Does global warming worry the Marriott hotel chain? "We face tremendous risk from climate change," Kathleen Matthews tells me. "Our hotels will be underwater, literally."

If, like me, you are a Washingtonian, you know Kathleen. She was an evening news anchor at the local ABC affiliate for 15 years as well a community activist who served on the board of Catholic Charities and Suited for Change (which provides clothes for women moving from welfare to work), among other groups. She's been married to Chris Matthews of "Hardball" fame since 1980. And since 2006, she has been an energetic and effective advocate for sustainability at Marriott International, where she is exec VP of global communications and community affairs.

Last week, Marriott invited its hotel guests to "green" their hotel stays by buying carbon offsets to protect rainforests in the Juma reserve in the state of Amazonas in Brazil. Marriott, in cooperation with nonprofit Conservation international, had previously agreed to donate $2 million to rainforest preservation in Amazonas. Protecting rainforests, as you probably know, is an important way to mitigate the threat of climate change because tropical forests remove lots of carbon dioxide from the atmosphere.

Marriott's initiative is noteworthy for several reasons. First, it's part of a broad green push by the company. Second, it's a great way to expose millions of people to the role of rainforests in preventing climate change. (I'm told that about half a million people are staying in a Marriott property on any given night.) Third, the company says that its s efforts will help attract so-called "green" meetings. Finally, the way Marriott announced its news speaks volumes about where the media business –– and corporate PR –– are going today.

As part of its overall environmental commitment, called Spirit to Preserve, Marriott has agreed to reduce its fuel and water consumption by 25 percent per room over the next 10 years, install solar power in as many as 40 hotels by 2017 and expand reuse and recycling programs. They are also greening their supply chain by buying key cards made of 50 percent recycled plastic (24 million a year!), replacing more than 100,000 pillows with new ones made from recycled bottles (let's hope they are as soft as the old ones), eliminating cardboard from more than 2 million rolls of toilet paper a year, and buying Bic pens (47 million) made with recycled material. The company is also ramping up its development of LEED-certified hotels.

In other words, Marriott is getting its own house in order, or at least starting to –– the essential first step to any corporate sustainability plan.

The new "green your stay" program invites guests who book on www.marriott.com to offset the carbon generated during their stay for as little as US $10, or US $1 per day for 10 days. The cost to offset the carbon generated in a single night in a hotel is about $1, Matthews explains, but the $10 minimum contribution helps insure that the vast majority of the funds donated will go to rainforest preservation, rather than to administrative costs.

This program expands a relationship between Marriott and a nonprofit called the Amazonas Sustainable Foundation, which supports about 2,500 residents of the Juma area who help protect the forest from illegal logging and farming. Contributions help fund people and equipment to monitor the forest, as well as other community services, designed to provide an alternative livelihood for the Brazilian poor.

For now, the Marriott website is the primary means of recruiting guests to participate. But the company may well expand that to email blasts to members of its Marriott Rewards program, tent cards in the rooms or promos on the hotel TV sets. "It's a big communications challenge," Matthews said. "A lot of companies that have launched these offset programs in the past haven't gotten huge traction."

Speaking of communication, Marriott is using social media –– often called Web 2.0 –– to spread the word about its new program. CEO Bill Marriott Jr. wrote about the program on his blog. There's a video promoting the project on YouTube. Marriott has set up a twitter feed alerting people to its green initiatives. The company has posted photos on Flickr. And, of course, there's lots of detail on Marriott's own website.

"We're going directly to the consumer, as opposed to trying to go through the media," Matthews says. That's smart, and it's a strategy that both reflects and accelerates the decline of traditional media.

In fact, Matthews told me, there are times when she travels the world for Marriott when she feels like she never left her role as a local TV reporter and anchor. She reports stories, and does her stand-ups. The only difference is, when reporting for Marriott, she's got to do her hair and makeup by herself.