Flying west? A warmer Pacific is whipping up air currents, making planes burn $3bn a year in extra fuel, study finds
By Alex Pashley
If you board a flight from Hawaii to Los Angeles, be sure to check if a strong El Nino is brewing.
It could slow your flight time by an average of 11 minutes, according to new research.
Warming waters in the Pacific Ocean around the equator affect air currents at cruising altitude, known as the jet stream.
Researchers at the Woods Hole Oceanographic Institution and University of Wisconsin Madison studied decades of flight data between Honolulu and the North American West Coast by four carriers.
The verdict: climatic conditions are costing billions in wasted fuel and stoking global warming.
“Upper level wind circulation patterns are the major factor in influencing fight times,” lead author, Kris Karauskas, said in a statement.
“Longer flight times mean increased fuel consumption by airlines. The consequent additional input of CO2 into the atmosphere can feed back and amplify emerging changes in atmospheric circulation.”
Winds generally blow from west to east, making eastbound flights quicker. But the two trends don’t cancel out.
While eastbound flights became 10 minutes shorter, the corresponding westbound journey became 11 minutes longer, researchers found after crunching Department of Transportation data.
Controlling for seasonal changes – the jet stream lessens in the summer – and changing temperatures in the Pacific produced the same result.
“Whatever was causing these flights to change their duration was the exact same thing and it wasn’t part of the airlines’ decision-making process. The hypothesis was born that climate variability (not just day-to-day weather) determines flight times,” Karauskas added.
In an industry with an estimated 30,000 commercial flights a day, that minute counts.
Researchers calculate it equates to an extra 300,000 more hours a year of flying time a year, requiring an additional 1 billion gallons of jet fuel, worth $3 billion.
Then there’s the climate change angle: those surplus hours spew 10 million tonnes more of CO2.
Global air travel contributes around 3.5% of greenhouse gas emissions driving climate change – similar to Germany’s annual emissions.
The industry has made a voluntary commitment to keep emissions level from 2020. It plans to bring in a market to offset any emissions growth with green projects, although this is behind schedule.
The study covers a small subset of total global airline traffic. The researchers plan to expand it to track all US and European flights.
“The airline industry keeps a close eye on the day-to-day weather patterns, but they don’t seem to be concerned with cycles occurring over a year or longer,” Karnauskas said.
“They never say, ‘Dear customer, there’s an El Nino brewing, so we’ve lengthened your estimated flight duration by 30 minutes.’ I’ve never seen that.”