it was not until the 1960s that significant research interest was rekindled. In 1963, the U.S. National Academy of Sciences published The Growth of World Population , a report that reflected scientific concern about the consequences of global population growth, which was then reaching its peak annual rate of two percent. In 1968, Paul Ehrlich published The Population Bomb , which focused public attention on the issue of population growth, food production, and the environment. By 1972, the Club of Rome had released its World Model , which represented the first computer-based population-environment modeling effort, predicting an “overshoot” of global carrying capacity within 100 years.