Now that green means business, determining which companies are delivering on their environmental claims is an increasingly tricky affair

Deep in Costa Rica's Osa Peninsula, suspended in harmony between ocean and rain forest, the Lapa Rios resort is one of the world's most impressive luxury eco-destinations. The gourmet meals and many handcrafted items in the rooms are locally sourced; the water is heated by solar panel, and the electricity comes from a biodiesel-fueled generator; the grounds, landscaped with native plants, are tended to with hand tools so as not to frighten away the spider monkeys and toucans that perch and play within a stone's throw of the dining terrace; and the swimming pool is chemical-free.

Green seems to be everybody's favorite color these days, and plenty of businesses are happy to oblige, but it didn't take too much digging to turn up a number of self-proclaimed "green" operations in Costa Rica whose claims could only be described as dubious at best. Driving around in my rented four-wheel-drive Ford "Eco-Sport" (which runs on unleaded, thank you very much, and no more efficiently than any other SUV in its class), I needed to look no further than the loud, exhaust-producing all-terrain-vehicle "ecotours" across Costa Rica to be convinced that greenwashing is a force to be reckoned with, both there and around the world. When I asked the manager of one so-called eco-hotel what makes his property green, he responded, "Well, for one thing, all of our rooms have air-conditioning, but mostly I think it's the ocean view." The proprietor of a similar establishment, when asked the same question, told me that her assistant manager was a volunteer firefighter in his spare time. Among the massive all-inclusive resorts and water-guzzling golf courses of the gated "Papagayo Eco-Development," I spoke to reservationists who assured me of strong commitments to the environment on the part of their employers, but when pressed could point to nothing specific.

A big part of the problem can be attributed to the fact that nobody is actually sure what "green" means; the buzzwords of this movement are sprawling and ill-defined, a challenge for even the best informed. What, for instance, is the calculus that allows a traveler to understand the benefits of staying at a hotel that is carbon-neutral but dumps raw sewage into the nearest river? How sustainable can a property be if, as is the practice of one Costa Rican fishing lodge whose Web site touts a monthly "eco-report," you lay off half your workforce in the low season? Recycling is great, but in many places in the developing world it remains expensive and impractical—or simply unavailable. Lapa Rios, for example, trucks its recyclable trash more than 230 miles to the nearest processing facility, in the capital of San José (using no small amount of diesel to do so), but with rooms that cost upwards of $400 per night, it can afford to. It would seem unfair to penalize Ojo del Mar Eco Lodge, a lovely and conscientious little spot just down the road that charges $45 a night, for not doing the same thing.