## About the Carbon Calculations

Below are the assumptions from which I worked. The information about how many bushels each acre yields came from the two farmers I spoke with; info about how much each bushel yields in processing came from my contact at Harmony Agricultural Products; and info about how much soy is needed to create a pound of tofu came from my time at Denver Tofu.

A note about Carbon Dioxide Equivalent, or CO2E: Because different emissions (such as carbon or methane) have different levels of Global Warming Potential (GWP), scientists and government agencies use the CO2E metric to express all emissions on the same baseline. For example, methane has 24.5 times the GWP of carbon; a pound of it would therefore be expressed as 24.5 pounds of CO2E. (Click here for more information.)

A note about Carbon Dioxide Equivalent, or CO2E: Because different emissions (such as carbon or methane) have different levels of Global Warming Potential (GWP), scientists and government agencies use the CO2E metric to express all emissions on the same baseline. For example, methane has 24.5 times the GWP of carbon; a pound of it would therefore be expressed as 24.5 pounds of CO2E. (Click here for more information.)

Assumptions
• One pound of tofu requires .4 pounds of dried soybeans • One bushel of soybeans is made of 60 pounds of whole soybeans • A bushel of farmed soybeans (pre-processing) is equal to 80% of a bushel of dried soybeans • Therefore, a pound of tofu requires ~.0078 of a bushel of farmed soybeans • The average acre of organic soy yields 45 bushels, SO • One bushel requires ~.022 of an acre • Therefore, one pound of organic tofu requires .00017 of an acre • The average acre of conventional soy yields 65 bushels, SO • One bushel requires ~.015 of an acre and • Therefore, one pound of conventional tofu requires .00012 of an acre Finally, Denver Tofu produces 100,000 pounds of tofu and tofu products per month, so one pound is equal to 1/100,000th of their monthly inputs. |
Calculation conversions
Transportation • Semi truck – ton/km .56 lbs CO2E (source) • Diesel – gallon 22.2 lbs CO2E (source) • Gasoline – gallon 19.4 lbs CO2E (source) Energy • Electricity – Colorado kWh 1.93 lbs CO2E (source) • Electricity – Ohio kWh 1.80 lbs CO2E (source) • Natural Gas – therm 11.02 lbs CO2E (source) • Kerosene – gallon 21.537 lbs CO2E (source) • Propane – gallon 12.669 lbs CO2E (source) Biocides (source) • Nitrogen – kg manufacture 7.21 lbs CO2E • Nitrogen – offgassing 1% applied is released as N2O • Herbicides – kg manufacture 50.27 lbs CO2E |