Planes,??? ?????? ??????? ???????? ??? ??????? trains, and climate changeis Mashable's ongoing series about the dramatic impacts transportation has on the planet’s warming, and our lives.
If the airline industry were its own country, it would emit more heat-trapping carbon dioxide into the air than nearly every nation on Earth.
To quell these prodigious emissions, and to prepare for a future where already-booming air travelis expected to tripleby 2045, major airlines Delta and JetBlue recently announced lofty designs to slash their carbon emissions. The airlines’ ultimate objective, the holy grail of climate ambition, is to go "carbon neutral" — which means dramatically cutting emissions while finding other ways to suck up the remaining emissions from the atmosphere. "Starting March 1, Delta Airlines will become the first airline to go fully carbon neutral on a global basis," Delta CEO Ed Bastian said last week. "It’s a big challenge," he added.
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To clarify those bold remarks, Bastian didn’t mean Delta will immediately stop pumping massive amounts of carbon dioxide, the result of burning jet fuel, into the air. That’s impossible. Airliners fly on carbon-rich fuel and will largely fly on this fuel through the 2020s, if not much of the 2030s, at least. Instead, he meant Delta would spend some $100 million a year over the next decade to advance aviation technologies that might put the airline on the road towards a carbon neutral future. There are compelling ways to cut carbon from the industry. But the change won’t be quick, or easy.
"It’s ambitious, but it’s not unthinkable," said Timothy Takahashi, an aerospace engineer at Arizona State University, in reference to major airlines going carbon neutral in the coming decades.
A chart showing carbon emissions from planes Credit: International council on clean transportation The airline industry is built upon thousands of expensive, extremely sturdy, fuel-gulping airliners that are designed to last for around half a century. These are the jetliners sold en mass today. Even so, there are realizable ways (that don’t require the stuff of science fiction) to radically slash carbon emissions from airliners.
Clever fuels
Though small and short-range planes might integrate electric motorsthroughout this decade and beyond, big airplanes — which make up around 95 percent of commercial aviationemissions — will continue to burn liquid fuels.
"We can’t really escape liquid fuels for long-range aircraft," said Arizona State’s Takahashi, noting that huge batteries or hydrogen fuel cells are too heavy for bigger planes.
Delta’s CEO, Bastian, agrees. "We will continue to use jet fuel for as far as the eye can see," he told NBC.
But, critically, Delta might want to ramp up investment in fuels that don’t require fracking new oil from the planet. These fuels, called biofuels because they’re commonly made from crops or plant waste, won’t add any new carbon to Earth’s already skyrocketing carbon-dioxide levels. “Instead of releasing carbon as CO2 that’s been in the earth for billions of years, this is from a plant,” said Andrew Sutton, who works on the Chemical Energy Storage Team at Los Alamos National Laboratory. (Sutton is researching ways to make current jet fuels more efficient.)
Already, the Federal Aviation Administration (FAA) has approved five different biofuels(made from the likes of corn and vegetable oils) to be blended together by up to 50 percent with petroleum jet fuel. Commercial planes have flown over 150,000 flights with biofuel blends, but just five airports in the entire worldcarry this fuel. It’s safe to say biofuels are barely being used: These greener fuels made up less than one-tenth of one percentof aviation fuels burned in 2018.
United began using a biofuel blend out of Los Angeles International Airport (LAX) in 2016. Credit: united Airlines But biofuels could make a giant impact if they were ambitiously expanded. “If [airlines] go heavy on biofuels, that a good start in the right direction,” said Takahashi.
Right now these greener fuels typically cost several times morethan jet fuels, but as with expanding solar energy, ramping up scale drives down costs. Starting around July, JetBlue says it will use biofuel blendson some 17 flights a day out of San Francisco (this is out of some 925 JetBlue planesthat take off each day).
If biofuels expand, though, they may run into a problem, specifically in the U.S. heartland. This future airline fuel might compete with food, i.e., two industries would be after the same crop. “You really don't want to compete with a food crop like corn,” said Los Alamos’ Sutton. On the other hand, a whopping 40 percent of the nation’s cornis used to make ethanol, a critical ingredient in automobile gasoline. In the coming decades, if the U.S. finally transitions to electric vehicles, that could free up a major part of the corn harvest for jet engines, not car engines.
