A carbon footprint is the total amount of greenhouse gases, including carbon dioxide (CO2), methane, and others, that are emitted directly or indirectly by an individual, organization, product, or activity. It is usually expressed in terms of carbon dioxide equivalent (CO2e) tons to account for the different global warming potentials of the gases. The carbon footprint includes emissions from all life cycle stages of a product or the entire scope of an organization's activities, such as manufacturing, transportation, energy use, and disposal. It helps quantify the impact on climate change and allows comparisons of environmental impacts across people, products, companies, and countries. Reducing carbon footprints is essential for mitigating climate change by lowering greenhouse gas emissions from various sources like transportation, food production, and industry.

The carbon footprint concept also encompasses:

• Direct emissions (e.g., burning fossil fuels),
• Indirect emissions from electricity consumption,
• Emissions from the full supply chain and lifecycle impact of goods and services.

In summary, a carbon footprint measures how much greenhouse gas pollution is caused by a certain entity or action, guiding efforts to reduce environmental harm and combat climate change.