It took four university researchers to figure out what an area trashman has known for years: Divorce can hurt the environment.

Elijah Thorne, founder of Grayhound Trash Removal Inc. of Bladensburg, Md. has seen divorcing couples throw away everything from wedding pictures and dresses to perfectly good furniture and even mattresses.

"It generates a lot of trash when households break up," said Thorne, who got his first trash truck 35 years ago. "They throw away a lot of stuff. Good and bad."

The authors of a study published this month in the journal Nature reached the same conclusion.

"By getting divorced, you could have more impact on the environment," said Jianguo "Jack" Liu, a Michigan State University professor and co-author of the article.

Divorce not only generates more waste in the short-term, but also down the road: Along with shrinking fertility rates, longer life spans and higher incomes, divorce is contributing to a worldwide trend toward a greater number of smaller households, the report said.

Liu, who is also associated with the Department of Fisheries and Wildlife, made this discovery while studying at a Chinese panda reserve, where the number of households grew by 110 percent even though the human population grew by only 70 percent. He found the same household growth pattern when he expanded his research to 141 countries, including Australia, India, Kenya, Brazil, Italy and the United States.

The growing number of houses threatens natural habitats around the world, said Stanford University Professor Paul R. Ehrlich, a co-author with Liu of the study, "Effects of Household Dynamics on Resource Consumption and Biodiversity."

"Every time you have fewer people living per house, you end up with another house plowing under another piece of land," Ehrlich said.

The study also found that smaller households are less efficient than big ones. Ehrlich notes that a large family may buy a 16-ounce box of cereal, while two smaller families each buy 8-ounce boxes, generating more waste.

"If you don't believe it, cut up the boxes and you'll see the two add up to more cardboard," Ehrlich said.

But splitting from a spouse doesn't always equal a larger number of households, according to some.

The Census said there were 222,275 divorced people living in Maryland in 2000, about 107,000 more divorcees than in 1990. But those divorces didn't necessarily lead to more households in the state, said some people who deal with marriage and divorce in Maryland.

"Quite often when people get divorced they're still young and wind up going back to live with mom and dad," said the Rev. Alberta Eden, an interfaith minister based in Baltimore County, who has performed weddings around the state.

Christopher Nicholson, chair of the family and juvenile law section of the Maryland State Bar Association, was initially skeptical.

"That's making the assumption that people who get divorced go out and form a distinct household," he said. "But that's not what we always see."

It is not uncommon for divorcees to live in larger, non-traditional households, he said.

Liu, who lives with his wife and two children, hopes his study will raise awareness of individuals' impact on the environment and prompt government to offer incentives for people to share households and resources.

And he said he welcomes any additions to his research from Thorne, the Bladensburg trash hauler.

"He's got to publish in leading journals that other people have access to," Liu said with a laugh. "That's what we scientists do."

Capital News Service contributed to this report.