By Amanda Gardner
Monday, December 3, 2007 12:00 AM
MONDAY, Dec. 3 (HealthDay News) -- Love not only makes the world go round, it may make it greener, too.
Rising divorce rates mean that fewer people are living in each household, causing them to take up more space and consume more energy and water, a new study suggests.
"People talk about divorce hurting the children. Divorce also has an impact on the environment," said Jianguo "Jack" Liu, senior author of the study and the Rachel Carson chair in sustainability at Michigan State University. "Nobody knew about it."
Liu started doing research in panda reserves in China years ago. "In the reserves, there are not only pandas but also more than 4,000 people," he said. "Surprisingly, the number of households increased much faster than the number of people in the last three decades, so we were wondering if that was true at the global level."
Pandas are naturally solitary creatures, living separately from each other. Humans, on the other hand, tend to be more social. But when the social bond falls apart and people start living more like pandas, the drain on the environment is greater, Liu said.
"If you increase the number of households, you need more land to build houses, you need to have energy to cook food and to heat in the winter time," Liu explained. "If you need more land, then you cut down the forest and cut down trees for fuel, you destroy more habitat for the pandas. There's a direct connection."
In China and elsewhere, one important reason for this increase in the number of households is divorce -- although other reasons include fewer generations living under the same roof and people staying single longer. In the United States, the households headed by a divorced person increased from 5 percent in 1970 to 15 percent in 2000, while the proportion of married households decreased from 69 percent to 53 percent during the same time period. In China, almost 2 million couples untied the knot in 2006.
For this study, published online in this week's edition of theProceedings of the National Academy of Sciences, Liu and his team compared differences between married and divorced households to see if they varied in their consumption of three important but increasingly limited resources: land (measured by number of rooms in the house), electricity and water.
Among their findings:
In 12 countries studied between 1998 and 2002, there were 1.1 to 1.8 fewer people living in an average divorced household, compared to an average married household. Another way to say it: The average divorced household was 27 percent to 41 percent smaller than the average married household.If divorced households in these 12 countries (which included the United States, Brazil, Greece, Mexico and South Africa) had combined to become the same size as a married household, there would have been 7.4 million fewer households overall. In the 12 countries, divorced households occupied 33 percent to 95 percent more rooms per person than married households. Expanding divorced households to the size of married households would have resulted in 8.4 million to 37.5 million fewer rooms in less developed and westernized countries, respectively. In the United States alone in 2005, 38.5 million rooms would have been unnecessary (along with heating and lighting costs) if divorced households combined to become the same size as married households.Also in the United States in 2005, divorced households used 73 billion kilowatt-hours of electricity and 627 billion gallons of water that could have been saved if the divorced households had remained the same size as married households.
As with so many things, love may be the solution.
"People can try to stay married and not get divorced," Liu said. "Or if there's no way two people can stay together then get divorced, then get remarried quickly or live together with other people."
Liu's study showed that, after remarriage, average household size and the number of rooms per person returned to the level of households that had stayed married the whole time.
To Dr. Maureen Lichtveld, chairwoman of the department of environmental health sciences at Tulane University School of Public Health and Tropical Medicine, the findings are another example of the inextricability of humans and their habitat.
"In order to find sustainable solutions for environmental health issues, we must take a holistic approach and that holistic approach requires looking at both the environment in the traditional sense of the word and the environment from the human health aspect," she said.
To measure your own ecological footprint, take this quiz from the Global Footprint Network.
SOURCES: Jianguo "Jack" Liu, Ph.D., Rachel Carson chair in sustainability, Michigan State University, East Lansing; Maureen Lichtveld, M.D., professor and chair, department of environmental health sciences, Tulane University School of Public Health and Tropical Medicine, New Orleans; Dec. 3-7, 2007,Proceedings of the National Academy of Sciences