Climate change and rising sea levels resulting from global warming are having a noticeable impact on the South Pacific islands. Natives I have known for more than 30 years tell me the seasons are now unpredictable (it's more likely to rain in the dry season, and vice versa), and the tides are higher than ever (in some places the lagoons lap on shore at high tide rather than the beach). Indeed, most islanders don't want to hear any corporate-induced spin about there being no evidence of global warming and its consequences. They know it's true from firsthand experience.

Carbon emissions, the prime cause of global warming, are released into the atmosphere each time you take a flight or drive a car. You can help neutralize this danger to our planet through "carbon offsetting" -- paying someone to reduce your carbon emissions by the same amount you've added. Carbon offsets can be purchased in the U.S. from companies such as Carbonfund.org and TerraPass (www.terrapass.org), and from Climate Care (www.climatecare.org) in the U.K.

Although one could argue that any vacation that includes an airplane flight can't be truly "green," you can go on holiday and still contribute positively to the environment. You can offset carbon emissions from your flight in other ways. Choose companies that embrace responsible development practices, helping preserve destinations for the future by working alongside local people. An increasing number of sustainable tourism initiatives can help you plan a trip and leave as small a "footprint" as possible on the places you visit.

Responsible Travel (www.responsibletravel.com) is a great source of sustainable travel ideas run by a spokesperson for responsible tourism in the travel industry. Sustainable Travel International (www.sustainabletravelinternational.org) promotes responsible tourism practices and issues a Green Gear & Gift Guide.

You can find eco-friendly travel tips, statistics, and touring companies and associations -- listed by destination under "Travel Choice" -- at the TIES website, www.ecotourism.org. Ecotravel.com is part online magazine and part eco-directory that lets you search for touring companies in several categories (water-based, land-based, spiritually oriented, and so on).

In the U.K., Tourism Concern (www.tourismconcern.org.uk) works to reduce social and environmental problems connected to tourism and find ways of improving tourism so that local benefits are increased.

The Association of Independent Tour Operators (AITO) (www.aito.co.uk) is a group of interesting specialist operators leading the field in making holidays sustainable.

For information about the ethics of swimming with dolphins and other outdoor activities, visit the Whale and Dolphin Conservation Society (www.wdcs.org) and Tread Lightly (www.treadlightly.org).

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.