You could choose to create a little less condom waste by choosing thinner varieties and buying in bulk to cut down on packaging. (Though if your condoms expire and you end up throwing them out, you'll negate your good work.) You can also try lambskin condoms—though be warned, they don't protect against STDs the way latex condoms do. Whatever you choose, always remember to wrap your used prophylactics in tissue paper and toss them in the garbage. Not only can flushing a condom clog up your plumbing; it'll increase the chance of your condoms ending up on a beach or in the ocean.
Though they're not necessarily better for the environment, there are vegan condoms on the market (made without the animal protein traditionally used in latex processing) and at least one fair-trade brand. Most of the world's condoms are sourced and manufactured in Southeast Asia, but keep your eyes on the American company Yulex—it's cultivating a native rubber-producing shrub it hopes will eventually be used to make condoms, which means that someday you should be able to minimize that factory-to-market journey.
What about other, less popular options? You've probably already realized that a reusable barrier like a cervical cap or a diaphragm will be greener than a condom. Yet both of these barrier methods have a somewhat higher failure rate with perfect use than regular condoms, so the eco-trade-off may not be entirely worth it, especially since an unwanted baby will be a massive carbon emitter. (Diaphragms are slightly more effective than condoms with typical use, however.) Then there are periodic abstinence plans—like the rhythm method—which are, in principle, the greenest kinds of birth control short of complete abstinence, as they require little more than a pencil and paper. But these methods can be difficult to pull off correctly—they have a 25.3 percent failure rate with typical usage.
Luckily, there is one clear champ in this contest. Among the nonpermanent forms of contraception, the one that is least wasteful and most effective—that is to say, the greenest—is the copper intrauterine device. The copper IUD is hormone-free; made from a small amount of a cheap, plentiful metal; and can last up to 10 years. It's also 99 percent effective in typical use, as compared with 82.6 percent for condoms and 91.3 percent for the pill. Nevertheless, less than 2 percent of contraception-using women in the United States use copper IUDs.
All this being said, the Green Lantern has a single piece of advice when it comes to contraception: Use it. No matter what type you choose, it's guaranteed to have less of an impact on the environment than the unwitting creation of a fossil-fuel burning, diaper-wearing copy of yourself. (For that matter, if you're absolutely sure you don't want children, you might opt for a permanent method of birth control like tubal ligation or vasectomy.) So if you're more likely to remember a once-monthly, estrogen-based option like the NuvaRing than you are to keep a condom in your wallet, by all means, choose the hormones.
Is there an environmental quandary that's been keeping you up at night? Send it to firstname.lastname@example.org, and check this space every Tuesday.