Biologist of evolution, Paul Ralph Ehrlich, passed away in Palo Alto, California on March 13, 2026, at the age of 93. Born in 1932 in Philadelphia to a modest family, Ehrlich studied zoology and later the biology of butterflies, which had interested him since childhood. In his book “Life. A Journey Through Science and Politics” published in 2023, he explained that his desire to study these animals stemmed from the fear of their disappearance due to pesticides and urbanization.
His scientific work focused on studying the dynamics of animal populations such as insects, tropical fish, and birds. After obtaining his doctorate, he became a professor at Stanford University in California. His book “The Population Bomb,” published in 1968, became hugely successful and established him as a leading figure in the emerging environmental movement. The book, an alarmist manifesto, warned of impending doom for humanity: “The battle to feed all of humanity is over. In the 1970s and 1980s, hundreds of millions of people will starve to death, despite any crash programs embarked upon now.”
To counteract this dire prediction, Ehrlich proposed policies such as mass sterilization incentives, financial penalties, or rewards based on family efforts. The book sold 2 million copies, making its author the spokesperson for neo-Malthusians who warned about overpopulation. The global population growth peaked between 1965 and 1970.
In 1972, the “Limits to Growth (in a Finite World)” report, also known as the Meadows Report, echoed some of Ehrlich’s ideas. It examined the links between ecological consequences of economic growth, resource limitations, and demographic evolution. Five years later, Ehrlich, his wife Anne, and John Holdren published “Ecoscience: Population, Resources, Environment,” offering new solutions to the population issue.
Ehrlich’s influence reached France in the 1970s. Agronomist René Dumont, the first ecological candidate for the presidential election, warned about the exponential population growth in relation to limited natural resources in his book “Utopia or Death” (1973).
The Intergovernmental Panel on Climate Change (IPCC), from its early reports, remained cautious regarding global population trends.
In 2009, Ehrlich and his wife published “The Population Bomb Revisited” to clarify his thoughts on the topic. In an interview with Le Monde in February 2013, he explained that his forecasts were scenarios rather than definite predictions. The same year, he published a lengthy text with Anne Ehrlich titled “Can a Collapse of Global Civilization Be Avoided?” stating that it was possible, but with only a 10% probability.
“The growth of population between science and science-fiction: when demographers and writers imagine the future,” an article from 2022 by Bénédicte Gastineau, Stéphanie Dos Santos, and Valérie Golaz, looks at demographic projections, a subject of debate within the scientific community.
Despite controversies, Ehrlich’s work has shaped the field of population biology, at the intersection of genetics, ecology, and evolution.
