Population growth, energy use, and the implications for the search for extraterrestrial intelligence

Abstract

Von Hoerner ("Population Explosion and Interstellar Expansion," Journal of the British Interplanetary Society, 28, 691-712, 1975; hereafter VH75) examined the effects of human population growth and predicted agricultural, environmental, and other problems from observed growth rate trends. Using straightforward calculations, VH75 predicted the "doomsday" years for these scenarios (≈2020-2050), when we as a species should run out of space or food, or induce catastrophic anthropogenic climate change through thermodynamically unavoidable direct heating of the planet. Now that over four decades have passed, in this paper we update VH75. We perform similar calculations as that work, with improved data and trends in population growth, food production, energy use, and climate change. For many of the impacts noted in VH75 our work amounts to pushing the "doomsday" horizon back to the 2300s-2400s (or much further for population-driven interstellar colonization). This is largely attributable to using worldwide data that exhibit smaller growth rates of population and energy use in the last few decades. While population-related catastrophes appear less likely than in VH75, our continued growth in energy use provides insight into possible future issues. We find that, if historic trends continue, direct heating of the Earth will be a substantial contributor to climate change by ≈2260, regardless of the energy source used, coincident with our transition to a Kardashev type-I civilization. We also determine that either an increase of Earth's global mean temperature of ≈12K will occur or an unreasonably high fraction of the planet will need to be covered by solar collectors by ~2400 to keep pace with our growth in energy use. We further discuss the implications in terms of interstellar expansion, the transition to type II and III civilizations, SETI, and the Fermi Paradox. We conclude that the "sustainability solution" to the Fermi Paradox is a compelling possibility.

Genome-Wide Association Study of Growth and Feeding Traits in Pekin Ducks

“…One of the biggest global challenges is how to ensure that an increasingly large population has enough food to meet nutritional needs in the near future. It is expected that the population of the entire planet will reach around 10 billion in 2050 (Mullan and Haqq-Misra, 2019). Food availability is a limited global resource.…”

Circular Economy and Bioeconomy Interaction Development as Future for Rural Regions. Case Study of Aizkraukle Region in Latvia

“…Increasing public awareness of sustainable resource use and economic development has made the issue of the circular economy and bioeconomy increasingly relevant [1]. This is also directly linked to the expected shortage of non-renewable resources [2], [3], population growth [4] and the environmental and climate challenges posed by human a ctivity. The circular economy and the bioeconomy are expected to address these challenges [5], [6].…”

Introduction: Detectability of future Earth

“…Examining the detectability of future Earth requires that we first consider the likely and possible trajectories for human civilization as we enter the Anthropocene and contemplate becoming a spacefaring civilization. In this special issue, Mullan and Haqq-Misra (2019) examine trajectories of human population growth and energy use to find that our technology may induce direct thermal heating (through the second law of thermodynamics) by the year 2260. Even if population growth stabilizes, these calculations indicate that exponential consumption of energy could eventually lead our civilization to a point where our energy use (fostered by the demand for higher standards of living) would contribute to additional global warming beyond fossil fuel emissions.…”

“…Fundamental limits imposed by thermodynamics and sustainability would restrict the rate of growth of any technological civilization and slow its expansion into other planetary systems. Mullan and Haqq-Misra (2019) likewise emphasize that slower-growth, less energy-intensive civilizations are more likely to be prevalent than any civilization that expands beyond the limits of its carrying capacity. The lack of observations of any such energy-intensive civilizations in the galaxy is a challenge for human civilization to adopt long-term sustainable practices as we enter the Anthropocene.…”