What is your carbon footprint?

Answer

Defining carbon footprint is easy. It is the amount of carbon (in the form of carbon dioxide, or CO2) you send into the atmosphere in the process of living your life. The average American has a carbon footprint of about 20 metric tons of CO2 every year. Europeans use about half as much, even though their standard of living is as high as ours. In India, where the standard of living is much lower, the average carbon footprint per person is less than 2 tons. If you look at the entire world, the average human has a footprint of about 51/ 2 tons.

These are only averages, though. Your own carbon footprint will be more or less, depending on lots of factors. If you live where it does not get too hot or too cold, you will use less energy than average to heat or cool your house, and generate less CO2. A small house uses less energy than a big house. A house that is energy-efficient because it is well insulated and uses high-efficiency heating, cooling, and appliances, uses less than one without those features. If you live close to where you work or go to school, you will use less energy on average than those who live far away (it also depends, of course, on whether you walk, bike, drive, or take public transportation, and if you drive, on what your car’s mileage is).

Many of these things are hard to control, but if you want to reduce your carbon footprint to fight climate change, there are ways to do it anyway. No matter how big or small your house is, for example, you can lower the thermostat a few degrees in winter and raise it a few in summer. You can turn out lights more often, and use more efficient bulbs, like compact fluorescents, wherever possible. You can make sure your next car gets higher mileage than your last car. You can use recycled products, and recycle more yourself, since it takes more energy to make new things from scratch than to make them from old things. And so on.

Unfortunately, there are aspects of your carbon footprint that you have much less control over. Take cars. The CO2 that comes from burning gasoline is part of your carbon footprint. But so is the energy used to make the car, and so is the energy used to make or mine the steel, plastic, and glass it’s built from. So is the energy it takes to get the car from the factory to the dealer. So is your share of the energy it takes to build and maintain the roads you drive on. When it comes to electricity, you might have little control over where it comes from. Some ways of generating it (nuclear, wind, solar) are almost carbon-free. Others, like burning coal, are huge carbon dioxide generators.

In most cases, these contributors to carbon footprint are beyond our personal control. In order to make major reductions in the average American’s carbon footprint, therefore, it will take not just individual action, but action on a large scale by companies and by the government.

Finally, a word of warning — read the fine print on carbon footprints. Sometimes the footprint “weighs” the full molecule of CO2, which is what was done in the lead paragraph above, and sometimes only the C (carbon) in the CO2. To get the weight of the CO2 from the weight of the C in the CO2, you would need to multiply by 44/12, so read the fine print.