Last March, Rep. Alexandria Ocasio-Cortez told an Instagram Live chat that “there’s scientific consensus that the lives of children are going to be very difficult” as climate change intensifies. She asked her audience, “Is it OK to still have children?”
The 29-year-old congressional representative for New York’s 14th district voiced a worry permeating the lives of many in the post-Baby Boomer generations. Last month, researchers in the peer-reviewed journal Climatic Change published what they claim is the first empirical study of how “overwhelmingly negative expectations” of the future climate is affecting reproductive choices.
It’s the latest in a growing literature suggesting that climate change is affecting the birth rate. But it’s also a cautionary tale about just how difficult that relationship is to measure scientifically.
Much has been written about climate anxiety among those under 40 who face a world of rising temperatures, droughts, and coastal inundation. But little rigorous research has been conducted. As far back as 1988, opinion polls have show that 65% of US respondents expected climate change to be a problem confronting their children or grandchildren. That perception has only become more acute. In 2020, an online poll by Morning Consult showed that one in four adults without children say climate change is a reason to not have children.
Those opinions, however tenuously demonstrated, are not unfounded. Population growth and greenhouse gas emissions are linked: A 2012 study in The Lancet showed emissions would be 40% lower by 2050 in a low population growth scenario relative to the high growth scenario (and 15% relative to a moderate growth scenario). And for many, the world in 2050 will be more dangerous and deadly—especially in the developing world, and especially without a concerted effort to slow climate change.
Authors of the new Climatic Change study conducted by researchers at the Yale-NUS College in Singapore speculated this climate anxiety may be playing a role in the long-term fertility declines in the US over the last decade, from 2.12 births per woman in 2007 to 1.73 in 2018 (in line with other industrialized countries).
In a survey, they asked 607 Americans between the ages of 27 and 45 about their plans for the future and any existing, expected, or hypothetical children, given their worries about climate change. Respondents were recruited through Facebook and Twitter, almost all of whom registered significant concerns about the climate.
On a scale of 1 to 5, worries about the climate’s impact on their children nearly topped the scale, averaging about 4.7 for parents and prospective parents alike. A full 96% of survey respondents felt “extremely to very” concerned about climate impacts on their children. Nearly 60% felt the same level of concern about the carbon footprint of having kids.
That might sound like a resounding result, especially when combined with some of the written responses the surveyors collected. “I feel like I can’t in good conscience bring a child into this world and force them to try and survive what may be apocalyptic conditions,” responded one 27-year-old project manager in Michigan who is still undecided about having children. Even those with children feared the world the “doomed world” their children could inherit. “[My children] have brought me so much joy, but I feel so guilty about it,” said a 38-year-old editor and mother in Florida. “I don’t want them to have to suffer through the future humans have created for them.”
All of this makes for fascinating reading. None of it is a scientifically accurate gauge of public opinion, argues Jon Krosnick, a professor of political science and communication at Stanford University. “It’s a preposterous methodology with no projectability to any population,” he says, citing problems including the composition of respondents, demographic definitions, recruitment methods, and framing of the questions.
The researchers noted the results reflect views among a specific slice of the population—predominately white (88%), liberal (70%), and well-educated (52% with a graduate or professional degree, and 41% with a bachelor’s degree), rather than a wider population since the sample was not randomly selected. “We’re very clear about the limitations of the methodology,” said Matthew Schneider-Mayerson, a co-author of the study. “We say explicitly that it’s not generalizable and even raised questions about demography.”
But even if the results are representative only of the survey participants themselves, says Schneider-Mayerson, “it provides a useful window into people’s self-reported experiences.” He defended the study as consistent with the best methodological practices in sociology.
Krosnick, who works in Stanford University’s political science department and leads its work on American Public Opinion on Global Warming, acknowledged the study at least raises a provocative question unanswered in the scientific literature: How are climate decisions affecting people’s reproductive decisions?
“It’s very unclear whether concerns about climate will actually affect people’s reproductive choices,” acknowledges Schneider-Mayerson.
Krosnick argues that answering the question would require a radically different approach. “The rewards of parenting are so powerful compared to the minimal costs [to the climate of one more child],” he said, “I’d want to see some solid empirical tests.”
First, a far more diverse, representative sample of people would need to be assembled. None, as in this survey, would be asked the obvious question of whether climate change is affecting their decision to have children directly. Over the last century, psychologists have confirmed survey respondents, when prompted, reliably invent the motives behind their actions, often without realizing it. “It turns out that vast majority of what we do and think is governed by unconscious processes,” says Krosnick.
To get around this, scientists have devised clever experiments to assess subjects’ answers against their behavior, attitudes, and circumstances that allow researchers to begin to disentangle the true drivers of behavior. The next scientific study, he says, should integrate climate concerns into the vast scientific literature on how fertility decisions are made, and then ask if we can better explain their decisions statistically by using people’s climate-related judgments.
Until then, Krosnick warned, studies like this are “provocative, but they are very far from definitive.” And they certainly shouldn’t be used as a guideline for personal decision-making. Consider this survey respondent, a pregnant 36-year old doctoral candidate in New York who rejected the idea of deciding whether to have a family based on the global political failure to curtail emissions.
“I feel frustrated with the idea that I should not have children because of their lifetime carbon footprint,” she wrote. “That puts an emphasis on individual sacrifice and responsibility that is not reflective of the actual causes (and possible solutions) for the problems we face with the climate—these are large scale, systemic problems.”
This story has been updated with comment from Matthew Schneider-Mayerson.