Blame it on Rio's 1992 Earth Summit, or credit a cash-starved hotel manager. Whatever.

The point is this: The "greening" of the hotel industry, and travel and tourism in general, is more than the latest European import. It's a feel-good moneymaker, and that means it's here to stay.

"It's just the right thing to do, ecologically and economically," said Kathy Hilgert, manager of the Four Points by Sheraton, a Norwalk property that is a member of the Green Hotel Association.

Hundreds of hotels have come to the same conclusion in recent years, and that explains those ubiquitous room cards asking guests if they'd care to forsake fresh towels and bed linens to help save the environment.

"Sure, OK," has been the answer from hundreds of thousands of guests; that has saved the hotel industry hundreds of thousands of dollars.

Talk about a win-win-win situation: Hotels save money; guests feel virtuous; and the environment benefits.

And, of course, there's the added plus of "we care" marketing. As it says at www.greenhotels.com, the Green Hotel Association's Web site: "Guests are persuaded to come to your property by your strong concern for our planet. ... Praise becomes dollars via return visits from ecologically aware guests."

And there's reason to believe there are such guests. A recent survey by the Travel Industry of America found that 83 percent of U.S. travelers want to support environmentally responsible suppliers of products and services and are willing to spend more money to do so.

That statistic is not lost on other parts of the tourism industry, especially those hoping to retain distinctive small-business images as they merge into ever larger corporations.

In the battle to balance dollars with details that distinguish a property from others, environmental measures can strike just the right note. There's the Canadian golf course that eschews chemicals, using only elk manure to fertilize its greens, and the inn on Florida's Sanibel Island that asks guests to record what they did for Mother Nature during their stay.

Budget Rent-A-Car now offers alternative fuel cars for rent in Los Angeles, and this summer, Carnival Cruise Lines announced its first "earth-friendly" laundry system aboard the new ship Paradise.

The industry trend is so prevelant that Conde Nast Traveler as well as Ski and Coastal Living magazines have begun to make annual environmental awards. "Most of the [measures] that happen to be good from an environmental standpoint are good for business, so why not?" asks David Stipanuk, associate professor at the School of Hotel Administration at Cornell University.

Common-Sense Approach

Take some parts of the Caribbean, where tourism directly or indirectly supports a majority of the economy. There, hotels are "the major business, and what they do and how they do it is significant," Stipanuk said.

Fresh water, power and landfill space are at a premium on most islands or in some remote locations, making those resort properties ideal for eco-measures, including the towel and linen programs, water-saving showers, energy-efficient light bulbs, soap and shampoo dispensers, low-flow toilets, fluorescent lighting, occupancy sensors to control lights and menus that make clear "drinking water served on request only."

And if you are going to take those measures -- measures that might annoy some guests -- why not turn them into positive publicity?

"Hotels are becoming more conscious of the amount of energy and water being used unnecessarily. They see [ecological measures] as a good cause... that also helps the bottom line," said Tia Gordon, a spokeswoman for the American Hotel and Motel Association.

And more and more the industry has reason to believe that clients will appreciate the efforts. "I think Americans are starting to be more conscientous [about ecology]," said Patricia Skozelas, vice president of Project Planet Corp.

Project Planet, with the Bass hotel group, operator of International Hotels in Europe and the Holiday Inn chain, created a towel and linen program that eventually was adopted in 2,300 hotels, motels and inns in the United States and the Caribbean.

Skozelas said guest response has been highly favorable, with only a handful complaining that they shouldn't be asked to conserve when only the hotel profits. To quell the criticism, some hotels have adopted Childreach, which promises to devote $264 annually from the money it saves to sponsor a needy child.

Depending on the size of the hotel, that might represent a large or small percentage of the savings. For example, a midtown Holiday Inn in New York City, which serves 400,000 guests annually, recently reported saving $121,000 in one year through the linen and towel reuse program.

Conserving Water, Detergent

Project Planet estimates that its Conserving for Tomorrow program saves 6,000 gallons of water monthly and 40 gallons of detergent a month (at an average 150-room hotel).

The four-color glossy foldout cards in thousands of hotels, motels and inns say: "We invite you to join with us to conserve water by using your towels and linens more than once. In addition to decreasing water and energy consumption, you help us use fewer environmentally harmful chemicals and reduce the amount of detergent waste water that must be recycled within our community. Help us in protecting the earth's natural resources for future generations to use and enjoy."

Project Planet asks guests to respond to the program with comment cards. "We get comments saying, 'We conserve at home, why not here?'" Skozelas said. "We got maybe 50 response cards [one week in mid- October] and only one of them was someone who was aggravated."

Guest approval ratings have been so high that some properties have become eco-braggers, sending out press releases about the latest ecological measures as they would a renovation or new chef.

Patricia Griffin, who started the Houston-based Green Hotel Association in 1992, says she urges her 200 member properties to publicize their efforts. "We tell them [member hotels] to do a press release once a year on their environmental activities. We want to do everything we can to help them get new business," said Griffin, who began the association after seeing towel and linen reuse programs in Europe nearly a decade ago.

Still, as popular as the environmental programs have been, they are not for everyone. Kathy Hilgert's 127-room hotel in Norwalk caters to mostly corporate clients, the clientele most likely to participate in towel and linen reuse programs.

On any given day, about a quarter of the hotel guests decline fresh towels and new bed linens, Hilgert said. But that's different from her experience as a manager of resort hotels in the Southeast that catered to mostly vacationing families.

"We had the same program available in the hotels, but fewer people took advantage of it," Hilgert said.

"It's a different mentality. When people are on vacation, they want to be pampered and waited on. They are spending their money. People on business...it's not their money they are spending."

Vacationing families also are more likely to make heavier use of towels and sheets due to their activities, numbers and longer stays, she noted.

It's Easy

Being Green

To learn more about the hotel industry's environmental efforts, visit the following Web sites:

Green Hotel Association at www.greenhotels.com.

Project Planet at www.projectplanetcorp.com.

The Green Tourism Association at www.greentourism.on.ca.

Green Globe, an organization created after the Rio Earth Summit, at www.greenglobe21.com.

The International Ecotourism Society (TIES), in Burlington, VT, at www.ecotourism.org.