Colonization of Venus
Venus's atmosphere is made mostly out of carbon dioxide, which, after filtering from sulfuric acid, can be used to grow food. Because nitrogen and oxygen are lighter than the carbon-dioxide that makes the atmosphere, breathable-air-filled balloons will float at a height of about . At this height, the temperature is a manageable ; or if we could get higher (see ).
Carbon capture and storage
Terraforming the planet Venus by removing CO from the atmosphere was first scholarly proposed by the astronomer Carl Sagan in 1961, although fictional treatments, such as "The Big Rain" of The Psychotechnic League by novelist Poul Anderson, preceded it. Adjustments to the existing environment of Venus to support human life would require at least three major changes to the planet's atmosphere: Reducing Venus's surface temperature of , eliminating most of the planet's dense carbon dioxide and sulfur dioxide atmosphere via removal or conversion to some other form, and the addition of breathable oxygen to the atmosphere. These three changes are closely interrelated, because Venus's extreme temperature is due to the high pressure of its dense atmosphere, and the greenhouse effect.