What is your carbon footprint? It’s the amount (in tons) of greenhouse gases that are released into the atmosphere as a result of your day-to-day activities―from driving a car to eating a ham sandwich. The name refers to carbon dioxide, which accounts for about 84 percent of human-made greenhouse-gas emissions. The word footprint “describes the amount of carbon dioxide that you contribute to climate change,” says Bill McKibben, author of Fight Global Warming Now (Henry Holt & Company, $13, amazon.com). So when you eat that ham sandwich, your carbon footprint includes the amount of pollutants produced by the tractor that harvested the corn that fed the pig and the wheat that made the bread, as well as the vehicles that moved the ham and the bread to your door.
What does it mean to offset your emissions? You can compensate for your footprint by donating money to organizations that fund clean energy or other projects that soak up carbon dioxide from the atmosphere. To try it, and to find easy, painless ways to reduce your emissions, visit these websites: standardcarbon.com, terrapass.com, and carbonfund.org.
Why would you want to? The United States ranks second among industrialized nations in greenhouse emissions. (Australia is first.) If everyone’s footprint were reduced, that could slow global warming―and the melting ice caps that come with it.