As the number of contributing factors to (and potential solutions for) climate change grows, one—population growth—is conspicuously absent from most discussions. For obvious reasons: After finally prevailing over climate change “skeptics,” why would U.S. climate advocates court more controversy by adding population, and thus family planning and even abortion, to the mix?

Because it could be an important—perhaps significant—and definitely cheap part of solving the climate crisis, argued David Wheeler of the Center for Global Development (CGD) at an ambitious June 23rd event in the CGD series on “Demographics and Development.” Covering both climate change and population issues, he offered a compelling economic analysis of the effectiveness of family planning and female education programs at addressing climate change. Equally impressive was Wheeler’s engaging style, including graphics and animations that could make Gapminder guru Hans Rosling blush.

Describing Pacala and Socolow’s oft-cited “wedge” theory of stabilizing emissions, Wheeler pointed out that slowing population growth is rarely discussed, compared to the more popular—and more costly—wedges related to reduced deforestation, energy efficiency and conservation, renewable electricity and fuels, and carbon capture and storage.

Wheeler argued that slowing population growth has great potential for reduce emissions at a lower cost. As population increases, so do emissions. As a country develops, its per-capita emissions increase, so population increases in more developed countries are especially important. As the middle class in the BRIC and other large developing nations grows, this sizable group of “New Americans” (to use Thomas Friedman’s term) will contribute more and more emissions.

Two interventions will contribute the most to slowing population growth: family planning and female education, said Wheeler. According to his calculations, a $10 billion increase in female education in the developing world would lead to a change in population growth substantial enough to achieve one of the stabilization wedges. Wheeler found that family planning and female education are among the most cost-effective strategies, as evidenced by their placement on the far left side of slides 22 and 25.

Though an economist by training, Wheeler did not make only financial arguments: He emphasized throughout his presentation that family planning and female education are worthy and necessary programs in their own right. And he pointed out the most glaring injustice of climate change: While people in developed countries have the largest carbon footprints, people in developing countries will disproportionately suffer the impacts. (Suzanne Petroni makes similar points in her ECSP Report 13 article, “An Ethical Approach to Population and Climate Change.”)

Tim Wirth, the president of the UN Foundation and the Better World Fund, called for more political and financial support for this link. Funding for family planning has fallen and support for female education is not as high as it should be. Reaching the unmet need of the world’s women would cost about $20 billion, and the U.S. “share” is $1 billion, an amount that many U.S. family planning leaders are advocating.

As CGD’s Rachel Nugent noted in her introduction, demography and climate are classic cases of long-term issues: difficult to understand and address. It is ironic and important, she said, that two such long-term issues are simultaneously at critical moments. The work of David Wheeler on population and climate change, along with that of Leiwen Jiang of Population Action International and Brian O’Neill of the National Center for Atmospheric Research, may help us find an important and inexpensive piece of an elusive and otherwise expensive pie.

More data is needed to confirm these initial findings. However, the devil may not be in the details but in the debate: convincing weary and wary climate warriors to take on a bit more controversy.