Brandalyn Bickner grew up convinced she would become the mother of 13 children. Raised in a Catholic family in Wauconda, a suburb of Chicago in the US state of Illinois, Bickner nurtured this vision through Catholic middle and high school; even after university she still figured she’d have a large family, though her ambitions had grown more modest – perhaps just four or five kids.

Then, at 23, she joined the Peace Corps in Malawi, and began seeing reasons to revise her plan.

“In Malawi for four years, I got to see quite a bit of the impacts of climate change on a country that is largely subsistence farmers,” says Bickner. She saw up close how changing weather patterns increasingly dictated whether or not her neighbours and friends would be able to eat – and she found herself feeling guilty over America’s carbon-intensive way of life. “I wanted to support policies that will help, but also wanted to see what I could do on a personal level.”

Bickner, now 28, quickly recognised that having a child in America – let alone four, five or 13 – would be the single most carbon-intensive choice she could make. In the developed world the carbon footprint of a child is roughly 58.6 metric tonnes annually, whereas that of a Malawian child has consistently been estimated between 0.07 and 0.1 metric tonnes annually.

While working in Malawi, and struggling with these personal questions, Bickner was also building a relationship with fellow Peace Corps member Chase Morgan. They started dating a year into their service, and now live together in Washington, DC. Bickner works as a public affairs specialist at a federal agency and Morgan works for an international development agency for energy infrastructure.