The degrowth movement is an emerging response to humanity living beyond its means. By suggesting the human enterprise is too big by some measure, such that it must downsize, degrowth implicitly suggests a limit on the size of the global economy. Indeed, limits are the essence of degrowth. Yet degrowth goes beyond ecological economics, sustainability and other expressions of the idea that humans must live within the Earth’s means – and therefore that an infinitely growing economy is biophysically impossible – by explicitly incorporating the notion that the economy has already exceeded those limits. The unmistakable warning of the jolting term degrowth, which derives from the French word décroissance, is not that the economy can and might become too big, but rather that it already is too big and therefore must degrow.