Summers in the South are difficult. It’s often beautiful outside, with bright, blue skies and plenty of lush, green vegetation. But it’s also so hot that you can’t reallyenjoy it. The air is heavy, like you’re constantly being hugged by a sweaty person. So you either stay inside, or you suffer. And it’s easy for most folks to stay inside because nearly everyone has air-conditioning.

At least, until they don’t.

The environmental and social costs of AC

AC comes with a host of problems. It is undoubtedly true that air-conditioning saves lives, especially among vulnerable populations like the elderly, but it also comes at a high price — and not just when it comes to your electric bill.

Air-conditioning in the U.S. currently accounts for an estimated 5 percent of our annual energy consumption, and spews about 100 million tons of carbon dioxide into the air each year. The CO2 emissions are bad enough, but air conditioners also contain refrigerants called hydrofluorocarbons (HFCs), another potent greenhouse gas, which can leak out during use, maintenance, and disposal of AC units. In fact, fluorinated gases like HFCs are the most potent and longest lasting of all the greenhouse gases emitted from human activities, and, according to the EPA, emissions have increased a staggering 258 percent since 1990. Currently, world diplomats are working on phasing out HFCs, but it will still take many years to happen.

In the meantime, the massive amount of greenhouse gases we emit to power our air conditioners actually increases our need for air conditioners. As Stan Cox, the author of Losing Our Cool, a definitive history of air-conditioning, told me: “It’s an especially vicious cycle because air conditioning inside makes it even warmer outside.”


Phoenix: Then and now

People have always lived in hot climates. Before Phoenix, Arizona, was Phoenix, for instance, the Hohokam people thrived in the region for 1,000 years, from about 450 to 1450 AD. At its peak, the population of Hohokam numbered between 25,000 and 60,000.

That same area is now home to more than 4 million people. It is a sprawling, suburban megalopolis where temperatures routinely top 110 degrees. Air-conditioning, as anyone who has visited Phoenix in summer knows, isn’t a luxury; it’s a necessity. But, still, the Hohokam made due in a climate not all that much cooler, and they did it without electricity, much less air-conditioning. So, how?

One critical strategy: They altered their physical landscape in ways that helped them survive extreme temperatures, according to AC chronicler Cox. “They built a huge system of canals. In that desert environment, water was everything, so they maintained this massive canal system that not only provided water but also had a cooling effect. They were able to grow vegetation along the banks of the canals.”

On hot days, the Hohokam would hang wet cloths in the entryways of their adobe structures, which would both cool and humidify the arid air. They also had plenty of shade trees, and stayed out of the sun during the hottest parts of the day. On hot nights, they slept outside.


Can we go back?

Many of the houses constructed during the post-War era still exist. And many, if not most, still have no insulation, poor ventilation, and single-paned windows that don’t effectively  keep the heat out. They are hot boxes, and millions of us live in them.

Yet there are things we can do to make our existing buildings more efficient. President Obama’s 2009 stimulus package — which was put together to spur economic growth in the wake of the recession — invested in a range of clean energy projects, including weatherizing over a million low-income homes. As Obama said at the time: “The simple act of retrofitting these buildings to make them more energy-efficient — installing new windows and doors, insulation, roofing, sealing leaks, modernizing heating and cooling equipment — is one of the fastest, easiest and cheapest things we can do to put Americans back to work while saving families money and reducing harmful emissions.” We should be doing a lot more of that.