Fill 'er up? Not so fast. Using 15 gallons of gas emits 300 pounds of carbon dioxide. That means one less trip to the gas station a month can make a big difference. Save money-and the planet-by carpooling, using public transportation, doing errands on foot or biking to work to reduce your fuel consumption. If you have the means, you can take an even bigger step, and buy a hybrid car. Hybrids dramatically increase your fuel efficiency while reducing carbon emissions. Plus, they're now available in all sizes - even SUVs. Nobody likes being addicted to gas, so put the brakes on your habit today. Set a goal of making one less visit to the pump each month.