Inequality can double the energy required to secure universal decent living.

Ecological breakdown and economic inequality are among the largest contemporary global challenges, and the issues are thoroughly entangled - as they have been throughout the history of civilisations. Yet, the global economy continues toward ecological crises, and inequalities remain far higher than citizens believe to be fair. Here, we explore the role of inequality, alongside traditional drivers of ecological impacts, in determining global energy requirements for providing universal decent living. We consider scenarios from fair inequality - where inequalities mirror public ideals - through a fairly unequal world, to one with a super-rich global elite. The energy-costs of inequality appear far more significant than population: even fair levels increase the energy required to provide universal decent living by 40%, and a super-rich global 1% could consume as much energy as would providing decent living to 1.7 billion. We finish by arguing that total population remains important nonetheless, but for reasons beyond ecological impacts.