Climate-change activists call for tax policies to discourage childbirth, by Valerie Richardson.

Climate-change activists are mobilizing to cut the birthrate, arguing that richer nations should discourage people having children in order to protect them from the ravages of global warming and reduce emissions.

Travis Rieder, assistant director of the Berman Institute of Bioethics at Johns Hopkins University, told NPR that bringing down global fertility by half a child per woman “could be the thing that saves us.”

“Here’s a provocative thought: Maybe we should protect our kids by not having them,” said Mr. Rieder, who has one child.

He proposed procreation disincentives such as government tax breaks for poor people and tax penalties for rich people, a kind of “carbon tax on kids.”