Recently American politician Ed Orcutt suggested (and late apologised) that cyclists contribute to atmospheric pollution by breathing more than other people, here’s the contents of an email he sent to a bike shop owner;
You claim that it is environmentally friendly to ride a bike. But if I am not mistaken, a cyclist has an increased heart rate and respiration…Since CO2 is deemed to be a greenhouse gas and a pollutant, bicyclists are actually polluting when they ride
This got me thinking about my ‘carbon footprint’ and if commuting by bike had actually reduced the amount of carbon I have produced (methane is another matter) in the past 12 months. I’ve taken some of these figures from a book by Mike Berners-Lee called How Bad Are Bananas? The Carbon Footprint of Everything so don’t blame me if they look a bit dodgy – read the book and make your our decision on how accurate they are. I have tried to be honest and the figures are based on the emissions of the food needed to power my legs.
Here are the numbers and assumptions;
- From March 2012 to today (8 March 2013) I have bike commuted just over 2600 miles;
- Consequently, I have avoided driving 2600 miles;
- For a cyclist, 100g per mile of CO2 is an average emission based on eating cereal and bananas (source);
- My car emits approximately 154g of CO2 per km (source)
- If I drive the car, I still need to eat.
Here are the sums;
- 154g per km is 247g per mile
- 2600 miles in the car would generate 642200g of CO2, which is 0.64 tonnes
- 2600 miles on the bike would generate 260000g of CO2, which is 0.26 tonnes
Based on this rather crude calculation if looks initially like I saved 0.38 tonnes of CO2 emissions, BUT the bicycle emissions are based on the carbon footprint of the food I consume to power said bicycle. Therefore, when you consider that I still eat when I drive a car, the saving is actually 0.64 tonnes. Before you ask, this does exclude the CO2 produced during the manufacture / transportation of both vehicles, which I guess would be more for the car.
Finally, and stolen from the Guardian. One other thing: by taking my car off the road in rush hour, I cut everyone else’s queuing time as well, and reduce the emissions they belch out while they wait. It’s a little-known fact that a car on a congested road can produce as much as three times the amount of CO2 as the same car travelling at a steady speed.
I’m not sure if this proof is conclusive but I would suggest that if we all ride our bikes more, we would be healthier and the planet might be saved!