title: Extra-metabolic energy use and the rise in human hyper-density.
abstract: Humans, like all organisms, are subject to fundamental biophysical laws. Van Valen predicted that, because of zero-sum dynamics, all populations of all species in a given environment flux the same amount of energy on average. Damuth's 'energetic equivalence rule' supported Van Valen´s conjecture by showing a tradeoff between few big animals per area with high individual metabolic rates compared to abundant small species with low energy requirements. We use metabolic scaling theory to compare variation in densities and individual energy use in human societies to other land mammals. We show that hunter-gatherers occurred at densities lower than the average for a mammal of our size. Most modern humans, in contrast, concentrate in large cities at densities up to four orders of magnitude greater than hunter-gatherers, yet consume up to two orders of magnitude more energy per capita. Today, cities across the globe flux greater energy than net primary productivity on a per area basis. This is possible by importing enormous amounts of energy and materials required to sustain hyper-dense, modern humans. The metabolic rift with nature created by modern cities fueled largely by fossil energy poses formidable challenges for establishing a sustainable relationship on a rapidly urbanizing, yet finite planet.
authors.affiliation: Department of Biology, University of North Carolina, Chapel Hill, USA.|North Carolina Museum of Natural Sciences, Raleigh, USA.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Burger
authors.affiliation: Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.|Instituto de Ecología y Biodiversidad (IEB), Santiago Chile.
authors.forename: Vanessa P
authors.initials: VP
authors.lastname: Weinberger
authors.affiliation: Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.|Instituto de Ecología y Biodiversidad (IEB), Santiago Chile.|The Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM, USA.|Laboratorio Internacional de Cambio Global (LINCGlobal) &Centro de Cambio Global UC, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Marquet
mesh_terms: D000465:Algorithms; D000818:Animals; D049628:Body Size; D017753:Ecosystem; D004734:Energy Metabolism; D004777:Environment; D006801:Humans; D008962:Models, Theoretical; D011156:Population Density; D014507:Urbanization