A carbon footprint is a measure of the impact that human activities have on the environment in terms of the amount of carbon dioxide (CO2) emissions produced. It is a way of quantifying the amount of CO2 emissions that are generated from a particular activity or individual, and can be used to evaluate the environmental impact of different actions and lifestyles. A carbon footprint is typically measured in units of carbon dioxide equivalent (CO2e), which is a measure of the global warming potential of different greenhouse gases.