"Picture a pasture open to all," wrote biologist Garrett Hardin in the journal Science in December 1968, less than two weeks before astronauts captured that iconic Earthrise photo.
In this public pasture, each herdsman tries to keep as many cattle as possible feasting off a commonly shared public good. "There is the tragedy. Each man is locked into a system that compels him to increase his herd without limit -- in a world that is limited."
The nine planetary boundaries are real-world examples of Hardin's shared pasture. Chemical pollution rounds out the ninth, symbolized here by the grand orbits of human industrial debris in what has become known as the Great Pacific Garbage Patch.
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