Factsheets

A carbon footprint is the total greenhouse gas (GHG) emissions caused directly and indirectly by an individual, organization, event, or product.¹  It is calculated by summing the emissions resulting from every stage of a product or service’s lifetime (material production, manufacturing, use, and end-of-life). Throughout a product’s lifetime, or lifecycle, GHGs such as carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), may be emitted. Differences in heat trapping are accounted for by the global warming potential (GWP) of each gas, resulting in a carbon footprint in units of mass of carbon dioxide equivalents (CO₂e) (See the Greenhouse Gases Factsheet). A typical U.S. household has a carbon footprint of 4 t CO₂e/yr,² with 16-20% occurring in other countries such as China and Canada³. On a per capita basis, GHG emissions of an individual in the U.S. (14.4 t CO₂e) is triple that of the global average (4.9 t CO₂e).⁴

Sources of Emissions

Food (See U.S. Food System Factsheet)

• Food accounts for 10-30% of a household’s carbon footprint, often a higher percentage in lower-income households.⁶
• Production accounts for 68% of household food emissions, restaurant, retail, and wholesale trade combined accounts for 27%, and transportation accounts for 5%.⁷
• Food production emissions consist mainly of CO₂, N₂O, and CH₄, which result primarily from agricultural practices.⁸
• Meat products have larger carbon footprints per calorie than grain or vegetable products because of the inefficient conversion of plant to animal energy and due to CH₄ released from manure management and enteric fermentation in ruminants.⁸
• Livestock emitted 192.6 Mt CO₂e of methane in 2022 from enteric fermentation, 137 Mt (71%) of this from beef cattle.⁹
• In an average U.S. household, eliminating the transport of food for one year could save the GHG equivalent of driving 1,000 mi, while shifting to a vegetarian meal one day a week could save the equivalent of driving 1,160 mi.⁸
• A vegetarian diet greatly reduces an individual’s carbon footprint, but switching to less carbon intensive meats can have a major impact as well. For example, beef’s GHG emissions per kg (30.4 kg CO₂e) are 7.2 times greater than those of chicken (4.2 kg CO₂e).¹⁰
• Diets from the top 20% of income earners accounted for 7.9 times the GHG emissions as those from the bottom 20% of diets in the U.S.⁵

Household Energy (See Residential Buildings Factsheet)

• For each kWh generated in the U.S., an average of 0.83 lbs of CO₂e is released at the power plant.¹¹ Coal releases 2.25 lbs/kWh, petroleum releases 1.43 lbs/kWh, and NG releases 0.86 lbs/kWh. Nuclear, solar, wind, and hydroelectric release no CO₂ when they produce electricity, but emissions are released from upstream production activities (e.g., solar cells, nuclear fuels, cement production).⁹
• Residential electricity use in 2022 resulted in 582.2 Mt CO₂e, 9.2% of the U.S. total.⁹
• Space heating and cooling were estimated to account for 44% of energy used in U.S. residential buildings in 2023.¹²
• Refrigerators are one of the largest users of household appliance energy. In 2020, an average of 686 lbs CO₂e per household was due to refrigeration.^{13, 14}
• 26 Mt CO₂e are released in the U.S. each year from washing clothes.^{13, 14} Switching to a cold water wash once per week can reduce household GHG emissions by over 70 lbs annually.¹⁵

Personal Transportation (See Personal Transportation Factsheet)

