Cycling Science (University of Chicago Press, 2012) by Max Glaskin takes readers through topics on cycling, such as tire rolling resistance, importance of aerodynamics and even the impact that shaved legs have on speed. Cyclists have much to gain from understanding the science of their sport. In this excerpt taken from chapter one, “Fundamentals,” see what kind of environmental impact cycling makes on the planet.
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The science endorses the gut feeling that cycling has a low environmental impact, compared to other modes of transport. For every $1,000 spent by manufacturers to make bicycles, 1 short ton of carbon is generated. Admittedly, this is 45 percent worse than the auto industry’s figure, but $1,000 will buy many more new bikes than cars. So, per vehicle, making bicycles is many times cleaner than making cars.
When new bikes hit the road, they are friendlier to the Earth, too. For a given journey, the energy consumed by a driver is at least 42 times more than by a cyclist, a bus passenger uses 34 times as much, and a train passenger 27 times as much. The cyclist requires less space than all but the train passenger and pedestrian. For journeys of up to 6 miles (10 km), the bike is definitely best for both rider and the planet. In terms of lifespan, life-cycle analysis at MIT shows that the bicycle consumes the lowest energy per passenger-mile across its entire life, compared to other forms of transport. If annual cycling distance is increased, revised life-cycle analysis calculations will boost the green credentials of the bicycle even further. And there is one more element of impact that vehicles have on the environment — noise pollution. Is there any vehicle quieter than a bicycle?
It’s all very well drawing comparisons with other modes of travel but there can be no doubt that riders do use some of the Earth’s resources to be able to cycle — in the form of food. Food production and transportation generate carbon dioxide and other greenhouse gases, the total weight of which is used as a measure of the impact on our planet. A rider cycling 1 mile (1.6 km) and metabolizing roughly 50 calories entirely from bananas would be responsible for the creation of 2 1/4 oz (65 g) of greenhouse gases. If instead they metabolized these calories from breakfast cereal with milk, the toll on our atmosphere would rise to 3 1/8 oz (90 g) of greenhouse gases. If those figures are hard to stomach, consider the impact of refueling with a cheeseburger — that’s 9 1/8 oz (260 g) of greenhouse gases.