True-blue green, with a bright yellow border

We’ve all heard of “greenwashing” — a propaganda tactic used to convince you that a product is good for the environment, when it’s not. (For a comprehensive and eye-opening look at the term, see this story by The Center for Media and Democracy.)

So how do you know if that eco-tour, eco-lodge, or eco-travel plan is really a good thing for the Earth and other living things?

Well, there is not one simple answer, but the best strategy is to ask a lot of questions –Budget Travel’s Dan Oko suggests four good ones — and also to seek out authorities you can trust. One of the expert sources that I rely on is the National Geographic Society’s Center for Sustainable Destinations. These folks at NGS have been around a while — over 100 years — and their goal has always been to explore the world, and inspire you to do the same. Their resources are expansive and include lots of smart staffers who have been everywhere. The CSD Web site has a long list of links to eco-tour providers, so if you’re planning a trip, this is a great place to start.