As Thanksgiving approaches, the annual flood of unwanted holiday gift catalogs has begun piling into mailboxes on their way to recycling and trash bins.

A new initiative by three environmental groups aims to reduce the flow. Last month, the organizations launched CatalogChoice.org, a free online service that allows consumers to request that merchants voluntarily remove their names from catalog mailing lists.

More than 125,000 people have signed up requesting merchants halt the delivery of more than 1 million catalogs.

April Smith, a spokeswoman for Catalog Choice, said all the merchants they have contacted have agreed to honor the requests. Among them: L.L. Bean; Lands' End; Gaiam and Gardener's Supply Company; and Lillian Vernon -- companies that collectively mail about 64,000 catalogs.

"We want to prevent the making of unwanted catalogs at the expense of the environment," said Smith, noting that most consumers still want to do business with the retailers. "No catalog company wants to mail catalogs to people who don't want them."

Every year American households receive about 19.8 billion catalogs -- about 110 catalogs per household annually, according to Resource Information Systems Inc., a group that tracks news about the forest product industry.Environmental groups estimate that it takes 53 million trees to produce 3.6 million tons of paper to make catalogs. The process adds 5.2 million tons of carbon dioxide emissions to the atmosphere annually, equal to the emissions of 2 million cars, according to the Environmental Defense, an environmental nonprofit group.

Catalog Choice was developed by the National Wildlife Federation, Natural Resources Defense Council and the Berkeley, Calif.-based Ecology Center. Its goal is to improve the efficiency of catalog distribution by reducing the number of repeat and unsolicited mailings. The project -- funded by private groups The Overbrook Foundation, the Kendeda Fund and the Merck Family Fund -- allows people to request that their names be removed from catalog lists maintained by more than 1,000 retailers. After the signing up and identifying the catalogs they don't want, Catalog Choice contacts the merchants. Consumers typically notice the change in four to 10 weeks, organizers say.

Daniel Katz, environmental program director at the Overbrook Foundation, said the organization led a research project on the catalog industry because of concerns about natural resources. Katz said he's been surprised at the positive response from consumers and numerous bloggers who have written about the service.

"Before, consumers had no control of what came in the mailbox," Katz said. "This allows individuals to empower themselves and believe that we can change the world collectively. It gives a great sense of satisfaction."

Mary Moffroid, 67, registered and canceled 30 catalogs since her daughter-in-law -- a freelance environmental researcher -- told her about Catalog Choice.

"If we can cut down on the number of catalogs that are mailed every year, we can save a lot of energy and a lot of trees," said Moffroid, a retired college professor and part-time Miami resident. "It is a big waste of money for many of these companies to mail a catalog people toss in the recycle bin."

Mc Nelly Torres can be reached at mntorres@sun-sentinel.com or 954-356-4208 or 561-243-6600, ext. 4208.