On the Environmental Virtues of Cohabitation

When science seems to take a stand on our romantic decision-making, people tend to get excited. So it's no surprise that Google News turned up more than 400 articles about new research suggesting that divorce is harmful to the environment. The gist of the study, which appears in the Proceedings of the National Academy of Sciences, is that the average divorcée uses more resources—specifically electricity, water, and residential space—than does the typical person in a couple or a family.

But the study tells only half a story. By focusing on people's decisions to stay married or get divorced, it comes to an incomplete conclusion. The real issue is whether we live alone or live with others. Marital status is immaterial.

Living alone requires greater use of resources. Each home or apartment needs to be built from raw materials, for one thing, and each household in the developed world tends to be furnished with its own energy-guzzling collection of lights, appliances, and consumer electronics. Adding a person to an existing household, or combining two households into one, creates efficiencies that can't be matched when people live by themselves. The new study, to its authors' credit, mentions that "declines in multigenerational households, delays in first marriages, increases in empty nesters, and increases in separated couples" can also increase resource use. (It covers that aspect of the subject in three sentences, however, and some news reports on the study overlooked it entirely.)

It follows that for singles, moving in with someone—anyone—is a green thing to do. Getting married? Great. Cohabiting? That's great, too, from an environmental standpoint. Shacking up with a roommate or two? Nature thanks you.

Marriages may in fact be bad for Mother Earth for a reason that the new study didn't consider. First comes love, as the nursery rhyme goes, and later comes a baby carriage. Each additional member of the species adds to the human race's demand for resources. No wonder Slate calls babies "the new SUVs."