Erik Daehler loves to travel. But every time he gets on an airplane, he knows his carbon footprint gets bigger. "It's had a horrible imprint on my carbon footprint," admits the 30-year-old physicist and aerospace engineer from Southern California.
What, might you ask, is a carbon footprint?
A carbon footprint is the measure of the amount of carbon dioxide -- the major man-made global warming greenhouse gas -- that goes into the atmosphere as you go about your daily life. Almost everything you do affects it: turning on a coffee maker, driving a car, buying food -- and in Daehler's case -- taking a ride on a passenger jet.
Air travel accounts for about 3.5 percent of the human contribution to global warming, according to the Intergovernmental Panel on Climate Change. The good news is you can offset -- if not eliminate -- your carbon footprint by making choices that can even save you money.
"What do I give up to do that air travel?" asked Daehler. "Well, maybe I won't use the heater as much this winter."
Making these kinds of choices has become a growing trend among people who want to reduce the size of their carbon footprints. At the same time, they must grapple with the question of whether their actions really make any difference.
Many people have employed a number of low-tech ideas that all play a small part in reducing their footprints: reusing canvas shopping bags, taking shorter showers, and walking or riding a bicycle for short trips around town.
Increasingly, many have turned to Web sites that offer carbon calculators, which add up how much carbon dioxide gas their lifestyle puts into the atmosphere. You increase your carbon footprint by driving a sport utility vehicle, for example, or reduce it by driving a hybrid.
Experts say one of the first things you can do to reduce your carbon footprint is to get smart about energy efficiency.
Many people may not realize that electricity production -- derived from coal-burning power plants -- is one of the biggest sources of carbon emissions. Seventy percent of all U.S. electricity is produced as a result of burning fossil fuels, according to the Union of Concerned Scientists.
"Efficiency is the least expensive way to cut down on your carbon footprint," said John Steelman, director of the climate program at the Natural Resources Defense Council.
On average, every American is responsible for about 22 tons of carbon dioxide emissions every year, according to statistics compiled by the United Nations. That is far above the world average of 6 tons per capita. Thus, experts say there's lots of ways to reduce your carbon footprint inexpensively by taking some simple steps at home.
How? Web sites like stopglobalwarming.org have carbon calculators that offer dozens of suggestions for cutting emissions around your house. For example, the site says that moving a thermostat down two degrees in winter and up two degrees in summer will save 2,000 pounds of carbon dioxide and $98 a year.
If every household in America replaced just three bulbs with energy-efficient fluorescent bulbs, we would all save $60 a year and collectively keep a trillion pounds of CO2 out of the atmosphere, according to the site.