Current mood:

contemplative

Counting Calories and Carbon

Between May 1st and November 1st, I estimate that I will have biked to work about 120 times (out of a possible 130 opportunities). At about 10 miles round-trip, that's 1200 miles that I haven't driven. My car gets about 25 miles per gallon in the city, so that's 48 gallons of gas I haven't burned. Gas averaged about $3.60 this summer, so that's about $170 in gas savings. On the environmental side, a gallon of gas produces 19 pounds of CO2, so I've reduced my emissions by 930 pounds of carbon dioxide.

However ... I don't hold my breath while biking to work. How much CO2 does biking produce? A quick Google search shows that most estimates say that a person exhales about 2.2 pounds of carbon dioxide daily. That CO2 comes from the food we eat, so if we assume 2200 calorie diet, then for every 1000 calories burned, about a pound of CO2 is produced.

Biking consumes about 500 calories per hour. It takes me 45 minutes to bike to and from work each day (20 minutes in and 25 minutes home -- it's downhill going in and I'm usually tired from rounds when going home). So 120 trips lasting 45 minutes amounts to 90 hours of biking. That's 45,000 additional calories consumed to propel myself to work. (For reference, a single gallon of gas has about 31,000 calories.) At 1 pound of CO2 per 1000 calories, it looks like I'm exhaling about 45 pounds of CO2 on my way to work.

My primary source of those additional calories is the slice of toast that I add to my breakfast during the summer. A slice of bread has about 100 calories, and there are 24 slices in a loaf, so I eat about 19 loaves of bread to power myself. At $2 per loaf, that's $40 that I spend in groceries for those additional calories.

So, to summary the savings and expenditures for biking to work:

• Savings


• Carbon Dioxide: 930 pounds


• Dollars: $170


• Expenditures


• Carbon Dioxide: 45 pounds


• Dollars: $40




• Net savings by biking to work during the summer:


• Carbon dioxide: 885 pounds


• Dollars: $130


• The opportunity to watch the sunrise (and often the sunset) each day as I enjoy the fresh air, the morning quiet and the occasional sighting of deer, foxes and other animals:
  
  • Priceless.