Hotter air may lead planes to carry fewer passengers | Science News for Students

Hotter air may lead planes to carry fewer passengers

Feverish temps could make it more difficult for planes to lift off
Jul 26, 2017 — 7:00 am EST
airplane takeoff

Global warming could force airplanes to carry a lighter load — such as fewer passengers — on each flight.

Chalabala/iStockphoto

Air travel can be annoying. But research now suggests global warming could make it much worse. To get off the ground in really hot weather, planes may be forced to carry fewer passengers. That might mean a little more elbow room, which would be good. However, it also would make flying more expensive. 

Average air temperatures around the world are rising. That global warming is happening because people are polluting the air with increasing amounts of greenhouse gases. These gases, such as carbon dioxide, are a byproduct of burning fossil fuels. Their rising levels help to hold in energy from the sun, causing ground-level temperatures to rise.

Those warmer temps can affect an airplane’s ability to fly. That’s because air molecules spread out more as the air warms. This generates less lift under a plane’s wings as it barrels down a runway. To compensate, a plane must be lighter to take off in hot weather than on cooler days.

It can even prove too dangerous for some planes to attempt a take-off. A record June heat wave in the American Southwest, for instance, caused flight cancellations in Phoenix, Ariz. One airline’s planes were cleared to operate only up to 47.8° Celsius (118° Fahrenheit). On June 20, Phoenix reached a blistering 48.3 °C (119 °F)!

Radley Horton is a climate scientist at Columbia University in New York City. Two years ago, he and graduate student Ethan David Coffel projected the impact of warming at four U.S. airports. The trajectory of expected warming could triple the number of days when planes face weight restrictions, they calculated.

Horton and his colleagues have now expanded on those earlier projections. They probed the impact of rising temps on five types of commercial planes flying out of 19 of the world’s busiest airports. In the coming decades, as many as one to three out of every 10 flights that take off during the hottest time of day could face weight restrictions, they found. In some cases, a typical 160-seat plane would have to jettison 4 percent of its weight. That would be the equivalent of taking a dozen people off the plane, the researchers calculated.

Their study was published online July 13 in Climatic Change.

Power Words

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atmosphere     The envelope of gases surrounding Earth or another planet.

average     (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.

carbon dioxide     (or CO2) A colorless, odorless gas produced by all animals when the oxygen they inhale reacts with the carbon-rich foods that they’ve eaten. Carbon dioxide also is released when organic matter burns (including fossil fuels like oil or gas). Carbon dioxide acts as a greenhouse gas, trapping heat in Earth’s atmosphere. Plants convert carbon dioxide into oxygen during photosynthesis, the process they use to make their own food.

climate     The weather conditions that typically exist in one area, in general, or over a long period.

colleague     Someone who works with another; a co-worker or team member.

commercial     (in research and economics) An adjective for something that is ready for sale or already being sold. Commercial goods are those caught or produced for others, and not solely for personal consumption.

fossil fuel     Any fuel — such as coal, petroleum (crude oil) or natural gas — that has developed in the Earth over millions of years from the decayed remains of bacteria, plants or animals.

global warming     The gradual increase in the overall temperature of Earth’s atmosphere due to the greenhouse effect. This effect is caused by increased levels of carbon dioxide, chlorofluorocarbons and other gases in the air, many of them released by human activity.

graduate student     Someone working toward an advanced degree by taking classes and performing research. This work is done after the student has already graduated from college (usually with a four-year degree).

greenhouse gas     A gas that contributes to the greenhouse effect by absorbing heat. Carbon dioxide is one example of a greenhouse gas.

jettison     To get rid of part of a vessel’s cargo or its materials. This lightens its load and can make it easier to maneuver.

lift     An upward force on an object. It may occur when an object (such as a balloon) is filled with a gas that weighs less than air; it can also result when a low-pressure area occurs above an object (such as an airplane wing).

online     (n.) On the internet. (adj.) A term for what can be found or accessed on the internet.

Citation

Journal:​ E.D. Coffel et al. The impacts of rising temperatures on aircraft takeoff performance. Climatic Change. Published online July 13, 2017. doi: 10.1007/s10584-017-2018-9.

Meeting:​​ ​ E.D. Coffel and R.M. Horton. Climate change and the impact of extreme temperatures on aviation. American Meteorological Society annual meeting, Phoenix, January 8, 2015.