WE travel to see the world -- but if we want to ensure that there will always be a world left worth seeing, we should start thinking of our sojourns not only as personal respites but also as the means by which to improve things little by little.
Here's what you can do to help.
1. Give as you go
Make your trip count by giving your tourism dollars to companies that take action to better the world. Intrepid Travel ( 847-8192, www.intrepidtravel.com), an adventure-tour outfit, matches clients' donations dollar for dollar for developing-world causes, such as protecting children and preventing AIDS.
Locally, Redondo Beach's Portofino Hotel & Yacht Club ( 379-8481, www.hotelportofino.com) donates proceeds from its Stay and Save a Sea Lion package to MAR3INE, a nonprofit supporting marine mammal rehabilitation.
2. Think when you fly
Experts speculate that negative emissions at high altitudes have greater effects, which would make airplanes prime culprits in global warming.
You can buy "offsets" to mitigate your carbon output. These are invested in energy-efficient and renewable-energy projects ( 273-2975, www.sustainabletravel.com). Or calculate your share and get other ideas at Terra Pass ( 879-8026, www.terrapass.com) or Be Green Now ( 691-6325, www.begreennow.com.)
Also choose airports such as Seattle-Tacoma International, Baltimore-Washington International and Oakland International that make significant trash recycling efforts.
3. Buy -- or don't -- for effect
Avoid souvenirs and products made from endangered plants or animals, which cannot legally be brought into the U.S. (That tortoiseshell necklace may look beautiful, but a century-old creature may have been slaughtered for it.) For souvenirs, choose items of local origin.
Wherever you go, take a reusable bag for your purchases; cloth totes work best.
4. Teach your children well
What you do for conservation and cultural sensitivity are all well and good, but will your children follow in your footsteps? By teaching younger generations how to live and travel responsibly, we can ensure a brighter future for all, so make their travels a time for learning.
5. Drive conscientiously
If you have to drive (the better alternative is mass transit), tread lightly.
Renting? Hertz ( 654-3131, www.hertz.com) recently launched its Green Collection, with more than 35,000 fuel-efficient cars, including the Toyota Camry and Ford Fusion. EV Rental Cars (in California and Phoenix,  387-3682, www.evrental.com) boasts an entire fleet of hybrids, the Toyota Prius included.
6. Stay green
Don't leave your eco-sense at home when traveling: Turn off lights, conserve water (avoid lengthy showers in water-needy spots) and use air conditioning and heating sparingly.
7. Support local culture
"Educate yourself on local culture and the environment before traveling -- it will not only make the trip more enjoyable, but provide you with a greater understanding of how you might help," says David A. Kelly, a travel expert at the Practical Traveler (www.thepracticaltraveler.com).
Also, choose travel companies with ethnographic awareness. For instance, Mountain Travel Sobek ( MTSOBEK [687-6235], www.mtsobek.com) partnered with the Nature Conservancy to help protect the cultures and languages on China's Yunnan peninsula -- a region that is slated for development.
8. Dine ethically
Your journeys are ideal for letting restaurants worldwide know that you don't support unethical food production. Make your stance known through what you order -- or refrain from.
Avoid foods such as veal, foie gras and shark-fin soup that involve harsh treatment of animals. And don't order seafood that threatens already endangered wildlife populations (Chilean sea bass, farmed salmon and bluefin tuna, for instance.)
The region-specific Monterey Bay Aquarium seafood watch lists are downloadable at www.mbayaq.org; print one and take it with you.
Also, check www.eatwellguide.org for a list of thousands of American and Canadian restaurants that serve food that is produced in ways not harmful to the environment.
9. Donate your vacation time
Volunteer. A recent Travel Industry Assn. survey indicated that almost 25% of travelers are interested in service-based vacations.
To find a charity-travel opportunity that caters to your interests, go to www.universalgiving.org or www.volunteermatch.org.
10. Just travel
According to LeLei LeLaulu, president of the global humanitarian group Counterpart International, "Tourism represents the greatest voluntary shift of wealth from rich to poor in history." It has become the world's largest and fastest-growing industry and may well be the most effective way to heal poverty, she said.
If you use common sense, you'll be doing a world of good simply by getting out there and seeing our planet.