While the world economy has become more efficient in one sense, i.e.
, ecological damage per dollar's worth of economic output, growth in human population size and per-capita production and consumption of goods and services have together far outpaced these gains. Grievous environmental harm has resulted, whether measured in terms of human sustainability through the ecological footprint, or non-human welfare through such indicators as the living planet index and the number of threatened species. Many have therefore called for a reorientation of economic priorities away from growth, and toward equality as a more environmentally-friendly way to enhance human well-being. In this paper, I test the merits of this proposal through analysis of a few key national economic and ecological variables across time and space. The results confirm the hypothesis that equality does far less harm to ecosystems than growth does. In fact, equality seems to benefit one crucial aspect of environmental quality, namely biological diversity.