Will Limited Land, Water, and Energy Control Human Population Numbers in the Future? David Pimentel & Michele Whitecraft & Zachary R. Scott & Leixin Zhao & Patricia Satkiewicz & Timothy J. Scott & Jennifer Phillips & Daniel Szimak & Gurpreet Singh & Daniela O. Gonzalez & Tun Lin Moe Published online: 12 August 2010 # Springer Science+Business Media, LLC 2010 Abstract Nearly 60% of the world’ s human population is malnourished and the numbers are growing. Shortages of basic foods related to decreases in per capita cropland, water, and fossil energy resources contribute to spreading malnutrition and other diseases. The suggestion is that in the future only a smaller number of people will have access to adequate nourishment. In about 100 years, when it is reported that the planet will run out of fossil energy, we suggest that a world population of about two billion might be sustainable if it relies on renewable energy technologies and also reduces per capita use of the earth’ s natural resources. Keywords Sustainable world population . Fossil fuels . Population growth . Agricultural land degradation Introduction Developed and developing nations need to provide a good quality life for their people while coping with rapid population growth, but “Population is the issue no one wants to touch” (Meadows 2000). The current world population is about 6.8 billion. Based on the present growth rate of 1.2% per year, the population is projected to double in approximately 58 years (Chiras 2006; PRB 2008). Because population growth cannot continue indefinitely, society can either voluntarily control its numbers or let natural forces such as disease, malnutrition, and other disasters limit human numbers (Bartlett 1997–98; Pimentel et al. 1999). Increasing human numbers especially in urban areas, and increasing pollution of food, water, air, and soil by pathogenic disease organisms and chemicals, are causing a rapid increase in the prevalence of disease and human mortality (Murray and Lopez 1996; Pimentel et al. 2007). Currently, more than 3.7 billion humans are malnourished worldwide—the largest number ever (WHO 2005a, b). The planet’ s numerous environmental problems highlight the urgent need to evaluate available land, water, and energy resources and how they relate to the requirements of a rapidly growing human population (Pimentel and Pimentel 2008). In this article we assess the carrying capacity of the Earth’ s natural resources, and suggest that humans should voluntar- ily limit their population growth, rather than letting natural forces control their numbers (Bartlett 1997–98; Ferguson 1998; Pimentel et al. 1999). In addition, we suggest appropriate policies and technologies that would improve standards of living and quality of life worldwide. Population Growth and Consumption of Resources All of our basic resources, such as land, water, energy, and biota, are inherently limited because of human abundance. At the current growth rate of 1.2% the world’ s population will double to 13 billion in 58 years (PRB 2008). The U.S. population doubled during the past 70 years from 151 million to more than 305 million, and based on current growth of approximately 1.1% per year (USCB 2002, 2009) is projected to double again to 600 million in the next 64 years. China’ s population is 1.3 billion, and despite government policy permitting only one child per D. Pimentel (*) : M. Whitecraft : Z. R. Scott : L. Zhao : P. Satkiewicz : T. J. Scott : J. Phillips : D. Szimak : G. Singh : D. O. Gonzalez : T. L. Moe College of Agriculture and Life Sciences, Comstock Hall, Cornell University, Ithaca, NY 14853, USA e-mail: dp18@cornell.edu Hum Ecol (2010) 38:599–611 DOI 10.1007/s10745-010-9346-y