Slate’s Brian Palmer wrote in an article this week that he’s thinking of switching his commute “from four wheels to two” but he’s concerned about the environmental impact of bicycling: specifically, “about all the energy it takes to manufacture and ship a new bicycle.” He wants to know how many miles he would “bike the drive” before he’s gone “carbon neutral.”
He estimates the average carbon cost of the manufacture of a new bike at about 530 pounds of carbon dioxide equivalents, based on a research paper published last year by MIT scientist Shreya Dave [PDF]. But Palmer never asks about the carbon cost of his car. According to an analysis by The Guardian, manufacturing a new mid-size car produces more than 17 tons of CO2e — about 75 times what it cost to make that bike. A top-of-the-line Land Rover would pollute twice as much, or 150 times the carbon footprint of the bicycle.
Palmer discounts the argument that bicycle “fuel” also harms the environment, since cyclists burn more calories and need to eat more. “As the Pacific Institute has shown, you’d have to be eating an all-beef diet to offset the environmental benefits of walking or bicycling,” Palmer said. “Given a ‘typical U.S. diet,’ you would have to ride your bike instead of driving for around 400 miles to cover the bike’s initial carbon footprint.”
