In recent years, young activists under 25 have increasingly advocated slowing global population growth through family planning as a climate change strategy. While this approach is developed and disseminated by population and development NGOs, young advocates transform the debate by asserting their role as activist leaders on issues of climate change, population, and women's empowerment. This article explores the logics and discursive strategies employed by a group of transnational youth during a workshop at the sixth annual Climate Change Conference of Youth (COY) as well as training workshops in the USA. It tracks the practices through which young climate change activists engage demographic-climate studies and broader development discourses as a basis for advocacy to influence international population and family planning policies. I argue that development paradigms, activist discourse, and new demographic-climate studies represent both an expansion of the range of issues considered under the climate change umbrella, and simultaneously a narrowing of understandings of sexual and reproductive health and rights (SRHR) issues for women through the technicalisation of women's rights.