Those most concerned about climate change in the United States tend to skew younger and female. Researchers from the Yale Program on Climate Change Communication found that women are more likely than men to believe that global warming will harm future generations and will harm them personally.

A 2018 Gallup analysis revealed a “global warming age gap” in beliefs about climate change: 70 percent of adults aged 18 to 34 said they worried about global warming, compared to 56 percent of adults aged 55 or older. An online survey published by Business Insider last March found that 38 percent of 18-to-29-year-olds believe a couple should consider climate change when deciding whether to have children. In 2018, in a survey of conducted by Morning Consult for The New York Times, 33 percent of the respondents — a nationally representative sample of 20- to 45-year-old men and women — cited climate change as a reason they had or expected to have fewer children than they considered ideal. Some research suggests that having fewer children may be one of the most effective ways for an individual to alleviate climate change: In 2017, a study published in Environmental Research Letters found that, in developed countries, having one fewer child would result in an average of 58.6 tons of CO2 equivalent emission reductions per year.

Overall, American women’s “fertility intentions,” as demographers describe hopes or desires regarding family size, have decreased, said Alison Gemmill, an assistant professor at Johns Hopkins Bloomberg School of Public Health. Women want fewer children now than they did a decade ago, and, in fact, they are having fewer children; the fertility rate in the United States reached a historic low in 2018, falling to 1.73 average births per woman from a 1957 peak of 3.77 births per woman. Though Gemmill has not formally studied the effect of climate fears on fertility, anecdotally she hears it mentioned as a factor in reproductive decision-making.

In recent months, forums have cropped up online for those who have made the decision not to have children to share their feelings. In September a student at McGill University in Canada launched a campaign called “#No Future, No Children,” pledging to not have kids until the Canadian government takes more significant action to combat climate change. Over 5000 people have pledged support; the group’s page offers a space to share stories about the emotional toll of the decision.

Conceivable Future, a network led by women and based in the United States, gathers testimonies on how the climate crisis affects decisions around childbearing and parenting. On the popular parenting community blog BabyCenter, posts about the impact of climate change on parenting have proliferated in recent years. “The environment (and the fact that our human race is destroying it) is the main reason we are OAD [One And Done]”, wrote a poster in 2016. A Reddit thread from early 2019, asking if it was “immoral to have children when climate change catastrophe is inevitable” garnered 175 comments. Posts on these forums tend to follow a similar pattern, describing a yearning to have children, followed by expressions of guilt.