If you’ve lived between the year 1560 and the present day, more power to you. Literally.
That’s one of several conclusions reached by University of Nebraska-Lincoln ecologist John DeLong, who has co-authored the first study to quantify the relationship between human population growth and energy use on an international scale.
The study compiled several centuries’ worth of data from Great Britain, the United States and Sweden to profile the dynamics between a skyrocketing population and its consumption of energy from fossil fuels and renewable sources.
The data showed that energy use has generally outpaced population growth over the last few hundred years. Each generation has thus produced and used more energy per person than its predecessor even as world population has climbed from about 500 million to more than 7 billion in the 450 years analyzed by the authors.
This increasing per capita energy supply has also hiked up Earth’s carrying capacity — the number of people it can sustain — and allowed the population to grow at an ever-faster, or exponential, rate.
“Broadly speaking, no one’s really quantified this,” said DeLong, assistant professor of biological sciences. “But it was important, because there are studies going back decades that assume this kind of positive feedback loop: We grow, we expand our capacity to extract energy, and then we grow some more.”
However, DeLong and colleague Oskar Burger also found that this dynamic has shifted in the decades following 1963, when the world’s population was growing faster than ever before or since. During the subsequent half-century, the ratio between energy increases and population growth has narrowed, with the former now aligning more closely to the latter. A 1:1 ratio would theoretically limit the planet’s population to a linear rather than exponential growth rate.
“I do think this should challenge our assumptions about future population growth,” DeLong said. “The study supports conventional wisdom to a degree, but it also reminds us that (abundant energy) is maybe not something that we can count on.
”Our study sort of plays into a deep cultural philosophy that we have the creativity and ability to solve whatever problem comes our way. The evidence shows that, from an energy point of view, we’ve done that a lot. But maybe that’s not a guarantee.”
DeLong said the study’s insights might also help inform and refine population projections. The United Nations currently projects that Earth’s population in the year 2100 will sit between 9 billion and 13 billion people. Past projections have been notoriously inaccurate, usually underestimating the growth rates and numbers.
“In the back of our minds, it definitely is a goal to make better, more mechanistic forecasts,” said DeLong. “What we’re saying is: Every other population on the planet depends on energy to fuel their activities and maintain their bodies. Ours must, too.”
Source: http://news.unl.edu/newsrooms/unltoday/article/study-is-first-to-measure-global-population-energy-relationship/DeLong and Burger, a biological anthropologist at the England-based Kent University, published their study in June. The paper appeared in the open-access journal PLOS ONE.