Carbon costs of two years of travel

And how airplanes compare to driving

One of the big surprises of the pandemic was how everybody got worse at driving. Case in point, my Prius was totaled on a road with no other traffic except a single moving truck. Whether the driver just didn’t see my car or “totally could have made it” in an normal car, seemed to vary moment-to-moment once the police showed up. Either way, at the end of April 2020 we ended up with a "new to us" car. The point of this story is that, because I bought a car I have a record of the miles it had just about 2 years ago.

The 2020 Toyota Corolla Hybrid we purchased had 16,021 miles on it. Its best feature is that it’s red, which my kids like. Also, we get an average of 53 mpg. In the almost exactly 2 years since purchasing it we’ve put 12,619 miles on the car. To get those miles we've burned 238 gallons of gas and generated 4,760 lbs of CO2.

In that same time, despite the pandemic, my family has taken a handful of flights. All four of us went to a wedding in Denver, Colorado and my wife went solo to visit family in Fort Wayne, Indiana. All of our flights were economy seats on full flights. Which is great in terms of carbon footprint, but wow, does that make for a stressful COVID-era flight. Especially with the kids.

CO2 equivalent emissions from travel, May 2020 - May 2022

The flight to Denver was on Frontier, an airline basically everyone loves to rag on, but they do fly direct from DCA to DEN. Also, they have modern, fuel efficient, planes. According to google flights, one seat in each direction is responsible for 192 kg of CO2 equivalent emissions (CO2e). For all 8 legs that would be 3,386 lbs CO2e.

I heard somewhere that a long distance drive alone produces effectively the same emissions as taking flight. This is counter to my intuition, so I've got to explore the question; what if we'd driven? …ignoring the pain that would accompany with a DC to Denver drive with young kids.

CO2 equivalent emissions, in lbs, for Travel to Denver

This DC to Denver and back road trip is 1,654 miles each way. Total emissions of 1,248 lbs of CO2e. Given that we can pack 4 people into our car it would have been much more efficient to drive, but interestingly it’s not so clear for a single person. It seems like the crammed Frontier flight would have actually been more environmentally responsible! I am surprised!

Part of me wants to explore the carbon footprint of taking the bus. I’m sure it’s much less. But a bus, or even driving really, to Denver is not actually feasible given my real-life constraints. It’s a 38 hour trip on Greyhound which has 4 transfers. The drive time if we took our own car is ~24 hours. We have 2 small kids. It would take far longer. Given the standard American PTO that we have, a week long trip is about all we can do. If we drove, most of that time would be spent in transit. We just wouldn't make the trip.

My wife’s trip to Fort Wayne was through Chicago and each direction generated 209 kg CO2e, the average according to google flights. Both directions together are 922 lbs of CO2e. For comparison's sake I went looking for a direct flight. Such a flight doesn't exist from the DC area, but it does from Philadelphia. Not a direct comparison, but that flight generates 173 kg of CO2e. To get to an actual comparison we’d need to account for the 128 mile drive from DC to Philadelphia International Airport, and back.

CO2 equivalent emissions, in lbs, for Travel to Fort Wayne

Driving to Fort Wayne and back is 552 miles each direction for 416 lbs of CO2. This compares more favorably to flying than it did looking at Denver. The drive has less than half the emissions of flying! Here we’re really seeing the cost of the indirectness of the travel and the less efficient older and smaller planes that get flown to Fort Wayne. That a direct flight from an airport over a hundred miles away emits less carbon is also a bit of a surprise.

All told my family generated 9,064 lbs of CO2 equivalent emissions with our travel over the last 2 years. As compared to our normal daily activities, the times when we travel significant distance are really the most carbon intensive things we do. Nowhere else in our lives to we generate this level of emissions in such short periods of time.