Terraforming Planets, Geoengineering Earth James Rodger Fleming Science, Technology and Society Program Colby College, Maine 04901 USA Can humanity survive on Earth into the indefinite future without taking control of the climate system and biosphere, or perhaps one day engaging in solar engineering? If we seek to colonize other planets, will we need to live sequestered from harsh environments in little residential capsules and venture out only in spacesuits, or should we practice terraformation to make the environment of other planets more Earthlike? In either case, we will need to master bio-geo-chemical engineering to generate fresh air, water, and food. Would it be better then to engineer planets for humans or to engineer humans and perhaps cyborgs to withstand harsh environments? Since prediction of new technological developments or inventions has proven to be notoriously inaccurate, what insights can we derive from the history of planetary manipulation proposals and fantasies? In 2248, according to science fiction writer Kim Stanley Robinson’s novel Icehenge, 1 heroine Emma Weil’s “five-hundred-year project is the terraforming of Mars,” while starship captain Eric Swann’s “is the colonization of a planet in another system.” “What’s the big difference?” asked Swann; “About ten or twenty light years,” replied Emma (22). One of the biggest challenges facing the starship was generating fresh air, fresh water, and food for the crew while recycling wastes with near 100 percent efficiency. The starship is a traveling biosphere, and engineers have to balance the photosynthetic coefficient for algae and the respiratory coefficient for the humans and animals to prevent too much build-up in either CO 2 or oxygen: “Light feeds algae. Algae feed plants and fish. Plants feed animals and humans and create oxygen and water. Animals feed humans, and humans and animals create wastes, which sustain microorganisms that mineralize the wastes (to an extent), making it possible to plow them back into the soil” (adapted from p. 29). Eighty percent efficiency in this system was good enough for a three-year voyage; 99 percent perhaps for 100-years, but perfect “Original Non-Fiction” finalist for the Canopus Award for Excellence in Interstellar Writing, http://canopus.100yss.org/?p=402...