I’ve biked to work almost every day for years, and during most of that time I figured I was doing the climate a big favor by not commuting by car.
Recently, though, I had a worrisome thought. I’m not losing any weight, which means that the calories which power my bike are coming entirely from the food I eat. Now, it’s true that it takes less energy to power a bicycle than it does to power a car, but it’s also true that producing food energy can be more ecologically harmful than burning gasoline, at least from a carbon footprint standpoint. Was I really reducing my carbon footprint by bicycling?
The answer is, as it so often turns out to be, “maybe”. Let’s start with a worst-case scenario, in which all of the extra food I eat in order to power my bicycle comes from hamburgers.
Given my weight and average speed, I’m burning somewhere around 50 calories per mile on the bike. That means that the 2,500 calories of beef will last me 50 miles.
In other words, my hamburger-fueled bicycle actually has a worse carbon footprint than driving alone in a car!
The good news is that, given the actual composition of my diet (which is considerably less than 100% hamburgers), I come out ahead on the carbon footprint – but it’s not the tremendous boon I first imagined it to be. If you’re looking to cut your carbon footprint, air travel might be a better first target.