Albert Allen Bartlett was an emeritus professor of physics at the University of Colorado at Boulder, USA. Professor Bartlett had lectured over 1,742 times since September, 1969 on Arithmetic, Population, and Energy. Bartlett regarded the word combination "sustainable growth" as an oxymoron, since even modest annual percentage population increases will inevitably equate to huge exponential growth over sustained periods of time. He therefore regarded human overpopulation as "The Greatest Challenge" facing humanity.
Professor Bartlett often explained how sustainable growth is a contradiction. His view was based on the fact that a modest percentage growth will equate to huge escalations over relatively short periods of time. Bartlett argued that, over time, compound growth can yield enormous increases. For example, an investor earning a constant annual 7% return on their investment would find his or her capital doubling within 10 years. But the same exponential power, so advantageous to patient investors, may be potentially calamitous when applied to human population. A population of 10,000 individuals, if it were to grow at a constant rate of 7% per annum, would reach a population size of 10 million after 100 years. Bartlett regarded the failure to understand the laws of the exponential equation as "The Greatest Challenge" facing humanity, and promoted sustainable living and was an early advocate on the topic of overpopulation. He opposed the cornucopianschool of thought, and referred to it as "The New Flat Earth Society". J. B. Calvert has proposed that Bartlett's law will result in the exhaustion of petrochemical resources due to the exponential growth of the world population. Bartlett made two notable statements relating to sustainability:
"The greatest shortcoming of the human race is our inability to understand the exponential function."
and his Great Challenge:
"Can you think of any problem in any area of human endeavor on any scale, from microscopic to global, whose long-term solution is in any demonstrable way aided, assisted, or advanced by further increases in population, locally, nationally, or globally?"
In August 2013, the Environmental Center at the University of Colorado at Boulder offered training on giving his presentation; the team "came together because they believe so strongly in Dr. Bartlett's message and want to ensure it continues to be delivered well into the future".