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Earth’s Oceans Were Once Green—And They Might Be Turning Green Again
For most of human history, Earth has been known as the “Pale Blue Dot,” a term popularized by astronomer Carl Sagan when ...
Earth’s Oceans Were Green a Billion Years Ago. They Could Soon Be Green Again.
Although the Earth’s been decidedly blue for 600 million years, rising populations of phytoplankton caused by rising ...