Readers of monthly magazines may have noticed that a number of their favorite glossies have been publishing a green issue every spring (usually the May issue) for about three years now. In late April, The Observatory published its second annual Green Issues Guide, rounding up and weighing the content of this year’s crop, from the likes of Time, Mother Jones, and Vanity Fair. The article left one fundamental question unanswered, however: How have these green issues performed relative to other regular installments of the same magazine?

We’re a culture newly and obsessively fixated on the environment, and it’s a good thing that magazines have noted their readers’ interest in related issues. What publishers and executive editors don’t say out loud (but are surely hoping) is that the green movement will actually translate into more dough. Clearly, the advertising incentive is there—all of the green issues are teeming with environmentally oriented promotions—but the competition for those ads is heating up, according to Corey Powell, the executive editor of Discover, which published a “Better Planet” special issue in May.

“A year or two ago I would have said definitely yes,” he replies when asked if such issues sell more ads than regular installments. “These days it’s a lot tougher, since so many magazines are doing green issues of various sorts. Advertisers have definitely become choosier, just as readers have become more cynical about these things. In principle, lots of advertisers (especially auto and energy companies) are eager to appear near green copy. In practice, advertisers no longer reflexively respond to environmental-themed editorial topics; overall, I’d say that our May issue was actually a fairly normal issue for ads.

“Perhaps the real question at this point is whether advertisers are now avoiding publications that are not embracing green issues. I suspect that is true, but given our long history of environmental coverage we obviously are not running that particular experiment.”

Of course, in today’s fractured, shoestring-budget media climate, magazines don’t launch new products or sell ads without dedicated readers. In a less-than-scientific comparison of green issues to regular issues, we found that these editions are attracting attention. Readers react to environmental articles, so publications produce more of them, causing readers to react again, and so on. As CJR’s Green Issues Guide pointed out, though some of the content is faddish “greenwashing,” the majority of it is high caliber. Unfortunately, it’s early in this game and still unclear whether green issues give publishers the financial incentive they need to keep churning them out.

“The best we can tell, they sell pretty well,” says Jay Harris, publisher of Mother Jones. “The May/June issue, which… is about energy-related issues and is fluorescent green and rather loud, it’s a little too early to tell how it’s doing, although I think the exposure has been good.” For Mother Jones, this good exposure will likely translate into more green content. And that’s just fine with Harris, as long as the information in the articles spurs action.

“I actually think the public is kind of leading this. They’re ahead of politicians on a lot of things green,” he says. “If it’s not just a kind of consumer fad but actually something that forces a much more profound change in how we can consume, that can be hugely important. If it’s just a kind of flash in the pan, that this year’s color is green, it doesn’t mean anything.”

Franklin Foer, editor of The New Republic, takes a slightly less policy-driven approach to the subject. He says TNR put out an environmental issue, which ran this year at the end of April, to meet reader demand. “We’ve done online surveys and asked our readers what they wanted to see more of,” he says. “Writing on the environment scores on top of the list.” To Foer, that’s a good enough reason to keep doing what he’s doing. “We do a lot of environmental coverage…and I’m sure we’ll only increase that as the political world begins to wake up.”

Not all publications gloss over the numbers. This year, newsstand sales for Outside’s March 2008 green issue were 4 percent higher than other 2008 issues, according to the magazine’s circulation manager, Paul Rolnick. That doesn’t signify much more than normal newsstand highs and lows, however. “We have an average sale for, in this case, all the issues in 2008…There’s a fair amount of volatility, which evens out that average,” Rolnick says. “The realization is that [the green issue] is probably going to be among the best-selling three or four issues of the year. There are peaks and valleys and this is a peak.”

Michele Wilson is a freelance writer who lives in New York City.