Special Section Introduction: From the Leonardo Archive

The estimated worldwide human population in the year 1500, in the era of Leonardo da Vinci, was 450 million. In 1850, at the beginning of the Industrial Revolution and the extensive use of fossil fuels, the human population is estimated to have been 1.2 billion. Today it has rocketed to 6.6 billion people, with a prediction that it will reach 9.3 billion by 2050. The need to respond effectively to this precipitous rise in the numbers of humans on Earth is the major focus of this article by Jonas Salk, and his message can be viewed as even more relevant today than at the time he wrote the article in 1985.

The point Salk makes is evident to most people trained in the sciences, but not generally discussed by our political leaders as we enter the 2008 U.S. presidential campaign. The Earth has a finite space available for the habitation of people, but, more important, there is a finite limit to the resources that would be required to enrich the standard of living of the world’s population. Human desires and expectations are boundless—witness our economists insisting on a real economic annual growth rate in the United States of at least 3%. Independent of what either our politicians or our economists say, however, there is a limit to the number of people supportable on the Earth, and that number is inversely connected to the human standard of living. Salk’s article establishes the premise that evolution must now become guided in part by a collective human consciousness. The alternative is, in Salk’s words, “the catastrophic course”; in the words of scripture, it is “Armageddon.” While such an anticipated outcome is perhaps popular in some circles, most of us with scientific training would consider such an outcome to be unworthy of the beauty of human existence, a failure unacceptable to humankind. Salk provides an alternative—perhaps the only alternative—to such a disastrous finale.