Nate Hagens describes the term 'ecological footprint' as a conceptual tool that quantifies the impact of human activities on Earth’s ecosystems. It measures the amount of biologically productive land and water area required to supply the resources a population consumes and to absorb its waste, particularly carbon emissions. By translating human demands into equivalent units of global hectares, this metric highlights the extent to which our consumption patterns exceed the planet's capacity for renewal. It serves as an illuminating indicator of the sustainability, or lack thereof, of our lifestyles, emphasizing the urgent need for systemic changes to align human economic and social systems with the natural limits of Earth's resources.

See also: carrying capacity, ecological economics, climate change, fossil fuel, population growth