Human overpopulation
Extraterrestrial settlement

An argument for space colonization is to mitigate proposed impacts of overpopulation of Earth, such as resource depletion. If the resources of space were opened to use and viable life-supporting habitats were built, Earth would no longer define the limitations of growth. Although many of Earth's resources are non-renewable, off-planet colonies could satisfy the majority of the planet's resource requirements. With the availability of extraterrestrial resources, demand on terrestrial ones would decline. Proponents of this idea include Stephen Hawking and Gerard K. O'Neill.
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