Energy return on energy invested (eroi): a quintessential but possibly inadequate metric for sustainability in a solar-powered world? [point of view]

Explores the open question of whether mankind, having run through its dowry of fossil fuels, will be able to maintain its advanced global society. Given our present knowledge base, no definite answer can be reached. It seems only common sense to believe that, to survive, a band of hunter gatherers must arrange its activities to acquire at least as much energy as it expends both directly in hunting and gathering and indirectly in essential ancillary activities, such as basal metabolism, which support the hunting and gathering.