Adventure Advisor:

For all the opportunities we have as travelers to pollute and exploit abroad, there are surprisingly few to make up for it. If not for the Earthwatch Institute (800-776-0188, www.earthwatch.org), there would be even fewer. This nonprofit has spent the last few decades perfecting the balance between do-gooder volunteerism and hard-core adventure travel. Their program menu now spans five continents and countless causes -- if there's any part of the world you want to see, chances are they've got a reason for you to be there.

Take the Indian Himalaya. Dozens of companies offer hiking trips through the valleys of Ladakh. But Earthwatch is there to help solve the problem of the endangered snow leopards that are being killed by herders who are protecting their sheep. There's nothing easy about conducting field research at 13,000 feet, especially with the added intellectual challenge of bridging economic, environmental and cultural concerns. But when you crawl out of your tent each morning to skim the ridges that separate the Himalaya and the Tibetan Plateau, you'd be hard-pressed to pass it off as just another day at work.

Other hits from this year's Earthwatch lineup: monitoring green turtles in Malaysia, developing a hippo sanctuary in Ghana, tracking lemurs in Madagascar, and studying orangutans in Sumatra. Suffice it to say, you won't lack for creative ways to cleanse your conscience and add some notches to your walking stick.

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