Getting Ready for World Population Day

Tomorrow (June 11th) is World Population Day, as proclaimed by the United Nations back in 1989. In preparation for that event, two very interesting articles have been posted to the Conversation. The first one is from Andrew Hwang, a mathematician at the College of the Holy Cross: "7.5 billion and counting: How many humans can the Earth support?" His ideas will be very familiar to you if you've read my book.

Humans are consuming and polluting resources – aquifers and ice caps, fertile soil, forests, fisheries and oceans – accumulated over geological time, tens of thousands of years or longer. Wealthy countries consume out of proportion to their populations. As a fiscal analogy, we live as if our savings account balance were steady income. According to the Worldwatch Institute, an environmental think tank, the Earth has 1.9 hectares of land per person for growing food and textiles for clothing, supplying wood and absorbing waste. The average American uses about 9.7 hectares. These data alone suggest the Earth can support at most one-fifth of the present population, 1.5 billion people, at an American standard of living.

A related article by Derek Hoff, an historian at the University of Utah (and author of a very interesting book titled The State and the Stork: The Population Debate and Policy Making in US History) focuses on the Neo-Malthusianism of Paul Ehrlich, but essentially draws the same conclusion as Hwang. The title of Hoff's article is "A long fuse: ‘The Population Bomb’ is still ticking 50 years after its publication".

“The Population Bomb” created more space to hold radical views on population matters, but its impact was fleeting, and maybe even harmful to the population movement. By the early 1970s, many critics were savaging Ehrlich and the larger goal of achieving zero population growth. And the politics of “morning in America” in the 1980s successfully marginalized Erhlich as a doomsdayer. 

But he got much right, even if many details and his timing were off. Global population has increased at a remarkably steady rate since 1968, and the United Nations projects that it will reach 9.8 billion by 2050 and 11.2 billion by 2100. Scientists continue to extend his prescient warnings that efforts to feed all these people through pesticide-intensive monoculture may backfire. And although Ehrlich exaggerated the threat of mass starvation, about 8,500 young children die from malnutrition every day.

Human-driven climate change is an overriding threat, and is unambiguously worsened by population growth. The Intergovernmental Panel on Climate Change estimates that limiting warming in this century to 3.6 degrees Fahrenheit (2 degrees Celsius) would require cutting global greenhouse gas emissions 40 to 70 percent by 2050 and nearly eliminating them by 2100. “Globally, economic and population growth continue to be the most important drivers of increases in CO2 emissions from fossil fuel combustion,” the panel observes.

The point of both articles is that the problem is not simply that the number of humans has exploded in the past 100 years. For the very same reasons that we were able to dramatically reduce death rates (and thus unleash population growth) we have figured out how to dramatically increase our standard of living. What we haven't yet figured out is how even all of us currently alive can sustain our current level of living, much less continue to increase it.