Hotter and Sicker: Climate Change, Human Health, and the Tangled Evolutionary Roots of Our Species' Dependence on External Energy
The dual crises of climate change and chronic, or non-communicable, disease (NCD) have emerged worldwide as the global economy has industrialized over the past two centuries. In this synthesis I examine humans’ dependence on external (non-metabolic) energy expenditure (e.g., fire, fossil fuels) as a common, root cause in these modern crises. The human lineage has been dependent on external energy sources since the control of fire in the Paleolithic, and this reliance has grown with the development of agriculture, the use of wind- and water-power, and the most recently with industrialization and the transition to fossil fuels. Industrialization and mechanization, powered by fossil fuels, have promoted centralization and processing in food production, reduced physical activity, and increased air pollution (including greenhouse gas emissions). These developments have led in turn to NCD and climate change, which are thus connected both to one another and to our species’ deep evolutionary dependence on external energy. With the impending exhaustion of oil, coal, and natural gas reserves, developing replacements for fossil fuels is essential if we are to confront the dual crises of climate change and NCD and maintain our species’ external energy portfolio and way of life.
Herman Pontzer, Ph.D., Associate Professor of Evolutionary Anthropology and Research Associate Professor of Global Health at Duke University, investigates energy expenditure and evolution in humans and other apes. Through laboratory and field studies, Dr. Pontzer’s work seeks to understand how our bodies evolved and how our deep past shapes our lives today. He and colleagues conducted the first measurements of daily energy expenditure in traditional hunter-gatherers, the Hadza of northern Tanzania. Surprisingly, despite lifestyles that are incredibly active, Dr. Pontzer and colleagues found that hunter-gatherers expend the same number of calories each day as sedentary Westerners. He is currently leading a multi-year effort to measure daily energy expenditure in non-Western human populations around the globe to understand how differences in daily energy requirements vary with respect to activity, diet, and other aspects of ecology. His book, Burn: New Research Blows the Lid Off How We Really Burn Calories, Lose Weight, and Stay Healthy will be published in March 2021.