*Editor's Note: This content was created in support of our partnership with Delta Air Lines.

Did you know that a seven-hour flight between London and New York City emits almost 2,000 pounds of CO2… per passenger?

Climate activists around the world have glued themselves to airport tarmacs, chosen to sail across the Atlantic ocean in lieu of boarding an aircraft, and a lot more, all to shed light on the harmful effects that air travel has on the environment. But in a world where airplanes have revolutionized the travel industry for the wealthy minority that fly regularly — reducing what would once require a days-long journey into a few hours — a future without flying seems highly unlikely.

In order for an airplane to fly, it relies on fuel derived from nonrenewable resources like crude oil, petroleum, and natural gas, all of which emit carbon dioxide (CO2). As a potent greenhouse gas, CO2 traps heat in our atmosphere and is a major contributor to global warming.

Keeping in mind the millions of flights that take place around the world, the global aviation industry is responsible for releasing around 1 billion tons of CO2 into the atmosphere every year — that’s 2.4% of total global annual CO2 emissions, and 10% of transport emissions worldwide. That means that if the aviation industry were a country, it would be the sixth largest greenhouse gas emitter, behind China, the US, India, Russia, and Japan.

To combat the negative environmental effects of air travel, airlines have committed to achieving net zero carbon emissions by 2050, in line with the goal laid out in the 2015 Paris Agreement to limit global warming to 1.5°C above pre-industrial levels. But in order to achieve this target, the aviation industry must continue to think creatively and make key investments in sustainable solutions. 

One option that has been investigated — and in some cases, already employed — is sustainable aviation fuel.

One airline that is at the forefront of investing in innovative solutions to create a more sustainable travel future is Delta Air Lines. With their recently announced “Path to Sustainability” strategy, investing in clean fuel, like sustainable aviation fuel, is one way they are making progress towards achieving a net zero future.

What Is Sustainable Aviation Fuel?

As with other transportation industries, discussions about decarbonizing aviation largely revolve around its reliance on fossil fuels. While traditional jet fuel is made from crude oil and petroleum liquids, sustainable aviation fuel (SAF) can be developed from a variety of organic substances or using carbon-capturing technologies.

Plant and animal waste, wood, oils, fats, and grease can all be converted into SAF. These forms of biomass absorb carbon dioxide over the course of their life cycle; even though they release that carbon when burned as fuel, they are considered a carbon-neutral energy source because they don’t add new emissions to the atmosphere.

When produced through eco-friendly agricultural methods, sustainable aviation fuel can reduce greenhouse gas emissions that arise from air travel, helping the aviation industry get one step closer to reaching their net zero target.

3 Things to Know About Sustainable Aviation Fuel

• SAF can be made from non-recyclable organic resources that would otherwise end up in landfills, such as plants, used cooking oil, and sewage, reducing air pollution.
• As a carbon-neutral biofuel, SAF can reduce greenhouse gas emissions from flights by up to 80% over the course of their life cycle, compared to traditional jet fuel.
• Over 450,000 flights have already taken place using SAF.

What Are the Benefits of Sustainable Aviation Fuel? 

One of the major benefits of SAF is its ability to be manufactured from different types of organic materials that have captured CO2 from the air. By drawing on the stores of energy found in these resources, SAF can effectively divert materials from the landfill and recycle the carbon that has already been emitted.

Further, this type of biofuel is considered a “drop-in” solution for the aviation industry — that means it can already be used in existing aircrafts without needing to develop new infrastructure. Currently, aviation guidelines allow airlines to use SAF as long as it is combined in 10% to 50% blends with traditional jet fuel.

Fans of the alternative fuel option also point to the increased economic opportunities for farmers. By supporting different types of biomass in the off season or selling agricultural waste to reduce farm losses, farmers can bring in additional financial opportunities that support SAF manufacturing.

There are also the environmental benefits — not only can growing different types of crops promote biodiversity on land, but repurposing manure or sewage to develop SAF can also help reduce the air pollution that comes from methane gas.

Why Isn’t Sustainable Aviation Fuel ‘the Answer’ to Decarbonizing the Aviation Industry?

While there is widespread support for the expansion of SAF, many climate scientists highlight that it cannot be a standalone solution for building a green aviation industry.

Some of the hesitancy over transitioning to this form of biofuel has to do with supply issues — namely, how SAF can power the growing aviation industry when researchers say current feedstock availability barely meets global jet fuel demand. According to the US Environmental Protection Agency, only 2.4 million gallons of SAF were produced in the United States in 2019, compared to the 21.5 billion gallons of traditional jet fuel that was used by airlines.

And while policy incentives have encouraged investments in alternative fuel options, some climate scientists ask whether the resources used to support SAF couldn’t be put to better use. According to a report from the World Resources Institute, dedicating crops or farmland to the production of biofuel is an inefficient use of land. 

“Any dedicated use of land for bioenergy inherently comes at the cost of not using that land for food, feed, or sustained carbon storage,” the report’s authors write. They warn that diverting resources away from food production or other environmental initiatives could have undue consequences, such as a decline in food supply or rising food prices.

Even with increased supply of the alternative jet fuel, another barrier for airlines is the cost. SAF is up to three times more expensive than jet fuel made from fossil fuels, partly due to the price of new production facilities and refineries.

While SAF is clearly not a long-term solution to eliminate CO2 emissions and carbon output from the aviation industry, many believe that investing in SAF and making it a more readily available near-term solution will give time for continuing innovations in the sector to develop. SAF alone will not solve the problem of the aviation industry’s carbon footprint, but it is a realistic and promising next step in making air travel more sustainable.

In Delta Air Lines’ Path to Sustainability strategy, for example, beyond investing in SAF, the company is also reducing single-use plastics onboard flights, electrifying their ground support equipment at Delta airport hubs, and revolutionizing their fleets with innovative partners to explore developing hydrogen-powered aircrafts in the future. Decarbonizing the airline industry will require all these bold tactics, and more.

How to Support Eco-Friendly Air Travel

Despite the pros and cons of SAF, we know that our current method of air travel is unsustainable — so how can Global Citizens take action to make aviation more eco-friendly?

One option is to take a cue from environmental advocates and reexamine your own travel habits. If you’re planning on boarding a flight for an upcoming trip, is it possible to take a car, bus, or train instead? If the flight is necessary, then consider carbon offsetting while on your trip.

While habit and lifestyle changes are important to improve our individual relationships with the planet, policy shifts carry much more weight when it comes to reducing emissions.

Decarbonizing the aviation industry will require Global Citizens everywhere to support green energy initiatives. Get started by taking our quiz to test what you know about sustainable travel, and find out more about important developments in travel that will help achieve a sustainable world — from increasing funding and research for SAF, to other potential solutions like electric and hydrogen-powered aircrafts. Until this increased support and investment is delivered, SAF remains the most promising initiative to reduce emissions in the short-term.