What does an ecological footprint measure?

An ecological footprint measures the demand human activities place on the Earth's natural resources and ecosystems. It quantifies how much biologically productive land and water area is needed to produce the resources consumed and to absorb the waste generated, essentially tracking the balance between consumption and the Earth's capacity to regenerate those resources. By assessing both demand and supply of natural resources, the ecological footprint provides insights into sustainability and highlights the impact of lifestyles and consumption patterns on the environment.

Other options, while related to environmental science, do not encapsulate the concept of an ecological footprint. Levels of pollution in urban areas refer specifically to pollution measurements and do not account for resource consumption. The diversity of local species pertains to biodiversity but is not a measure of human impact in terms of resource use. Investment in renewable energy reflects actions taken to shift energy sources but does not directly measure resource consumption or ecological impact.