One of the best things we can do for the planet is stop putting new humans on it, which means promoting safe and effective birth control for people who want to keep their offspring levels between zero and "get that, would you, Deirdre." But hormonal birth control comes with side effects like weight gain, mood swings, blood clots, and Rush Limbaugh. Luckily, there's a birth control option that's safe, quick, easy, reversible, and 100 percent effective for 10 years. But back off, ladies: For once in our lives, this birth control's just for dudes.

Babies! They use so much energy that the best thing you could do to save the human race from climate change might be to avoid having one altogether. But if you choose the reproductive path, at least the 6,000 poopy diapers that your offspring will produce in the course of his or her early years could have a second life as part of your house -- specifically, as the shingles tiling your roof. The diapers, thank goodness, are sterilized first. Then they’re separated out into their components. The, um, "organics" go to waste-to-electricity products, and the plastic part goes into …

Cross-posted from Policy Innovations. As human numbers approach 7 billion, the question is, "Where do we go from here?" The U.N. recently published new population projections, which envision a range of possibilities for the 21st century. In the U.N.'s low projection, our numbers peak at 8 billion by mid-century, then decline to 6 billion by 2100. By contrast, the medium and high projections envision continued growth for the foreseeable future. According to the medium projection, the world's population would reach 10 billion by 2100; according to the high projection, nearly 16 billion. Now, I don't believe there is an optimal …

Take a look in the mirror.Population growth tends to get blamed on other people: Africans and Asians who have "more kids than they can feed," immigrants in our own country with their "large families," even single mothers in the "inner city." But actually the population problem is all about me: white, middle-class, American me. Steer the blame right over here. Well-meaning people have told me that I'm "just the sort of person who should have kids." Au contraire. I'm just the sort of person who should not have kids. Population isn't just about counting heads. The impact of humanity on …

Who knew feminist trailblazer Gloria Steinem was such a greenie? In an interview on ABC News' "Nature's Edge" a few months ago, she raised the alarm about climate change, talked about how climate is connected to women's rights and population, and gave a basic lesson on ecofeminism and deep ecology (all while fielding insipid questions from the interviewer): Quotable bits: "The overpopulation is still the biggest reason for global warming, for all the pressure on the environment." "The truth is that global warming is a nuclear holocaust slowed down slightly." "The important thing, I think, about both ecofeminism, as a …

Betty White, honorary forest ranger and ardent environmentalist.Photo: USDAWhite is the new green! Did you know that the octogenarian actress is a longtime environmentalist? She's starring in a new campaign for The Wilderness Society: "Keep it wild with Betty White!" "Wilderness is harder and harder to find these days on this beautiful planet, and we're abusing our planet to the point of almost no return," White said last year when she was made an honorary forest ranger. She's also a huge animal lover. She has long been involved with the Monterey Bay Aquarium, the Los Angeles Zoo, and other organizations …

As I've talked to and read about people coming to terms with their decisions not to have kids, the comparison has come up over and over. "I felt like a gay person must feel, coming out of the closet and having these people validating me." -- Jason Gill, quoted in a New York Times Magazine article on the childfree "My friends and I have occasionally likened coming out as childfree to coming out as a gay person 40 or 50 years ago. There's the same sense of shock -- perhaps that's too strong a word. But it's a lifestyle people …

As we zoom toward 7 billion, population growth is looking ever more hairy and daunting. The big-picture solution is empowering women everywhere and making sure they have the tools, knowledge, and support to control the size of their families, but that's not something an average person can tackle on a lunch break. Of course you can (and you should) badger your congresspeople to fund family planning, both abroad and at home, and donate to nonprofits that work on these issues. But what can we do ourselves, in our own lives and communities? Here are a few ideas. Add your own …

Childlessness is nothing new -- for as long as we've had parents, we've had people who are not parents. Across centuries and cultures, at least 10 percent of women never have children, writes Elizabeth Gilbert. But it is relatively new to have a cohort of people who are deliberate, outspoken, and even proud about being childless -- or, as we prefer to say, childfree. We nonparents have traditionally been a quiet minority. And we're still a minority -- albeit a growing one, now about 20 percent in both the U.S. and the U.K. -- but we're no longer so quiet. …

Deciding to be childfree doesn't have to mean forgoing all the joys and oys of parenting. In a new piece in YES! magazine, Wendy Call describes her life as a co-parent -- "not some new alternative but an old tradition," she writes. Call and her partner Aram are confirmed GINKs (green inclinations, no kids). But they've rejected the "stark" choice to either "become parents for every minute of every day, or not at all." She and Aram are co-parents a few hours at a time, a few times a week, to the 3-year-old daughter of close friends and neighbors.   …