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Carbon Footprint Calculator - Methodology and Sources

Household Electricity Use

Single Family: 12.3 kWh per sqft per year
Apartment / Multi-Family: 15.2 kWh per sqft per year
EIA, 2001
http://www.eia.doe.gov/emeu/efficiency/recs_5c_table.htm

Average Space Heating Energy/Square Foot: .025917 MBTU
http://www.eia.doe.gov/emeu/recs/recs2001/ce_pdf/spaceheat/ce2-52u_sqft_demo2001.pdf

CO2e Emission Co-Efficients:
Natural Gas: 117.080 lbs per MBTU (http://www.eia.doe.gov/oiaf/1605/coefficients.html) Heating Oil: 173.906 lbs per MBTU (http://www.eia.doe.gov/oiaf/1605/coefficients.html) Electricity: by state, e-Grid intensities, DOE

Waste and Recycling

2.1 tons per person per year average
U.S. Environmental Protection Agency. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2004. Table 8-1. 2006.
Recycling household trash can reduce your overall waste stream, and thus emissions by 42%.
U.S. Environmental Protection Agency. Personal GHG Calculator.
80% in home
20% out of home
A: full reduction
S: half reduction
N: no reduction

Transportation

AIR TRAVEL

from www.whatsmycarbonfootprint.com/faq.htm

"We created "averages" for each flight definition. For short haul, rather than average between 0 and 727; we assumed that few would fly if the distance they need to travel can be driven in 4 hours or less. So, 4 hrs. @ 55 mi/hr = 220 (low value) + 727.45 (high value) = 947.45/2 = 473.7 for an average short haul flight.

For medium haul, we went with the assumptions from GHG Protocol Initiative - less than 2575.04 miles, and averaged that with the 727.45 value of the upper limit for short haul. 1651.25 miles is the result.

For long haul, we researched the 10 longest distance non-stops and averaged that number to get the higher value for the range: 8,793 miles. We then averaged again between 8,793 and the 2575.04 miles that represents the low value for the long haul category to achieve an average for the long haul of 5684.02 miles."

LBS/AIR MILE

http://www.ghgprotocol.org/calculation-tools/all-tools
Short: .53 lbs/mile
Med: .42 lbs/mile
Long: .39 lbs/mile

CAR

http://www.ghgprotocol.org/calculation-tools/all-tools
lbs CO2/gallon motor gasoline: 19.52

Food and Diet

Credit: The Nature Conservancy

Average: Agricultural activity (crop, land, and animal including management, and including farm vehicles) accounts for 7% of all greenhouse gas emissions in the United States, with 91% of that being from methane and nitrous oxide emissions.

U.S. Environmental Protection Agency. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2004. Table 6-1, Table A-104. 2006.

Behaviors: Vegan and vegetarian diets emit 72% and 42% less than the typical American diet, respectively. A heavy meat diet emits 24% more than the average.

Martin, Pamela A. and Gidon Eshel, "Diet, Energy, and Global Warming". Earth Interactions. 2006. Paper 10-1009.