How air conditioning gave us skyscrapers, President Reagan and saved countless lives

During these sweltering days of heat waves, many people likely take air conditioning for granted — one of those modern-day conveniences that make a visit to the mall, life at work, or sleep at home a little more pleasant.

But air conditioning has been a literal lifesaver for countless individuals, and as some suggest, a world-changing invention.

"Air conditioning reshaped the world," economist and Financial Times columnist Tim Harford said in a 2017 interview with The Atlantic.

The author of the book Fifty Inventions That Shaped the Modern Economy, Harford devoted one of those chapters to AC.

As Harford further noted in an essay for the BBC, air conditioning has fuelled the economy, in part by making people more productive, allowing them to work longer and better. And it has also had an impact on demographics, he wrote, spurring on the development of cities in countries with unbearable heat, like Dubai and Singapore.

Air conditioning also changed how buildings were constructed, sparking the construction of tall skyscrapers, where air conditioning can provide cool air to the heat-drawing top floors, Harford said. What's more, as computers are vulnerable to heat, air conditioning has allowed server farms to thrive.

A political effect?

Air conditioning has also prompted migration in places like the U.S., where it was responsible for the single largest migration in that country's history, according to author Steven Johnson, who wrote How We Got to Now: Six Innovations That Made the Modern World. The migration to the U.S. Sun Belt — including some places that had been nearly inhabitable without air conditioning — would also have political implications.

Many of those who relocated down south were older and tended to vote Republican, causing a major transformation to the U.S. Electoral College, Johnson said. In a 2014 interview with PBS, he explained that Sun Belt coalition would end up being crucial to Ronald Reagan's election in 1980.

"Now it's possible that Reagan could have gotten elected without air conditioning, but he would have had to have built a completely different political coalition to do it. So AC is absolutely a part of that story," he said.

The invention can be traced back to U.S. engineer Willis Carrier — the so-called "father of air conditioning."

In 1902, Carrier's employer was called upon to help a Brooklyn printer, who found that the humidity in his plant was smearing the ink. Carrier figured out a way to dehumidify the air in the plant, said Johnson, but also discovered an advantageous side effect: It made the air cooler.

Carrier would continue to refine his invention, and eventually air conditioning would become a staple in the majority of U.S. homes, office buildings and shopping malls.

Much of the general public, however, was first exposed to air conditioning in the "burgeoning movie theatres of the 1920s," Harford noted.

"The enduring Hollywood tradition of the summer blockbuster traces directly back to Carrier," he wrote in the BBC piece.

Most importantly, manufactured cold air has been a lifesaver.

In 2013, a group of American researchers released a study that looked into heat-related deaths in the U.S. and the impact of air conditioning on the country's mortality rates.

They found that "the mortality effect of an extremely hot day" dropped by roughly 80 per cent for the period of 1960 to 2004, when compared to 1900 to 1959 — and it was essentially attributable to the adoption of residential air conditioning.

"It changed dramatically," said Alan Barreca, an environmental economist and associate professor at UCLA's Institute of the Environment and Sustainability, as well as one of the study's co-authors.

"Our vulnerability to extreme heat has fallen 80 per cent," said Barreca. "We can confidently say that if we did not have air conditioning, [heat-related fatality rates] would be in the tens of thousands [annually]."

Considering the environmental impact

Yet despite the benefits, air conditioning takes a major toll on the environment.

The International Energy Agency released a report last year that found the growing use of air conditioners in homes and offices around the world will be one of the top drivers of global electricity demand over the next three decades.

Global energy demand from air conditioners is expected to triple by 2050, the IAE said, and will consume as much electricity as all of China and India today.

With fossil fuels still the major source of electricity, the agency says this demand will have a significant impact on climate change.

"Growing electricity demand for air conditioning is one of the most critical blind spots in today's energy debate," IEA executive director Fatih Birol said in a news release about the 2018 study.

Maxime Roy, a physician who works for Montreal's public health authority, agrees that air conditioning is potentially a life-saving measure, especially for individuals who are vulnerable to heat, including young children and the elderly.

However, while air conditioning cools off homes, the hot air pumped outside can cause temperature increases in neighbourhoods, said Roy, also co-author of the report looking at the 66 heat-related deaths in Montreal last year.

"If we live in a larger city and every individual who is vulnerable — or maybe not so vulnerable — to heat has air conditioning, we're actually making things worse in our city," he said.

But Barreca believes the net benefits of air conditioning still outweigh the negatives.

"It seems to me to be a worthwhile trade-off — that protecting our lives is worth it," he said. "And the question is, where can we cut back elsewhere? This seems to be too important to give up."