Too Hot to Fly

Phoenix’s heat wave grounded planes and stranded customers. It’s about to become much more common.

The airline industry is now faced with rising costs because of climate change.


A few weeks ago, in mid-June, I was making my first trip to Phoenix. I was supposed to be flying in during a time when, we were hearing, it was too damn hot to fly. Airlines were canceling or delaying flights out of Phoenix Sky Harbor International Airport as the mercury hit a blazing 119 degrees Fahrenheit.

By the time I landed around 9:30 p.m. on June 21, temperatures had cooled to a manageable 103 degrees. I figured I missed the worst of the heat wave.

Temperatures did slightly cool off. Flights were no longer grounded, and news was no longer made. But at the end of my trip, Delta still called me to ask if, for a $300 voucher, it could bump me to a later flight. Temperatures were 114 degrees—which meant that my full but not overbooked airplane would still be taking off, but it would be subject to “weight restrictions.” I declined, as did most fellow passengers apparently. Still, Delta couldn’t let everyone get on that plane. High heat means thinner air, which requires more power for planes to take off safely or lighter planes requiring less power. It was too damn hot to fly with all of us. When I reached my gate, the offer went up to $600.

It took $1,000 flight vouchers for Delta to persuade enough passengers—about 11 of us—to take another flight. One day of Phoenix heat easily cost the airline thousands of dollars.

That’s about to get a lot more common. On Thursday, researchers at Columbia University published a new analysis quantifying exactly how increases in extreme heat expected (and already seen) in a warming world will affect airplanes. They conclude that my experience in Phoenix—forcing passengers, cargo, and fuel off full planes—could be echoed for between 10 and 30 percent of planes flying during the hottest times of day.

Airports in hotter locales, with shorter runways, or at higher altitudes (where air is already thinner) are particularly at risk of these extreme heat effects. The aviation industry has dealt with this before, says Marshall Turner, a partner at aviation industry law firm Condon & Forsyth LLP. And there are a few ways it can address the problem: Airplanes could install more powerful engines, they could schedule flights for cooler times of day, or they could reduce weight.

Reducing weight could mean that companies upgrade their planes so they are lighter, but it’s likely that, at least in the near term, flights will boot customers when it’s too hot, like Delta did to me. For most scenarios, the Columbia researchers found that by mid-to-late century, planes would need to regularly cut weight by 0.5 to 4 percent. That might not sound like much, but it adds up—“for an average aircraft operating today, a 4 percent weight reduction would mean roughly 12 or 13 fewer passengers on an average 160-seat craft,” a Columbia press release noted. And at an airport like Dubai, a Boeing 777-300, holding nearly 400 passengers, could need to cut weight more than half the time when flying in midday heat.

Of course, there’s irony in the fact that the industry delayed addressing its emissions problem based on economic arguments and is now faced with the specter of rising costs because of climate change. (The 1997 Kyoto Protocol exempted the aviation and marine industries from its scrutiny of climate pollution, and in 2005, when the European Union tried to force U.S. and European airlines into a cap-and-trade program, it eventually backed down because U.S. airlines, along with China, cried foul.) Last year the United Nations International Civil Aviation Organization finally agreed on steps to reduce globe-warming emissions from aviation, but they’re voluntary and don’t take effect till 2021.

Research already suggested that it was possible for flights to cut emissions in ways that would have paid for themselves. Now, facing larger costs just to keep operating in our warming world, perhaps it will become more obvious that the cost of doing nothing is more expensive in the long run.