What does your "carbon footprint" measure?

Your carbon footprint is a measure of the total greenhouse gases, primarily carbon dioxide, that your everyday activities are responsible for releasing into the atmosphere, whether directly, such as burning gasoline while driving, or indirectly, such as the emissions created generating the electricity that powers your home. It combines many everyday choices, like transportation, home energy use, diet, and consumption habits, into one overall estimate of your personal contribution to the greenhouse gas emissions driving climate change.

The size of your actual shoe print is a literal, physical measurement with nothing to do with emissions or environmental impact; the term "footprint" here is used metaphorically. How much water you drink daily concerns hydration and health, an entirely separate topic from greenhouse gas emissions.

Because larger carbon footprints often correlate with wealthier lifestyles involving more travel, larger homes, and more consumption, researchers point out that individual carbon footprints vary enormously between people in different countries and income levels, sometimes by a factor of many times over.