Nature provides much of what we consume, and processes much of our waste. The ecological footprint is therefore a good measure of consumption, or more specifically, the average amount consumed per person. Ecological footprint has units of area per person per year, where area is typically "global hectares," or just "hectares" (one hectare is about 2.47 acres).
The total number of "footprints" available to us and other species is more easily described as one "Earth" (11.9 billion hectares).
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