An editorial in a British medical journal suggests giving contraceptives to people in developing countries as a way to combat climate change.
The Lancent editorial says slowing population growth could ease the pressure on the environment.
It cites a British report that said family planning is five times cheaper than usual technologies used to fight climate change. According to the report, each $7 spent on basic family planning would slash global carbon dioxide emissions by more than 1 ton.
The editorial says more than 200 million women worldwide want contraceptives, but don't have access to them. In countries with access to condoms and other contraceptives, average family sizes tend to fall significantly within a generation.
Climate change experts have previously recommended that people cut their meat intake to slow global warming by reducing the numbers of animals using the world's resources.