When to Drive and When to Fly?

     At this point in the winter, it’s hard to avoid looking toward summer. With summer often comes the promise of traveling, whether it’s to visit family or to do some adventuring. However, there are a lot of questions to answer when making travel plans. Today’s blog post will seek to demystify the question: is it better for the environment to drive or to fly?     
    To answer this question, we will start with some background information on the fuel expenditure of cars and planes, as well as their respective short-term and long-term environmental impacts. From there, we can draw conclusions about making the right travel decisions. 
     Light vehicles (read: cars) contribute 59% of the United States’ domestic transportation emissions. Meanwhile, the US aviation industry contributes just 11% of domestic transportation emissions. 
     Additionally, one gallon of jet fuel produces relatively similar carbon dioxide emissions to gasoline. However, air travel includes several other concerning emissions: water vapor, nitrous oxide, and sulphur oxide, all of which contribute to the global greenhouse effect. 
      While airplanes have (along with cars, buses, and trains) gotten more fuel efficient over the years (per passenger per mile), studies indicate that these reductions are tapering off. To make matters more confusing, a University of Michigan study conducted by Michael Sivak found that car travel to be two times as energy intensive as flying. This finding comes as a result of the fact that cars are increasingly being driven with only one person in them.
     So, what does this all mean for you? Is there even a right choice? Yes, but it depends. Namely, on the distance traveled (short trips versus long trips) and the number of people traveling. For example, consider the difference in travel needs between a cross-country business trip and a family road trip to Wisconsin. 
     For a short trip with one person, take a plane. Driving by oneself can be very energy-intensive. For a short trip with multiple people, take the car. If someone has a hybrid or an electric car, opt to use that vehicle. For a long trip with one person, take a plane. Choose economy class; a full plane is more fuel efficient than an empty one. For a long distance trip with multiple people, the answer lies in the fuel efficiency of the vehicle being used. Wherever possible, opt for the smallest, lightest, most fuel-efficient option available for use. If the only option is an excessively large SUV, air travel may be a more efficient alternative. 
      Bear in mind that these are just general guidelines. If you are curious to learn more about the carbon emissions of a specific trip, try these online carbon-calculator web tools to get the information you’re looking for. This one, from CoolCalifornia, calculates carbon emissions from various sources, including household, travel, and even shopping. Another web tool, this one from the Nature Conservancy, offers specific ways to drop your carbon footprint from 16 tons/year to 2 tons/year. Lastly, ICAO’s Carbon Emissions Calculator tackles air travel specifically.
      As with any travel, there are certain steps you can (and should) be taking to cut down on your carbon footprint, whether it’s driving or flying. Here are five rules of thumb to consider when planning your transportation, especially in and around the city. These will save you time, money, and carbon emissions. 

1. Combine trips. Opt to run errands all in the same day, and plan a route that has stops in one area, rather than back-and-forth across town.
2. Don’t go if you don’t have to. Do you really need those eggs today, or can they wait until you run your Sunday errands?
3. Carpool/rideshare. Coordinating your driving with a friend or family member is a great way to spend quality time while making eco-friendly choices.
4. Make use of public transit. Minneapolis has an incredible transit system, and it’s a great way to see the city.
5. Bike and walk. Minnesota summers are short; biking and walking are excellent ways to spend time outside while getting where you need to go.
   
   This post is a synthesis of information from various sources. For a full-length analysis of this issue, check out this article from Yale Climate Connections.