Flying Dirty: Why Airlines Emissions Rise Even When They Try to Cut

  • Major airlines are using new aerodynamic devices like winglets, and experimenting with cleaner fuels to reduce their emissions.
  • Still, their total carbon footprint is increasing. The grounding of flights due to the pandemic will provide only a temporary respite.

When the Wright brothers first took flight back in 1903, it’s unlikely they considered that the industry would become notorious for pollution. Today, aviation is responsible for 12 percent of all carbon emissions in the transport sector, and 2 percent of overall global emissions.

The industry itself has emphasized in recent years its efforts at becoming carbon neutral. And indeed, several airlines have turned to more efficient engines and streamlined aircraft while also experimenting with alternative (and less polluting) fuels. That’s helping them reduce their carbon emissions per passenger, for each mile they fly.

But airlines — before the coronavirus pandemic temporarily stopped most air travel — were adding passengers and looking to take on more routes. As an industry, that pattern is expected to resume once the crisis passes, even though it might take a few years and several carriers might not survive. For those that grow once again, adding more passengers could wipe out any gains from their climate change initiatives, suggests recent research led by Susanne Becken, professor of sustainable tourism at Griffith University in Melbourne, and a member of the sustainability advisory panel at Air New Zealand.

Every single one of the world’s 58 largest airlines increased its total carbon emissions between 2017 and 2018.

Collectively, these airlines increased their carbon footprint by 5.2 percent — with passengers flying 4.5 billion times during that time frame. It’s a stunning pointer to just how far the industry is from realizing its own emission targets.

In 2009, the International Air Transport Association, the global trade association for cargo and passenger air carriers, set the goal for airlines to turn carbon neutral (no increase in emissions) by 2020, and a 50 percent reduction in emissions by 2050.

Getting there though, will be a challenge, acknowledges Jacqueline Drumheller, a now-retired sustainability manager who spent 20 years with Alaska Airlines. In 2017-18, the company cut its per passenger emissions by 20 percent but still increased its total carbon footprint by 3 percent. “They’ve pretty much exhausted most of the efficiencies that they can do,” says Drumheller.

Spanish flag carrier Iberia reduced emissions per seat by 6 percent but increased absolute emissions by 8 percent. China’s Hainan Airlines reduced its emissions by 24 percent but increased absolute emissions by 45 percent, Becken’s research shows.  

If any airline shows a reduction in total emissions this year, that’ll only be because globally, more than 16,000 planes are grounded because of travel restrictions aimed at curbing the spread of the coronavirus. The impact of the lockdowns on the environment is already clear — and not just because of the aviation industry. “In California we’ve seen drops in pollutants in every county across the board,” says Caroline Parworth, sensor technologist at environmental intelligence firm Aclima.

airplane on runway ready for take off

Aviation emissions aren’t going down.

Source Getty

For sure, emissions per passenger mile flown have dropped by about 50 percent since 1990. But the number of passengers who’ve flown has grown 150 percent in an even shorter period — since 2004.

Some of the efficiencies planes have adopted include winglets — devices mounted on wingtips used to improve the aerodynamic efficiency of the carrier by up to 15 percent — and new aircraft and wing designs to cut noise and emissions. Many airliners have also begun to experiment with fuels that emit less CO2 while we wait for a bold, long-term plan some scientists are hatching to convert carbon emissions back into fuel. “You’re going to need a transitional plan,” says Noah Malmstadt, a chemical engineering professor at the University of Southern California.

So, what’s the solution? For starters, Becken argues in her research, airline companies need to become more transparent. She found that half of the world’s major airlines are engaging in carbon offsetting practices — where companies compensate for their emissions through programs designed to make reductions in emissions from other parts of the economy. Air New Zealand, for instance, is helping restore native forests in the country. But only 13 airlines provide information on the measurable impact of these initiatives, making it harder to hold them accountable to their promises, she says.

She also found that while 18 of the 58 top carriers were investing in alternative fuels, the scale of their commitment remains miniscule. In 2018, Air Canada declared a 160 ton carbon saving by blending 230,000 liters of biojet fuel — which is made from vegetable oils and animal fats, and is cleaner than traditional aviation fuel — into its fuel mix for 22 domestic flights. But on its own, that’s not enough fuel to fill the tank of a single A380 plane. Increasing research and development investments will be key, Becken argues.

Airlines know that the pressure to act is mounting. Delta announced in mid-February that it would invest $1 billion over the next 10 years to become the world’s first carbon-neutral airline (including by using carbon offsets). Meanwhile, engineers at MIT are flying the first-ever plane without moving parts, powered by an ionic wind instead of propellers or turbines, designed to improve fuel efficiency and cut emissions.

Yes, the Wright brothers have indirectly led us here, but it would be in their spirit to find a way out too.

(An earlier version of this article cited the International Civil Aviation Organization’s projections — detailed in its documents and on its website — showing that unless airlines do more, the industry’s carbon emissions could triple by 2050. However, the ICAO has said it does not stand by those figures.)

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