Climate engineering. Computer artwork of a large mirror (circular) in Earth orbit with a spacecraft (lower left). The mirror is designed to shield the Earth (lower right) from the Sun (behind mirror), in an attempt to control changes in the climate of the Earth. This proposed method is one of several that could be used to reduce the effects of manmade global warming (the process where the heat of the Sun is trapped by manmade changes in the composition of the Earth's atmosphere). Many such mirrors would be needed. It is not known for certain how climate change will progress, or how easy or dangerous it is to attempt to control the Earth's climate.