Those resources that we use cannot be used by another living organism at the same time. Therefore, we appropriate a part of the global resources by our living on the planet. The space required to maintain our supply of renewable resources is part of our global footprint. This simplification makes the ecosystem sound like an engineered system. However, for a glimpse at the complexity in the soil food web, read the article by Dr. Elaine Ingham .
Humans add an additional burden on the system.
For example, almost all of the gold mined today is used for jewlery. Today with extensive processing, trade and storage technology, it is difficulty to recognize our footprint. What we eat may be grown thousands of miles away, and stored for weeks or even years. The total footprint includes the resources used in manufacture of equipment for processing, shipping and storage, and a portion of the resources to sustain the people who operate the equipment. We depend not only on the living organisms that transform solar energy to food that we eat, but also upon the solar energy that is required to produce, process, move, and store it for us.