’s basic trajectory has been from a curiosity and luxury to an amenity to a necessity. It has changed how we live and where we live, and reconfigured our cities, houses, politics and identity. And now it is bound up with our hope for survival as a species.