This is one of a series of occasional columns from Transition Town – All St. Anthony Park, the neighborhood-based group working for a local response to climate change: a smaller carbon footprint and a stronger community. You can find out more about Transition Town at www.TransitionASAP.org.
By Michael Russelle
No way around it: Travel takes energy. Whether we’re using gasoline, diesel, electricity or jet fuel, production and use of those fuels emit carbon into the atmosphere—“carbon” being shorthand for the carbon dioxide equivalents of the greenhouse gases that are most responsible for climate disruption.
Just how big is travel’s carbon debt? When my wife travels to Switzerland to visit her 95-year-old father this year, her portion of that flight’s carbon debt will double her carbon debt for the entire year.
The easiest way to shrink a travel footprint is to live locally, but there are important reasons for some long-distance travel, like visiting family, conducting business or volunteering in a disaster area. When a phone call or videoconference won’t suffice, we can shrink our travel footprint by choosing the mode of transport with our eyes open and then finding ways to offset the carbon cost. We can even make a game of it, inviting others to join us in some energy-saving habits to help pay the carbon debt of our trip.
How do we calculate that cost? On top of the direct fuel-burning effects, there are the indirect carbon costs of producing the fuel and of building and maintaining vehicles and infrastructure. Here, the term “carbon debt” reflects some of those costs, as well as other greenhouse gases and upstream emissions. (See the reference list on our website, TransitionASAP.org.). Let’s look at an example.
Your choices, by the numbers
You’d like to visit friends in Chicago with another person. What are your options?
Flying: Of all your choices, and even with improvements in jet fuel use efficiency, air travel emits the most carbon. Flying nonstop to Chicago, it’s about 0.643 pound per passenger mile. So at 684 miles, you have a 440-pound carbon debt per person in an economy seat for flight—not counting the cost of getting you to and from each airport for each flight.
Amtrak: Take the Empire Builder and you cut that cost by nearly half. Even with a 20 percent longer trip than flying, at 0.307 pound per passenger mile, your carbon debt is still just 257 pounds.
Gas-powered car: Gasoline releases greenhouse gases when it’s produced and burned. So if you drive the 784-mile round trip with another person, your carbon emissions per person will be 380 pounds at 25 miles per gallon and only 190 pounds at 40 miles per gallon.
Electric vehicle: Most EVs are charged from the regional power grid, and in the Midwest the grid’s carbon emission rate is 1.61 pounds per kilowatt hour (kWh). The most efficient gets EV 3.57 miles per kWh, resulting in 177 pounds carbon per person. (If the EV is powered by renewable electricity, only very small indirect emissions contribute—about 8 pounds carbon for the entire trip.)
More riders reduce the carbon cost of driving even more.
Bus: Because of that ride-sharing magic, commercial bus service runs at just 0.171 pound per passenger mile. With the bus route of 842 miles, your carbon output is just 144 pounds.
Now find debt relief!
If you decide to fly this time, how will you pay that 440-pound carbon debt? Online carbon-offset calculators can help: myclimate.org is a good one. Even better, you could ask other people—maybe even the Chicago friends you’re visiting—to carbon-trade with you by changing some habits, and you can offer to do the same if they visit the Twin Cities. Some examples:
Driving habits: If five people each reduce their gas use by about 5 gallons, they’ll cover your debt—and they may find they like to walk or bike their routes instead, or may skip some trips altogether. (A gallon of gas emits 19.4 pounds of carbon, so here’s the math: 440 pounds divided by 19.4, divided by 5 people = 4.5 gallons of gas per person.)
Eating habits: Or if they’re burger-eaters, those five people could each skip a weekly quarter-pounder for 13, say, July through September. Not difficult for some, but pretty hard for others, eh? (Each pound of beef has a carbon cost of 27 pounds, so 440 pounds divided by 27 = 16.3 pounds of meat total.) Another option for an ambitious friend: Grow a couple of hundred pounds of vegetables at home rather than buy them at the store. One report concluded that every pound of homegrown veggies saves just under 2 pounds of carbon emissions. Could you help convert a lawn to a garden?
Natural gas use: Or you could ask five households to each save 6 therms of natural gas. How? Do laundry in cold water rather than hot (and hang it up to dry), take shorter showers and turn down the thermostat in winter. A family that uses 50 gallons of hot water a day could save 15 therms a year just by lowering its water heater temperature from 130° to 120°F. (Natural gas produces about 14.5 pounds of carbon per therm, including upstream emissions, so your 440-pound debt equals 30.3 therms.)
So find those buddies, do some math and let’s work together to reduce climate change.
Michael Russelle helps guide Transition Town ASAP’s projects. A University of Minnesota soil scientist, he also serves on the St. Anthony Park Community Council and in many other local groups.