Aviation has come a long way since 1903. From the first flights of prototype planes to the robust aviation industry of commercial flights we see today, human accomplishment has been able to bring forth possibilities for travel that had never been seen in the centuries before. Today air travel by commercial airlines allows for speedy trips at the largest scales. A trip to New York that once took days could now take only a few hours thanks to the wonders of air travel today.

Unfortunately, CO2 emissions have also come a long way since 1903. When we consider the rise of GHG emissions like CO2, we often think of transportation as one of our major sources for emissions in the atmosphere. Whether it’s trains that travel across the country on track, or cars that lull amidst traffic on the freeway, many common modes of transportation we utilize today produce CO2 emissions to varying degrees.

Air travel is a significant source of emissions

Air travel stands out as a significant source of CO2 emissions compared to other modes of transportation, making up 2.5% of global CO2 emissions annually. On average, planes produce 25 kg in emissions per passenger traveling 100 km—a stark contrast to trains, which produce 4 kg per passenger on average for every 100 km.

Among other countries, the United States has the highest number of passengers traveling by air in the world. Many different factors contribute to the CO2 emissions that are produced from air travel, such as the disproportionate distribution of passengers among flights (which puts strain on airlines and their efficiency), and the low fuel efficiency of various different aircrafts.

The International Council on Clean Transportation (ICCT) has stated “if everyone in the world took just one long-haul flight per year, aircraft emissions would far exceed the US’s entire CO2 emissions.” BBC’s climate and environmental journalist Jocelyn Timperley, wrote in 2019 that “mile for mile, flying is the most damaging way to travel for the climate… For those of us that do fly, it is likely to make up a significant slice of our personal carbon footprint.


Source Visual Carbon: http://www.saxifrages.org/eco/show85h0s/Kilometers_per_tonne_of_climate_pollution

This chart from Visual Carbon shows the distance you can travel per ton of climate pollution emitted. The chart explains how a carbon budget that keeps the world below 2.0C of warming dictates that each American and Canadian emit an average of 1 ton of CO2 per year for travel for the next 35 years. Currently we travel over 20,000km per year on average.

Ideally, if you want to travel long distances with a low carbon footprint, public transportation services like the train or bus would be your best choice. Nevertheless, should you choose to travel by air, there are many different steps that you can take if you want to reduce your carbon footprint.

Flying Economy class

One simple solution to reduce your carbon footprint while flying would be to book Economy class tickets rather than Business class tickets. Compared to Business class, flying in Economy class can not only be an economical way to save money on your trip, but it can also improve the overall efficiency of the aircraft. By flying Economy class, airlines can maximize the number of passengers that are flown to their choice of destination.

Book nonstop flights

Trips with layovers generally tend to produce more CO2 emissions than trips with nonstop flights. To compare, an American Airlines flight listing with a nonstop flight from SMF to LAX produces about 103 kg CO2 emissions; meanwhile another American Airlines flight from SMF to with a layover in Phoenix, Arizona produces 172 kg CO2 emissions. If they’re available, booking nonstop flights can help to reduce overall CO2 emissions, in addition to saving you extra time without stops.

Flying with fuel-efficient aircraft

Some airlines like Frontier have taken to address the issue surrounding CO2 emissions by improving the overall fuel efficiency of their aircraft. Frontier Airlines has developed the Airbus A321neo as one of the most fuel-efficient aircraft models in the country. If you are flying with Airlines like Frontier, you can look forward to a selection of their aircraft providing enough fuel efficiency to bring about a reduction in CO2 emissions.

Sustainable Aviation Fuel

A novel innovation that is seeing a rise within the aviation industry is sustainable aviation fuel (SAF). Unlike conventional jet fuel, SAF is a biofuel made from renewable biomass and waste materials, such as corn grain feedstock, algae, manure, wastewater sludge, and agricultural residue. SAF has been shown to reduce CO2 emissions from air travel by 80%. The production and use of SAF also provides numerous benefits that extend beyond aviation, including increased employment opportunities within U.S. manufacturing, the financial support of farmers, erosion management from biomass crops planted, and improved water quality from biomass.

The following graphic is sourced from the International Air Transport Association. It visualizes the processing and implementation of sustainable aviation fuel from feedstock to flight fuel.

Some individual airlines and airports have made it their objective to incorporate SAF into their aircraft. United Airlines has made advancements to increase the production of SAF for use in commercial flights. Neste co. is working with LAXFuel (among other collaborators) to bring SAF to the aircraft flying out from the Los Angeles International Airport (LAX). JetBlue flights from LAX have been using SAF since 2021, and as of last December, they’ve agreed to purchase 92 million gallons of SAF as part of their goal to ensure that 10% of their flights use SAF by 2030.

As more airlines and airports continue to incorporate the use of SAF into their commercial flights, it’s more likely we may see a general reduction in emissions from air travel. For now, you can look into the sustainable flight options that United Airlines has to offer as part of their new initiative, or you can find out more about airlines like JetBlue that use SAF by flying through the Los Angeles International Airport.

Google Flights

Since 2021, Google has added a new feature to their Google Flights search tool. This new feature allows users booking through Google Flights to view and sort flights by their CO2 emissions. To do this, you can go onto the Google Flights site and search for your desired flight. There, you will find many flight options that list the average CO2 emissions of said flights alongside other flight details. To sort these flight listings, you can click where it says “Sort By” at the top-right of listings, then choose “emissions” from the drop-down menu. You will see flights that have significantly lower emissions labeled with a green badge just below emissions listings. This way, by booking through Google Flights, you can streamline your process for choosing flights and find more sustainable flight options with ease.

Emissions calculators

Calculators can serve as an additional tool if you are interested in learning more about how to track CO2 emissions. The Air Miles Calculator is one easy tool that can calculate your emissions based on the airport locations and airlines that you input. Google also has a simplified tool for calculating emissions on their sustainability page. The International Civil Aviation Organization (ICAO), a specialized agency of the United Nations, also provides an air travel carbon dioxide emissions calculator for use in offset programs.

In short…

Air travel continues to be a significant contributor towards our global CO2 emissions. That said, it can be beneficial to know about the many different options you have available that could help reduce emissions. Hopefully in the future, you will have new resources to utilize when you’re planning your next flight.

More Cool Davis content for you

Two recent Cool Davis articles show how significant air travel emissions are: Leslie Crenna’s flight to the east coast last summer equaled about a normal full month’s worth of total emissions. Davis resident and long-time climate change hero, Chris Jones, using the Cool California Calculator, determined that Johan Verink’s yearly trip to the Netherlands, doubled his transportation impact for the year.