Eco-friendly travel is on the rise, but vacation planners should proceed with caution. (TPopova/Getty Images/iStockphoto)

Green may not be the most fashionable color this spring, considering the recent policy shift in Washington on climate change. But it’s still the “in” thing for many travelers.

A survey by the Singapore-based online travel agency Agoda.com found that 58 percent of hotel guests preferred staying at an environmentally friendly property. Nearly 40 percent said they’re willing to spend an extra $10 a night to sleep in a sustainable resort.

If you’re a hotelier, hanging a sign on your door that says you’re green — even if you aren’t — can boost revenue. A study by market research firm Mandala Research found that 60 percent of U.S. travelers have taken a “sustainable” trip in the last three years and that these travelers spend on average $600 per trip, and stay three days longer than the average guest. Brian Mullis, founder of the nonprofit organization Sustainable Travel International, calls the burgeoning green-travel market “too big to ignore.”

Yet some travelers remain skeptical.

“For me, green implies no manufactured products,” says Carl Lehman, an audit manager from Windsor, Ontario. And by that standard, no airline, cruise line or hotel can truly measure up.

In a perfect world, for a hotel to be considered green, it would have to be bulldozed to the ground, trees would be planted and people would let nature take its course. But that’s not the world we live in. Still, at a time when terms like green, sustainable and environmentally friendly get tossed around too much — often with the intent of luring you into a booking — it’s worth asking how to separate real green from AstroTurf.

Bret Love, who publishes an eco-travel blog out of Atlanta called Green Global Travel, advises travelers to “do your research and ask questions” to determine whether green travel options are legit.

For example, many hotels promote their Leadership in Energy and Environmental Design (LEED) Certification from the U.S. Green Building Council, which judges on sustainable-site development, water savings, energy efficiency, material selection, indoor environmental quality and innovation in design. But if you travel abroad, you’ll need to be aware of other sustainability-certification programs, such as Australia’s EarthCheck or Britain’s Green Tourism Business Scheme.

“Membership in organizations such as the International Ecotourism Society or affiliations with National Geographic or World Wildlife Fund can be a good sign,” Love says. “But they don’t guarantee true sustainability commitment.”

Hotel chains sometimes have their own sustainability standards. InterContinental Hotels Group, which owns the Holiday Inn and Crowne Plaza brands, runs an internal program called IHG Green Engage that lets its hotels measure their environmental impact. Owners can pull reports on water use and utility consumption with an eye toward reducing their carbon and water footprint.

“It makes our hotels more cost-effective and ultimately allows us to improve the value of service we offer to our guests,” says Paul Snyder, IHG’s vice president of corporate responsibility.

When it comes to airlines and cruise lines, there’s a consensus among experts that there’s almost no such thing as green — only shades of fake green. “There’s a lot of greenwashing,” says Donna Zeigfinger, owner of Green Earth Travel, a travel agency based in Cabin John, Md., that specializes in ecotourism. She says that both airlines and cruise lines pollute and dump to such an extent that some travelers find it difficult to justify a booking.

Tour operators, which combine airline, hotel and excursions into a single package, can be even more challenging to figure out because of their many components.

“It’s not always easy to tell apart authentic green, eco-friendly and sustainable tour operators from fakes,” says Joost Schreve, co-founder and chief executive of kimkim, a company based in Palo Alto, Calif., that specializes in curating independent customized tours by local travel specialists. “My best advice is to get on the phone or Skype with your travel operator and ask some detailed questions.”

Those include: What hotels do you prefer to send your travelers to and why? What common travel practices do you see that you don’t like? How do you operate in a more eco-friendly way? Can you tell me about the guides you work with and how you recruited them?

“By putting in a little bit of extra effort and asking the right questions, you can increase the likelihood that you are dealing with someone who shares your values,” Schreve says.

Ask for more than numbers, experts say.

“Aside from what bulbs they use, how many recycling bins you see, or whether they give you the option to decline daily room service, it’s hard to tell on the surface how sustainable they are really trying to be,” says Alan Muskat, who runs No Taste Like Home, a foraging-ecotour company in Asheville, N.C. “I would want to see where they are sourcing their food, what they do with leftovers and what cleaning products they use.”

If you don’t like the answers or if they seem evasive, look elsewhere. “Simply stating they are green or eco-friendly does not guarantee they are not greenwashing,” says Terry Dunn, founder of EcoTripMatch, an Albuquerque-based website that helps travelers find ecotourism providers.

Dunn says that the homework isn’t easy, requiring that you “dig deep” on the provider’s website to determine things such as the building materials used to create the lodge or hotel, its efforts to save fuel and conserve water, and green certifications. If that information is missing, perhaps the hotel or tour operator’s commitment to sustainability just isn’t there.

For guests like Rick Jarrell of Madison, Wis., it all adds up to an almost impossible task. When he and his girlfriend were looking for an off-the-grid evening on a road trip from Los Angeles to San Francisco recently, they found a glamping resort in a California state park. The hotel appeared to be green, with an organic farm and an ambitious recycling program. But upon closer inspection, he found that it was using generators rather than solar panels for electricity and the food was anything but organic.

“We were by no means roughing it,” he says.

No travel provider will come up perfect. After all, every airline, cruise line, hotel and resort pollutes the environment. Perhaps the best travelers can hope for is that their penchant for sustainability will make the industry more responsive to their concerns. Because, in the end, the only green the travel industry probably cares about is your money.

Elliott is a consumer advocate, journalist and co-founder of the advocacy group Travelers United. Email him at chris@elliott.org.