Study Shows Full Decarbonization Of US Aviation Sector Is Within Grasp

Nov 15, 2022

Everyday, 45,000 planes fly across the United States, carrying some 1.7 million passengers. Aviation dominates a frequent traveler's individual contribution to climate change, and yet is one of the most challenging sectors to decarbonize.

New research published on November 14 in the journal Nature Sustainability shows a pathway toward full decarbonization of U.S. aviation fuel use by substituting conventional jet fuel with sustainably produced biofuels.

The study, led by a team of Arizona State University researchers, found that planting the grass miscanthus on 23.2 million hectares of existing marginal agricultural lands—land that often lays fallow or is poor in soil quality—across the United States would provide enough biomass feedstock to meet the liquid fuel demands of the U.S. aviation sector fully from biofuels, an amount expected to reach 30 billion gallons/year by 2040.

"We demonstrate that it is within reach for the United States to decarbonize the fuel used by commercial aviation, without having to wait for electrification of aircraft propulsion," said Nazli Uludere Aragon, co-corresponding author on the study and a recent ASU Geography Ph.D. graduate.

"If we are serious about getting to net zero greenhouse gas emissions, we need to deal with emissions from air travel which are expected to grow under a business-as-usual scenario. Finding alternative, more sustainable liquid fuel sources for aviation is key to this."

The team then analyzed whether growing energy crop feedstocks on these lands would have detrimental effects on the surrounding climate or soil moisture and predicted the potential productivity of yields of two different grasses—miscanthus and switchgrass—as suitable biomass energy feedstocks. Finally, the team quantified the amount and the cost of biojet fuel that would be produced and distributed nationwide at scale.

"The current way we produce sustainable jet fuel is very land inefficient and not on a large scale," said Nathan Parker, an author on the study and an assistant professor in the School of Sustainability. "There are very limited ways that aviation could become low carbon emitting with a correspondingly low climate impact and this is one way we've shown that is feasible and can get the aviation industry to be carbon neutral through agriculture."

The scientists emphasized that this integrated systems perspective was critical to the study. In the past, research around the potential of biofuels has largely consisted of isolated assessments that have not been well-integrated, for example, overlooking key data on how the altering crop cover influences the surrounding climate.

A template for the future

The researchers say that in finding further solutions to the Earth's climate crisis it is important that the scientific community bridges disciplines and moves past incremental reductions in emissions. Rather, the researchers emphasize the importance of realistic solutions that scale.

"This was an interdisciplinary team with expertise from ecosystems sciences, climate modeling and atmospheric sciences and economics," said Georgescu, who acknowledged this research was a culmination of eight years of modeling work and collaboration. "To truly address sustainability concerns, you need the expert skills of a spectrum of domains."

"As academics, we should remember economics drives people's decisions on the ground. It is vitally important to find the circumstances when these decisions are also aligned with desirable environmental outcomes."

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Video: Why Your Food Future Could be Trapped in a Seed Morgue

In a world of PowerPoint overload, Rex Bernardo stands out. No bullet points. No charts. No jargon. Just stories and photographs. At this year’s National Association for Plant Breeding conference on the Big Island of Hawaii, he stood before a room of peers — all experts in the science of seeds — and did something radical: he showed them images. He told them stories. And he asked them to remember not what they saw, but how they felt.

Bernardo, recipient of the 2025 Lifetime Achievement Award, has spent his career searching for the genetic treasures tucked inside what plant breeders call exotic germplasm — ancient, often wild genetic lines that hold secrets to resilience, taste, and traits we've forgotten to value.

But Bernardo didn’t always think this way.

“I worked in private industry for nearly a decade,” he recalls. “I remember one breeder saying, ‘We’re making new hybrids, but they’re basically the same genetics.’ That stuck with me. Where is the new diversity going to come from?”

For Bernardo, part of the answer lies in the world’s gene banks — vast vaults of seed samples collected from every corner of the globe. Yet, he says, many of these vaults have quietly become “seed morgues.” “Something goes in, but it never comes out,” he explains. “We need to start treating these collections like living investments, not museums of dead potential.”

That potential — and the barriers to unlocking it — are deeply personal for Bernardo. He’s wrestled with international policies that prevent access to valuable lines (like North Korean corn) and with the slow, painstaking science of transferring useful traits from wild relatives into elite lines that farmers can actually grow. Sometimes it works. Sometimes it doesn’t. But he’s convinced that success starts not in the lab, but in the way we communicate.

“The fact sheet model isn’t cutting it anymore,” he says. “We hand out a paper about a new variety and think that’s enough. But stories? Plants you can see and touch? That’s what stays with people.”

Bernardo practices what he preaches. At the University of Minnesota, he helped launch a student-led breeding program that’s working to adapt leafy African vegetables for the Twin Cities’ African diaspora. The goal? Culturally relevant crops that mature in Minnesota’s shorter growing season — and can be regrown year after year.

“That’s real impact,” he says. “Helping people grow food that’s meaningful to them, not just what's commercially viable.”

He’s also brewed plant breeding into something more relatable — literally. Coffee and beer have become unexpected tools in his mission to make science accessible. His undergraduate course on coffee, for instance, connects the dots between genetics, geography, and culture. “Everyone drinks coffee,” he says. “It’s a conversation starter. It’s a gateway into plant science.”