An Airplane’s Footprint

Let’s take a closer look at air travel’s environmental impact, how you can reduce your impact, and the plans that are in the works to make flying greener.

If you’ve never heard the term “carbon footprint,” you’re not alone. Actually, you are because it’s 2019 and everyone knows that term. But just to be sure that we’re all on the same page, a carbon footprint is “the amount of greenhouse gases (GHGs) and specifically carbon dioxide emitted by something (such as a person’s activities or a product’s manufacture and transport) during a given period.” So, in the context of air travel, it’s the amount of GHGs that a plane spews into the atmosphere during a flight.

You might be thinking, “I know planes emit GHGs, but don’t cars emit them too?” Yes, they do. While flying still isn’t particularly energy efficient, it has improved dramatically over the past few decades and is more energy efficient than cars in some cases, particularly if you’re traveling solo over a long distance. The graph below shows the energy efficiency trends for several modes of transportation since 1980.

Vehicle fuel efficiency chart
Flying is getting better but if you can take a train, do it.
Source: Yale Climate Connections

Improved energy efficiency is all fine and good but there is one wildcard that amplifies the environmental impact of flying: contrails (which are not chemtrails you conspiracy theorist nutjobs). Contrails are the long, white, cloud-like lines you see behind planes when they pass overhead. Contrails are made of water vapor which means they’re man-made clouds. As the contrails disperse, the water vapor traps heat in the atmosphere, resulting in a short-term increase in the greenhouse effect from flying. With thousands of planes emitting contrails every day, they make an impact.

Learning the environmental impacts of flying isn’t great if you love to travel but don’t get your undies in a bunch just yet. You can purchase these things called carbon offsets to make up for your rampant environmental destruction. Carbon offsets are investments in projects that reduce GHG emissions. They don’t prevent any of the carbon from your flight from being released into the atmosphere but many of them do help to fund projects that reduce carbon emissions elsewhere.

To make sure you’re putting your carbon offset money towards a worthy cause, you’ll need to make sure that the project ensures “additionality.” Additionality is a made-up word but it was made up by scientists so you don’t have to feel dumb using it. Basically, it means that the project you’re funding is supporting new (or additional) carbon emission reduction efforts, not just funding something that was going to happen anyway. An example from NRDC: You contribute to a fund to pay a farmer not to clear a piece of the rainforest for new crops. However, if the farmer wasn’t going to clear that plot of land anyway, there is no increased carbon savings as compared to what would’ve happened without your contribution. In that case, your carbon offset purchase hasn’t really changed anything or, in made-up scientific terms, there is no additionality.

Short of going to visit a project site yourself, there isn’t a lot you can do to reliably verify the additionality of your carbon offset purchase. Fortunately, there are a few reputable sites that verify the legitimacy of carbon offset projects or have their own projects. My favorite carbon offset site is because it’s incredibly convenient and verifies its carbon offset projects. FlyGRN is a travel search engine that automatically calculates the cost of offsetting your flight’s carbon emissions. The best part is that if the flight you book is through one of FlyGRN’s partners, they receive a fee from the partner that they apply to the cost of your offsets, sometimes fully covering your carbon offsets at no additional cost to you.

So, you bought your carbon offsets for your next flight. Great work! You’re off scot-free, right? Wrong. You’re still taking a flight and, even though you bought carbon offsets, that doesn’t change the fact that your flight is putting GHGs into the atmosphere. To make this whole going green thing work, you need to make offsets one piece of a larger strategy. Finding ways to reduce your emissions by flying less, staying at eco-friendly hotels, reducing your waste, etc. need to be part of your regular travel practices in addition to purchasing carbon offsets. I know, a pain in the butt, right? But you know what’s a bigger pain in the butt? The potential collapse of civilization and mass extinctions from climate change.

Now that you’re doing your part to go green, what’s the aviation industry doing? I’m a little cynical so I wasn’t expecting much but according to Scientific American, “aviation became the first global industry to limit its carbon footprint as ICAO [International Civil Aviation Organization] approved a plan to offset carbon emissions growth from international flights after 2020.” So far, 111 countries have submitted plans to the ICAO detailing how they will offset their aviation emissions. Not bad.

Airlines, energy companies, and governments are also increasing investments to make aviation greener. United and Jet Blue are starting to use more biofuels, NASA developed a new plane design that increases fuel efficiency, and companies like Carbon Engineering are figuring out how to use carbon captured directly from the air as fuel for planes. All of these improvements face barriers to full implementation but the progress is promising.

Now that you’re armed with a little insight into the environmental impacts of flying and carbon offsets, and a touch of hope for aviation’s green future, you’re set to book your next flight without an overwhelming sense of guilt. Huzzah!

Merriam-Webster, Yale Climate Connections, Center for Biological Diversity, NRDC, Scientific American, ICAO, Fast Company

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