Would Airlines Solve Much Of Their Environmental Problems If They Just Flew Higher?

Before the pandemic aviation was putting climate change on the agenda, or at least trying to get ahead of government restrictions.

Delta claimed they’d be carbon neutral starting in March, but this was mostly coming from buying carbon offsets which are dubious. United’s efforts center on biofuels, which at current technologies are too resource-intensive to scale. American Airlines just buys newer, more fuel-efficient planes.

It’s unclear how much passengers actually care about the environmental footprint of their travel. When given the choice they decline to buy carbon offsets (Catholic indulgences). Governments care, though.

It turns out what while aviation’s contribution to global emissions has been growing as worldwide air travel has grown (pre-pandemic), it hasn’t increased in relative importance. Between 2000 and 2018 aviation has steadily accounted for about 3.5% of climate-affecting emissions, and that includes commercial and cargo flights, according to a new study from climate scientist David Lee and Manchester Metropolitan University.

What’s especially interesting though is just how aviation appears to affect climate. It’s contrails that matter most – water vapor and exhaust forming ice crystals. And while this is the main pollutant, they’re only about half as much of a driver of warming than once believed.

Better still, they’re “the easiest” of what planes emit to reduce.

[T]he most cost-effective would be to change the altitudes of the 15 percent of (U.S.) flights that fly in conditions that lead to the formation of contrails. They estimate that a 2,000-foot increase in cruise altitude for those flights would reduce contrail impact by 62 percent, while a 4,000-foot increase would reduce it by 92 percent. This would require better meteorological data in flight planning, but its cost in terms of fuel burn and flight time would be small.

Hydrogen-based fuels won’t solve the contrails problem, which is the largest environmental challenge – but if these ever did scale airlines could fly at higher altitudes as a mitigation step, too.

As we learn more about the true environmental impact of travel, we’ll need a mix of strategies and need to start with the low hanging fruit. Sure, burning less fuel matters holding everything else equal. And using less-emitting fuels would be nice if they were technologically feasible. But there are easy things we can do now, as a bridge to a better technological future.

About Gary Leff

Gary Leff is one of the foremost experts in the field of miles, points, and frequent business travel - a topic he has covered since 2002. Co-founder of frequent flyer community InsideFlyer.com, emcee of the Freddie Awards, and named one of the "World's Top Travel Experts" by Conde' Nast Traveler (2010-Present) Gary has been a guest on most major news media, profiled in several top print publications, and published broadly on the topic of consumer loyalty. More About Gary »

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  1. How are ice crystals a pollutant? If that’s the real issue, then AOC and her crowd can just ban snow and we’re all set, right?

  2. Airlines all normally fly their planes at or near the service ceilings for each type for the fuel savings. Flying higher would require new types, new wings, new engines capable of those higher altitudes. All this costs huge money to design, build and purchase. Flying higher wont work because airlines are already flying their planes to their performance limits.

  3. I am doing what I can to help the environmental impact of aviation. I have abstained from daily jet travel during the COVID-19 pandemic. Once the metrics for infection and death rates return to pre-pandemic levels, I will need to fly six times more than usual to reclaim my shares of saved up carbon dioxide (C02) emissions determined when calculating my environmental carbon footprint.

  4. I wonder if jets could be powered by battery-operated electric engines, which in addition to reducing or eliminating CO2 emissions, might reduce the need to carry and burn fuel.

  5. Every cloud has a silver lining. If you care at all about global warming then you can take some solace from the fact that COVID-19 has forever changed demand patterns for business travel.

    Restrictions on flying has brought home to the old timer baby boomer executives the truth that they no longer need to ferry their underlings across the continent for inquisitions or for those popular “feel good” meet and greet events that include sermons from “experts” for hire.

    On-line streaming meetings will do more to curb airline emissions than flying 2,000 feet higher, if that is even an option. This of course applies to auto emissions as well, with working from home now recognized as a valid option by companies that only recently would never have approved that choice.

  6. @Pete I agree, the best way to reduce these emissions is to reduce the amount of flying. Let’s be honest with ourselves, spending hours a week in narrow body economy plus to fly to a terrible office building in the Southwest to provide ‘change management consulting’ is not a good use of time or money. Glad people are finally seeing this and hopefully can spend more time enjoying their lives rather than traveling and eating mediocre food in a crowded metal tube.

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