"It’s just a matter of cost."
There’s also another type of fuel, which doesn’t rely on plants, that may hold a big promise for future flights. They're called "synthetic hydrocarbons." Instead of being created from plants, this fuel uses CO2 directly, like capturing carbon from the air, to create a synthetic fossil fuel. It's an attractive fuel option because it wouldn’t have to be blended with jet fuel — it is jet fuel, just made without drilling for oil; the fuel exploits what’s already in the air. Researchers know how to make the fuel, but lack the hundreds of millions of dollars needed to build fans to capture carbon and construct a chemical plant to prove the technology.
"There's no fundamental reason you can’t do it," said Tim Lieuwen, who researches alternative fuels at the Georgia Institute of Technology. "It’s just a matter of cost."
Clever flying
To slash carbon emissions, airlines can also change the way they fly.
To burn markedly less fuel, future planes need to fly higher, explained Takahashi. The higher you go in the atmosphere, the less air, and the less resistance. Today, commercial airliners fly at some 30,000 to 35,000 feet. (More than 50 years ago, that's what the industry decided would be optimal for a complicated nexus of safety, engine performance, and so on.) But if newly designed planes flew around 48,000 feet, which is still not as high as the Concordeflew, Takahashi’s models show there could be huge fuel savings.
"We’re talking 30 percent increases in efficiency are possible," said Takahashi. "That’s big."
Grounded Boeing 737 Max planes in Seattle Credit: GARY HE / EPA-EFE / Shutterstock This would, however, require newly engineered planes. Aircraft manufacturers and airlines don’t like that; it means agencies like the FAA must rigorously certify the new planes, and it requires expensive training for pilots. That’s why many airlines went all-in on the now beleaguered Boeing 737 Max, which essentially just added more fuel-efficient engines to a trusty, 50-year-old airplane design. (That plan, tragically, failed).
If airlines are serious about cutting carbon, they may also consider carving up the longest international flights into two shorter legs, explained Takahashi. Long flights mean planes must carry tons more fuel, making the aircraft heavier and demanding more fuel to stay aloft. "You don’t want a plane carrying 12 hours of fuel," he said. "So we might have a lot of Alaska or Hawaii stops," he mused.
Forests
Airlines love carbon offsets. That’s because it’s clearly difficult to disrupt planes, their fuel, and how they fly. But it’s easy to buy offsets, which means paying for projects that absorb carbon from the air (conserving land, planting trees) or technology that replaces fossil fuel burning (wind and solar projects). Delta’s total planned investment of $1 billion includes "investigating carbon removal opportunities through forestry, wetland restoration, grassland conservation, marine and soil capture, and other negative emissions technologies."
Indeed, plants naturally absorb carbon from the atmosphere, and everyone likes trees, but protecting forests and wetlands aren’t a truly permanent carbon solution. Most carbon on Earth is stored away in rocks, trapped in layers of ancient mud or limestone where it stays for millions of years. That’s Earth’s long-term solution for storing carbon. Humanity, meanwhile, can only preserve so much carbon-absorbing land in the short-term, while each year global carbon emissions continue rising, and the planet continues relentlessly heating.
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If Delta sinks most of its $1 billion into carbon offsets, its planes will still saturate the skies with carbon.
Of course, the aviation industry’s carbon burden surely isn’t Delta’s alone. The greater industry already transports more than 4 billion passengersaround the planet each year, while aviation CO2 emissions have risen by 32percent since 2013. Around 20,000 planes fly around Earth today, but some 50,000 planesare projected to take to the air by 2040.
SEE ALSO: Even the 'optimistic' climate change forecast is catastrophicWe can all do the math. To reach carbon neutrality, airlines will need to radically ramp up new fuels — and engineer new, more efficient planes.
"We’re not talking about electric hovercrafts here," said Takahashi. “But I’m hoping stuff will come up within my lifetime that isn’t just patching up a 50-year-old design anymore."