Why? Talking about population control requires walking a tightrope: There's nuance between encouraging access to birth control and a China-style one-child policy, but that doesn't always translate in the retelling, and it can all too easily sound like a developed world leader telling people in the developing world that they should stop having children—especially because much of the population boom is coming from regions like sub-Saharan Africa.

And there's a coalition of critics ready to pounce on any speaker who slips, or even to twist the words of those who don't.

Just look at what happened to Hillary Clinton in 2009, when as Secretary of State she acknowledged the overpopulation issue during a discussion with Indian environment minister Jairam Ramesh. Clinton praised another panelist for noting "that it's rather odd to talk about climate change and what we must do to stop and prevent the ill effects without talking about population and family planning."

"And yet, we talk about these things in very separate and often unconnected ways," Clinton added.

Right-wing critics pounced, with the Alex Jones-run Info Wars calling her comments "Malthusian."

Oddly enough, Clinton has found herself criticized for falling on the other side of issue as well. In 2013, a line mentioning overpopulation was edited out of an essay for a Clinton-backed publication written by Bindi Irwin, the then-14-year-old daughter of the late "Crocodile Hunter" Steve Irwin (The Daily Mail chronicled the bizarre spat here).

But the Woodrow Wilson Institute researchers are quick to point out that they're not talking about touchy "population control" strategies like forced sterilization (prominently employed and quickly abandoned in India in the 1970s) or China's one-child policy. Rather, they're focusing on "voluntary family planning"—emphasis on the "voluntary"—programs that countries are already looking at. Sex education has been linked to reduced fertility rates, as has distribution of contraception.

"Achieving universal access to family planning throughout the world would result in fewer unintended pregnancies, improve the health and well-being of women and their families and slow population growth, all benefits to climate-compatible development," reads a draft statement from the group, which is crafting a full report to be released at the end of the year.

The connection isn't necessarily new: Plenty of academics have made it, and Natural Resources Defense Council President Frances Beinecke has blogged about it in the past. The U.N. Intergovernmental Panel on Climate Change has noted the burden of "population pressures" on natural resources, while separately looking at the health impact of family planning. Some national climate-adaptation plans around the world have brushed on family planning.