Transportation -- particularly air travel -- is where most travelers have the biggest environmental impact. According to USA Today, a flight from New York to Denver produces as much carbon dioxide per passenger as an SUV produces in a month. To minimize your environmental footprint, try the following steps: Offset the carbon emissions produced by your flight. For shorter trips, take the train instead of flying -- especially in Europe or other regions where train service is fast and frequent. When renting a car, choose the smallest vehicle that can comfortably accommodate you. Decline any "free" upgrades (which will cost you more in gas). Rent a hybrid car.
Taking a long road trip? If your personal vehicle is large and not very fuel-efficient, consider renting an economy car instead. You'll save gas and avoid putting miles on your own vehicle. Whenever possible, use public transportation instead of a taxis or rental cars. Better yet, walk or bike.
When it comes to visiting the world's most beautiful places, the old adage rings true: Take nothing but photographs, and leave nothing but footprints. Travel with a tour operator that's environmentally responsible. Before you book, be sure to ask about group size (smaller groups tend to make less of an environmental impact), whether the tours are led by locals, how the tour operator gives back to the community, and what kind of lodging is included. When hiking, always stay on marked trails and maintain a safe distance from any animals you encounter. Deposit your trash in marked receptacles or take it with you when you leave. Light campfires only in established fire rings and be sure they're completely extinguished before you leave. When snorkeling, do not touch the coral or stir up sediment, as these actions can damage the reef's fragile ecosystem. Try to buy local products whenever possible instead of those that have been flown or shipped in from overseas. You'll support the local economy and get a taste of native cuisine. Do not, however, buy souvenirs or other products made from endangered animals or plants -- in most cases you can't get them through Customs anyway. Treat the locals with respect. Learn a few words in the native language, be open to cultural differences, and read up on the area before your trip so you're sensitive to issues of dress and behavior. Consider taking a volunteer vacation to give back directly to the place you're visiting.