Astronomer devises giant sun shield to reverse global warming

An astronomer has proposed to reverse global warming by creating a giant sunshield to protect the planet.

By Jessica SalterLast Updated: 9:19AM GMT 19 Feb 2009

Professor Roger Angel thinks he can diffract the power of the sun by placing trillions of lenses in space and creating a 100,000-square-mile sunshade.
Each lens will have a diffraction pattern etched onto it which will cause the sun's rays to change direction.
He intends to use electromagnetic propulsion to get the lenses into space.
If work was started immediately Prof Angel thinks the sunshield could be operation by 2040.
He said: “Things that take a few decades are not that futuristic.”
Researchers at the University of Victoria, Canada, have started experiments using computers to test the idea.
Climate scientists are beginning to imagine options like the sunshield as a way of halting climate change.
However Prof Martin Hoffert from New York University said: “What you have to be prepared for is that many of these experiments aren’t going to work – this is the way science and engineering progress. You build something, you try it, it doesn’t work, you try it again. This is sometimes called learning by doing.
“We’re not doing and therefore we’re not learning.”
One of the world's leading environmental scientists warned this week that global warming is likely to accelerate at a much faster pace and cause more environmental damage than previously anticipated.
Professor Chris Field, of the Intergovernmental Panel on Climate Change (IPCC), said that higher temperatures could ignite tropical forests and melt the Arctic tundra, releasing billions of tons of greenhouse gas into the atmosphere.
Ways to Save the Planet, every Sunday, 7.00pm, Discovery Channel