Giant screen might save the earth.

A parasol in space to shield the Earth from the sun could prevent a worldwide disaster due to the greenhouse effect, Michael Mautner, a New Zealand physical chemist, has suggested to the World Future Society. The warming of the planet due to human activities could cause the polar ice caps to melt and oceans to rise, flooding heavily populated coastal areas.

Current proposals to forestall the greenhouse effect, such as by reforestation to absorb excess carbon dioxide, likely will prove insufficient, Mautner believes, because of the staggering amount of energy released by the sun. However, a space-based approach could succeed. He proposes a climate-controlling fleet of screens that can be placed in orbit between the Earth and the sun in order to redirect an amount of energy up to 1,000,000 times larger than what is required to deploy them.

To compensate for the predicted greenhouse effect, "we need to screen out about three percent of the solar...