ABSTRACT
Discussions of ecological sustainability typically focus on greenhouse gas emissions, biodiversity, and other measurements of the natural world. They may include economic and social trends in production or population. But they rarely feature time use. Yet patterns of human time use are key drivers of ecological outcomes. People combine time, money, and natural resources to carry out their daily lives and activities. Firms combine time, physical capital, and natural capital to create production. To a great extent, time and natural resources are substitutes for each other: doing things faster usually takes a greater toll on Earth. So time-stressed households and societies tend to have heavier ecological footprints and greater per capita energy use.
