Airline Flight Length: Increase Because of Climate Change

https://www.eurekalert.org/pub_releases/2015-07/whoi-ata070915.php
https://www.whoi.edu/news-release/air-travel-and-climate
https://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2715.html
Air flights are taking longer, and it is because the wavy jet stream is slowing the planes in the air. That is, climate change and El Niño affecting flight times-and longer flights mean more fuel use, which contributes to greater climate change, say researchers from the Woods Hole Oceanographic Institution (WHOI) and University of Wisconsin-Madison, who recently published their findings in Nature Climate Change.

"Upper level wind circulation patterns are the major factor in influencing flight times," says lead author Kris Karnauskas, an associate scientist in WHOI's Geology and Geophysics Department, according to a release. "Longer flight times mean increased fuel consumption by airliners. The consequent additional input of CO2 into the atmosphere can feed back and amplify emerging changes in atmospheric circulation."

After one scientist's flight from Honolulu to the east coast took far less time than expected, two of the researchers looked at flight-level wind data on a NOAA website. They saw that the jet stream was very fast that day. Then they studied decades worth of data on fights between Honolulu and Los Angeles, San Francisco, and Seattle, by four different air carriers, the release said.

Even after accounting for the fact that the jet stream is a bit stronger in winter and weaker in summer, flight-level wind explained 91 percent of the year-to-year variance. El Niño also seemed to be an influence, as they said in their report.

The temperature of the equatorial Pacific Ocean directly influenced atmospheric waves set of toward the higher latitudes of both hemispheres. They there changed circulation patterns, the researchers say in a release.

According to Karnauskas, in the release, the change seems minor but is actually costly. "The wind really fluctuates by about 40 mph, so multiply those couple of minutes by each flight per day, by each carrier, by each route, and that residual adds up quickly. We're talking millions of dollars in changes in fuel costs."

The researchers think their information could be useful for the airline industry to more efficiently plan for future fuel costs and predict flight durations. The scientists also plan to expand the study to include all U.S. and European flights, their release noted.