How much of Earth’s resources does your lifestyle require? The ecological footprint is a measure of our demand on nature. Ecologists use 5,400 different measures gathered from government agencies and scientific publications to calculate a footprint, a measure of how much biologically productive land and water area (cropland, forests, grazing lands, fishing area, and built-up land) a human population requires to produce the resources it consumes and to absorb the waste it produces.