“Ihad the hormonal urges,” said Prof Camille Parmesan, a leading climate scientist based in France. “Oh my gosh, it was very strong. But it was: ‘Do I really want to bring a child into this world that we’re creating?’ Even 30 years ago, it was very clear the world was going to hell in a handbasket. I’m 62 now and I’m actually really glad I did not have children.” Parmesan is not alone. An exclusive Guardian survey has found that almost a fifth of the female climate experts who responded have chosen to have no children, or fewer children, due to the environmental crises afflicting the world. Such decisions were extremely difficult, they said. Dr Shobha Maharaj, an expert on the effects of the climate crisis from Trinidad and Tobago, has chosen to have only one child, a son who is now six years old. “Choosing to have a child was and continues to be a struggle,” she said. Maharaj said fear of what her child’s future would hold, as well as adding another human to the planet, were part of the struggle: “When you grow up on a small island, it becomes part of you. Small islands are already being very adversely impacted, so there is this constant sense of impending loss and I just didn’t want to have to transfer that to my child.” “However, my husband is the most family-oriented person I know,” Maharaj said. “So this was a compromise: one child, no more. Who knows, maybe my son will grow up to be someone who can help find a solution?” The Guardian approached every contactable lead author or review editor of all reports from the Intergovernmental Panel on Climate Change since 2018. The IPCC’s reports are the gold standard of climate knowledge. Of the 843 contacted, 360 replied to the question on life decisions, a high response rate. Ninety-seven female scientists responded, with 17, including women from Brazil, Chile, Germany, India and Kenya, saying they had chosen to have fewer children. All but 1% of the scientists surveyed were over 40 years old and two-thirds were over 50, reflecting the senior positions they had reached in their professions. A quarter of the respondents were women, the same proportion as the overall authorship of the IPCC reports. The findings were in response to a question about major personal decisions taken in response to the climate crisis by scientists who know the most about it, and who expect global temperatures to soar past international targets in coming years. 7% of the male scientists who responded said they had had either no children or fewer than they would otherwise have had. Most of the female scientists interviewed had made their decisions about children in past decades, when they were younger and the grave danger of global heating was less apparent. They said they had not wanted to add to the global human population that is exacting a heavy environmental toll on the planet, and some also expressed fears about the climate chaos through which a child might now have to live. The role of rising global population in the destruction of nature and the climate crisis has been a divisive topic for decades. The publication of The Population Bomb by Prof Paul Ehrlich in 1968, mentioned by several of the scientists in their survey responses, was a particular flashpoint. The debate prompted past allegations of racism, as nations with fast-rising populations are largely those in Africa and Asia. Compulsory population control is not part of today’s population-environment debate, with better educational opportunities for girls and access to contraception for women who want it seen as effective and humane policies. Parmesan, at the CNRS ecology centre in France, said: “When I was making my choice, it was very clear in the ecological community that human population growth was a problem: preserving biodiversity was absolutely dependent on stabilising population.” Prof Regina Rodrigues, an oceanographer at the Federal University of Santa Catarina in Brazil, who also chose not to have children, was influenced by the environmental destruction she saw in the fast-expanding coastal town near São Paulo where she grew up. “The fact of the limitation of resources was really clear to me from a young age,” she said. “Then I learned about climate change and it was even more clear to me. I’m totally satisfied in teaching and passing what I know to people – it doesn’t need to be my blood. [My husband and I] don’t regret a moment. We both work on climate and we are fighting.” Prof Lisa Schipper, an expert on climate vulnerability at the University of Bonn in Germany, chose to have one child. She said that coming from the global north, where each person’s carbon footprint is much bigger than those living in the global south, there is a responsibility to think carefully about this choice. “It is honestly only now that I am starting to panic about my child’s future,” she said. “When she was born in 2013, I felt more optimistic about the possibility of reducing emissions. Now I feel guilty about leaving her in this world without my protection, and guilty about having played a part in the changing climate. So it’s bleak.” An Indian scientist who chose to be anonymous decided to adopt rather than have children of her own. “There are too many children in India who do not get a fair chance and we can offer that to someone who is already born,” she said. “We are not so special that our genes need to be transmitted: values matter more.” She said rich people who choose to have large families were “self-centred and irresponsible in current times”, citing low infant mortality and the huge gap between the emissions of the rich and the poor. The links between environmental concerns and fertility choices are complex and research to date has found little consistency across age groups and nationalities. According to a recent review, choosing to have fewer or no children for environmental reasons could be the result of fears about the future, population levels or not having the resources needed to raise the children. A study of Americans aged 27 to 45 – younger than the IPCC scientists surveyed – found concern about the wellbeing of children in a climate-changed world was a much bigger factor than worries over the carbon footprint of their offspring. However, a focus group study in Sweden across all ages found few had changed or would change their plans for children owing to climate fears. There has been almost no research in the global south. Many researchers noted that some women do not have the freedom or ability to choose if they have children, or how many. On the debate on the role of population growth in environmental crises, Schipper said: “How many people we have is irrelevant if only a small percentage are doing most of the damage.” Parmesan disagreed, saying the total impact is the combination of people’s level of consumption and the total number of people: “Don’t cherrypick half of the equation and ignore the other half.”