
The total greenhouse gas emissions caused by an activity, here targeted for reduction.Carbon footprint is the total amount of greenhouse gases—primarily carbon dioxide—emitted directly or indirectly by an individual, organization, event, or product, usually expressed as carbon dioxide equivalent (CO2e). It encompasses emissions from energy use, transportation, manufacturing, and even the lifecycle of goods. The concept is central to climate change mitigation, as it provides a measurable target for reducing environmental impact.
The term 'carbon footprint' gained popularity in the early 2000s, popularized by the oil company BP's advertising campaign in 2004, though the underlying concept of measuring greenhouse gas emissions dates back to earlier climate accounting methods.
Calculating a carbon footprint involves summing emissions across all relevant activities, often using emission factors that convert energy consumption or material use into CO2e. For example, burning one liter of gasoline produces about 2.3 kg of CO2. The footprint can be offset by reducing emissions or investing in carbon capture and renewable energy projects.
Carbon footprints are used by companies to report sustainability metrics, by governments to set emission reduction targets, and by individuals to make eco-conscious choices, such as choosing lower-carbon diets or transportation.
The average carbon footprint of a person in the United States is about 16 tons of CO2e per year, which is roughly 10 times the global average.



