This document discusses carbon footprints and how to calculate them. It begins by explaining what a carbon footprint is - the total amount of greenhouse gases produced directly and indirectly by human activities, usually measured in tons of carbon dioxide equivalent. It then discusses where carbon footprints come from, primarily the burning of fossil fuels like oil, gas and coal. The document provides details on how to calculate a carbon footprint using online calculators, which ask questions about location, household size, electricity/gas usage, transportation mileage. It concludes by offering tips to reduce carbon footprints in various areas of life like transportation, home energy use, travel, weddings, offices, and consumption habits.