I hate to belabor this point, but I'm starting to wonder if we're all approaching carbon emissions for transportation the wrong way.
Yesterday, Will from Green Couple wrote a post entitled, "What's the Best Way to Get From Here to There." He had recently driven with some friends to Wisconsin, and he calculated the carbon emissions that the trip generated. Then he calculated what his emissions would have been had he taken a bus, train, or plane. The plane was the most emissions-heavy, followed by the train, the bus, and then the car. So, Will made the most emissions-efficient choice, correct? And we should all try and carpool when we are traveling long distances, right?
Except, hold on a second. As Will points out, "A plane, train, or bus isn’t going to produce that much less CO2 just because we’re not riding."
And therein lies the logical fallacy. It's all very well to try to calculate individual carbon emissions, but the truth is, carbon emissions don't really work like we're pretending they work.
In fact, had Will taken a train, or a bus, or even (quel horreur!) a plane, the total world carbon emissions would have decreased by the amount of carbon emissions caused by the car, and increased by the amount of carbon emissions caused by Will and his friend's weight. In other words, driving a car is only the most carbon efficient method IF the carbon emissions Will and his friends's weight cause on a plane, bus, or train is GREATER than the TOTAL emissions of the car. Which seems pretty unlikely.
To put it differently, let's consider this: because Will chose not to take the bus, the per passenger miles per gallon on the bus went down. So Will might think, oh hey, my individual carbon emissions were lower because I was in the car, but actually he caused the carbon emissions of every passenger on the bus to go up because he chose to ride in a car instead of a bus.
So what's the answer here? I hesitate to draw this out to airplanes and long distance trains, but in terms of city-wide public transport, the answer is pretty clear to me. In my opinion, a city's public transit belongs to every single citizen of the city, and NOT just the citizens who use it. So the true calculation of carbon emissions would be where we calculated the total carbon emissions caused by a city's public transport, and divided it up by every citizen in that city. Then an individual calculating her emissions would add that to her individual car emissions to get her actual total.
But that's not fair! I don't ride the bus!
True. But we pay for a lot of things we don't use. To me, the best analogy here is that even if you choose to send your child to a private school, you still have to pay for public schools. Similarly, even if you still drive to work, you should have to pay for the carbon emissions of public transit. That's the point of a "public" system. We may not all use it, but its there for everyone's benefit.
Ok, Arduous, but does this nerdy mathery really matter?
I think it does. Look, a lot of us are in uncharted waters. We are faced with decisions like "organic in plastic" or "conventional in glass" every day. And a lot of the time, we rely on things like what I'd call conventional green wisdom or carbon calculators to figure out what makes the most sense. But sometimes, conventional wisdom, even conventional green wisdom, is wrong. And that can lead us to make decisions that might not make the most sense. For example, if a bus I was taking only had three people in it, I might think, oh well then I might as well drive because that is the most carbon efficient. Or I might think it made more sense to drive across country to see my sister than to fly. But the reality is, those buses and planes ARE going to be in service no matter what I do. So, to me, the logical choice is to always err on the side of a communal form of transportation, be it a bus, a train, or yes, even a plane. Because while I believe that it is possible to eventually cause a decrease in bus paths or plane rides, we also have to deal with the here and now. Besides which, you have to ask yourself, do we really want all those people on buses, trains, and planes in cars and on the roads instead? Is that really the answer?
(By the way, Will, I hope you understand I just used you as a guinea pig. I thought your post was great, and incredibly thought provoking which is why I ended up writing this post in response. And, needless to say, I am certainly not casting aspersions on your choice to take a car to Wisconsin. I like road trips myself. And I'm currently hating on the bus. But that's another story for another day.)
4 months ago