With global protests underway about inaction on global warming, I thought it was a good time to take stock of my personal carbon footprint. According to a 2017 New York Times article, in 2014 the average American generated 17.9 tons of carbon dioxide. In comparison, Germans, Brits and Brazilians generated 9.8, 7.2 and 2.9, respectively.
I like to think that I do better than average because I commute about 2,000 miles annually on my bicycle. According to one study, the average European cyclist has a carbon footprint 10-times less than the average European car commuter (this includes the contribution from manufacturing). I “cheat” a bit because I ride a class III e-bike, which means I have a very heavy bike with a large lithium battery. Nevertheless, my “commuter pickup” is probably considerably larger than the average European vehicle so I’m probably still batting a 10-fold improvement in carbon footprint. Besides, shooting up the hills of Pullman in “turbo mode” can make you feel like Superman, and that gives a substantial boost to one’s morale!
Unfortunately, a major carbon footprint challenge for many Americans comes from airline travel. A round-trip flight from New York City to San Francisco emits about 1 ton of carbon dioxide per person, or about one ton every 5,170 miles. It doesn’t take long to rack-up a lot of carbon dioxide at this rate. Over the next two weeks, my job involves traveling close to 19,000 miles, generating about 3.7 tons of carbon dioxide. That is about 20 percent of my average annual allocation pumped into the atmosphere in less than 5 percent of the year — frankly, that’s pretty depressing.
Throughout the course of my career, I will probably log around 800,000 airline miles, generating around 155 tons of carbon dioxide. Assuming that the average tree absorbs 1 ton of carbon dioxide by the time it reaches 40 years old, I need to plant 155 trees to wipe out my airline-based carbon debt. On a positive note, over the course of the past 10 years, I have planted close to 40 trees on our hobby farm so I’m making some progress!
My other challenge is our home heating system. Heating, cooling and hot water are attributed to 40 percent of the annual American carbon footprint. When we first moved to our house, which was built in 1968, heat was generated by electrical wires that loop through the ceiling. Besides producing a bizarre effect of having a very warm head and very cold feet during the winter, it was extremely expensive and inefficient (electrically-heated ceilings represent the ultimate optimism about abundant energy). Our first investment was to install a wood pellet stove. Up until now we’ve been burning about 2 tons of compressed wood pellets per year.
I always thought that this type of combustion has significant gains in efficiency because the heat is transferred directly inside the home, and combustion is maximized for heat production. In preparation for this column, I pulled up some scholarly papers to figure out the carbon footprint from this practice. This turned out to be a frustrating exercise with my final numbers showing that I generate 4,500 pounds of carbon dioxide when I burn 4,000 pounds of wood pellets. I doubt that I’ve stumbled on a way to circumvent the law of mass conservation, so I really don’t know the true carbon impact of wood pellets as we use them. The most common “claim” is that wood pellets are slightly worse than burning coal (even if the pellets are made from “renewable” sources). Consequently, it is probably safe to assume that burning pellets is far from carbon neutral and should be a supplement at best.
Not long after installing the pellet stove, we installed a geothermal system that uses our pasture as the heat source/sink. Besides being twice as efficient as heating with natural gas, over a 20-year lifespan a 3-ton residential geothermal system saves the equivalent carbon dioxide of 1.2 acres of trees.
A group at MIT recently estimated that given the American lifestyle and dependencies on fixed facilities and sources of energy, we’d be lucky to ever push our average annual carbon footprint below 9.4 tons. I don’t know if I can ever get there as long as I have to travel, but with the pluses and minuses in my ledger, you can bet the geothermal system will be humming along this winter and I’ll be zooming to and fro on the e-bike.
Douglas Call is a microbiologist. He and his family have lived on the Palouse for more than 20 years.