In 1968, Stanford ecologist Paul R. Ehrlich, published The Population Bomb, arguing that rapid growth in human numbers would result in environmental catastrophe and widespread famine. Overall the dire predictions of The Population Bomb did not come to pass, with the Green Revolution staving off the specter of mass starvation. With eight billion people today, the world population has doubled since 1970, and global TFR (totality fertility rate) is now 2.4, down from 4.5 in 1970. When it comes to our planet's most populous nations, as of 2019, China and the U.S. had sub-replacement fertility levels at 1.69 and 1.71 respectively, while India hovered near the replacement rate at 2.2, and Indonesia slightly surpassed it with a TFR of 2.32. A 2020 Lancet study projected that the global population could peak in 2064 at around 9.7 billion, then declining to about 8.8 billion by the end of the century, largely due to decreasing fertility rates.

On this episode of Unsupervised Learning Razib talks to Lillian Tara, executive director of Pronatalist.org, an organization devoted to reversing the trend toward sub-replacement fertility worldwide as nations develop. Tara is notable as the youngest guest on Unsupervised Learning, born after 9/11, she is focused on the future with an awareness of the past. A recent graduate of the University of Virginia in politics and policy, set to matriculate  at Harvard University in the fall of 2023 for her master's, Tara believes that humans are a vital resource and that a future with ever-dwindling populations is a future of ever-dwindling possibilities. Following in the path of Julian Simon, an economist who was Ehrlich’s great nemesis in the 1970’s and 1980’s, Tara outlines the anti-Malthusian economic case that far from capsizing "lifeboat earth," innovation and technology will lift all boats over time. Though Pronatalist.org promotes a change in the culture when it comes to expectations about reproduction, Tara is also an enthusiast of cutting-edge next-generation reproductive technology, from surrogacy to in vitro fertilization. She is particularly focused on how to incentivize high-status individuals to have more children. Tarra believes that cultural leaders and influencers set the norms for society as a whole and that it is critical to make having larger families cool and an aspiration, rather than the practices of marginal religious sects.