• U.S. fuel economy (mpg) declined by 12% from 1988-2004, then improved by 35% from 2004-2022, reaching an average of 26 mpg in 2022.¹⁶
• Annual per capita miles driven were 9,937 in 2019, an increase of 9% since 1995.¹⁷ The average daily trip length for a U.S. commuter was 13.43 mi in 2022, a 17.2% increase since 2017.¹⁸ 
• Cars and light trucks emitted 1.03Gt CO₂e or 16% of total U.S. GHG emissions in 2022.⁹
• Of the roughly 66,000 lbs CO₂e emitted over the lifetime of an internal combustion engine car (assuming 93,000 miles driven), 84% come from the use phase.¹⁹ See the Electric Vehicle Factsheet for GHG emissions from ICEVs and EVs.
• Gasoline releases 19.4 lbs CO₂ /gal when burned, compared to 22.5 lbs/gal for diesel.²⁰ However, diesel has 11% more BTU per gallon, which improves its fuel economy.²¹
• The average passenger car emitted 0.74 lbs of CO₂ per mile driven in 2022.¹⁶
• Automobile fuel economy can improve 7-14% by simply observing the speed limit. Every 5 mph increase in vehicle speed over 50 mph is equivalent to paying an extra $0.27-$0.54 per gallon.²²
• Commercial aircraft GHG emissions, which vary by aircraft type, trip length, occupancy, and passenger and cargo weight, were 138 Mt CO₂e in 2022.⁹ The average domestic commercial flight emitted 0.43 lbs of CO₂e per passenger mile.^{9, 23}
• Domestic air travel fuel efficiency (passenger miles/gallon) increased 112% from 1990-2022 largely due to increased occupancy.²³ Emissions per domestic passenger-mile decreased 42.6% from 1990-2022, but the period of 2019-2021 saw a increase of 16% due to Covid restrictions.^{9, 23}
• In 2022, rail transportation emitted 35.6 Mt CO₂e, accounting for 2% of transportation emissions in the U.S.⁹

Solutions and Sustainable Actions

Ways to Reduce Your Carbon Footprint

• Reduce meat in your diet and avoid wasting food.
• Walk, bike, carpool, use transit, or drive a best-in-class vehicle.
• Ensure car tires are properly inflated. Fuel efficiency decreases by 0.2% for each 1 PSI decrease.²⁴
• Smaller houses use less energy. Average energy use is highest in single-family houses (80.9M Btu), followed by mobile homes (61.3M Btu), apartments with 2-4 units (53.5M Btu), and apartments with 5+ units in the building (33.7M Btu).¹³ Whether you hand wash dishes or use a dishwasher, follow recommended practices to decrease water and energy use and reduce emissions.²⁵
• Energy used by electronic devices in standby mode accounts for 5-10% of residential energy use, adding up to $100 per year for the average American household. Unplug devices or plug them into a power strip and turn the power strip off when not in use.²⁶
• Choose energy-efficient lighting. Switching from incandescent to LED light bulbs saves an average household more than $200/year.^{27, 28}
• Revamp the way you heat, cool, and power your home by making it energy efficient. Through 2032, homeowners can use federal tax credits to cut energy-efficiency upgrade costs by up to 30% or $3,200 annually, as well as receiving a 30% tax credit for clean energy equipment, such as rooftop solar, geothermal heat pumps, and energy storage.²⁹
• Reduce and reuse to minimize personal waste. See the Municipal Solid Waste Factsheet.
• Think green before buying. Ask yourself: Do I really need it? Can I get it used? How long will it last? ³⁰
• Reduce food waste by only buying what you need, composting food scraps, and donating unused food to food banks or shelters.³¹ 
• Purchase items with a comparatively low carbon footprint. Some manufacturers have begun assessing and publishing their products’ carbon footprints.
• Covering 80% of roof area on commercial buildings in the U.S. with solar reflective material would conserve energy and offset 125 Mt CO₂ over the structures’ lifetime³², equivalent to turning off 34 coal power plants for one year³³.
• Replacing the roof and wall panels on the global fleet of shipping containers with aluminum would save $28 billion in fuel.³⁴

U.S. Greenhouse Gas Emissions, 2021³⁵

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Carbon Footprint Calculator

• Estimate your personal or household greenhouse gas emissions and explore the impact of different techniques to lower those emissions:
• U.S. Environmental Protection Agency: www3.epa.gov/carbon-footprint-calculator/ 
• The Nature Conservancy: www.nature.org/greenliving/carboncalculator/
• Global Footprint Network: https://www.footprintcalculator.org/