Marriott International announced a broad strategy Monday to reduce its impact on the environment, pledging $2 million to protect the Brazilian rain forest and promising that by the end of the year its guests will be able to offset greenhouse gas emissions from their hotel stays.

The Bethesda, Md., firm's new greening tactics, detailed among singing birds at the National Zoo's Amazonas rainforest exhibit, come as the hotel industry is seeing the kind of demand for environmentally sound products that is already being felt by companies ranging from Wal-Mart to Alcoa.

Marriott is reducing fuel and water consumption, as well as furnishing its rooms with Bic pens made from recycled plastic. But the centerpiece of its strategy is the effort to protect 1.4 million acres of endangered rain forest in the Brazilian state of Amazonas.

Besides the $2 million that Marriott has committed to a fund to help pay for a rain forest protection plan, the company will also help guests offset their hotel stays with contributions of as little as $1 to the same fund. With more than 539,000 rooms, and if only a small portion of guests contribute, environmentalists said the company's impact could be profound. Meeting participants will similarly be able to offset their use of hotel facilities.

"It's meaningful. It's unique. It's innovative," said Jeff Hayward, verification services manager for the Rainforest Alliance, a New York advocacy group.

But it's not entirely altruistic. Besides meeting customer demand for more environmentally conscious hotel stays and corporate meetings, Marriott chief executive J.W. Marriott Jr. said he is worried that climate change poses a serious threat to many of the company's 3,000 hotels, including some of the most profitable.

"We've got to protect our hotels," he said. "We've got a lot of beachfront hotels. We don't want two feet of water in the lobbies. We're also in New York City. We have a lot of coastal properties, which I worry about the ocean rising and coming right in, in places it's not supposed to come."

When some of his executives asked for the $2 million, Marriott recounted, "I said, 'Good. Do it.' I was glad to do it. It's really good from a PR standpoint and it will help the environment. I don't know how you could spend your money any better."

Hayward, of the Rainforest Alliance, said "as committed as they may be to the environment, they are making a calculated guess that their guests or some portion of their guests are concerned about the environment." In the tourism sector in particular, Hayward said, "there's a certain amount of guilt people feel when they go on these long haul flights to get somewhere."

In an example of the company's delicate interplay between business and image as it tries to go green, Marriott's environmental efforts are being led by senior company executives on the business and public relations sides: Arne Sorenson, the chief financial officer, and Kathleen Matthews, head of global communications.

Those executives are working with Conservation International, an advocacy group that has also counseled Wal-Mart, Alcoa, Starbucks, Fiji Water, and Bank of America.

Glenn Prickett, a senior vice president at the organization, said Marriott's efforts were particularly important because of the rain forest initiative. The company's announcement noted — with the agreement of environmentalists — that the clearing of rain forests is more damaging to the environment than the impact of the world's cars, trains, and trucks combined.

Besides the rain forest initiative, Marriott has committed to reducing fuel and water consumption by 25 percent per available room in the next decade. By 2017, it wants to install solar power in as many as 40 hotels, a very small portion of the properties it manages and franchises. The company also wants to expand recycling programs: While 90 percent of its hotels recycle, only some of them recycle in-room guest trash.

Marriott is also updating design guidelines for its hotels to meet the U.S. Green Building Council's LEED standards.

The company is also pressuring its suppliers to provide greener products. The company said it will order 47 million of the greener BIC pens a year. It is also buying one million "room-ready" towels, which eliminate the initial wash cycle, saving 6 million gallons of water a year. Marriott is also looking into key cards that turn to compost and recyclable carpet.

Next month, Marriott plans to introduce a green meetings concept which will feature recycled paper and responsible packaged water, among other things.

"People really want to know now if you are an environmentally friendly company," Marriott said.