references

The Wildlife-friendly Wedding Calculator was created to illustrate the high carbon footprints that can come with planning a wedding. It is an educational tool to help environmentally conscious couples make more sustainable choices and is not intended for formal emissions inventory purposes.

Below are the calculations and assumptions used for each section.

Calculation: ((Emissions per unit x roundtrip mileage x number of guests flying roundtrip)/1,000)x 2.7

• The emissions per unit (kg of CO2/passenger-mile) came from the U.S. Environmental Protection Agency, Emission Factors for Greenhouse Gas Inventories (table 8).
• The mileage was estimated by picking the middle of the distance range and multiplying by 2 to account for a roundtrip flight.
• User provides the estimated number of guests flying in each distance category.
• Divide by 1,000 to convert kilograms to tons.
• Multiple by 2.7 to account for radiative forcing.

Calculation: (Emissions per unit x roundtrip mileage x number of vehicles)/1,000

• The emissions per unit (kg of CO2/vehicle-mile) came from the U.S. Environmental Protection Agency, Emission Factors for Greenhouse Gas Inventories (Table 8).
• The mileage was estimated by picking the middle of the roundtrip distance range.
• User provides the estimated number of cars in each distance category.
• Divide by 1,000 to convert kilograms to tons.

Calculation: (Emissions per unit x number of buses x number of passengers x roundtrip mileage)/1,000

• The emissions per unit (kg/passenger-mile) came from the U.S. Environmental Protection Agency, Emission Factors for Greenhouse Gas Inventories (Table 8).
• User provides estimated number of buses, how many people will use the buses and number of miles roundtrip.
• Divide by 1,000 to convert kilograms to tons.

Greenhouse gas emissions for entrees are based on the main protein source, since that’s where the biggest variation is among ingredients and emissions. Common options were chosen for estimation purposes.

Calculation: (Emissions per serving x number of guests eating that meal)/1,000

• Beef entrée (1/4 lb. ground beef): 3.084 kg CO2/serving
• Chicken entrée (5 oz. chicken breast): 0.998 kg CO2/serving
• Fish entrée (5 oz. salmon): 1.687 kg CO2/serving
• There can be a large variation in emissions based on species of fish and whether it is farmed vs. wild caught. This estimate is based on farmed salmon.
• Vegetarian entrée (with 2 oz. of cheese): 0.765 kg CO2/serving
• Vegan entrée (with 4 oz. of tofu): 0.227 kg CO2/serving

Comparison to the average wedding is based on the emissions estimate of 63 tons of CO2 from The Green Bride Guide by Kate Harrison, and is based on around 120-140 guests.

Comparison of total to amount of miles driven (based on the U.S. EPA greenhouse gases equivalencies calculator): 

1 ton of CO2 emissions = 2,445 miles driven

• Miles driven/2,800 miles (distance to drive from New York City, NY to Los Angeles, CA) = number of cross-country road trips