In 1970, he was recognized as a key figure in ecology, appearing on the cover of Time magazine as the Paul Revere of environmental activism. The following year, he published The Closing Circle, which passionately warned about the dangers of environmental pollution and the need for sustainable practices.

In 1972, the Club of Rome released The Limits to Growth, utilizing computer models to predict that unchecked economic and industrial expansion could lead to global catastrophe by the century's end. They emphasized the importance of controlling population growth and resource consumption to prevent environmental collapse.