Wednesday, May 9, 2012

Pay me to commute by bicycle?

I’ve been trying to ride my bicycle into work at least once a week now that the weather is agreeable. My main goal is to get in shape for the Kirkwood Triathlon, but it struck me on one of my rides that it could also be a potential way to get some of that sweet, sweet carbon offset money. And since I just read a book on carbon footprints, I thought I’d figure out what my commute by bike might be worth.

Since this is America, I’ve provided the carbon footprint equivalents in pounds versus grams or kilograms.

1.9 lbs/mile driving a standard sized car

9.8 lbs/mile driving a standard sized car in congested traffic

But let’s assume a little of both, so I’m going to split the difference:

5.85 lbs/mile driving a standard sized car on average

When it comes to cycling, the author provides a range of different food (power) sources. I eat yogurt in the morning, so this was the closest comparison.

0.2 lbs/mile riding a bike powered by cereals with milk

My commute is approximately 14 miles round trip. So when I drive, my output is 81.9 lbs total (5.85 X 14). When I ride my bike, my output is 2.8 lbs total (0.2 X 14).

A ton is 2000 lbs and the maximum equivalent price per ton of carbon in the UK (the figure cited in the book) is $18.

So I will reach a total of one ton of carbon roughly every 24.5 times I commute by car (2000 ÷ 81.9). On the other hand, it takes me approximately 714 trips to reach a ton of carbon by bike (2000 ÷ 2.8).

That’s a ratio of roughly 29:1 (81.9:2.8). So commuting by bicycle twenty nine times has the same carbon footprint equivalent as one trip by car.

Put another way, by riding my bike I use up only 2.8 lbs of my normal 81.9 lbs, leaving a surplus of 79.1 lbs/commute. By dividing 2000 by 79.1, the total comes out to be about 25.5 times, which, as I’ve pointed out above, is the approximate equivalent of 24.5 car trips, or one ton of carbon. So, more accurately, 25.5 bike rides equal 24.5 car trips—basically, one bike ride by me offsets one car trip by you (assuming an equidistant commute). And since one ton of carbon is worth about $18, I figure if you want to ease your conscience, you can pay me $17 in carbon offsets (to account for the difference in ratio) every time I ride my bike and you decide to drive.

Please make checks out to That Tad Guy.

*It’s been awhile since I’ve used the old math muscles, so my apologies if any of these numbers are off or inaccurate.