Surfing The Wind Could Cut Long-Distance Flights' Environmental Costs

Stephen Luntz | IFL Science | 27 January 2021

Airlines flying intercontinental routes are spending more money on fuel and emitting more greenhouse gasses than necessary by failing to ride the winds to their full potential, researchers claim. Better use of satellite data could lower the environmental cost of air travel.

The fact that a good tailwind can bring an airplane in early is not news to seasoned travelers. Pilots and airlines are even more aware they can save a lot of fuel if they let natural forces do a lot of the work for them. One flight surfed the winds from Storm Ciara creating a new New York to London record last year. However, when University of Reading PhD student Cathie Wells studied the way flights between Europe and North America operate she found they are leaving major opportunities for reducing their environmental impact on the table.

Flights from Europe to North America already tend to fly north of the most direct route to avoid the maximum effect of the eastward flowing jetstream, but Wells found they could do a lot better.

"Although winds are taken into account to some degree when planning routes, considerations such as reducing the total cost of operating the flight are currently given a higher priority than minimizing the fuel burn and pollution," Wells said in a statement. "Current transatlantic flight paths mean aircraft are burning more fuel and emitting more carbon dioxide than they need to."

In Environmental Research Letters, Wells and supervisor Professor Paul Williams studied 35,000 flights between New York and London in the winter of 2019-20. The authors compared the shortest route relative to the wind around them, using the jetstream flying east, or avoiding it on the American-bound leg of the journey, with what the planes actually did.

The authors concluded some flights burned 16 percent more fuel than necessary, translating to an equivalent increase in environmental damage. Even the average figure was over 2 percent. The results may not translate perfectly to other routes, particularly those in north-south directions, but are unlikely to be unique.

Air travel contributes roughly 2.4 percent of greenhouse gas emissions, but is rising fast and is likely to prove much harder to address than other major emissions sources.

"Upgrading to more efficient aircraft or switching to biofuels or batteries could lower emissions significantly, but will be costly and may take decades to achieve," Williams said. "Simple tweaks to flight paths are far cheaper and can offer benefits immediately."

The lack of radar coverage over the middle of the Atlantic has forced planes to keep further apart than they would elsewhere. Combined with how crowded the route gets, this has reduced opportunities for flights to choose their ideal wind conditions. However, Wells and Williams note this is no longer necessary, with a new generation of low-Earth orbit satellites now keeping airplanes in view over oceans as well as land.

The benefits Wells and Williams are promoting are separate from avoiding contrail-forming conditions, a practice that marginally increases fuel consumption while drastically cutting the overall environmental cost of flights.