Thursday, July 13, 2017

CLIMATE CHANGE: AS TEMPERATURES SOAR, AIRPLANES CAN'T

On June 19th, the Arizona Republic published this headline:

Nearly 50 flights cancelled Tuesday as Phoenix nears 120-degree day

My first thought was that the tarmac had melted, but of course a modern international airport is paved with concrete, not asphalt. The problem turns out to be basic physics--hot air is less dense than cold air. That's what gives a hot-air balloon lift, but it steals lift from a plane. Every plane has a rated temperature beyond which it can't take off if fully loaded--it can't pick up enough speed to get airborne before running out of runway. 

As the world warms, we can expect more planes stuck at gates
Photo credit: AP

At 120 degrees, smaller commuter aircraft were stuck in Phoenix until the heat abated, while larger, more powerful planes, like the Airbus or the Boeing 747 still had 6 or 7 degrees to spare.

Don't expect this to be an isolated incident, a new study warns. Researchers at Columbia University examined the impact rising temperatures due to global warming will have on 20 major airports worldwide, including Phoenix, Denver, LaGuardia and Ronald Reagan, in Washington, DC. As reported in the journal Climatic Change, under a "business as usual" scenario, on hot days, 10 to 30 percent of flights could be affected and airlines on average would lose about four percent of capacity.

That may not sound like a lot, but since more than 8 million people fly every day, that could mean 320,000 hot and unhappy passengers. In addition, given the slim profit margins of most airlines, that kind of loss could have serious financial implications.

And, the authors point out, those unbearably hot days may come around much more frequently as the atmosphere continues to warm. Daily maximum temperatures at major airports may rise by 4 to 8 degrees C (7.2 to 14.4 F) by 2080 under many scenarios. That would mean far more frequent and intense heat waves and far more delayed, cancelled or weight-restricted flights.

"Our results suggest that weight restriction may impose a non-trivial cost on airline and impact aviation operations around the world," writes lead author Ethan Coffel, at Columbia University.

One more non-trivial reason to take climate change seriously, and do everything we can to slow it down.

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