Today we face multiple, cascading ecological crises, including but not limited to rapid climate destabilization, accelerated species extinction and loss of biodiversity, chemical contamination of land and water, and soil erosion and degradation. These realities will require our species to down-power, either consciously through rational planning or as a result of larger forces beyond our control. Coming decades—not in some science-fiction future, but in the lifetimes of many of us—will be marked by permanent contraction. Like it or not, the future is not “more and more” but “fewer and less.” If there is to be a decent human future—perhaps if there is to be a human future at all—we must face the inevitability of fewer people consuming less energy and fewer material resources…The end of the fossil-fuel era is inevitable, and no combination of renewable energy sources can fuel continued expansion.